Health and Wellness–Related Travel: A Scoping Study of the Literature in 2010-2018

Health and wellness–related travel, also known as medical tourism, is a topical phenomenon with a wide range of effects in both local and transnational contexts. This scoping study examines the literature on this phenomenon from the perspective of travelers. The literature search was conducted using three databases (EBSCOhost, Web of Science, and SCOPUS) and covered the period from 2010 to 2018. The results show that the literature is divided into two academic fields: social sciences and tourism. Travel from the Global North to the Global South still dominates the field of medical travel research, and studies on South-to-South or intra-regional travel are underrepresented. There is a need for a more in-depth qualitative understanding of travelers’ lived experiences and for studies with more advanced quantitative methods and longitudinal research designs. We call for more interdisciplinary and theoretical approaches to health and wellness–related travel and propose a conceptual model that considers travelers’ intent (medical/wellness) and status (patient/tourist).


Introduction
Health care has traditionally been local and national, but globalized health markets have dramatically changed this situation (I. Cohen, 2013a;Connell, 2015;Hall, 2011;Österle et al., 2013). The ease of travel and the new digital technologies have created unprecedented opportunities for using health services outside of one's own country. Furthermore, improved living standards, more mobile lifestyles and individualistic ideals related to self-care have contributed to the popularity of traveling for reasons related to health and wellness (M. Cohen, 2008;. Thus, although health and wellness-related travel is not a new phenomenon, the global trade around it has grown exponentially in recent decades (Connell, 2013;Durham & Blondell, 2017;Kaspar et al., 2019). Deepening our understanding of this phenomenon is important for recognizing both the individual and collective effects of this type of mobility and for effectively addressing contemporary health challenges in the local and transnational contexts.
This review aims to scope the state-of-art of health and wellness-related travel in 2010-2018. We use the end users' perspective to address this type of travel. We are interested in the lived experiences of people who use health and/or wellness-related services abroad. By including not only basic and specialized health care but also travel motivated by health enhancement and wellness, we aim to provide a comprehensive account of this phenomenon. Within the increasingly global, specialized, and commercialized health and wellness markets, we view these phenomena as intertwined and thus include both health and wellness-related travel in our study Smith & Puczkó, 2014;Stara & Peterson, 2017).
Previous review articles (Balaban & Marano, 2010;Crooks et al., 2010;Hanefeld et al., 2014;Hopkins et al., 2010;Johnston et al., 2010; have documented studies on health and wellness-related travel in the early 2000s and highlighted the growing academic interest in the issue. These reviews have expected this type of travel to grow exponentially in the next 5 to 10 years (Balaban & Marano, 2010). Nevertheless, they have also called for further research  and for better quality data and methods (e.g., Hopkins et al., 2010). Reviews documenting the situation post-2010 have approached the issue from the perspective of specialized health care (Foley et al., 2019;Lunt et al., 2016), particular treatment options (Pereira et al., 2018), and specific service user groups (Mathijsen & Mathijsen, 2020). In tourism studies, general growth and trends within the industry (Connell, 2013;Kazakov & Oyner, 2020;Lunt et al., 2016;Woodhead, 2013) and service users' motivations have been reviewed John & Larke, 2016;Mutalib et al., 2016). The more recent reviews have highlighted the need for more evidence on the phenomenon from service users' perspective, including travelers' motivations, decision-making, and safety.
Conceptual inaccuracy in the literature on health and wellness-related travel is also a subject matter, and it has been repeatedly raised in earlier review articles (e.g., Connell, 2013;Foley et al., 2019;. Recent literature has shown significant changes in both the operational environment and end users' preferences that have influenced the concepts and approaches to health and wellness-related travel (Frohlick, 2020;Hall, 2013;Kaspar et al., 2019;Ormond & Lunt, 2020;Smith & Puczkó, 2014). Concepts such as medical tourism, health tourism, and wellness tourism are typically used to describe the phenomenon, along with the cross-border utilization of health care and medical travel, among others. The different terms are often used interchangeably, or their definitions are overlapping and vague. As shown by Foley et al. (2019), conceptual inaccuracy makes it difficult to record the phenomenon statistically and to identify the risks, inequalities, and ethical issues in the increased transnational use of health and wellness services.
The conceptualization of patients, citizens, tourists, or customers traveling abroad for services related to health and wellness is also inconsistent and theoretically underdeveloped (Bolton & Skountridaki, 2017;Foley et al., 2019). Kangas (2010b) argued that the terms chosen for describing the phenomenon frequently reflect the worldviews of the authors. In addition, referring to the phenomenon as tourism associates it with leisure and frivolity and, thus, may hide the hardships and suffering service users face (Kangas, 2010b). Similarly, Bolton and Skountridaki (2017) were concerned about the terminology that reconceptualizes patients as tourists and places them within the economic realm as the homo economicus, who are subject to the commercialized logic of health care choices.
In recent research, the explanations of health and wellness-related travel have been increasingly presented in a wider context of mobile lifestyles and transnational social networks (Bochaton, 2019;Kaspar et al., 2019;Mathijsen & Mathijsen, 2020). The concept of "therapeutic mobility" is one of the most recent conceptualizations developed to bring together fragmented concepts and approaches within the field (Bochaton, 2019;Kaspar et al., 2019). Furthermore, it is now generally acknowledged that health seeking in the transnational context is not necessarily and always about the movement of people but also about movements of health-related practices and knowledge (Kaspar et al., 2019;Ormond & Lunt, 2020). Due to the apparent complexity of the phenomenon, various scholars have called for broadening the theoretical discussion on health and wellness-related travel (e.g., Bochaton, 2019;Connell, 2013;.
The present study contributes to theory by providing a model that acknowledges the ambiguous nature of the phenomenon and its different conceptualizations. Previous studies have discussed conceptual ambiguities and provided examples of why certain terms and concepts are not suitable for describing specific types of travel behavior or certain customer segments. However, they have failed to provide a comprehensive account of how to examine the conceptual field of health and wellness-related travel. Therefore, we aim to fill this research gap with a detailed examination of previous literature and by synthesizing the typical approaches and terminologies related to the phenomenon. Specifically, this review examines the following questions: and reviewing the data. A more detailed report of the search strategy, study selection, and data processing is provided in the appendix.
Recent research has divided health tourism into two categories based on the intent of the traveler: in medical tourism, the primary intent is to undergo medical treatment, whereas in wellness tourism the intent is to focus on relaxation, recuperation and, in general, more holistic means for health promotion (e.g., Smith & Puczkó, 2014;Willson et al., 2018). Correspondingly, we have included both health and wellness services in our review. Furthermore, we are interested in different types of services: basic health care, specialized health care, and wellness services. In this article, we use the term basic health care for services aimed at promoting, monitoring, and maintaining health and treating diseases. By specialized health care, we refer to surgical interventions, obstetrics, regenerative medicine, and other reactive and proactive biomedical procedures. The category of wellness services refers to services designed for holistic health and enhancement of general well-being. The literature search was based on this categorization (see more about the search strategy in the appendix).
The literature search was conducted using three databases (EBSCOhost, Web of Science, and SCOPUS) to cover a variety of research fields, from marketing to social sciences and psychology. EndNote citation management software was used to store, organize, and share the sources among the authors. The first round of searches resulted in a large number of studies (n = 2,992 after removing duplicates). Next, the titles and abstracts of the papers were screened, clearly irrelevant records were discarded, and the remaining articles (n = 851) were categorized according to their focus on basic or specialized health care or wellness services. After that, the articles were given a closer look, abstracts were read again and irrelevant articles were discarded according to our inclusion/exclusion criteria (see the appendix). Finally, the full texts of all the remaining papers (n = 350) were retrieved. These articles were analyzed according to our research questions (terminology and concepts used, travelers' countries of origin and travel destinations, applied methods, and general themes of the study). The results of this article are described based on this charting.

Results of the Scoping Review
This chapter presents the results of the review for the following service categories: basic health care, specialized health care, and wellness. Basic health care is further divided into two categories, as during the review process, we noticed that some studies examined the phenomenon from the point of view of patient mobility, whereas others took a tourism approach to the subject. Furthermore, we found that many studies did not clearly specify the kinds of health services the end users were looking for. Therefore, our categorization, which is based on service types, is neither exhaustive nor explicit, but it was chosen for this study for practical reasons. At the end of this chapter, the research questions presented in the introduction will be answered.

Travel for Basic Health Care: The Patient Approach
Our review found 58 studies that examined travel for basic health care from the patients' perspective. There has been a slight yearly increase in the number of published articles in this topic from 2010 to 2018. These studies were usually published in journals on public health, health service use, medical anthropology and sociology, as well as on ethnicity and migration studies. Most of the articles in this category used concepts of medical travel, medical tourism, or cross-border or transnational health care. However, many used several terms interchangeably. Also, terms such as patient mobility/movement/travel, health fields, and health practices were used. Even in the cases where the main concept referred to tourism (e.g., medical tourism), the users of the services were most often referred to as patients.
The research examined patients from various countries. The most common countries of origin were the United States, the Netherlands, Canada, Germany, Laos, the United Kingdom, Finland, and Denmark. In total, 14 studies included several countries of origin or reviewed patient experiences on a more general level without specifying a country of origin. Of the destination countries, the most studied were Mexico, South Korea, and Thailand. Five studies examined travel within the European Union (EU), and 13 did not specify the destination country.
Most of the studies on this theme concentrated on the movement of patients from the Global North to the Global South. Lately, research has started paying attention to the South-South patient movement, namely the travels of patients from one developing country to another. Durham and Blondell (2017) have reviewed these studies in their realist synthesis. They argue that the South-South patient travel is mainly motivated by the lack of services in one's home country and/or the unacceptability of local services. Patients with greater volumes of different resources (cultural, social, and economic) have more options for seeking health care, even though those with more limited resources engage in patient travel too. The few studies examining this issue came from the Indonesian-Malaysian intra-regional travel (Ormond & Sulianti, 2017;Whittaker et al., 2017) and from the studies of Laotian and Bangladesh patients traveling to Thailand (Ali & Medhekar, 2018;Bochaton, 2015;Charoenmukayananta et al., 2014). Authors found that socioeconomic status, social networks, and existing co-ethnic communities in the destination country were important means facilitating patients' travel for health care across the border in this area.
There are few studies on South-South travel outside Asia. Chikanda and Crush (2019;see also Crush & Chikanda, 2015) studied South Africa as a destination country and argued that the South-South movement to South Africa is numerically and financially more significant than the North-South movement, which is often seen as the main type of medical tourism there. They show that the main reason for the incoming patients from other South African countries is general lack of access to medical diagnosis and treatment in their countries of origin.
The Middle Eastern countries represent an interesting case outside the typical North-South perspective. Kangas (2010aKangas ( , 2011 studied Yemeni patients who travel to Jordan for treatment not available in their home country. Kangas's ethnographic accounts reveal the suffering and the high prices of medical travel of Yemeni patients, whose home country's health infrastructure has been destroyed by war. Similarly, Dewachi et al. (2018) have shown how Iraqi patients look for help in Lebanon, where the health system has recovered better from the war than the one in Iraq. Also, Whittaker's (2015) study has revealed poor health infrastructure to be the reason why the governments of the Gulf Cooperation countries send their patients to Thailand for treatment. Some patients feel this outsourcing forces them to travel abroad for health care.
The European (2011) directive on cross-border care allows EU citizens to access health care in any EU country. Using the Eurobarometer survey, Perelta-Santos and Perelman (2018) and Riedel (2016) have found that mobility within the EU has grown from 3.3% in 2007 to 4.6% in 2014. Thus, the EU patient directive (2011) has not altered the situation much. The main motivation for using services abroad was the unavailability of the treatment in the home country. Studies on the experiences of German (e.g., Panteli et al., 2015) and Dutch (Verra et al., 2016) patients within the EU have documented problems related to the continuity of care, exchange of information and medical records between the two health care systems, awareness of entitlements and problems with the dispensation and the reimbursement of medication.
Another strand of studies has examined travel for health care in the North American context. The push factors for the North American interview respondents were unmet health service needs and dissatisfaction with local services, long waiting times, and costs (Eissler & Casken, 2013;Johnston & Garman, 2015;Stewart Ferreira, 2016). Kingsbury et al. (2012) have taken a different approach using literature analysis to describe the emotional aspects, such as feelings of anxiety and otherness, of traveling for health care to a different sociocultural milieu.
Laugesen and Vargas-Bustamante (2010) have compared the U.S. and European evidence on patient mobility. They conclude that in the United States, the decision to engage in medical travel is often associated with the lack of comprehensive insurance. In both the United States and Europe, patients look for complementary services not offered in their home countries. In Europe, people look for faster or better quality treatment in other countries because they do not face insurance coverage issues such as the U.S.-based patients.
Traveling abroad for health care seems to be more common among the migrant populations in Europe and the United States than it is for other population groups. Our review found 31 articles that investigated transnational health care-seeking practices of people with migration background. Besides a few studies concentrating on dental services (Calvasina et al., 2015;Jang, 2018) and children with asthma (Grineski, 2011), most studies did not differentiate which type of health problem the migrant-patients were seeking help for. Most of these studies came from the U.S.-Mexico border studies (e.g., Bergmark et al., 2010;González-Vázquez et al., 2016;Grineski, 2011;Horton, 2013;Horton & Cole, 2011;Jesus & Xiao, 2013;Su et al., 2014;Su & Wang, 2012), but North American studies also considered the Korean migrants' experiences in the United States (De Gagne et al., 2014;Jang, 2016Jang, , 2017 and Canada (Wang & Kwak, 2015). The European evidence on migrants' travel for health care examined various migrant groups in different host societies traveling to their countries of origin for health care. Some articles concentrated on one specific migrant group (e.g., Kemppainen et al., 2018;Main, 2014;Şekercan et al., 2018;Sime, 2014;Stan, 2015;Tiilikainen & Koehn, 2011) and others compared migrant groups of different origin in one host country (Gideon, 2011;Lafleur & Romero, 2018;Lokdam et al., 2016;Nielsen et al., 2012;Şekercan et al., 2015). Villa-Torres et al. (2017) review partly touches upon migrants' health care use abroad but widens the approach to include other forms of transnational health care, such as immobile practices and telemedicine.
In the U.S.-Mexico studies, the concept of cross-border utilization of health care was used in most studies, but some also referred to the phenomenon with concepts such as transnational health practices, transnational medical travel, or transnational health fields. In the studies of Korean migrants, the terms medical tourism or medical tours were used as well. In European migrant studies, the conceptual field was more scattered, and all the abovementioned terms were used to describe the phenomenon. Outside North America and Europe, there were fewer studies; J. Y. Choi (2013) has studied Korean migrants in Hawaii and J. Lee et al. (2010) have studied Korean migrants in New Zealand.
In their representative survey from the United States, Jang (2018) found that 17% of the migrants had received health care abroad and 33% had used dentists abroad. Among the Mexican and Latin American migrants in the United States, approximately 9% had traveled abroad for health care (Jesus & Xiao, 2013). The close proximity of the border increased travel (Su et al., 2014). In the Canadian sample, approximately 13% of the migrants residing in Canada received dental care abroad (Calvasina et al., 2015). De Gagne et al. (2014) have found that 22% of the surveyed Korean migrants in North Carolina had traveled to Korea for health care.
Using health care services abroad was associated with the lack of insurance (Calvasina et al., 2015;Jang, 2018;Jesus & Xiao, 2013;Su et al., 2014), low language skills (Jesus & Xiao, 2013), lower cost (Bergmark et al., 2010), and the perceived quality and familiarity of care (Su et al., 2014). Acculturation to the U.S. society diminished medical travel (Su & Wang, 2012). Accessing health care abroad was also used as a way of "class transformation" when income acquired in the new host country allowed migrants to use Mexican private clinics, a service that they could not afford to use in the United States (Horton, 2013). Finally, migrants may look for complementary and alternative medicine, such as herbal treatments or spiritual healing, from their countries of origin (González-Vázquez et al., 2016).
In the studies of Korean migrants to the United States and Canada, structural barriers to health care, the preference for co-ethnic doctors, and language issues came to the fore as important reasons for engaging in medical travel (Jang, 2016(Jang, , 2017Wang & Kwak, 2015; see also similar findings in Hawaii by J. Y. Choi, 2013, and in New Zealand by J. Lee et al., 2010).
In view of the existing European evidence, migrants' engagement in using health care services abroad ranged from 26% in the case of Turkish migrants in Denmark (Nielsen et al., 2012) to 15% by Russian-origin migrants in Finland (Kemppainen et al., 2018) and to 3% of Surinamese-origin migrants in the Netherlands (Şekercan et al., 2015). In the European evidence, lower cost, perceived quality, and familiarity of care acted as push factors (Gideon, 2011;Main, 2014;Şekercan et al., 2015. Also, health status and cultural distance to the local health care system were reported as associated with traveling abroad for health care (Şekercan et al., 2015). The aforementioned class transformation (Horton, 2013) showed up in the European evidence too among migrants from the Eastern European countries (Main, 2014;Sime, 2014;Stan, 2015). This is related to the lower cost of private services in the Eastern European countries, which migrants see as a question of status but also as better quality care. In addition, experiences of structural barriers to health care (Sime, 2014), discrimination, and lower integration status in the country of residence (Kemppainen et al., 2018) were associated with use of health services in another country. At the same time, it was suggested that migrants do not want to give up their contacts in their country of origin due to the uncertainty of the length of settlement in the host country (Sime, 2014).

Travel for Basic Health Care: The Tourism Approach
In addition to the patient-centered research on the use of health care services abroad, there was a large quantity of studies that approached this topic from a tourism perspective. Often, studies in this category did not specify the service users' exact motivations for travel, whether it was for basic or specialized health care. The total number of articles included in this section was 99. The amount of these studies has grown from around five studies per year in 2010 and 2011 to around 15 per year from 2015 onwards. Considering the publication forums, tourism journals-especially Journal of Travel and Tourism Marketing, Current Issues in Tourism, and Tourism Management-were strongly represented. Also, health and service-related journals as well as journals on business, marketing, and management published notable numbers of studies on this subject.
Terminologically, medical tourism was by far the most common notion, whereas other terms, such as medical travel or health or health care tourism, were less frequent (Aydin & Karamehmet, 2017;Johnson & Garman, 2015). Many studies used various terms more or less in parallel (Hanefeld et al., 2015;Karuppan & Karuppan, 2010), but there were also suggestions to create conceptual order and/or hierarchies. For example, Majeed et al. (2018) proposed to use health tourism as an umbrella concept to cover medical and wellness tourism. The end users were typically called tourists or customers, but also other terms were used, including patients (Hwang et al., 2018;Kian & Heng, 2015), medical travelers (Chomvilailuk & Srisomyong, 2015), patient-travelers (Han & Hyun, 2014), and tourist-patients (Menvielle et al., 2014) although the phenomenon as a whole was referred to as tourism.
From a geographical perspective, Asian countries, especially Thailand (Noree et al., 2014;Prajitmutita et al., 2016) and Malaysia (Kian & Heng, 2015;Na et al., 2017), were frequently studied as destination countries of this type of tourism. Countries of origin were more widely spread out, covering not only Asian (Han & Hwang, 2013;Zhang et al., 2013) but also European (Menvielle et al., 2014;Noree et al., 2014) and North American countries (Adams et al., 2013;Karuppan & Karuppan, 2010). Most typically, studies considered travel for health care to an Asian country either from other Asian countries (e.g., Tabassum & Aurangzeb, 2014;Yu & Ko, 2012) or from across the globe (e.g., Chomvilailuk & Srisomyong, 2015;Han & Hyun, 2014). As an exception, Kesar and Mikulić (2017) have studied the subject in intra-European context. Garcia-Garzon et al. (2016) have used multilevel modeling to explore service users' decision-making in choosing destination countries. They concluded that service users' from Europe are more likely to agree to travel to north European countries, the United States, Australia, and New Zealand for health care. Southern Europe, the Middle East, and Southern Asia were not compelling options for their European respondents.
Some review articles on medical tourism were published during our review period. Heung et al. (2010) reviewed the existing theoretical frameworks of this type of tourism, and proposed a framework that covers prior models' key areas and integrates supply and demand sides of medical tourism. Hanefeld et al. (2014) reviewed 100 articles published in 2011 and 2012 and discussed, among other factors, the complexity of patient motivation, the volume of travel in 13 countries and the possible inequities for the populations in the destination countries due to price inflation and doctor concentration in the private sector. Moreover, they found that complications resulting from the usage of health care services abroad were often treated within national systems. John and Larke (2016) have examined the literature on push and pull motivations for medical tourism published between 2000 and 2016. The review identified common push factors (recommendations, insurance coverage, privacy, and confidentiality) and pull factors (costs, quality, accreditation, and waiting times). Less commonly studied push factors included lacking treatment options and distrust in the domestic health care, whereas the corresponding pull factors were practitioners' reputation and tourists' sociocultural familiarity with the destination context. The review by Mutalib et al. (2016) has added bioethical legislation and food and tourist attractions as important pull factors for tourists who seek health care services abroad. They also discussed ethical issues of the phenomenon, such as the inequity of health care distribution between the local population and the foreign service users.  have reviewed medical tourism studies and raised the issue of people looking for a combination of medical and wellness services (see also Bristow & Yang, 2015). They called for comparisons between the experience of medical tourism and other forms of tourism and for studies on the different self-identification patterns of tourists as travelers, medical tourists, patients, and general tourists.
Another common perspective was to study retrospectively the experiences of service users and inquire about their demographic profile, travel motivations, information sources, the treatments used and subjective considerations on quality, satisfaction, and problems (e.g., Ren et al., 2017;Tabassum & Aurangzeb, 2014;Um & Kim, 2018;Wongkit & McKercher, 2016;Yin, 2014). Specifically cultural aspects were studied, for example, by Rahman et al. (2017) and Iranmanesh et al. (2018), who elucidated the perspectives and needs of Islamic service users. Moreover, different typologies of end users were constructed; for example, Wongkit and McKercher (2013) considered end users' trip purpose and planning schedule to obtain a fourfold classification of dedicated, hesitant, holidaying, and opportunistic medical tourists.
Finally, there were a small number of studies that utilized other approaches. Noree et al. (2014Noree et al. ( , 2016 used hospital records to study the demographic profiles, treatment use, and expenditure of medical tourists in Thailand. In a rare theoretical account of medical tourism, Cook (2010) elaborated on the notions of authenticity and embodiment and positioned the study in relation to prior works.

Travel for Specialized Health Care
This section of our scoping review covers travel for specialized health care, by which we refer to cross-border use of special biomedical treatments and procedures that serve the needs that go beyond the most common or basic health care services and wellness goals. The search for literature on such travel produced 51 articles. Biomedical treatments and procedures in question range from cross-border surrogate arrangements (Arvidsson et al., 2015;Hammarberg et al., 2015) to aesthetic surgery (Bell et al., 2011;Holliday et al., 2015) and from regenerative procedures such as stem cell treatments (H. Chen & Gottweis, 2013;Ryan et al., 2010) to assisted suicide (Richards, 2017) The modes of specialized health care travel that surfaced in this scoping study were roughly thematized into three distinct yet perhaps partly overlapping categories. The first category was that of reproduction: travel that relates to reproduction, surrogacy, fertility treatments, and the use of assisted reproductive technology (ART) as well as birth and abortion. The second category was surgical services: travel that relates to surgical procedures for cosmetic or medical purposes and, for example, organ transplantation. The third category referred to experimental and other procedures and treatments, including a variety of experimental treatments such as stem cell therapies and phenomena such as assisted suicide.
Articles in this category were typically published in social scientific journals and specifically in the fields of (medical) anthropology, gender studies, and sociology. Notably, seven of the articles-related to the topics of reproduction, transformative surgical tourism, stem cell cures, and assisted suicide-were published in the journal Medical Anthropology. Other social scientific journals that showed up in the search were, for example, Anthropology & Medicine, Body & Society, Gender & Society, Sociology of Health & Illness, and Health, among others. Furthermore, research on issues related to travel for specialized health care services has been published, for example, in medical journals that focus on a specific field of biomedicine (e.g., reproduction or genetics), in philosophically oriented journals that foster bioethical discussions and in journals in the field of tourism studies, such as Current Issues in Tourism.
A clear majority of empirical research on travel for specialized health care was qualitative or theoretical by design. There were only a few quantitative, survey-type studies (Gerdts et al., 2016;Stafford-Bell et al., 2014;De Neve et al., 2012), examining the experiences of abortion travelers to the United Kingdom, the outcomes of Australians' overseas surrogacy arrangements and cross-border health care in a Turkish hospital, respectively. There was one study with a mixed-methods approach (Bennett & Pangestu, 2017), drawing from ethnography as well as survey data in mapping Indonesian couples' travels for assisted reproduction.
There were also some review articles that reviewed literature on specific aspects of travel for specialized health care. For example, Pereira et al. (2018) have mapped the literature on complications and epidemiological issues affecting those who travel abroad for cosmetic surgery. Couture et al. (2015) have reviewed the literature on crossborder reproduction and specifically reprogenetic services, referred to as the "movement of patients and biopsied embryo cells for pre-implantation genetic diagnosis and its different applications" (Couture et al., 2015, p. 1), and have thematized existing research according to five themes: scope, scale, motivations, concerns, and governance. Overall, the emphasis of the specialized health care category was on qualitative and theoretical investigations and the conceptualization of end-user experiences and motivations related to travel for biomedical purposes. The few tourism studies journals in this sample also seemed to host both quantitative empirical research (Cheng, 2016) and solely theoretical accounts (Bell et al., 2011).
Sometimes, medical mobility was discussed through the idea of commodification, in which case the use of the concept "tourism" may have been justified by the idea that specific, previously noncommodified medical services are "packaged" in new ways for tourist consumption (see Voigt & Laing, 2010). However, cross-border movement was often characterized as "travel" or simply "care" instead of tourism, and especially in relation to reproductive issues it was common to refer to "cross-border reproductive care" (e.g., Culley et al., 2011;Gürtin & Inhorn, 2011;Hammarberg et al., 2015;Van Hoof et al., 2015). Sometimes, specific textual strategies, such as putting the word tourism in quotation marks, were used to question whether tourism is a suitable concept to describe people's movement across borders in their search of solutions to medical issues and conditions (Inhorn, 2011b).
There were also some attempts at developing new kinds of conceptualization for the specific forms of medical travel or tourism. For example, Inhorn et al. (2012) have argued that in relation to travel for assisted reproduction, the concept of tourism could as well be reconceptualized as "exile" because mobility is essentially often driven and prescribed by an experience of (legal) restrictions in the home country. Song (2010) has evoked the concept of "biotech pilgrimage" to highlight how cross-border medical travel for stem cell treatments relates to religious discourses and narratives of salvation as experimental treatments intertwine with faith in contemporary biotechnology. Bennett and Pangestu (2017) have conceptualized the Indonesian travel for assisted reproduction as "reproductive quests," with the notion of a "quest" pointing to the understanding that travel is part of infertile couples' arduous long-term processes of having a child within the framework of rigidly familyoriented Indonesian culture.
In terms of the end users involved in specialized health care abroad, in this body of literature (Brophy, 2017;Couture et al., 2015;Ferraretti et al., 2010;Hudson et al., 2016;Prasad, 2015;Richards, 2017;van Balen et al., 2016;Winter et al., 2016) it was typical to refer to "patients" or to people in general terms related to the treatment or procedure in question. Thus, conceptually, the figure of the "tourist" was not at all common or unquestioned in the accounts of this type of mobility. Rather, service users were considered to be people who seek to make use of specific medical technologies and treatments (e.g., ART, cosmetic surgery, stem cell therapies) and/or are subject to a specific condition or state (from neurodegenerative diseases to infertility) for which a cure or correction is needed. Sometimes, the procedure in question related to biological bodily processes rather than a pathological state (as is the case with, for example, pregnancy and birth/ abortion tourism), in which case users were characterized, for example, as "pregnant women." In the case of cross-border reproductive care and especially surrogacy arrangements, users were sometimes characterized as couples or parents (Bergmann, 2011;Deomampo, 2013;Inhorn, 2011b). Accordingly, it was not easy to characterize end users in any general terms (e.g., as opposed to "wellness tourists" as more or less "healthy" people), although some studies (e.g., Bell et al., 2011;Bennett & Pangestu, 2017) pointed out that biomedical travel and cross-border access to biomedical procedures is, in general terms, more readily available to people who are financially relatively well off.
In terms of regions of origin and destinations for biomedical travel, many studies in this category of articles described travel in the West-to-East and the North-to-South manner, especially in cases of surrogacy, stem cell treatment, and surgery-related travel (Aizura, 2010;Brophy, 2017;I. Cohen, 2013b), in which cases travel often took place from North America, Europe, or Australia to Asian destinations, such as China, India, or Thailand, or from North America to Central America. However, studies of reproductive travel also accounted for flows within regions; for example, within Europe legislative issues have generated flows from Germany, France, and the United Kingdom to countries such as Spain, the Czech Republic, and Belgium (Bergmann, 2011;Culley et al., 2011;Van Hoof et al., 2015). In Asia, cosmetic surgery services have generated travel flows between Asian countries, such as from China to South Korea (Holliday et al., 2017). There was also research on reproduction-related intra-regional service use in Southeast Asia (Bennett & Pangestu, 2017), with Singapore, Malaysia, and Thailand emerging as main destinations for assisted reproduction. In addition, due to its legislative liberties, Switzerland emerged as a West-to-West travel destination in relation to the phenomenon of suicide tourism. South-to-South reproductive travel was studied in the Middle East, where Iran emerged as a local destination hub (Inhorn, 2011a), and in West Africa, where Ghana has become a central destination for fertility-related travel (Gerrits, 2018). Particularly, travel that focuses on giving birth often seems to flow into Western destinations such as the United Kingdom or the United States.

Travel for Wellness Services
Our review indicates that the scientific interest in the transnational use of wellness services has gradually increased within different disciplines during the past decade. The total amount of articles in this category was 34, majority of which was published during the years 2017 and 2018. The studies on wellness-related travel were mainly published in journals specialized in leisure, tourism, and hospitality research (e.g., Current Issues in Tourism), which also often emphasize a business and/or marketing perspective (e.g.,

Journal of Travel & Tourism Marketing, Journal of Destination Marketing and Management).
A few articles were also published in journals that were centered on a particular holistic treatment or wellness environment (e.g., Balneo Research Journal and The Journal of Alternative and Comparative Medicine). The present sample included only a couple of articles with a purely social scientific, an anthropologic, and/or a cultural approach to the use of wellness services abroad (Huang & Xu, 2018;Koskinen & Wilska, 2019;Quintela, 2011).
Most studies in this category referred to travel for wellness services as "wellness tourism." In addition, the concept of "health tourism" was frequently used although the travel destinations and characteristics of the end users were more or less the same as in the studies that applied the concept of wellness tourism. Many scholars saw health tourism as an umbrella term for various terms describing health and wellness-related travel, and thereby wellness tourism was defined as a subcategory of health tourism (e.g., Koskinen & Wilska, 2019;Medina-Muñoz & Medina-Muñoz, 2014). However, this definition was not prominent in all the studies, and the concepts of health tourism and wellness tourism were also used interchangeably.
The reviewed articles also often involved a conceptual discussion on the characteristics of "medical tourism" and "wellness tourism." On this conceptual issue, there was a consensus among the researchers in different fields that medical tourism is concerned with curing and treating illness, whereas holistic and preventive well-being promotion is central to wellness tourism. Other concepts used in this category of research reflect the servicescape of the destination. For example, the terms spa tourism (e.g., Alina-Cerasela, 2015;Elias-Almeida et al., 2016;Trihas & Konstantarou, 2016), spiritual retreat tourism (Ashton, 2018), yoga/spiritual tourism (Bowers & Cheer, 2017), wellness spa tourism (Han et al., 2017), and thermalism-medicine-tourism (Quintela, 2011) were used in the reviewed articles. Only one of the articles in this sample (Hritz et al., 2014) consistently discussed health and well-being "travel" instead of "tourism." Based on this review, the health condition of the end user is a key distinguishing factor between those traveling for medical services and those traveling for wellness services. The wellness service users are generally defined as relatively healthy people who are not in need of curative treatments but look for physical and mental improvements, self-pampering and a better state of being. Thus, the clear majority of the studies referred to the end users as tourists and not, for example, as patients. In spa and retreat-related studies, it was also typical to describe the end users as visitors (e.g., Dryglas & Salamaga, 2017;Kelly, 2012;Trihas & Konstantarou, 2016). However, the terms "customer" and "consumer" were used consistently only in two of the articles, although there is generally a strong emphasis on the customer experience perspective within the wellness-related research (Elias-Almeida et al., 2016;Kamenidou et al., 2014).
In the reviewed literature, the travel destinations included spas, resorts, retreats, and other kinds of wellness environments that provide accommodation and services such as spa, beauty, or other wellness treatments, physical/ mind-body exercising, health and well-being-related workshops/lectures, and other "therapeutic" environments and offerings in the destination. Typically, it was pointed out that people traveling to wellness destinations aim to promote their overall well-being and quality of life in a holistic sense-physically, mentally, or even spiritually. Furthermore, it was frequently stated that people traveling for wellness are interested in services and consumer environments that combine different methods and elements of wellness enhancement in an experiential and unique manner (e.g., Y. Choi et al., 2015;Clark-Kennedy & Cohen, 2017;Han et al., 2017;Kim et al., 2017;Težak Damijanić & Šergo, 2013). The more recent studies underlined also the transformative nature of wellness-related travel, such as its effects on an individual's quest for comprehensive self-development, stress management, and personal growth (e.g., Ashton, 2018;Bowers & Cheer, 2017).
Regarding both the travel destination and the nationality of the people traveling for wellness services, there were studies on a relatively broad scale. In our sample, Spain was the most studied travel destination, followed by Thailand and Taiwan. The other destinations mentioned were India, Poland, Portugal, Croatia, Greek, Hungary, Romania, Korea, Australia, China, Brazil, the United Kingdom, Estonia, Mexico, France, Japan, and Turkey. Interestingly, only approximately half of the reviewed articles specified the travelers' home country, and only in three of the articles was cultural differences the main theme of the study (Alina-Cerasela, 2015;Han et al., 2017;Quintela, 2011). When the home country was mentioned, it was most often Germany or the United Kingdom. In addition, Russia, Spain, the United States, and Australia were mentioned in more than one article as a home country of the travelers.
In the survey studies, end users from several countries were examined within the same research, and the respondents were not segmented or otherwise examined based on their nationality but on the basis of their other sociodemographic characteristics. However, the survey-based study by Damijanic & Ruzic (2015) that investigated service users' sociodemographic background and travel motives showed that the respondents' country of origin was the most important factor behind the various travel motives. Similarly, the study by Han et al. (2017) indicated that the respondents' cultural background-by which the authors established whether the travelers came from a more collective or individualistic cultures-had an impact on their satisfaction with and customer loyalty to the wellness spa destination.
A clear majority of the reviewed papers were quantitative studies comprising a survey. Although the need for qualitative methods was mentioned in some of the articles, only a few of the studies were purely qualitative (Huang & Xu, 2018;Medina-Muñoz & Medina-Muñoz, 2013;Quintela, 2011) or applied a mixed-methods approach (Bowers & Cheer, 2017;K. Chen et al., 2013;Islam, 2012;Kelly, 2012).
Approximately half of the studies were focused on categorizing and segmenting the end users based on sociodemographic information (age, gender, etc.) and/or their other characteristics, preferences, travel motivations, or the benefits sought. The next most common topic of research was to examine end users' satisfaction with the travel destination or perceived value of their visit to estimate their future behavior (i.e., customer loyalty). Our review also involved a couple of theoretical papers that focused either on identifying the gaps between the current theoretical conceptualizations of wellness and the actual wellness tourism practices (Stara & Peterson, 2017) or on detecting general trends in wellnessrelated travel (Blazevic, 2016;Hartwell et al., 2018). Our review shows that the academic discussion on health and wellness-related travel is divided between tourism studies and the social sciences and the publication forums reflect this division. While social scientists are interested in the lived experiences of people who seek health and/or wellness services abroad and often consider and name them as patients, tourism researchers are interested in travelers from an industry point of view. This means that the end users are often examined to better design, develop, and target the services for different customer segments and not to enhance knowledge of the sociocultural aspects of the phenomenon. Typically, these discussion forums remain separate, and interdisciplinary discussions are rare (however, see, for example, Huang & Xu, 2018;Koskinen & Wilska, 2018;Quintela, 2011). In addition, publications in geography journals were rare (Bristow & Yang, 2015;Kingsbury et al., 2012;Liang et al., 2017), which may be considered surprising given the clearly geographical nature of the phenomenon. Social, cultural, or human-geographical approaches could help distinguish different geographical patterns of travel and bring new insights. Regarding migrants' healthrelated travel, comparative studies on the prevalence of health and wellness-related travel among different migrant populations are lacking, and the existing evidence is restricted to few ethnic groups.

Answering Research Questions
The tourism studies approach could benefit from a more detailed analysis of the service users' sociocultural backgrounds. Most of the studies that take the travelers' point of view concentrate on mapping the end users' attitudes, interests, motives, perceived benefits, customer loyalty, or the overall tourism behavior but often pay no attention to people's nationality or cultural background. In general, the findings indicate a lack of studies that are focused on examining cultural differences in relation to health and wellness-related travel, although it is acknowledged in the existing literature that the country of origin has a bearing on the tourists' intentions and motives (e.g., Damijanic & Ruzic, 2015;Han et al., 2017;Huang & Xu, 2018;Koskinen & Wilska, 2019). Overall, the tourism-oriented view on health and wellnessrelated travel is very destination-centered, meaning that the travel destination per se comes to be seen as the key source for tourists' increased health and wellness and thus essential for the overall tourism experience. However, seeing some destinations only as tourist destinations may ignore that some service users' intentions are not at all touristic. The case of Thailand is an interesting illustration of this: Thailand is a destination for purely leisure type of wellness travel but also a health care destination for intra-regional travel pushed by lack of services at home (Ali & Medhekar, 2018). The most extreme example is the case of the "outsourced" Gulf patients, some of whom feel they are forced to travel to Thailand for health care due to the poor health infrastructure of their home region (Whittaker, 2015).
Furthermore, apart from travel for specialized health care, qualitative studies are still weakly represented in the literature, which may be partly due to the abovementioned lack of interest in people's experiences in a nonbusiness sense. Thus, there is room for further contributions by in-depth studies regarding the understanding, discourses, narratives, and the overall experiences of people traveling for medical or wellness services to complement the sizable but methodologically limited body of cross-sectional, small-n survey studies. Also, random-sample studies and longitudinal panel designs would be extremely helpful in addressing both the methodological and theoretical lacunae of the existing literature. The latter would enable providing responses to one of the gaps identified by Hanefeld et al. (2013), namely the longterm health outcomes of health and wellness-related travel.
Based on our review, we argue that the literature on health and wellness-related travel as a whole is still theoretically rather underdeveloped and often unable to consider the multiplicity and interplay of factors and actors that propagate and arrange movement and mobilities across international borders in a thoroughly globalized world. Some useful theoretical resources for such considerations appear in qualitatively oriented studies on travel for specialized health care, for example, when research on reproductive travel draws on human-geographical ideas of "global reproscapes" (Inhorn, 2011b), or when cosmetic surgery tourism is interpreted through the notion of "assemblages" (Holliday et al., 2015). Such concepts enable a focus on the lived experiences of users while encouraging and even necessitating researchers to consider a variety of cultural, material, economical, legal, ideological, global, and local factors in understanding health-related cross-border travel and the related servicescapes. Moreover, our review points toward the need to consider explicitly the inherently geographical nature of the phenomenon and connect studies on health and wellness-related travel more closely to the field of human geography, including discussions on transnationalism, global networks, and global inequalities.

RQ2:
What are the concepts and terms used to describe this type of travel and the people who engage in such travel?
This scoping study traced the conceptual choices and approaches within the literature on health and wellnessrelated travel with a special focus on the users of the services, the people who travel. As a whole, the results illustrate the diversity and vagueness of the conceptual choices in the reviewed studies. The terminological choices often reflect more the field of study and the studied type of service than the end users' travel intentions or the sociocultural circumstances that initially encourage traveling abroad for care.
The studies on the use of health and wellness services in the cross-border context can be divided into two separate approaches based on whether the end user is seen as a "patient" or "tourist." The patient-centered studies mainly come from the social sciences, whereas tourism and marketing studies label the end user as a tourist or a consumer. While tourism studies often concentrate on the question of attracting tourists, social studies are more broadly concerned with patient experiences, safety, and inequalities.
In the studies that focus on health care, and especially on specialized health care, the destinations often involve specialized facilities or clinics (Culley et al., 2011;Prasad, 2015;Ryan et al., 2010;Song, 2010). This, together with the fact that the will to travel for clinical care is often propagated by a medical diagnosis of some sort, may be one crucial factor that affects the characterization of end users mainly as patients rather than tourists in the research on this subject. The conceptual choices in literature on the use of specialized health care in transnational contexts point to the understanding-especially characteristic of many studies on the topic in the social sciences-that the concept of "tourist" may sit uneasily with the experiences and practices of people traveling for medical services. The concept of tourism is then often used as a way of creating conceptual links to relevant literature rather than as an attempt to conceptualize and characterize the perceived nature of people's movement in the cross-border context. In contrast to traditional conceptions of leisurely "tourism," travel either for health care services or for biomedical procedures often involves features that are uncomfortable, painful, and even frightening. Moreover, legislative issues in the home country may motivate this type of travel. Travel may be encouraged by a search for a cure for medical conditions deemed incurable at home. Furthermore, the motivation may stem from many other kinds of cultural frameworks, norms, and expectations within the regions of origin (see Inhorn et al., 2012;Song, 2010).
However, the tourist approach to seeking health care abroad often bypasses the question of who the travelers are, where they come from, and which kinds of services or experiences they are looking for. Typical to tourism studies, the main focus is on developing a certain area or clinic to become more attractive for international patient-tourists. Similarly, in the context of wellness services, the end users are mainly referred to as tourists, which reflects a view of wellness-related travel as voluntary and pleasant cross-border mobility. In general, wellness tourism is illustrated as a form of experiential consumption that responds to the needs and desires for self-development and self-actualization in the form of different health-enhancing, self-pampering, relaxing, and unique consumer experiences. There seems to be a consensus among the different scholars that travel for wellness services is, to certain extent, an "elitist" phenomenon reflecting the cultural values and prevailing trends of the more affluent societies as well as the consumerist lifestyles and desires of rather well-to-do citizens. Accordingly, the users of wellness services are primarily discussed as consumer-citizens who are realizing their wellness-oriented lifestyle via the usage of wellness services abroad rather than as patients seeking help for or relief from actual health concerns.

RQ3:
What are the typical geographical flows of travel? What countries appear as the sending and destination countries?
Geographically, most of the reviewed studies focusing on the usage of health care services examine the North-South movement, whereas studies on South-to-South and intraregional travel are still scarce. Some areas, including Africa, Latin America, and (North) Europe, remain understudied. With regard to the health and wellness-related travel of people with migration backgrounds, the context of the U.S.-Mexico border dominates the field. The European evidence on migrants' medical travel and their reasons is growing but still scarce. A limited number of studies have considered this subject outside of North America and Europe. With regard to the use of wellness services in the transnational context, the flows of travel seem to be between countries of the Global North. Furthermore, travel to exotic destinations, which are typically located far from the country of origin of service users, is apparent in the existing literature.

RQ4:
What motivates people to travel abroad for health and wellness-related services? What are their intentions and rationales for travel?
In terms of motivation for travel, our review shows that people seek health care services outside the country they reside for various reasons. Often, the reasons to look for health care and specialized medical treatment abroad were related to the unavailability of services at home, lower costs, dissatisfaction with local services, and long waiting times. Also, in some cases the legislative issues, mainly with regards to reproductive health, may push people to seek services abroad. Among people with migration background, health travel to their countries of origin is related to the more familiar health care system and culture, but also experiences of discrimination and lower levels of integration were associated with these "medical returns." From a tourism point of view, the most common push factors were recommendations, insurance coverage, privacy, and confidentiality, and the pull factors were costs, quality, accreditation, and shorter waiting times. In the case of wellness services, more holistic ideas of health were prominent; people were looking for overall well-being and quality of life physically, mentally, and spiritually.

Discussion
This scoping study reviews the literature on health and wellness-related travel in the period of 2010-2018. On the basis of our findings, we call for a more careful conceptualization of health and wellness-related travel and travelers (Connell, 2013;. We argue that sensitivity to service users' intentions, needs, and current situation in life is useful to better approach the phenomenon (see also Bolton & Skountridaki, 2017;Kangas, 2010b). We illustrate this with a graph (Figure 1), which shows two conceptual axes: one that focuses on the intent of the travel (medical/wellness) and one that focuses on the traveling status of a person (patient/tourist). The intent axis elucidates the underlying purpose of the trip from the actors' own perspective, which extends from medical, often involuntary, reasons to voluntary wellness-motivated travel. The status axis shows not only the institutional role travelers are assigned to and that they assign themselves to but also the scientific or epistemic perspective, from which their actions and behaviors are examined, understood, explained, or predicted. It also presents the types of services travelers aim to use during the trip and the overall characteristics of the travel destination.
In relation to these axes, the individual research articles can be situated in the graph to designate their general approach. For example, marketing research usually discusses tourists, whereas medical anthropology or sociology is more interested in travelers as patients. Furthermore, the use of wellness services is more often studied from a tourism perspective, whereas research on the use of health care services is commonly patient-centered. However, a closer examination of the articles shows that placing them in this graph based only on the terminology used is not always definite. This reinforces our argument that concepts or terminologies do not always correspond with the content of a study. Thus, there is a need for conceptually more accurate and context-specific views on health and wellness-related travel.
The above-presented model provides multiple ways to further investigate the phenomenon. As most studies on basic and specialized health care are characterized by patients' perspectives and travelers' intent to get treatment, they are situated on the lower left of our graph. In the tourism studies approach, the focus is on business travel, and travelers' intent is often left undefined. Both streams of research could benefit from a more intensive exchange of ideas. For example, examining travel for health care through the lens of tourism in the social sciences may contribute to enhancing the understanding of tourism (e.g., Bell et al., 2011). Conversely, business-oriented studies could benefit from a more detailed examination of their studied subjects' sociodemographic and cultural backgrounds and their interrelation with travel intentions and choices. However, although tourism as a concept may initially be ill-fitted to describe the experiences of most medical travelers, many forms of medical travel, from cosmetic surgery journeys to transplant-related and reproductive mobility, may now be increasingly constructed and packaged as a "tourist experience," for example, through the blogosphere, the media, or related broker activities (see Ackerman, 2010;Scheper-Hughes, 2011;Voigt & Laing, 2010), which may also affect how people experience travel.
Moreover, based on the conceptual choices, the articles dealing with wellness services can be situated almost entirely in the upper-right corner of the graph. Although this indicates consistency in the way travel for wellness services is comprehended in different fields, it also reveals a lack of studies on other-than-pleasant and "frivolous" aspects of this type of travel. As revealed by Kangas (2010b), framing the phenomenon as tourism contributes to underestimating the less positive events and circumstances that may have led to seeking health services abroad. For example, people who have experienced burnout decide to participate in a wellness retreat to overcome this difficult situation. In this case, the travel experience can be accompanied by troublesome emotions and physical and mental pain that clearly do not fall into the general category of voluntary and enjoyable wellness tourism.
The main problem in the literature on health and wellness-related travel is that it does not pay enough attention to travelers' lived experiences, which are substantially affected by the conditions in their country of origin and travelers' health conditions and overall intentions to travel. Thus, even though our model of the intention and status of travelers is somewhat schematic and ideal-typical, as conceptual models often are, it may still help us be more specific in forming a conceptual understanding of the studied phenomenon. Even if most cases are "wellness tourists" or "medical patient-travelers," there are other types and combinations of travel as well. Furthermore, our model demonstrates that neither the intent of travel nor the status of a traveler easily falls into a clear-cut category but is better illustrated as a continuum. For example, the roles and perspectives of travelers in their health or wellness-related trips may be multiple and complex. Naturally, the experiences and dynamics of intentions are also far from having clear categories, as, for example, a wellness-motivated trip may also have rationales related to stress management and relaxation as preventive or even corrective measures associated with diagnosed or self-perceived medical problems. In this way, we can also identify and position the dimensions of the phenomenon that fall between or beyond the existing terminologies.
Although scoping study proved to be a suitable method for identifying and summarizing the extensive amount of research on health and wellness-related travel, some limitations of this study should be highlighted. First, this literature search was conducted using three databases, and despite their wide coverage, some publications relevant to the subject matter may have been overlooked. Second, as the search was limited to the period of 2010-2018, this timeframe does not provide an overall picture of the studies published over the past 2 years. Note that the recently published reviews discussed in the introduction offer some promising theoretical perspectives for a comprehensive examination of the phenomenon. Specifically, recent research drawn from the mobility perspective (Bochaton, 2019;Kaspar et al., 2019) concurs well with the ideas presented in this article. Finally, as this research focused on the end users' perspective, it does not involve a detailed examination of how the different intangible and technologymediated forms of health-related mobility would suit the model we presented. Nevertheless, the abovementioned aspects should be taken into account in future studies. Stage 1: Identifying the research question. The preliminary research questions were formulated on the basis of previously published reviews and the authors' previous knowledge on the subject matter. The preliminary questions concerned the terminology, themes, and approaches in the literature on health and wellness-related travel, especially from the end users' perspective. During the research process, the research questions were sharpened and defined in their final form (see also Daudt et al., 2013).

Stages 2 and 3:
Identifying the relevant studies and study selection. Our categorization of the search terms for health and wellness-related travel followed the conceptual division among basic health care, specialized health care, and wellness services. We developed together an initial search strategy based on a reading of recent studies on medical tourism and our prior knowledge of the research areas. The search strategy was further worked on in collaboration with a university librarian specialized in the social sciences. The  Figure A1. Flowchart of the research process.
search was conducted using three databases (EBSCOhost, Web of Science, and SCOPUS) to cover a variety of research fields, from marketing to the social sciences and psychology. The literature search was performed in October 2018.
The criteria for all searches were that the articles must be in English, peer reviewed, and published between the years 2010 and 2018. EndNote citation management software was used to store, organize, and share the sources among the research team. The search terms are listed in Table A1. The articles found were distributed among the four authors based on our preliminary categorization so that each author examined one of the categories (basic health care, specialized health care, and wellness services). In addition, the search resulted in a new category of the touristic approach to health care, which did not specify the exact service and approached travel from a tourism studies perspective.
The first round of searches included a large number of studies (n = 2,992 after removing duplicates), of which irrelevant records were sourced out based on the reading of titles and abstracts of papers. Finally, 851 papers were included. During the next stage, each researcher read the abstracts of their category and discarded the irrelevant articles according to the inclusion/exclusion criteria (see Table A2). The exclusion of articles was cross-checked by a second reviewer and, in the cases of conflicting views on the exclusion, the articles were discussed with the whole research team, and the exclusion/inclusion of the article was jointly decided. After screening the titles and abstracts, the full texts of all the remaining papers (n = 350) were retrieved. The full list of included articles is available from the authors upon request.
Stage 4: Charting the data. After reading and selecting the articles to be included in the review, the articles were charted in Excel. The chart included the terminology used, the definition of the users or the services, countries of origin and destination, methods, limitations, and key findings. The results of our article are based on this charting.

Declaration of Conflicting Interests
The author(s) declared no potential conflicts of interest with respect to the research, authorship, and/or publication of this article.

Funding
The author(s) disclosed receipt of the following financial support for the research and/or authorship of this article: The research was been funded by the Academy of Finland (grant 312310 for the Centre of Excellence for Research on Ageing and Care, RG 3 Migration, Care and Ageing), the Strategic Research Council at the Academy of Finland (Grant 327145 and 327148 for the DigiIn project), Kone Foundation (project Crossing Borders for Health and Well-being), and the University of Helsinki Research grants (Project TransHealth).