Health Tourism Evolution: A Review Based on Bibliometric Analysis and the China National Knowledge Infrastructure Database

: To systematically understand the evolution of health tourism in China, the present study visually analyzes the theme evolution and frontiers of Chinese health tourism research on the basis of the China National Knowledge Infrastructure (CNKI) database through bibliometric analysis. The ﬁndings reﬂect the existence of diverse clustering themes in health tourism research, and the formation time of each theme is different. The ﬁndings also indicate that the change in the theme is led by government policy. Theoretically, the ﬁndings of the present study can, on the one hand, contribute to the health tourism literature by comprehensively exploring and summarizing the themes and topics of health tourism development in China since its appearance (i.e., 1981), and, on the other hand, provide references for future health tourism exploration directions. Findings of the present study can provide references for effective future development directions of the health tourism industry.


Introduction
Along with the outbreak of the novel coronavirus (COVID-19) pandemic, people have been paying more attention to health [1].Consumers are more willing to pay attention to health risks, such as COVID-19-related health issues, and would like to participate more in health tourism.For example, a recent study [2] proved the moderating role of risk communication for health tourism to improve the physical and mental health of people affected by the COVID-19 pandemic.With the effective control of the pandemic in different countries and regions, the tourism industry may have more opportunities for health tourism development [3].For instance, one recent study reflected the great needs of diversified provision of health tourism packages for different consumer groups [4].As a result, it is expected that after the pandemic, tourists' travel behavior may be changed [5], and the expected changes may require tourism destination organizations to be more responsible for the health concern of consumers [6].Hence, a comprehensive overview of health tourism is conducive to explore current research gaps in order to identify future research directions and ultimately contribute to the development of the health tourism industry.
With the rapid development of health tourism, a number of studies have examined it [7].Smith outlines some of the major lifestyle aspects affecting the health tourism sector (e.g., spas, health hotels, nursing homes, and medical facilities) in developed Western countries [8], and Smith and Puczkó conducted research on health tourism and balneology in Hungary [9].India is considered a successful medical destination, where low-cost skilled labor, the latest medical technology, standards, and high-quality medical services exist simultaneously.Furthermore, India has an environment where English is widely used [10].Specifically, India provides many different kinds of medical services, ranging from alternative treatments such as ayurvedic medicine and yoga to complicated procedures such as heart surgery, joint replacements, and hip resurfacing [11].South Korea on the other hand enjoys a high reputation and competitiveness in providing minor treatments such as plastic surgery [12].Using Bama longevity villages in China as a case study, Yan and He studied the co-evolution of therapeutic landscapes and health tourism through an actor-network perspective [13].Kaoula and Bouchair adopted life cycle analysis to assess the environmental impact of different hotel buildings [14].Nonetheless, with the intensification of aging and changes in people's lifestyles, health tourism may face challenges in the future, although opportunities also exist simultaneously [15].
Although compared with the health tourism development in western countries, China's health tourism started late, it has been developing rapidly driven by various policies advocated.For example, following the policies of the "Several Opinions on Further Promoting Tourism Investment and Consumption" (2015) [16] and the "Notice on the Establishment of National Traditional Chinese Medicine Health Tourism Demonstration Zones (Bases and Projects)" [16], China's traditional Chinese medicine tourism sector is developing rapidly.The State Council also issued the "Guiding Opinions on Promoting the Development of Global Tourism."[17].In addition, as the Chinese government provided enough support to Hainan to become a world-class health tourism destination and a major source of international medical tourism [18], China's health tourism is constantly developing towards this trend.Thus, the Chinese government attaches great importance to the development of health tourism in China, particularly inbound health tourism.It can be expected that after the pandemic, Chinese health tourism, such as traditional Chinese medicine health tourism, may become popular.Nevertheless, compared with the abundant research on health tourism in other countries or regions, the research on health tourism in China is rarely known internationally.Hence, it is of great importance to explore the development of health tourism in China so as to indicate future research directions and enrich the literature of health tourism.As a result, this study summarizes the related studies on health tourism in China since its appearance and fills the gap of comprehensive understanding of health tourism development in China.Furthermore, unlike most bibliometric reviews, this study also integrates bibliometric findings with policies, aiming to explore more deeply about the internal dynamics of its development.
Specifically, the research objectives of the present study are to identify the development process of health tourism in China in the past 41 years; to find out the driving factors for the change of health tourism research hotspots in China; and to predict the future development trend of health tourism research in China.This paper makes the following contributions.First of all, although China is developing its health tourism, its current development status and progress is still not well known.Thus, a comprehensive literature review of health tourism development in China is needed to facilitate a deeper understanding of China's health tourism for academic researchers and tourism practitioners.Secondly, rather than simply describe and summarize the existing literature, the present study analyzes the data by taking policy into consideration, as the findings indicate that policy does indeed drive health tourism development in China.Thirdly, through the analysis and elaboration of previous studies, the present study explores the regular pattern of health tourism research and predicts the future development of health tourism in China and provide references for other countries and regions for future studies relating to health tourism development.
This paper firstly reviews the literature related to health tourism, and then introduces the data collection and analysis in detail in the method section.A detailed analysis of the number, topics, hotspots and evolution of health tourism related articles is then carried out in the results section, followed by discussions, implications and conclusions.

Controversy of Health Tourism
Health tourism refers to domestic and international tourism for individuals to improve their health in order to achieve the purpose of treating individuals and protecting their well-being [19].The concept of health tourism evolved from medical tourism to healthcare tourism, and to the concurrent health tourism [20].Goodrich et al. [21] believed that health tourism destinations not only have beautiful scenery, but also provide health service infrastructure, such as hotel accommodation, water sports, and golf.Since 2000, the definition of health tourism has been gradually diversified.Ross [22] reflected on the health tourism industry as related activities in which tourists travel from the place of residence to the destination for health reasons, such as medical treatment.Sheldon and Bushell [23] pointed out health tourism as a kind of tourism that can improve tourists' lives and life quality, which include medical treatment, hygiene, beauty, sports/fitness, and adventure, although Hunter-Jones and Blackburn [24] believe that the concept of health tourism is narrow.On the other hand, UNWTO [25] recommends separating the concepts of health tourism and medical tourism.It can be seen that different academic researchers have different perceptions on the internal boundaries of health tourism.The main controversy is whether health tourism is for the purpose of curing diseases or for the purpose of healthcare.In particular, the consensus in the literature on the relationship between health, medical and wellness tourism has not been reached.This paper adopts Sheldon's definition of health tourism and explores the relationship and development between different types of health tourism and contributes to the current health tourism controversy.

Types of Health Tourism
In terms of different types and characteristics of health tourism, rich classification systems were formed among academic researchers, such as tourists, products, and resources.From the perspective of tourists, health tourism can be divided into two types, the first type is active pursuit and the second one is passive realization, as with the current trend that an increasing number of people are paying more attention to their health and have actively pursued health tourism.Health products can be divided into two categories: one is medical-oriented (passive) and the other is health-oriented (active).Medical-oriented products mainly refer to medical tourism, whereas health-oriented products mainly include spiritual and religious tourism, yoga tourism, outdoor activities, sports and adventure, and volunteer tourism [26].In terms of resource types, health tourism can be divided into health culture, religious experience, medical care, hot spring recuperation, forest recreation, and mountain fitness [27].Different countries have different unique health tourism resources, such as spa tourism in Thailand, plastic surgery tourism in South Korea, and medicine tourism in China.
In addition, regarding function of health tourism, it can be divided into four types: medical maintenance such as medical tourism, leisure adjustment such as wellness tourism, physical enhancement such as sports tourism and self-realization such as adventure tourism [28].Health tourism can be divided into three types: physical promotion, psychological promotion, and social adaptation [29].From the perspective of satisfaction for health tourism, health tourism can be divided into three alternative types: restoring, continuing, and enriching health [30].In summary, based on previous studies, different perspectives have been adopted to classify health tourism.Since the health tourism market has been continuing to grow, different types of health tourism may emerge.Thus, exploring the development of existing health tourism will be helpful to clarify its scope, products and types so as to predict the future development trends of health tourism.

An Overview of Health Tourism-Related Articles
Through a literature review search in the core collection-Web of Science database, 189 literature reviews related to health tourism were found.These literature reviews can be mainly divided into three categories.The first category is related to the environment, such as public environmental occupational health and environmental sciences.The second category is related to medicine, such as health care sciences services and multidisciplinary psychology.The third category is related to leisure and management, such as hospitality leisure sport tourism and management.Among them, the literature review relating to hospitality leisure sport tourism is shown in Table 1.The main research topics are health tourism, wellness tourism, medical tourism, health and medical tourism.These review articles mainly explain the definition, stakeholders, components, and development trends of health tourism.Compared with the fruitful international research results of the United States, the United Kingdom [31], Switzerland [32], and Germany [33], China's health tourism research results are rarely displayed internationally.Kazakov and Oyner [34] discussed the future development of wellness tourism by re-observing and analyzing the related literature in the past 75 years.However, this study only provides a simple description, and a thorough quantitative analysis of the literature is lacking.Thus, the present study conducted a comprehensive review study of the articles retrieved from the CNKI database by adopting a quantitative approach to explore the development of China's health tourism research over the past 41 years.

Health tourism
Concept, Trends and structural shifts, the determinants of travelers choosing health tourism destinations, Comparative Analysis of Spas [32,33,35,36] Wellness tourism Future development, Components [34,37] Medical tourism Definition, Stakeholders, The development and implications of medical mobility, Medical tourism industry, Motivation of medical tourists, Ethical issues in medical tourism, Marketing of health and medical tourism [31,[38][39][40] Health and medical tourism The relationship between Health and medical tourism, Define health and medical tourism and estimating the size of trade in healthcare [41,42]

Data Collection
As CNKI(http://www.cnki.com.cn/,accessed on 1 February 2022) is considered the largest and most authoritative database in China, containing the vast majority of papers written in Chinese, CNKI was selected as the database for the article retrieval for the present study.Data were collected in February 2022.Nevertheless, the selected time frame is from 1981 (i.e., the first article relating to health tourism published in China) to 2021.The keywords "health and wellness tourism", "wellness tourism", "health tourism", and "medical tourism" were used in the database to search for articles related to health tourism.Only peer-reviewed journal articles were retrieved; other types of research were not included.Finally, a total of 2561 articles were retrieved.The first article was published in 1981, and up to the present (i.e., 2021), health tourism-related articles have been published for 41 years.

Data Analysis
A comprehensive literature review normally analyzes the concepts, methods, and development trends in this field in order to identify knowledge gaps, predict future research directions or develop new theoretical frameworks [45].Some of these review articles adopted meta-analysis while other articles analyze the literature mainly under the topic, using bibliometric review.Compared with other types, bibliometric review is one of the domain-based literature reviews, as it can comprehensively analyze the themes, authors, and citations in related fields.Since the number of research papers on health tourism in China has been increasing over the past 41 years, topics and hotspots of health tourismrelated research have also been constantly changing, it is of great necessity to analyze all the retrieved articles relating to health tourism.Thus, the present study analyzes the relevant literature of health tourism through bibliometric analysis.

Article Visualization Tools
Visualization tools currently used for bibliometric review mainly include VOSviewer and CiteSpace.Compared with VOSviewer, CiteSpace can have more comprehensive analysis such as obtaining research frontiers and key turning points with citation burst algorithm [46].In addition, CiteSpace allows academic researchers to evaluate various bibliographic networks, including research topics [47], and development trends [48].Furthermore, CiteSpace allows different modes such as cluster, timeline or time zone view to reflect the dynamics of the bibliographic network [49].
At present, CiteSpace is mainly used to analyze specific journals or specific fields.In terms of specific journals, for example, Mou, et al. [50] adopted CiteSpace's bibliometric method to conduct quantitative and visual analysis of papers in six e-commerce journals from 1999 to 2016.In terms of specific areas, Jiang, et al. [51] used CiteSpace to analyze and visualize the knowledge structure in the field of tourism crisis and disaster management.Li et al. [49] systematically sorted out the evolution and emerging research trends in the field of inbound tourism.Research trends have also been found in urban tourism [52] and mobile technology in tourism [53].Nevertheless, limited studies analyzed tourismrelated topics within a certain country or region.Thus, the present study comprehensively analyzed health tourism development in China to explore its development process and future development trends.

Number of Publications
The findings indicate that the first research paper related to health tourism in China was published in 1981 as shown in Figure 1, which is later than international research on health tourism.The reason may be due to the late start of the development and investigation of the health tourism market in China.Since 2004, research on health tourism began to grow; and in 2020, the topic of health tourism was paid the most attention among academic researchers [54].From 2014 to 2017, China's health tourism research has started to grow rapidly.At the same time period, the Chinese government formulated and introduced a series of policies to support the development of health tourism.For example, in 2015, the Chinese government issued "Several Opinions on Further Promoting Tourism Investment and Consumption", preparing to launch demonstration products of Chinese medicine health tourism [16].Later, in 2016, the Chinese government issued the "Healthy China 2030 Outline", which elevated "Healthy China" to a national strategy [17].Furthermore, in 2017, the Chinese government issued the "Guiding Opinions on the Development of Health Tourism", which pointed out that China should develop a certain number of international healthy tourism destinations [55], which facilitates the internationalization of China's health tourism.Along with the formulation of health tourism-related policies and the support from the Chinese government, the number of health tourism-related articles reached the maximum number in 2020 over the past 41 years.

Themes and Topics
Figure 2 shows the collinear map of keywords.The most frequent identified keywords can be divided into three types.The first type is related to the category of health tourism, such as health tourism, wellness tourism, health and wellness tourism, medical tourism, international medical tourism, Chinese medical tourism, and forest tourism.Among them, health tourism was the first studied by academic researchers, and the most academic researchers have studied wellness tourism and medical tourism.Although Chinese medical tourism has also been included in the research recently, the research timeframe is still relatively short.Nevertheless, Chinese medical tourism may become a future research direction.
2015, the Chinese government issued "Several Opinions on Further Promoting Tourism Investment and Consumption", preparing to launch demonstration products of Chinese medicine health tourism [16].Later, in 2016, the Chinese government issued the "Healthy China 2030 Outline", which elevated "Healthy China" to a national strategy [17].Furthermore, in 2017, the Chinese government issued the "Guiding Opinions on the Development of Health Tourism", which pointed out that China should develop a certain number of international healthy tourism destinations [55], which facilitates the internationalization of China's health tourism.Along with the formulation of health tourism-related policies and the support from the Chinese government, the number of health tourism-related articles reached the maximum number in 2020 over the past 41 years.

Themes and Topics
Figure 2 shows the collinear map of keywords.The most frequent identified keywords can be divided into three types.The first type is related to the category of health tourism, such as health tourism, wellness tourism, health and wellness tourism, medical tourism, international medical tourism, Chinese medical tourism, and forest tourism.Among them, health tourism was the first studied by academic researchers, and the most academic researchers have studied wellness tourism and medical tourism.Although Chinese medical tourism has also been included in the research recently, the research timeframe is still relatively short.Nevertheless, Chinese medical tourism may become a future research direction.
The second type includes the keywords relating to policies and industries, such as the tourism industry, health industry, and pioneer district.The second type shows that the research on health tourism is closely connected with policies and industry, and the industry mainly refers to the tourism health industries.From the government's perspective, as the Chinese government proposed the policy of establishing an international medical tourism pioneer district, academic researchers started to pay more attention to "international medical tourism" and "pioneer district".Findings show that China's health tourism research development is keeping up the pace with the policies formulated by the Chinese government.To develop an international health tourism destination in China, an international pioneering district with local characteristics can be considered.The third type relates to research methods such as SWOT analysis.Results reveal that health tourism-

Analysis of Phased Frontier Research Fields
The burst of the keywords can reflect the research fields that have great influ over a period of time, with the red color reflecting the most influenced periods from to 2021.A total of 20 burst words were obtained from the analysis of keywords i health tourism literature (Figure 3).The results indicate that "health culture" laste the longest time period (i.e., 15 years), and most other prominent words lasted for fi ten years.
Based on time series, before 2005, there were few papers related to health tou and no burst words were formed.The burst words identified from 2006-2010 are m medical tourism, wellness tourism, health care, ecotourism, and tourists.From the The second type includes the keywords relating to policies and industries, such as the tourism industry, health industry, and pioneer district.The second type shows that the research on health tourism is closely connected with policies and industry, and the industry mainly refers to the tourism health industries.From the government's perspective, as the Chinese government proposed the policy of establishing an international medical tourism pioneer district, academic researchers started to pay more attention to "international medi-cal tourism" and "pioneer district".Findings show that China's health tourism research development is keeping up the pace with the policies formulated by the Chinese government.To develop an international health tourism destination in China, an international pioneering district with local characteristics can be considered.The third type relates to research methods such as SWOT analysis.Results reveal that health tourism-related studies mainly pay attention to the practical implications; however, limited studies focus on the theoretical foundation of health tourism.

Analysis of Phased Frontier Research Fields
The burst of the keywords can reflect the research fields that have great influence over a period of time, with the red color reflecting the most influenced periods from 1981 to 2021.A total of 20 burst words were obtained from the analysis of keywords in the health tourism literature (Figure 3).The results indicate that "health culture" lasted for the longest time period (i.e., 15 years), and most other prominent words lasted for five to ten years.

Health Tourism-Related Hotspots and Evolution
Through adopting clustering and timeline analysis, research on health tourism over the past 41 years can be divided into nine hotspots, as shown in Figure 4. Nine tourismrelated hotspots include international medical tourism, Chinese medical tourism, wellness tourism, health tourism, forest tourism, wellness culture, health and wellness tourism, all-for-one tourism, and influencing factors.In terms of the types of health tourism, health tourism, health and wellness tourism appeared first, followed by medical tourism in 2001.After that, wellness tourism, forest tourism, ecotourism, and rural tourism appeared in 2007.Later, more different types of health tourism appeared.Judging from the nine hotspots in the health tourism research, although different hotspots appear in different years, one trend that can be found is that health tourism development is policy driven.Based on time series, before 2005, there were few papers related to health tourism, and no burst words were formed.The burst words identified from 2006-2010 are mainly medical tourism, wellness tourism, health care, ecotourism, and tourists.From then on, the types of health tourism began to diversify, and medical tourism and ecotourism appeared; in the meantime, researchers began to pay attention to the needs of tourists.The burst words identified in 2011-2015 are travel, scenic areas, medical service and resources, tourism environment.During this time period, studies mainly investigated on health tourism scenic spots, explore and evaluate the construction of health tourism scenic spots.The burst words identified in 2016-2020 are Chinese medicine, medical service, pilot zone and forest tourism.During this time period, "Chinese medicine" and "services" appeared, indicating that China's health tourism began to focus on the characteristics of the products and services to improve core competitiveness.Since the Chinese government proposed building an international health tourism center in Hainan Province, health tourism-related studies in Hainan have become a hot topic during this time period.The burst words identified in 2021 are health and wellness tourism, forest health, and health care industry.In 2021, researchers' attention to health and wellness has increased significantly, which is inseparable from the epidemic.Along with the emergence of the aforementioned keywords, findings reveal that China's health tourism research closely follows the government policies and guidelines and has shown a trend of policy-driven health tourism development.

Health Tourism-Related Hotspots and Evolution
Through adopting clustering and timeline analysis, research on health tourism over the past 41 years can be divided into nine hotspots, as shown in Figure 4. Nine tourismrelated hotspots include international medical tourism, Chinese medical tourism, wellness tourism, health tourism, forest tourism, wellness culture, health and wellness tourism, all-for-one tourism, and influencing factors.In terms of the types of health tourism, health tourism, health and wellness tourism appeared first, followed by medical tourism in 2001.After that, wellness tourism, forest tourism, ecotourism, and rural tourism appeared in 2007.Later, more different types of health tourism appeared.Judging from the nine hotspots in the health tourism research, although different hotspots appear in different years, one trend that can be found is that health tourism development is policy driven.Specifically, the research of Chinese medical tourism has also developed with the guidance of policies.The government has announced in the policy that it is necessary to develop a batch of characteristic Chinese medicine tourism products to promote the development of Chinese medicine health tourism [16].At this point, the academic field began to study the culture of Chinese medicine and the general health industry.
Studies on medical tourism are moving into the direction of international medical tourism.Under this theme, the "Pearl River-Xijiang Economic Belt" appeared, which is consistent with the economic belt's policy of establishing an international medical tourism demonstration zone, as it is considered an important part to connect with other disciplines.In addition, wellness tourism research has been paying attention.Under this theme, "the era background" and "tourism poverty alleviation pilot area" appeared, which reflects that the research of wellness tourism is produced under the background of tourism poverty alleviation.Findings show the research direction of wellness culture as it integrates health culture and tourism through in-depth exploration of culture to develop Specifically, the research of Chinese medical tourism has also developed with the guidance of policies.The government has announced in the policy that it is necessary to develop a batch of characteristic Chinese medicine tourism products to promote the development of Chinese medicine health tourism [16].At this point, the academic field began to study the culture of Chinese medicine and the general health industry.
Studies on medical tourism are moving into the direction of international medical tourism.Under this theme, the "Pearl River-Xijiang Economic Belt" appeared, which is consistent with the economic belt's policy of establishing an international medical tourism demonstration zone, as it is considered an important part to connect with other disciplines.In addition, wellness tourism research has been paying attention.Under this theme, "the era background" and "tourism poverty alleviation pilot area" appeared, which reflects that the research of wellness tourism is produced under the background of tourism poverty alleviation.Findings show the research direction of wellness culture as it integrates health culture and tourism through in-depth exploration of culture to develop tourism products and enhance the cultural connotations of tourism destinations.
Another research direction of health tourism is focusing on national health, such as food hygiene, health management, and social medical services.The research of forest tourism started relatively early; in the initial stage, it focused on the health needs of tourists such as forest bath and forest health.Nevertheless, as the government promoted the establishment of the national forest park policy, the theme turned to the study of tourist destinations such as national forest parks and global geological parks.Most prior studies on health and wellness tourism are related to "ancient towns" and "cities", such as "Huangyao Ancient Town" and "China's Excellent Tourist City".In addition, in the background of the rural construction, rural tourism has also become an important research part of health and wellness tourism.
In the initial stage of health tourism development, limited studies examined all-for-one tourism the academic field, focusing on exploring the development strategy and the path of all-for-one tourism.After the Chinese government put forward "Notice on Carrying out the Establishment of the All-for-one Tourism Demonstration Zone" in 2015, related research has started to grow.The research on influencing factors is mainly carried out from the perspectives of tourists and the tourism industry, such as the factors that influence the decision making of tourists, and the factors that influence the medical tourism industry.

Discussion
Findings of the present study show that the development type of health tourism is diversified, depending on tourism resources and culture such as forests to form the mode "tourism with health as a plus."In addition, recently, the research direction has turned to the development of international medical tourism.Furthermore, studies have shifted the focus from forest tourism and ecotourism to medical tourism and Chinese medicine tourism.The aforementioned points reflect that health tourism development tends to be systematic under the guidance of recent policies.Meanwhile, the findings show that most studies investigated health tourism from the perspectives of medical tourism and health tourism, and mainly focus on the influencing factors and effects of health tourism.Nonetheless, compared with the discussion of practical implications, discussions of the theoretical foundations of health tourism are limited [54].
Table 2 summarizes the themes and hotpots of health tourism in China at different stages.During 1981-2005, there were few studies on health tourism, and no hot topic was identified, but various scattered topics started to gain attention from academic researchers.From 2006 to 2010, there were many studies relating to tourists.In this period, medical industry, ecotourism, forest tourism and rural tourism started to gain attention from academic researchers.From 2011 to 2015, academic researchers began to pay attention to the tourism environment.Topics such as international medical tourism, forest park, industry convergence became popular.From 2016 to 2021, policy-related research has become a hot topic, such as pilot zone, health care industry, and health town.
Specifically, after the outbreak of Severe Acute Respiratory Syndrome (SARS) in 2003, health tourism has been continuously an object of attention.For example, Beijing proposed the "Happy Life and Healthy Tour", Ningbo established a health tourism area, and Hangzhou launched health tourism from the perspective of humanistic care [56].With the government's vigorous advocacy of health tourism, an increasing number of academic papers started to carry out research related to health tourism.2004 was the year that academic researchers regarded health tourism as the core research object [28].The key word in the academic circles from 2014 to 2016 was "health service industry".In 2016, the state council issued the "Outline of the 'Healthy China 2030' Plan" [57], which proposed the initiatives to improve the health service system [17].In summary, after SARS, the Chinese government took leadership in proposing the development of health tourism, academic researchers following the pace then.With the deepening of health tourism-related research, currently, academics have devoted effort to proposing the concept of health service industry, supporting the government in formulating and introducing health service policies.For health and wellness tourism research, the government first proposed the goal of developing health and wellness tourism.Since then, academic researchers have started to carry out relevant research.For example, in 2012, Panzhihua City first proposed the goal of building a "China Sunshine Health and Wellness Tourism City" [58], which officially opened the prelude to the development of the health and wellness tourism industry led by the Chinese government.In January 2016, the former China National Tourism Administration issued the "National Health and Wellness Tourism Demonstration Base" standard, proposing that health and wellness tourism should pay attention to the harmony of nature [17].After that, the academic research hotspots turned to "health and wellness tourism industry" and "forest health".Since then, academic research results have gradually supported the government in publishing the standards of health and wellness tourism demonstration bases and the definition of health and wellness tourism.The issuance also helps to standardize the academic research on health and wellness tourism, thereby urging the research on health and wellness tourism to develop a deeper level with more dimensions.
In terms of Chinese medicine tourism, in 2015, the state council issued "Several Opinions on Further Promoting Tourism Investment and Consumption", with the purpose of preparing the launch of a batch of Chinese medicine health tourism demonstration products [16].In 2016, the China National Tourism Administration and the State Administration of Traditional Chinese Medicine jointly issued the "Notice on the Establishment of National TCM Health Tourism Demonstration Zones (Bases and Projects)", requesting to explore new concepts and new models for the development of traditional Chinese medicine health tourism [16].Since then, "Chinese medicine" and "Chinese medicine health tourism" have become academic research hotspots in 2016.
In reference to global tourism, since Jinzao Li, the director of the National Tourism Administration, published an article "The Value and Approach of Global Tourism" in People's Daily in March 2016, global tourism has become a national tourism research hotspot.Later, in 2018, the State Council issued the "Guiding Opinions on Promoting the Development of Global Tourism" [17].Since then, global tourism has become a key word in academic papers in 2018, as academic researchers have carried out in-depth research on global tourism, particularly its development path.
In summary, the research process and the development of health tourism in China is shown in Figure 5.As shown in Figure 5, the first publication of health tourism in China is in 1981.At the beginning of the 21st century, health tourism entered a stage of rapid development.Under the guidance of policies, various types of health tourism have emerged, such as medical tourism, health tourism, forest tourism, and rural tourism.The development during this period paid more attention to the quantity.Starting from 2010, the government began to issue various health tourism standards to regulate the health tourism market, and academic researchers began to focus more on the quality of health tourism (e.g., service quality).In recent years, health tourism is in the stable stage.That is, with the government's construction of a high-level international health tourism center, the academic field has begun to explore innovative models and paths for the development of health tourism.

Conclusions
Theoretically, this study is expected to make meaningful contributions.First, this paper makes up for the lack of international understanding of China's health tourism sector by reviewing health-related papers from the database in China, thereby helping to better develop Chinese and international academic and industrial cooperation.Second, on the basis of bibliometric results, this study takes policies into consideration, and analyzes the driving forces of China's healthy tourism development in a more in-depth manner, helping to predict its future development more accurately.Third, through the analysis of the development process of China's health tourism, the study provides a reference for the development of health tourism for other countries and regions.
Practically, this study is expected to bring some practical implications for the government and the market.First, for the government, the results found that academia has been fruitful in health tourism-related policy formulation and feedback.As such, a government can take academic research results into consideration when formulating health tourismrelated policies.Second, for the destination market, the results found that the trend of health tourism is often related to government policies.Therefore, when developing resources related to health tourism, destination organizations can refer to the government's macro policies to grasp the general direction.
In conclusion, through retrieving 41-year health tourism-related studies, the present study examines the current research topics and hotspots in this field and the characteristics of the research content.Findings show that research topics are closely related to the national policy.In other words, development of health tourism is policy-driven.In terms

Conclusions
Theoretically, this study is expected to make meaningful contributions.First, this paper makes up for the lack of international understanding of China's health tourism sector by reviewing health-related papers from the database in China, thereby helping to better develop Chinese and international academic and industrial cooperation.Second, on the basis of bibliometric results, this study takes policies into consideration, and analyzes the driving forces of China's healthy tourism development in a more in-depth manner, helping to predict its future development more accurately.Third, through the analysis of the development process of China's health tourism, the study provides a reference for the development of health tourism for other countries and regions.
Practically, this study is expected to bring some practical implications for the government and the market.First, for the government, the results found that academia has been fruitful in health tourism-related policy formulation and feedback.As such, a government can take academic research results into consideration when formulating health tourism-related policies.Second, for the destination market, the results found that the trend of health tourism is often related to government policies.Therefore, when developing resources related to health tourism, destination organizations can refer to the government's macro policies to grasp the general direction.
In conclusion, through retrieving 41-year health tourism-related studies, the present study examines the current research topics and hotspots in this field and the characteristics of the research content.Findings show that research topics are closely related to the national policy.In other words, development of health tourism is policy-driven.In terms of the focus of future health tourism research, the following suggestions are provided.First, research focused on health tourism development may continue to be government oriented and continue to develop along with change of government policies.
Considering the aging of the population, changes in disease spectra, and changes in people's health concerns affected by COVID-19, the government will continue to develop Chinese medicine tourism.Hence, it is expected that the development of the medicine industry in China will be positive in the future.In addition, health tourism-related research may be more inclined to interdisciplinary.Furthermore, there may be more studies relating to the culture of Chinese medicine.As China constantly advocates maintaining good health through Chinese medicine, and an increasing number of retired people have urgent needs for rural old-age care and maintaining good health, research hotspots have shifted from wellness tourism to medical care for good health maintenance.Hence, the means to realize the industrial integration of traditional Chinese medicine health "wellness with culture as a plus" and "tourism with health care as a plus" may become new industrial development directions and hot research spots in the near future.
Second, forest healthcare is expected to continue to be the research focus of academic researchers, in addition to the intensive release of national and local policy documents on Chinese medicine in recent years.Moreover, since gene technology, three-dimensional (3D) printing technology, big data, artificial intelligence, and other new technologies are closely connected with medical tourism, a combination of the aforementioned technologies with medical tourism is suggested for future studies.Under the background of the implementation of the health tourism development policy in China, health care will be a focus for future studies, and social medical insurance will also be taken into consideration.Affected by the COVID-19 pandemic, with Hainan's unique advantages in forest resources, ecological environment and free trade port, it will become an important ground for the release of national health and wellness consumption.
Finally, as the existing tourism or wider non-tourism research policy literature rarely discusses approaches to research policy and their impact, the findings of the present study reveal that China's health tourism research is government oriented, academia follows the government's vane to carry out relevant hot research, and the results can support the government in formulating corresponding government policies and standards.Thus, a virtuous circle of government and academia will be formed to jointly help the development of health tourism industry in China in the future.The present study has some limitations.The present study only selected one database to study health tourism in China.Hence, future studies can consider including more health tourism articles from databases, such as ScienceDirect and Web of Science, to provide more comprehensive implications of future international health tourism development directions.

Figure 1 .
Figure 1.Number of publications

Figure 2 .
Figure 2. The collinear map of keywords.

Figure 2 .
Figure 2. The collinear map of keywords.

Sustainability 2022 ,
14, x FOR PEER REVIEW 8 of 15government policies and guidelines and has shown a trend of policy-driven health tourism development.

Figure 4 .
Figure 4.The timeline view of keywords.

Figure 4 .
Figure 4.The timeline view of keywords.

Figure 5 .
Figure 5. Research process of China's health tourism.

Table 1 .
Topics of Health Tourism.