Global research trends on diseases in the elderly population: a visualization analysis

doi:10.21203/rs.3.rs-1651379/v1

Background

Currently, populations around the world are rapidly ageing. Hence, the number of scientific publications on diseases in the elderly population (aged 60 and over) has been expanding.

Objective

This study aimed to use bibliometric analysis method to illustrate the global research trends over the past 20 years and to summarize the research hotspots that are likely to be addressed in future studies.

Methods

A literature search for medical publications on diseases in the elderly population in the period from 2000 to 2021 was conducted in the Web of Science Core Collection on April 20, 2022. Visualization analysis was performed using VOSviewer software (version 1.6.16).

Results

A total of 12,108 publications of the period from 2000 to 2021 were retrieved. The annual publication output grew gradually from 177 in 2000 to 1,236 in 2021. Articles (n = 10,264, 84.77%) were the most common type of documents. The USA issued the largest number of publications (n = 3,632, 30.00%) and had the most citations (citations = 141,230), with the United States Department of Health and Human Services making the largest contribution (n = 1,904, 15.73%). The Lancet had the most citations (citations = 28,548). A total of 545 meaningful topics were identified and further classified into 5 different clusters. The keywords ‘COVID-19’, ‘muscle mass’, ‘depression’ and ‘non-alcoholic fatty liver disease’ have drawn substantial attention in recent years, indicating that these areas will be the centre of attention in future studies on the elderly population.

Conclusions

This study provides an unbiased visualization analysis of this topic in a scale-efficient manner and includes directions for further research.

elderly population

diseases

Web of Science

VOSviewer

Population ageing is occurring in most countries worldwide. As a result of declining mortality and decreasing fertility, population ageing has led to a decrease in the proportion of the population who are of working age and in increase in the elderly proportion of the population(1). Globally, the proportion of the population accounted for by elderly individuals (aged 60 and over) rose from 9.2% in 1990 to 11.7% in 2013 and will continue growing to 21.1% by 2050(2). According to World health organisation (WHO) and other global organizations, elderly population or older individuals are generally considered as people who aged 60 and over(3, 4). The rate of change in the elderly population has greatly increased. Longevity is very valuable and depends on one key factor: health. When the years past the age of 60 are accompanied by a decline in physical or mental capacity, it can lead to a decrease in affection on the part of families and society for elderly individuals. Hence, increasing attention is being paid to diseases in the elderly population. With the increase in life expectancy that has been observed globally, there have been substantial changes in disease mapping, and the causes of mortality have been altered. Most diseases in the elderly population are noncommunicable diseases, and they result in the greatest burden on society(5). Studies have shown that the following three disorders are common in the elderly population and cause the most deaths: ischaemic heart disease, stroke, and chronic obstructive pulmonary disease(6, 7). However, the impact of the conditions that lead to severe disability, such as osteoporotic fracture and Alzheimer's disease, must not be ignored. The burden from the diseases most common in the elderly population is substantial across low-income, middle-income and high-income countries. The increase in the of diseases in the elderly population has led to an increase in the publication of research papers online. Additionally, the areas of focus of these publications have varied.

Some studies have been performed with an aim of quantifying the causes of death worldwide in the past 2 decades(8), whereas others have focused on the prevention and treatment of a specific disease(9–11). The current prevalence of diseases in the elderly population and the challenges involved in the treatment of these diseases have been summarized in some reviews(12, 13). Hence, it is helpful to review the developing advancements in this field before performing research. However, developing a scale-efficient method of quickly learning about the current landscape of the research on one specific topic remains a challenge. To summarize the current evidence and establish directions for future research, it is essential to perform a visualization analysis, which can provide a picture of the landscape of the published studies on diseases in the elderly population.

This study was performed with the aim of conducting a bibliometric analysis of the published literature on diseases in the elderly population to illustrate the research trends over the past 20 years and to summarize the research hotspots that are likely to be investigated in future studies.

Data sources and search strategies

The Web of Science Core Collection database was selected as the target database from which to retrieve the relevant studies. This database, which contains collections of high-quality scholarly content, is widely known as one of the best online databases for bibliometric research. Data, including keywords, citations, reports, authors, affiliated countries, institutions, and journals, were captured from each document.

The relevant literature with subject terms (TS) involving the ‘elderly population’ and ‘disease’ was searched with the appropriate keywords in the Web of Science Core Collection online database. Only articles published in English were included. Medical publications focusing on this area were searched for, with the publication period limited to between January 1, 2000, and December 31, 2021. The detailed strategy was as follows: ((elderly)OR(aged)[TS]) AND((disease*)[TS])AND ((population*)OR(people)OR(group)OR(adult*)[TS]).

Bibliometric And Visual Analyses

Bibliometric indicators, including the number of publications, publication year, type, funding information, countries, authors and institutions, were captured and analysed using Microsoft Excel (Redmond, WA, USA) spreadsheets.

VOSviewer software (version 1.6.9; Leiden University, Leiden, the Netherlands) was used to perform the coauthorship, co-occurring keyword, and citation reference analyses. The networks of countries, authors, institutions and keywords were visualized and explored based on their co-occurrence. In network, overlay and density visualizations, keywords appearing more than a certain number of times were included. Unequal-size nodes or tags represented the frequency of the occurrence or the number of citations of the keywords, making it easier to identify the terms related to research hotspots. Lines between nodes indicated the strength of collaborations.

Search results and growth trends

A total of 12,108 publications from the period from 2000 to 2021 were retrieved. As shown in Figure 1A, the annual publication output grew gradually from 177 in 2000 to 1,236 in 2021. Before 2016, the growth was fewer than 800 publications per year. Subsequently, that number increased rapidly, with a clear increase in 2020. In 2021, the number of publications was five times the number in 2000, indicating developments in this area. Among the publications, articles accounted for 84.77%, indicating that they were the most popular form of literature. The other nine types of publications accounted for the remaining 15.23% of the total and included meeting abstracts, reviews, and proceedings papers (Supplementary table 2). As shown in Figure 1B, geriatrics and gerontology were the main research category in this topic (n=1,739, 14.36%). In addition, public environmental and occupational health ranked second (n=1,356, 11.20%).

Top active countries

From 2000 to 2021, authors from a total of 146 different countries participated in the publication of studies on diseases in the elderly population (Figure 2A and 2B). The top ten most active countries produced more than eighty percent of the publications (Figure 2C); the United States (n=3,632, 30.00%) had the most publications, with more than one-third of all records published by authors in the United States. The United States also had the most citations (times=141,230). The next countries in order of frequency were China (n=1,328, citations=17,485), England (n=1,066, citations=55,322), Japan (n=730, citations=15,429), and Italy (n=724, citations=23,704). As shown in Figure 2A, we drew a network map of global research relationships among the leading countries actively researching diseases in the elderly population. This visualized map of associations included the countries that had at least 10 publications. The 71 included countries were classified into four clusters. The blue cluster included Asian countries (e.g., China, Japan, South Korea, etc.) and North American countries (e.g., USA, Canada, Brazil, etc.). The green cluster mainly consisted of European countries (e.g., France, Italy, Germany, etc.). Since the clusters were classified by active collaborations between countries, Figure 2A provides a clear visualization map of global collaborations. Figure 2B provides an overlay visualization map of countries according to the mean time of publication in years. As we can see in the picture, the United States and European countries had a relatively early average time of publication, indicating they had an early start in this area. Also, developing countries, such as China and South Korea, gradually joined in collaborations.

Institutions and funding agencies

The top 20 universities or institutions that made contributions to research on diseases in the elderly population are shown in Figure 3. The top 5 were as follows: the University of California system (n=427), the University of London (n=389), Harvard University (n=335), the National Institutes of Health USA (n=313) and INSERM (Institut national de la santé et de la recherche médicale) (n=292). However, the top five most-cited affiliated institutions were the following: the University of London (times=12,657), Harvard University (times=12,052), the University of Pittsburgh (times=10,076), the University of California at San Francisco (times=9,944) and the National Institute on Aging (NIA USA) (times=9,378). As shown in the global network map and the overlay visualization of institutions (Figure 3A and 3B), trends occurred in a pattern that was almost parallel to the trends in the countries. As shown in Supplementary table 3, US funding agencies were still the top 3 most active in the field, with the United States Department of Health and Human Services making the largest contribution (n=1,904, 15.73%). After them, the European Commission ranked 4^th. The National Natural Science Foundation of China (n=1,954) ranked 5^th. Two UK funding agencies were also in the top ten: UK Research Innovation (n=320) and the Medical Research Council (n=280).

Journals and top-cited publications

The top 10 journals with the most publications related to diseases in elderly populations are listed in Supplementary Table 1. The journal PLOS ONE had the most publications (n=322). The journal BMC GERIATRICS, which ranked 8^th, had the highest IF (impact factor) of the top ten journals (IF=27.474). Supplementary figure 1A and 1B shows the overlay visualization map of global research relationships among the most cited journals on diseases in the elderly population according to the average year of publication. Blue circles represent years before 2010, and red circles represent years after 2018. The Lancet had the most citations (citations=28,548). The Journal of the American Geriatrics Society (JAGS) (citations=9,298) ranked 2^nd. The top 10 most cited papers are summarized in Table 1(8, 9, 11, 14-20). Notably, the burden of disease, blood pressure, frailty and macular degeneration were hotspots. The top 10 most cited publications in different parts of the articles, including the background, supporting evidence, differences, and discussion sections, are also summarized in Supplementary Table 4.

Keywords and overlay visualization analysis

Keywords with a minimum number of occurrences greater than 30 in all included publications were analysed using VOSviewer software (Figure 4A and 5B). Of the 29,105 keywords in this area, 545 meaningful topics were identified and further classified into 5 different clusters (Figure 4A). The most common research topics included ‘risk factors’, ‘dementia’, ‘Alzheimer’s disease’, ‘cardiovascular disease’ and ‘hypertension’. The red cluster contained the nodes ‘cardiovascular disease’ and ‘metabolic syndrome’, representing the primary research topics in this cluster. In this cluster, the relationship between metabolic disorders and cardiovascular risk was emphasized. These components include BMI, diabetes, uric acid, CKD, cystatin C, etc. Also, according to the overlay visualization (Figure 4B), the keyword ‘carotid plaque’ was relatively new. The blue cluster contained the large nodes of ‘epidemiology’ and ‘mortality’. The primary research in this cluster was causes of death in the elderly population. Keywords such as ‘cancer’, ‘stroke’, ‘ischemic heart disease’ and ‘heart failure’ belonged in this cluster. The ‘NHANES’ study has been popular in recent years. The green cluster contained two large nodes, ‘Alzheimer’s disease’ and ‘dementia’, indicating that the primary research topic in this cluster was neuropathy. Keywords including ‘cognitive decline’, ‘memory’, ‘hippocampus’ and ‘neuroimaging’ were highlighted in this cluster. Additionally, ‘biological age’ and ‘cognitive ageing’ are relatively new. The light blue cluster included ‘physical activity’ and ‘quality of life’. Keywords such as ‘depression’, ‘activities of daily living’, ‘sleep quality’, ‘accidental falls’ and ‘oral health’ were highlighted, representing the attention given to the topic of how to improve the health and quality of life of the elderly population. Additionally, ‘diet quality’, ‘sleep quality’ and ‘multimorbidity’ have occurred more frequently in recent years. The purple cluster included the tag ‘COVID-19’. This cluster is small and relatively new (Figure 4B). With the start of the COVID-19 pandemic and the susceptibility of elderly individuals to this disease, ‘vaccine’ and ‘immunogenicity’ have rapidly gained substantial attention. Additionally, this study applies overlay visualization analysis to the keywords in publications from the 5 most recent years. The keywords ‘COVID-19’, ‘muscle mass’, ‘depression’ and ‘non-alcoholic fatty liver disease’ have also drawn substantial attention in recent years, indicating that these areas will be the centre of attention in future studies on the elderly population.

An analysis of the literature is one of the most efficient ways to understand the current state of a specific research area and the trends in its development (21). The global increase in the proportion of the elderly population, especially in developed and developing countries, has led to the growth of scientific literature in the areas of diseases and health in the elderly population(22, 23). An analysis of the literature in this area is needed to identify the current hotspots and new directions for future studies. In this study, we summarized 12,108 publications identified from the Web of Science database and provided an analysis of the literature using bibliometric and visualization methods for disease mapping in the elderly population. By using VOSviewer to analyse cocitations, in this study, we identified the most cited papers and the most active journals, countries and institutions; we also presented results on the collaboration between authors in various countries. Furthermore, we identified keywords used in this area of study and provided recommendations for future studies.

In total, 12,108 records were identified that were published in 2,467 journals from 11,766 institutions in 146 countries. As shown in the results, the number of publications has increased yearly. The United States had the largest number of publications, followed by China, England, Japan, Italy, Australia, other European countries (Sweden, Germany, the Netherlands, Spain and France), and Canada. As we can see in Fig. 2A, the associations between the United States and its collaborators are quite strong. In addition, there are associations between England and other European countries. The top 3 financial funding sources associated with the greatest number of publications were from the United States. Together, these findings reflect the leading contributions of the United States to this field. The ranking of the funding agencies in China, Europe and Japan was nearly consistent with the distributions by country and institution. The strong infrastructures and abundant support for scientific services in these countries led to greater research output; hence, the results were in accordance with expectations.

As a trend that is closely associated with ageing in almost every country in the world, disease and health in the elderly population have been very popular topics in journals. Of all the top-cited papers, most were published in the early years of our period of study (before 2012); as time passed, the number of citations that accrued on these earlier papers increased. However, a randomized controlled trial published in 2015 was in the top 10. That study, which was published in The Lancet, illustrated those interventions involving diet, exercise, cognitive training, and vascular risk monitoring had a positive effect on the prevention of cognitive decline in elderly people. Breakthroughs such as this have shifted the trends in research on the elderly population.

From among the 29,105 keywords in this area, 545 meaningful topics were identified. The results of the cocitation analysis showed that these topics could be further divided into 5 different clusters. The red cluster mainly involved cardiovascular disease and its risk factors, primarily metabolic disorders. The co-occurring increases in type 2 diabetes, hypertension, hyperlipidaemia and obesity all result in fatal cardiovascular events in the elderly population(24). As the results of overlay visualization analysis showed, studies on ‘carotid plaque’ were mostly published in the early years of the study period(25).

In the green cluster, the topics centred on neuropathy in the elderly population. There has been a lot of effort exerted to improve the cognitive condition of elderly individuals. Many studies have achieved substantial breakthroughs in Alzheimer’s disease (26–28). Additionally, the quality of life, especially one’s mood, has been shown to be associated with one’s cognitive condition. This explains the light blue cluster, which represents studies on improvements in the quality of life of the elderly population. In this cluster, physical activity, diet and sleep quality were highlighted as important factors. It has become clear that interventions promoting lifestyles have positive impacts on both healthy and unhealthy individuals in the elderly population.

The last cluster is the purple cluster. This cluster was entitled ‘COVID-19’. With the outbreak of COVID-19 and the greater susceptibility and high rate of mortality in the elderly population, the attention given to this area has rapidly increased. The safety of the vaccine in the elderly population with multimorbidity was analysed(29, 30). Finally, we also analysed the keywords in publications from the 5 most recent years. The keywords ‘COVID-19’, ‘muscle mass’, ‘depression’ and ‘non-alcoholic fatty liver disease’ have drawn substantial attention in recent years, indicating that these areas could be the centre of attention in future studies on the elderly population.

Limitations

First, this study only searched the WoSCC database, and only publications in English were included, which might have introduced some bias into the results. However, the study included 12,108 publications, and we believe that the number is sufficiently large to provide an overview of the topic. Second, to exclude many irrelevant publications, our strategy was to limit the search to subject terms and not include the entire text. Despite these limitations, we believe that the results of this study provide a credible picture of the landscape of research on diseases in the elderly population at a global level.

This study showed that there has been substantial attention given to the field of diseases in the elderly population and that this trend will continue in the future. This study provides an unbiased visualization analysis of this topic in a scale-efficient manner that can be applied to further research. To date, the United States has made the most significant contributions to this field. We believe that in the future, popular research topics might be the improvement of the quality of life and cognitive function.

Ethics approval and consent to participate

Since the data from this study were obtained from a public database, ethics approval from an institutional review board or ethics committee was not needed.

Consent for publication

Not applicable.

Data Availability Statement

The original results presented in the study are included in the article. Further inquiries regarding the data can be directed to the corresponding author.

Competing interests

The authors declare that they have no competing interests.

Funding

This research was supported by the National Key R&D Program of China provided by the Ministry of Science and Technology of the People’s Republic of China (2019YFC0840701) and the CAMS Innovation Fund for Medical Sciences (2019-I2M-5-027).

Authors’ contributions

MZ and LZ designed the study, collected the data and analysed the data. MZ made major contributions to the literature search, and LZ made major contributions to drafting the manuscript. All authors read and approved the final manuscript.

Acknowledgements

Not applicable.

Christensen K, Doblhammer G, Rau R, Vaupel. JW 2009 Ageing populations: the challenges ahead. Lancet (London, England) 374:1196–1208.
United Nations DoEaSA, Population Division. (2013). 2013 World Population Ageing. ST/ESA/SERA/348.
Kontis V, Bennett JE, Mathers CD, et al. 2017 Future life expectancy in 35 industrialised countries: projections with a Bayesian model ensemble. Lancet (London, England) 389:1323–1335.
Meyer AC, Drefahl S, Ahlbom A, Lambe M, Modig K. 2020 Trends in life expectancy: did the gap between the healthy and the ill widen or close? BMC medicine 18:41.
2020 Global burden of 369 diseases and injuries in 204 countries and territories, 1990–2019: a systematic analysis for the Global Burden of Disease Study 2019. Lancet (London, England) 396:1204–1222.
Chatterji S, Byles J, Cutler D, Seeman T, Verdes E. 2015 Health, functioning, and disability in older adults–present status and future implications. Lancet (London, England) 385:563–575.
Meinow B, Li P, Jasilionis D, et al. 2022 Trends over two decades in life expectancy with complex health problems among older Swedes: implications for the provision of integrated health care and social care. BMC public health 22:759.
Lozano R, Naghavi M, Foreman K, et al. 2012 Global and regional mortality from 235 causes of death for 20 age groups in 1990 and 2010: a systematic analysis for the Global Burden of Disease Study 2010. Lancet (London, England) 380:2095–2128.
Lewington S, Clarke R, Qizilbash N, Peto R, Collins R. 2002 Age-specific relevance of usual blood pressure to vascular mortality: a meta-analysis of individual data for one million adults in 61 prospective studies. Lancet (London, England) 360:1903–1913.
Pilotto A, Custodero C, Maggi S, et al. 2020 A multidimensional approach to frailty in older people. Ageing research reviews 60:101047.
Williams CD, Stengel J, Asike MI, et al. 2011 Prevalence of nonalcoholic fatty liver disease and nonalcoholic steatohepatitis among a largely middle-aged population utilizing ultrasound and liver biopsy: a prospective study. Gastroenterology 140:124–131.
Lawes CM, Vander Hoorn S, Rodgers A. 2008 Global burden of blood-pressure-related disease, 2001. Lancet (London, England) 371:1513–1518.
Spinewine A, Schmader KE, Barber N, et al. 2007 Appropriate prescribing in elderly people: how well can it be measured and optimised? Lancet (London, England) 370:173–184.
Good CD, Johnsrude IS, Ashburner J, et al. 2001 A voxel-based morphometric study of ageing in 465 normal adult human brains. NeuroImage 14:21–36.
Clegg A, Young J, Iliffe S, Rikkert MO. Rockwood K 2013 Frailty in elderly people. Lancet (London, England) 381:752–762.
Martin DF, Maguire MG, Ying GS, et al. 2011 Ranibizumab and bevacizumab for neovascular age-related macular degeneration. The New England journal of medicine 364:1897–1908.
Ngandu T, Lehtisalo J, Solomon A, et al. 2015 A 2 year multidomain intervention of diet, exercise, cognitive training, and vascular risk monitoring versus control to prevent cognitive decline in at-risk elderly people (FINGER): a randomised controlled trial. Lancet (London, England) 385:2255–2263.
Cawthon RM, Smith KR, O'Brien E, Sivatchenko A, Kerber. RA 2003 Association between telomere length in blood and mortality in people aged 60 years or older. Lancet (London, England) 361:393–395.
Steffen TM, Hacker TA, Mollinger L. 2002 Age- and gender-related test performance in community-dwelling elderly people: Six-Minute Walk Test, Berg Balance Scale, Timed Up & Go Test, and gait speeds. Physical therapy 82:128–137.
Falsey AR, Hennessey PA, Formica MA, Cox C, Walsh EE. 2005 Respiratory syncytial virus infection in elderly and high-risk adults. The New England journal of medicine 352:1749–1759.
Agarwal A, Durairajanayagam D, Tatagari S, et al. 2016 Bibliometrics: tracking research impact by selecting the appropriate metrics. Asian journal of andrology 18:296–309.
Beard JR, Officer A, de Carvalho IA, et al. 2016 The World report on ageing and health: a policy framework for healthy ageing. Lancet (London, England) 387:2145–2154.
Prince MJ, Wu F, Guo Y, et al. 2015 The burden of disease in older people and implications for health policy and practice. Lancet (London, England) 385:549–562.
Incalza MA, D'Oria R, Natalicchio A, et al. 2018 Oxidative stress and reactive oxygen species in endothelial dysfunction associated with cardiovascular and metabolic diseases. Vascular pharmacology 100:1–19.
Bos D, Arshi B, van den Bouwhuijsen QJA, et al. 2021 Atherosclerotic Carotid Plaque Composition and Incident Stroke and Coronary Events. Journal of the American College of Cardiology 77:1426–1435.
Lane CA, Hardy J, Schott JM. 2018 Alzheimer's disease. European journal of neurology 25:59–70.
Hodson R 2018 Alzheimer's disease. Nature 559:S1.
Mangialasche F, Solomon A, Winblad B, Mecocci P, Kivipelto M. 2010 Alzheimer's disease: clinical trials and drug development. The Lancet Neurology 9:702–716.
Chen Y, Klein SL, Garibaldi BT, et al. 2021 Aging in COVID-19: Vulnerability, immunity and intervention. Ageing research reviews 65:101205.
Soiza RL, Scicluna C, Thomson EC. 2021 Efficacy and safety of COVID-19 vaccines in older people. Age and ageing 50:279–283.

Table 1

List of the top 10 publications from the period from 2000 to 2021 with the most citations of diseases in the elderly population
Ranking	Authors	Article Title	Source Title	Document Type	Times Cited	Publication Year	DOI
1st	Lozano, R et al.	Global and regional mortality from 235 causes of death for 20 age groups in 1990 and 2010: a systematic analysis for the Global Burden of Disease Study 2010	LANCET	Article	7814	2012	10.1016/S0140-6736(12)61728-0
2nd	Lewington, S et al.	Age-specific relevance of usual blood pressure to vascular mortality: a meta-analysis of individual data for one million adults in 61 prospective studies	LANCET	Article	6854	2002	10.1016/s0140-6736(02)11911-8
3rd	Good, CD et al.	A voxel-based morphometric study of ageing in 465 normal adult human brains	NEUROIMAGE	Article	3553	2001	10.1006/nimg.2001.0786
4th	Clegg, A et al.	Frailty in elderly people	LANCET	Article	3020	2013	10.1016/S0140-6736(12)62167-9
5th	Martin, DF et al.	Ranibizumab and Bevacizumab for Neovascular Age-Related Macular Degeneration: The CATT Research Group	NEJM	Article	1926	2011	10.1056/NEJMoa1102673
6th	Williams, CD et al.	Prevalence of Nonalcoholic Fatty Liver Disease and Nonalcoholic Steatohepatitis Among a Largely Middle-Aged Population Utilizing Ultrasound and Liver Biopsy: A Prospective Study	GASTROENTEROLOGY	Article	1445	2011	10.1053/j.gastro.2010.09.038
7th	Ngandu, T et al.	A 2 year multidomain intervention of diet, exercise, cognitive training, and vascular risk monitoring versus control to prevent cognitive decline in at-risk elderly people (FINGER): a randomized controlled trial	LANCET	Article	1393	2015	10.1016/S0140-6736(15)60461-5
8th	Cawthon, RM et al.	Association between telomere length in blood and mortality in people aged 60 years or older	LANCET	Article	1261	2003	10.1016/S0140-6736(03)12384-7
9th	Steffen, TM et al.	Age- and gender-related test performance in community-dwelling elderly people: Six-Minute Walk Test, Berg Balance Scale, Timed Up & Go Test, and gait speeds	PHYSICAL THERAPY	Article	1232	2002	10.1093/ptj/82.2.128
10th	Falsey,AR et al.	Respiratory syncytial virus infection in elderly and high-risk adults	NEJM	Article	1225	2005	10.1056/NEJMoa043951

Supplementaryfiguresandtables.docx

Global research trends on diseases in the elderly population: a visualization analysis

Status:

Version 1

Abstract

Background

Objective

Methods

Results

Conclusions

Figures

Introduction

Materials And Methods

Data sources and search strategies

Bibliometric And Visual Analyses

Results

Discussion

Conclusion

Declarations

References

Tables

Supplementary Files

Status:

Version 1