---
title: "Estimated Size and Distribution of College MSM in Hainan Using the Blued App"
id: "plos-one-11-exploration-of-the-population-size-of-men-who-have-sex-with-men-in-hainan"
canonical_url: "https://medichelpline.com/clinical-feed/plos-one-11-exploration-of-the-population-size-of-men-who-have-sex-with-men-in-hainan"
content_type: "clinical_feed_article"
specialty: "Infectious Disease"
source_name: "PLOS ONE (Medicine)"
source_url: "https://journals.plos.org/plosone/article?id=10.1371/journal.pone.0358788"
published_at: "2026-09-21T14:00:00.000Z"
evidence_level: "Journal Feed"
license: "CC-BY-NC-4.0 / Informational Use"
---
# Estimated Size and Distribution of College MSM in Hainan Using the Blued App
## Provenance & Clinical Metadata
- **Canonical URL:** https://medichelpline.com/clinical-feed/plos-one-11-exploration-of-the-population-size-of-men-who-have-sex-with-men-in-hainan
- **Specialty:** [Infectious Disease](https://medichelpline.com/clinical-feed/infectious-disease.md)
- **Primary Source:** PLOS ONE (Medicine)
- **Source URL:** [Original Journal Publication](https://journals.plos.org/plosone/article?id=10.1371/journal.pone.0358788)
- **Published At:** 2026-09-21T14:00:00.000Z
- **Evidence Rating:** Journal Feed
## Executive GIST (TL;DR)
- The study estimated the number and spatial distribution of **MSM** (men who have sex with men) among college students across Hainan Province using data from the geosocial networking app **Blued** and a questionnaire-derived multiplier. - Blued user data were collected from May 9–18, 2023, within geofenced campus radii; anonymized public data (nickname, age, height, weight, gender role, online status) were recorded and de-duplicated. - A supporting questionnaire (April 6–10, 2025) showed 89.28% of student MSM reported being registered on Blued and 76.00% used it to seek sexual partners. - From 3,128 valid Blued annotations (after excluding 341 anomalies) the average number of college students online was 939 and total registered users was 1,579. Using a multiplier method with the app-use proportion, the estimated MSM population in Hainan colleges was 3,504 (95% CI: 3,464–3,544). - Active users (online ≥5 days during the 10-day period) comprised 33.13% (860/2,596) of observed users; sensitivity analyses with 4- and 6-day thresholds showed similar patterns. - Multivariate logistic regression found higher odds of active use among younger students (18–19 and 20–21 vs 22–24) and those in undergraduate institutions versus junior colleges; college type (normal and sports colleges) also differed relative to comprehensive universities. - Geographically, students using Blued were concentrated in Haikou (72.22% of observed users) and Sanya (20.75%); Danzhou and Wenchang showed high proportions of active users despite small registrant counts. - The authors recommend focusing sexual health education and STD surveillance on specific colleges and regional hotspots identified. - Ethical approval was obtained from Hainan Medical University; data used were anonymized and aggregated, and no personally identifiable information was collected. - Funding sources and lack of competing interests were reported. Details not reported in the source: full questionnaire instrument, complete regression coefficient table beyond reported aORs, and extended discussion text truncated in the source.
## Clinical Analysis & Structured Key Points
Exploration of the population size of men who have sex with men in Hainan colleges: A cross-sectional study based on geographical social network App | PLOS One Browse Subject Areas ? Click through the PLOS taxonomy to find articles in your field. For more information about PLOS Subject Areas, click here . Article Authors Metrics Comments Media Coverage Reader Comments Figures Figures Abstract Men who have sex with men (MSM) have historically been a high-risk group for sexually transmitted diseases. In Hainan, the incidence of HIV and syphilis among MSM has increased rapidly. Additionally, there is a growing number of young students being diagnosed with HIV, with MSM identified as the primary demographic affected. However, the size and distribution of the MSM population within colleges and universities in Hainan Province remains unknown. In this study, the Blued App was employed to collect data on users within Hainan colleges and universities from May 9 to May 18, 2023. Using the users information and questionnaire survey data, we applied the multiplier method to estimate the population size of student MSM. Multivariate and geographic density analyses integrating survey data were conducted to identify regional disparities. A questionnaire survey revealed that 89.28% of student MSM reported using the Blued App, and 76.00% of the individuals utilized it for seeking sexual partners. The estimated population size of MSM in colleges across Hainan Province was 3504 (95%CI: 3464–3544), with Haikou and Sanya identified as hotspots. The proportion of active users was 33.13% (860/2596). Notably, Danzhou and Wenchang, relatively small urban areas with limited Blued registrants, exhibited high proportion of active users (42.22% and 41.30%). These findings suggest that particular attention should be directed towards sexual health education, and sexually transmitted disease surveillance in specific colleges. Citation: Chen S, Chen X, Feng R, Chen G, Lu C, Zhao D, et al. (2026) Exploration of the population size of men who have sex with men in Hainan colleges: A cross-sectional study based on geographical social network App. PLoS One 21(9): e0358788. https://doi.org/10.1371/journal.pone.0358788 Editor: Hamid Sharifi, Kerman University of Medical Sciences, IRAN, ISLAMIC REPUBLIC OF Received: January 25, 2026; Accepted: September 5, 2026; Published: September 21, 2026 Copyright: © 2026 Chen et al. This is an open access article distributed under the terms of the Creative Commons Attribution License , which permits unrestricted use, distribution, and reproduction in any medium, provided the original author and source are credited. Data Availability: All relevant data are within the paper and its Supporting Information files. Funding: This work was supported by the Natural Science Foundation of Hainan Province, China (824RC519) awarded to D.Y.; the Joint Program on Health Science and Technology Innovation of Hainan Province (WSJK2024MS155) awarded to D.Z.; the Student Innovation and Entrepreneurship Project of Hainan Medical University (X202411810111) awarded to S.C.; and the Undergraduate Innovation and Entrepreneurship Project of Hainan Province (S202511810032) awarded to R.F. The funders had no role in study design, data collection and analysis, decision to publish, or preparation of the manuscript. Competing interests: The authors have declared that no competing interests exist. Introduction The role of men who have sex with men (MSM) in the sexually transmitted diseases (STD) epidemic is considerable. In China, the national prevalence of HIV among MSM from 2001 to 2018 was estimated to be 5.7% [ 1 ]. The prevalence of HIV among student MSM was 4.4% [ 2 ]. Additionally, a meta-analysis reported that the HIV prevalence among MSM in high schools and colleges across China was also 3.8% [ 3 ]. Moreover, the prevalence of HIV among MSM who had heterosexual sex was significantly higher, at 9% [ 4 ]. In the United States, MSM comprised 53% and 67% of new HIV cases in 2006 and 2014, respectively [ 5 , 6 ]. Globally, MSM are experiencing an escalating risk of HIV infection, with the number of cases rising [ 7 , 8 ]. Furthermore, the death rate among MSM is much higher (8%) [ 9 ]. The HIV epidemic among Chinese college students has worsened due to technological advancements [ 10 , 11 ]. The utilization of online platforms and social media may elevate the risk of STD by facilitating the search for sexual partners [ 12 ]. In Germany, MSM represented 45.6% of users on online dating and social networking platforms [ 13 ]. In the USA, Rosenbaum et al. demonstrated that mobile social apps can facilitate the spread of syphilis and gonorrhea [ 14 ]. In South China, Guo reported that 63.8% of MSM utilized social software to seek sexual partners, emphasizing the geosocial app's significance in MSM communities [ 15 ]. Song's study showed that 53.7% of MSM reported having used gay apps to find sexual partners [ 11 ]. Hong et al. reported an HIV prevalence of 7.9% among gay app users and demonstrated that HIV infection was significantly associated with app use [ 16 ]. A behavior associated with higher-risk sexual practices and potential HIV infections, attributed to the rapid growth of internet technology [ 17 ]. The Blued, a prominent MSM mobile geosocial network App in China [ 18 ], plays a significant role in promoting healthy relationships among gay individuals and in advancing HIV prevention strategies, including the implementation of “Internet + HIV” models [ 19 ]. Internet and mobile apps revolutionize MSM dating, introducing discreet platforms [ 20 , 21 ]. Notably, Blued is widely used in the medical research, driving the optimized development of medical research and public health strategies [ 22 , 23 ]. According to a survey results, 98.2% of MSM in China have used gay apps at some point in their lives, with Blued being the most popular (97.5% usage rate). This is far higher than the usage of other platforms like Finka (18.4%), making Blued about 5.3 times more prevalent than other single platforms [ 24 ]. However, the lack of comprehensive MSM data in China presents significant challenges to the development and implementation of effective STD prevention strategies. The utilization of big data derived from social media platforms may offer a solution to this challenge, as technological advancements transform the socialization and partner-seeking behaviors of MSM. Hainan Province, located in the southernmost region of China, is a key tourism and population hub near Southeast Asia. Between 2011 and 2019, young students in Hainan Province accounted for 5.99% of the annual HIV/AIDS cases. Notably, 91.38% of HIV-positive male students in higher education institutions acquired HIV through homosexual contact [ 25 ]. This trend indicated a potential uncontrolled transmission of HIV among college MSM students in Hainan. Accurately estimating MSM population within colleges is essential for calculating STD incidence in this group. However, the scarcity of comprehensive studies on college MSM in Hainan Province limits understanding and addressing the STD prevalence. To tackle this, we assessed the risks by estimating MSM population, distribution, and behaviors through Blued App to improve disease control. Methods Study colleges and universities In Hainan Province, a total of 21 colleges and universities with 25 campuses, are enrolling students in 2023. These higher education institutions include 8 undergraduate colleges and 13 junior colleges, with disciplines spanning financial colleges (five), science and engineering colleges (four), comprehensive universities (four), medicine colleges (three), normal colleges (two), language and literature colleges (one), political science and law colleges (one), and sports colleges (one). The geographical distribution of the 25 campuses is as follows: 15 are located in Haikou City, six in Sanya City, and one each in Danzhou, Wuzhishan, Qionghai, and Wenchang City. The geographical characteristics and MSM population density analysis We performed a comprehensive analysis of the geographical characteristics associated with the estimated population data of MSM across all colleges in Hainan Province. Initially, the total number of college users of the Blued App within the same City was calculated. The MSM population density across colleges in various regions of Hainan Province was determined by dividing the total MSM population by the number of male students enrolled in all colleges within the region. The MSM population density in colleges across different cities in Hainan Province was accurately mapped using ArcMap 10.8.1 to identify geographical hotspots. Exploratory analysis Multiplier method is perhaps the most common because of its simplicity and ease of use [ 26 , 27 ]. The basic principle of this method is that the count of individuals from the target population observed at designated institutions within a defined time period is equal to the total size of the estimated population multiplied by the proportion of the population who attended the selected institutions. The multiplier formulas to estimate the size of MSM are following (1,2), where N is the estimated size of student MSM, r is the number of recorded individuals; m is the multiplier, p is the proportion of recorded individuals among observed population. CI represents the confidence interval of population size. (1) (2) In this study, r represents the number of MSM registered on Blued, and p is the proportion of student MSM who use the Blued App, as obtained from the questionnaire survey. Since the total number of MSM among college students is unknown, we consider that and N are approximately equal n in this study, and thus N is used as a substitute for n to calculate the CI . The average number of registered on these dates was used as the observed individuals, and the Multiplier method was employed to estimate MSM. Data collection and management This study employed Blued App to examine MSM students across all colleges and universities in Hainan Province. Data collection from the Blued App was conducted in accordance with Blued’s Terms of Service and Privacy Policy. In 2023, we collected data on Blued online users across colleges and universities in Hainan over ten consecutive days from May 9 to May 18 between 10:30–11:30 every night. Briefly, the Blued App was employed to locate the central location of the target campus and identify the radius according to the size of the campus (ranging from 0.20 to 0.90 km). Then, information on each user, encompassing nickname, age, height, weight, gender role, and online status was recorded. Users registered on the Blued platform via mobile phone verification and were identified by self-selected pseudonyms. This study utilized fully anonymized and aggregated data sourced exclusively from the platform's public domain. No personally identifiable information (PII) was collected or accessed. Furthermore, all datasets underwent a rigorous de-identification process prior to analysis to ensure individual privacy was maintained. At the same time, we also gathered pertinent data regarding student numbers from the Hainan Statistical Yearbook 2022. Initially, data were gathered from individual colleges and subsequently integrated into a comprehensive dataset. This dataset was then meticulously examined for potential errors or discrepancies. For quality control, data from 3128 MSM aged 18–24 were analyzed, excluding 341 individuals due to anomalies like prolonged inactivity, age discrepancies, being outside the capture range, and inaccurate personal information, to ensure the efficient processing of the survey data. To gain a deeper understanding of Blued App usage within the MSM population, a pertinent questionnaire survey was carried out from April 6th to 10th, 2025, and obtained written informed consent to assess the reliability of utilizing Blued App in this study. The definition of the relevant indicators In this study, the following definitions were adopted for the key terms used in the study. Registered user: A unique Blued account observed within the campus geofence at any time during the 10 day study period, after removing duplicate accounts, used for estimating the total MSM population among college students in Hainan. Active user: A registered users who were online for five or more days were defined as active users. Online activity: The total number of male students enrolled in colleges in the same city of Hainan is summed, and the number of active users in this city is then divided by this total, and the ratio obtained indicates the online activity within the city. Sensitivity analyses using thresholds of four and six days yielded similar patterns, supporting the robustness of this definition. Online user: A registered user whose status was online at the time of data collection. Offline user: A registered user whose status was offline at the time of data collection but still appeared in the user list within the geofence. Secret user: A registered user with ‘private’ mode enabled on Blued, making them invisible for matching. Only 37 such users were identified (2.34% of registered users), so their impact on the results is minimal. BMI: Body Mass Index. Statistical analysis The dependent variable is a binary indicator of online activity status, where a value of 1 denotes online activity lasting five days or more, and a value of 0 signifies online activity lasting less than five days. The independent variables include age, BMI, college level, college location, college classification, and university campus. Multivariate binary logistic regression was used to examine factors associated with active user status. Adjusted odds ratios (aOR) with 95%CI are reported. All tests were two-sided with α = 0.05, using SPSS 27.0. Ethical approval and informed consent This study was conducted in accordance with the ethical principles of the Declaration of Helsinki and received approval from the Ethical Committee of Hainan Medical University, Hainan, China (HYLL-2024–838). This study utilized completely anonymous aggregated data, without involving any specific personal privacy information. Moreover, all the data were strictly safeguarded. Results The usage of Blued App in the Hainan MSM population In this study, we conducted a questionnaire survey involving 181 MSM residing in Hainan regarding the usage of the Blued App. Of the 181 participants, 164 individuals had utilized the Blued App (90.61%), with college students comprising 15.47% (28/181). Among the 28 student MSM, 25 (89.28%) students reported engaging with the Blued App. Of those who have utilized the app, 76.00% (19/25) have been doing so for a duration exceeding two years. Additionally, our research reveals that 76.00% (19/25) of these student MSM primarily use Blued for seeking sexual partners, while 56.00% (14/25) utilize it for social interaction ( Table 1 ). Download: PNG larger image TIFF original image Table 1. A survey on the usage of social media in student MSM. https://doi.org/10.1371/journal.pone.0358788.t001 The number and behavior dynamics of college Blued users in Hainan Province The data was collected from May 9th to 18th, 2023, over a period of ten consecutive days. The total number of online annotations was 3362. And 234 were eliminated for duplicate annotations and abnormal data, leaving 3128 as valid data. During the 10 day survey period, 2596 users had used the Blued App, and the average number of college students online on the Blued App was 939, while the total number of registered users was 1,579. Among these registered users, 2.34% (37/1,579) were identified as secret users ( Table 2 ). According to the survey among MSM students, 89.28% reported being registered Blued ( Table 1 ) . Thus, the estimated MSM size in colleges across Hainan Province was 3504 (95%CI: 3464–3544). Download: PNG larger image TIFF original image Table 2. The number of MSM using the Blued App in colleges on Hainan Island, China (n). https://doi.org/10.1371/journal.pone.0358788.t002 The influencing factors of online activity of the MSM population at Hainan colleges and universities We found that the proportion of active users was 33.13% (860/2596), and the proportion has statistically significant associations ( P < 0.05) between age, college level, city, and various colleges, indicating their pivotal roles in shaping the online activity patterns of MSM in Hainan colleges. N represents the proportion of users who engaged with the Blued software online for at least five days within the total caseload. Notably, Danzhou and Wenchang, relatively small urban areas with limited Blued registrants, exhibited a high proportion of active users (42.22% and 41.30%). The multivariate logistic regression analysis identified that users aged 18−19 years (aOR = 1.49, 95%CI: 0.20–1.84) and 20−21 years (aOR=1.52, 95%CI: 1.26–1.85) exhibited a higher likelihood of being active users than individuals aged 22−24 years. Additionally, the proportion of active users among MSM from undergraduate colleges was 1.90 times (95%CI: 1.38–2.61) greater than that among those from junior colleges. In terms of the colleges’ category, the normal colleges (aOR = 0.55, 95%CI: 0.36−0.84) and the sports colleges (aOR = 0.27, 95%CI: 0.10−0.72) had a higher proportion of active users than comprehensive universities. ( Table 3 ) Download: PNG larger image TIFF original image Table 3. The determinants on the Blued App usage days of the student MSM in Hainan colleges, China. (n = 2596). https://doi.org/10.1371/journal.pone.0358788.t003 Geographical distribution of MSM population in colleges and universities in Hainan Province The results showed that the MSM population in colleges and universities in Hainan Province was mainly concentrated in Haikou, accounting for 72.22% (2259/3128), while Sanya ranked second with 20.75% (649/3128). The distribution of other cities was relatively scattered, with no notable patterns of aggregation established ( Fig 1 ). We also found that the highest online activity was in Wenchang at 1.21% (19/1600), followed by Sanya at 0.82% (208/25169), and Haikou at 0.74% (663/89827) ( Fig 2 ). Download: PNG larger image TIFF original image Fig 1. The geographical distributions of student MSM in Hainan Province. The blue dots in Fig 1 represent the estimated geographic densities of MSM populations in colleges across different regions of Hainan. The denser he blue dots are, the higher the concentration of MSM populations in that region, while areas with fewer dots indicate lower concentrations. Map source: National Standard Map Service Website of the Ministry of Natural Resources of the People's Republic of China ( http://bzdt.ch.mnr.gov.cn/ ), Approval No. GS (2024) 0650. https://doi.org/10.1371/journal.pone.0358788.g001 Download: PNG larger image TIFF original image Fig 2. The distribution of active users in cities and counties of colleges across Hainan Province. https://doi.org/10.1371/journal.pone.0358788.g002 Discussion The MSM population exhibits a higher risk for STD than the general population, including HIV, syphilis, hepatitis B virus, and other infections. Student MSM has also become a high-risk population for STD in China [ 2 ]. Understanding the size and distribution of the MSM population is crucial for effectively preventing AIDS and achieving the UNAIDS 95-95-95 targets by 2030 [ 28 ]. The significance of this study lies in providing data to support more effective prevention and control of the spread of STD among MSM by accurately estimating the size and distribution of the MSM population among male college students in Hainan. We utilized the multiplier method in conjunction with the Blued weekend usage rate, as determined by a questionnaire survey, to estimate the size of the college student MSM across Hainan Province. The decision to focus on weekend usage rates was made because the extended du
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