Estimating the regional distribution of men who have sex with men (MSM) based on Internet surveys

Abstract

BackgroundMeasurement of prevalence and incidence of infections in a hard to reach population like men who have sex with men (MSM) is hampered by its unknown size and regional distribution. Population-based surveys have recently been used to estimate the total number of MSM, but these surveys are usually not large enough to measure regional differences in the proportion of MSM in the population. We explored the use of the proportional regional distribution of participants of large internet-based surveys among MSM from Germany to estimate the regional distribution of MSM in Germany.MethodsWe compared participants from two separate MSM behavioural surveys with each other and with the distribution of user profiles of the largest contact and dating website for gay and other MSM in Germany in terms of the representativeness of the regional distribution. In addition, we compared the regional distribution of reportedly HIV positive survey participants with the regional distribution of HIV notifications within the national surveillance system that can be attributed to transmission through homosexual contacts.ResultsRegional distribution of survey participants was almost identical in both surveys, despite little overlap between survey participants. Slight discrepancies between surveys and user profiles could be observed. Proportional regional distribution of survey participants with HIV diagnosis resembled national surveillance data.ConclusionConsidering the difficulties to obtain representative data by other sampling methods for "hidden" populations like MSM, internet-based surveys may provide an easy and low cost tool to estimate the regional population distribution – at least in Western post-industrialized countries. Some uncertainties remain about the exact place of residence of MSM in larger cities or catchment areas of these cities. Slightly different results from different datasets may be due to unequal popularity of MSM websites in different regions. The total population size of the MSM population can be estimated based on e.g. data from representative national population surveys. Both estimates can then be combined to calculate the absolute size of regional MSM populations.

Epidemiology of Sexual Health in the Virtual Environment: A Multinational Online Survey of Spanish- and Portuguese-Speaking Men who use an Internet Sexual Networking Site

“…Given the complexity of self-identification of MSM in Latin America and the widespread use of Internet-based sexual networking websites among men seeking male partners, online surveys that aim to assess sexual health may reach an important, and often hidden, population [19,20]. Internet surveys examining the sexual health of MSM are increasingly common: from 2009 to 2010, three large surveys assessed the sexual health of MSM across the United States, Europe, and Asia [9,22,23].…”

“…However, as Internet access has increased dramatically throughout the world, social and sexual networking websites have become increasingly popular tools for men to meet other male partners [20], with an estimated 2.5-6.2 million MSM using virtual tools for establishing sexual connections [21]. Given this widespread use, samples of MSM recruited through the Internet may in fact be representative of MSM in countries with significant Internet access [19]. This presents a valuable opportunity to conduct assessments related to sexual health for users of these websites, in addition to more traditional venue-based approaches.…”

“…Other studies have found that anywhere from 1 to 20 % of men surveyed reported having sex with another man in the past year in Latin America and the Caribbean [13,17,18]. Given the complexity of MSM identities in Latin America, surveys that aim to reach MSM in physical venues where MSM go to find sexual partners may exclude certain subsets of the MSM population [19]. However, as Internet access has increased dramatically throughout the world, social and sexual networking websites have become increasingly popular tools for men to meet other male partners [20], with an estimated 2.5-6.2 million MSM using virtual tools for establishing sexual connections [21].…”

Evaluation of a temporary vaccination recommendation in response to an outbreak of invasive meningococcal serogroup C disease in men who have sex with men in Berlin, 2013–2014

“…It has been estimated that 80,000 MSM (95%CI 74,000-104,000) aged 20-59 years live in Berlin [21][22]. Among these, an estimated 10,800 MSM had been diagnosed with HIV as of the end of 2013 [22].…”

A cluster of invasive meningococcal disease in young men who have sex with men in Berlin, October 2012 to May 2013

“…From October 2012 until the end of June 2013, the incidence of MenC IMD among the MSM community in Berlin was 6.3/100,000 based on five reported cases and an estimated number of 80,000 MSM in the community [9]. This is below the threshold of an epidemic situation (defined in Germany as ≥10 cases/100,000 in a given region within three months), but almost 10-fold higher than expected for young male adults in this age group for the entire year (0.65/100,000 with inclusion of all serogroups).…”