Journal of Urban Health

Employing data from two Chicago-based household probability samples of men who have sex with men (MSM) implemented 5 years apart (the “UMHS 1997” and the “2002 MSM supplement” studies), we evaluated changes in risk behavior as well as the potential viability of two alternative perspectives for explaining these changes—risk management and safe-sex norm abandonment. We found significantly increased rates of unprotected insertive and receptive anal intercourse in the 2002 study. Sixty-eight percent of UMHS men reported having sex with partners having HIV positive or unknown status, compared with 38% of the MSM supplement men (p < .0001). Serosorting mediated and moderated the most extreme forms of risk behavior. Positive statistical associations between drug use and unprotected sex were stronger in the UMHS sample than in the MSM supplement. Findings suggesting that “risk management” strategies have shaped MSM behavior as it emerged in the early part of this decade have considerable implications for HIV prevention strategies.

Community pharmacies serve as key locations for public health services including interventions to enhance the availability of syringes sold over-the-counter (OTC), an important strategy to prevent injection-mediated HIV transmission. Little is known about the community characteristics associated with the availability of pharmacies and pharmacies that sell syringes OTC. We conducted multivariable regression analyses to determine whether the sociodemographic characteristics of census tract residents were associated with pharmacy presence in Los Angeles (LA) County during 2008. Using a geographic information system, we conducted hot-spot analyses to identify clusters of pharmacies, OTC syringe-selling pharmacies, sociodemographic variables, and their relationships. For LA County census tracts (N = 2,054), population size (adjusted odds ratio [AOR], 1.22; 95 % confidence interval [CI], 1.16, 1.28), median age of residents (AOR, 1.03; 95 % CI, 1.01, 1.05), and the percent of households receiving public assistance (AOR, 0.97; 95 % CI, 0.94, 0.99) were independently associated with the presence of all pharmacies. Only 12 % of census tracts had at least one OTC syringe-selling pharmacy and sociodemographic variables were not independently associated with the presence of OTC syringe-selling pharmacies. Clusters of pharmacies (p < 0.01) were located proximally to clusters of older populations and were distant from clusters of poorer populations. Our combined statistical and spatial analyses provided an innovative approach to assess the sociodemographic and geographic factors associated with the presence of community pharmacies and pharmacies that participate in OTC syringe sales.

Residential transience may contribute to adverse mental health. However, to date, this relationship has not been well-investigated among urban, impoverished populations. In a sample of drug users and their social network members (n = 1,024), we assessed the relationship between transience (frequently moving in the past 6 months) and depressive symptoms, measured by the CES-D, among men and women. Even after adjusting for homelessness, high levels of depressive symptoms were 2.29 [95%CI = 1.29–4.07] times more likely among transient men compared to nontransient men and 3.30 [95% CI = 1.10–9.90] times more common among transient women compared to nontransient women. Stable housing and mental health services need to be available, easily accessible, and designed so that they remain amenable to utilization under transient circumstances.

This study aims to estimate the number of men who have sex with men (MSM) in Ho Chi Minh City (HCMC) and Nghe An province, Viet Nam, using a novel method of population size estimation, and to assess the feasibility of the method in implementation. An innovative approach to population size estimation grounded on the principles of the multiplier method, and using social app technology and internet-based surveys was undertaken among MSM in two regions of Viet Nam in 2015. Enumeration of active users of popular social apps for MSM in Viet Nam was conducted over 4 weeks. Subsequently, an independent online survey was done using respondent driven sampling. We also conducted interviews with key informants in Nghe An and HCMC on their experience and perceptions of this method and other methods of size estimation. The population of MSM in Nghe An province was estimated to be 1765 [90% CI 1251–3150]. The population of MSM in HCMC was estimated to be 37,238 [90% CI 24,146–81,422]. These estimates correspond to 0.17% of the adult male population in Nghe An province [90% CI 0.12–0.30], and 1.35% of the adult male population in HCMC [90% CI 0.87–2.95]. Our size estimates of the MSM population (1.35% [90% CI 0.87%–2.95%] of the adult male population in HCMC) fall within current standard practice of estimating 1–3% of adult male population in big cities. Our size estimates of the MSM population (0.17% [90% CI 0.12–0.30] of the adult male population in Nghe An province) are lower than the current standard practice of estimating 0.5–1.5% of adult male population in rural provinces. These estimates can provide valuable information for sub-national level HIV prevention program planning and evaluation. Furthermore, we believe that our results help to improve application of this population size estimation method in other regions of Viet Nam.

This study used a natural experiment of a new metro line in Hong Kong to examine trade-offs between transit-related and non-transit-related physical activity (PA) among 104 older people (aged ≥ 65 years) based on longitudinal accelerometer data that distinguished transit-related and non-transit-related PA. Difference-in-difference (DID) analysis compared PA changes between treatment and control groups. We found that new metro stations have trade-off effects between transit and non-transit PA. After opening metro stations, transit-related PA increased by 12 min per day on average, but non-transit-related PA decreased by 18 min per day. In addition, the proportion of time spent in transit-related PA increased by 6%. The results suggested that new metro stations could generate transit-related PA, but it might shift from non-transit-related PA among older people. Our findings revealed trade-off effects of public transit interventions and have significant implications for transport and healthy ageing studies.