HIV infection and sexual risk among men who have sex with men and women (MSMW): A systematic review and meta-analysis

Objectives: To estimate the number of men who have sex with men and women who are HIV-positive in the United States, and to compare HIV prevalence rates between men who have sex with men and women, men who have sex with men only, and men who have sex with women exclusively. Methods: Following PRISMA guidelines, we conducted a systematic review and meta-analysis of reports referencing HIV prevalence and men who have sex with men and women. We searched PubMed and Ovid PsycINFO for peer-reviewed, U.S.-based articles reporting on HIV prevalence among men who have sex with men and women. We conducted event rate, effect size, moderation and sensitivity analyses. Results: We estimate that 1.0% of U.S. males are bisexually-behaving, and that 121,800 bisexually-behaving men are HIV-positive. Men who have sex with men and women are less than half as likely to be HIV-positive as men who have sex with men only (16.9% vs. 33.3%; OR = 0.41, 95% CI: 0.31, 0.54), but more than five times as likely to be HIV-positive as men who have sex with women exclusively (18.3% vs. 3.5%; OR = 5.71, 95% CI: 3.47, 9.39). They are less likely to engage in unprotected receptive anal intercourse than men who have sex with men only (15.9% vs. 35.0%; OR = 0.36, 95% CI: 0.28, 0.46). Men who have sex with men and women in samples with high racial/ethnic minority proportions had significantly higher HIV prevalence than their counterparts in low racial/ethnic minority samples. Conclusions: This represents the first meta-analysis of HIV prevalence in the U.S. between men who have sex with men and women and men who have sex with men only. Data collection, research, and HIV prevention and care delivery specifically tailored to men who have sex with men and women are necessary to better quantify and ameliorate this population's HIV burden. © 2014 Friedman et al

The Effect of Partner Sex: Nondisclosure of HIV Status to Male and Female Partners Among Men who Have Sex with Men and Women (MSMW)

A common concern within HIV prevention is that HIV positive MSMW do not disclose their HIV status to female partners who are thus at increased risk for HIV infection. The present study uses unique data to examine whether MSMW disclose more often to male rather than female partners. Data were collected on most recent male and/or female primary partner and four most recent casual partners from 150 MSMW (50 African American, 50 Latino, 50 White). MSMW reported on 590 partners (31% female; 69% male). Disclosure was coded as disclosure before sex, disclosure after sex, or nondisclosure. A series of multinomial logistic regressions with partners clustered within respondents were conducted to evaluate effects of respondent characteristics and partner characteristics on timing of disclosure. In bivariate and multivariate analyses there were no significant differences in odds of disclosure to male and female partners before or after sex. Although MSMW were substantially less likely to disclose to HIV negative partners before sex compared to HIV positive partners regardless of sex, when we fully interacted the multivariate model by partner sex, the odds of disclosure to HIV negative male partners compared to HIV positive male partners before sex were significantly higher than the odds of disclosure to HIV negative female partners compared to HIV positive female partners. Patterns of mutual nondisclosure and nonreciprocal disclosure were observed with both primary and casual partners. The paper makes additional methodological contributions to the measurement and analysis of disclosure

Factors associated with vasopressin release in exercising swine

This study examined the effect of dynamic exercise on vasopressin release in the miniswine and factors that may elicit this response (n = 15). Thus lysine vasopressin (LVP), the catecholamines epinephrine and norepinephrine (EPI and NE), plasma renin activity (PRA), and plasma volume, Na+, and osmolality were measured before and during treadmill running at work intensities of 60, 80, and 100% of each swine's maximal heart rate reserve (HRR). LVP increased in a progressive manner similar to that of humans, ranging from 5.9 +/- 0.4 pg/ml before exercise to 30.1 +/- 4.5 pg/ml during maximal exercise. EPI, NE, and PRA [an index of angiotensin II (ANG II) activity] demonstrated a pattern of response comparable to LVP. Although these hormones can influence the release of LVP, only PRA displayed a strong correlation with LVP (r = 0.84). When ANG II synthesis was blocked (captopril, 1-3 mg/kg, intra-atrial injection) during exercise (80% HRR), plasma LVP was reduced from 9.9 +/- 0.6 to 7.5 +/- 0.6 pg/ml (P &lt; 0.05). In addition, moderate-to-strong correlations were found between plasma concentrations of LVP and plasma osmolality (r = 0.79) and body temperature (r = 0.78). Plasma LVP also correlated with decreases in plasma volume (r = 0.84). These data suggest that the miniswine model is a good one for studying vasopressin effects during exercise and that ANG II appears to be a particularly strong stimulus for the release of this hormone. </jats:p