Social Stressors and Intoxicated Sex Among an Online Sample of Men who have Sex with Men (MSM) Drawn from Seven Countries

Background: Rates of drug and alcohol use are higher among men who have sex with men (MSM) than the general adult male population, and are often associated with increased sexual risk-taking. Objectives: We aim to examine the prevalence of drunk or high sex and their associations with socio-demographic characteristics, gay social network size, and social stress among an online sample of MSM drawn from seven countries. Methods: Sexually-active MSM aged over 18 residing in Australia, Brazil, Canada, South Africa, Thailand, the United Kingdom, or the United States were recruited through Facebook for a quantitative survey (n = 2,403) in 2012. Two outcomes were examined via logistic regression: reporting being buzzed/drunk at last sex, and reporting being high at last sex. Results: Results highlight the role of social stressors in shaping drug use among MSM. Results were context-specific, though commonalities were seen across countries. Being in a male–male sexual relationship was associated with lower odds of being buzzed/drunk at last sex in five countries. Higher scores on measures of external homonegative discrimination and internalized homonegativity were associated with greater odds of reporting being high at last sex in three countries. Conclusions/Importance: Social networks and minority stressors can have significant effects on drug use and sex while drunk or high. This points to the importance of focusing on structural issues when designing interventions for MSM aimed at reducing the transmission of HIV and other STIs. © 2018 Taylor & Francis Group, LLC

The normal appearing grey matter in primary progressive multiple sclerosis. A magnetisation transfer imaging study

Background In 10-15 % of patients with multiple sclerosis (MS), the clinical course is characterized by slow progression in disability without relapses (primary progressive (PP) MS). The mechanism of disability in this form of MS is poorly understood. Using magnetization transfer ratio (MTR) imaging, we investigated normal appearing white matter (NAWM) and normal appearing grey matter (NAGM) in PPMS and explored the relationship of MTR measures with disability. Methods Thirty patients with PPMS and 30 age matched controls had spin echo based MTR imaging to study lesions and normal appearing tissues. The brain was segmented into NAWM and NAGM using SPM99 with lesions segmented using a semiautomated local thresholding technique. A 75% probability threshold for classification of NAWM and NAGM was used to diminish partial volume effects. From normalized histograms of MTR intensity values, six MTR parameters were measured. Mean lesion MTR and T2 lesion volume were also measured. Disability was assessed using Kurtzke's expanded disability status scale (EDSS). Results Compared with controls, patients exhibited a significant reduction in mean NAWM (p = 0.001) and NAGM (p = 0.004) MTR. Spearman's rank correlation of EDSS with the six MTR parameters in NAWM and NAGM, mean lesion MTR, and T2 lesion volume, was only significant with mean NAGM MTR (r = -0.41, p = 0.02), the 25(th) percentile of NAGM MTR intensity (r = -0.37, p = 0.05), and T2 lesion volume (r = 0.39, p = 0.04). Multiple regression analysis of the relationship between EDSS and 4 MR parameters representing each tissue type (mean NAWM MTR, mean NAGM MTR, mean lesion MTR, T2 lesion volume) showed that the association of EDSS with mean NAGM MTR remained significant. Conclusions There appear to be significant abnormalities in the NAGM in PP MS. Further investigation of the pathological basis and functional significance of grey matter abnormality in PPMS is warranted