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The role of sexual networks in the epidemiology of human immunodeficiency virus (HIV) among black men who have sex with men (MSM) is poorly understood. Using data from 1,306 black MSM in the BROTHERS Study (2009-2010) in the United States, we examined the relationships between multiple sexual dyadic characteristics and serodiscordant/serostatus-unknown condomless sex (SDCS). HIV-infected participants had higher odds of SDCS when having sex at least weekly (odds ratio (OR) = 2.41, 95% confidence interval (CI): 1.37, 4.23) or monthly (OR = 1.94, 95% CI: 1.17, 3.24) versus once to a few times a year. HIV-uninfected participants had higher odds of SDCS with partners met offline at sex-focused venues (OR = 1.79, 95% CI: 1.15, 2.78) versus partners met online. In addition, having sex upon first meeting was associated with higher odds of SDCS (OR = 1.49, 95% CI: 1.21, 1.83) than was not having sex on first meeting, while living/continued communication with sexual partner(s) was associated with lower odds of SDCS (weekly: OR = 0.64, 95% CI: 0.47, 0.85; monthly: OR = 0.60, 95% CI: 0.44, 0.81; yearly: OR = 0.58, 95% CI: 0.39, 0.85) versus discontinued communication. Persons with primary/steady nonprimary partners versus commercial partners had lower odds of SDCS regardless of HIV serostatus. This suggests the need for culturally relevant HIV prevention efforts for black MSM that facilitate communication with sexual partners especially about risk reduction strategies, including preexposure prophylaxis., (© The Author 2017. Published by Oxford University Press on behalf of the Johns Hopkins Bloomberg School of Public Health. All rights reserved. For permissions, please e-mail: journals.permissions@oup.com.)

To our knowledge, no study has investigated the association of long-term exposure to traffic pollution with markers of atherosclerosis in 4 vascular beds simultaneously in an all-African-American cohort. Among participants in the Jackson Heart Study (Jackson, Mississippi; baseline mean age = 55.5 (standard deviation, 12.7) years), we used linear regression to estimate percent differences in carotid intima-media thickness (CIMT) at baseline (2004) and used modified Poisson regression (robust error variance) to estimate prevalence ratios for peripheral artery disease (PAD), coronary artery calcification (CAC), and abdominal aortic calcification (AAC) at the first follow-up visit (2005-2008) for persons living less than 150 m (versus more than 300 m) from major roadways, adjusting for confounders. Living less than 150 m from such roadways was associated with a significant 6.67% (95% confidence interval: 1.28, 12.35) increase in CIMT (4,800 participants). PAD prevalence among persons living less than 150 m from a major roadway was 1.17 (95% confidence interval: 0.73, 1.86) times that of persons living more than 300 m away (4,443 participants), but this result was not statistically significant. There was no association for CAC or AAC. The association with CIMT was stronger in participants with a cardiovascular disease history than in those without one (P = 0.04). We observed an association in the carotid vascular beds but not the coronary, abdominal, or peripheral vascular beds. Our results highlight the need to consider residential proximity to roadways as a potential cardiovascular disease risk factor for blacks.

Recent advances in geographic information systems software and multilevel methodology provide opportunities for more extensive characterization of "at-risk" populations in epidemiologic studies. The authors used age-restricted, geocoded data from the all-African-American Jackson Heart Study (JHS), 2000-2004, to demonstrate a novel use of the Lorenz curve and Gini coefficient to determine the representativeness of the JHS cohort to the African-American population in a geographic setting. The authors also used a spatial binomial model to assess the geographic variability in participant recruitment across the Jackson, Mississippi, Metropolitan Statistical Area. The overall Gini coefficient, an equality measure that ranges from 0 (perfect equality) to 1 (perfect inequality), was 0.37 (95% confidence interval (CI): 0.30, 0.45), indicating moderate representation. The population of sampled women (Gini coefficient = 0.34, 95% CI: 0.30, 0.39) tended to be more representative of the underlying population than did the population of sampled men (Gini coefficient = 0.49, 95% CI: 0.35, 0.61). Representative recruitment of JHS participants was observed in predominantly African-American and mixed-race census tracts and in the center of the study area, the area nearest the examination clinic. This is of critical importance as the authors continue to explore novel approaches to investigate the geographic variation in disease etiology.