Faculty Bibliography

Prenatal arsenic exposure is associated with adverse birth outcomes and disease risk later in life, which could be mediated through epigenetic dysregulation. We evaluated the association between arsenic and gestational age (GA) that was mediated through DNA methylation (DNAm) using data from a Bangladeshi birth cohort. Arsenic exposure was measured in maternal drinking water at ≤16 weeks GA and maternal toenails collected ≤1 month postpartum. Cord blood DNAm was measured using Infinium HumanMethylation450 arrays (n = 44, discovery phase). Top loci identified in the discovery phase were then pyrosequenced in a second group (n = 569, validation phase). Structural equation models (SEM) evaluated the direct and indirect effects of arsenic and DNAm on GA. In the discovery phase, arsenic was associated with differential DNAm of 139 loci that were associated with GA (P < 1.10X10^-6; |β regression|>0.10). Each doubling in water arsenic concentration decreased GA by 2 days, which was fully mediated through the main principal component of the top-ten CpGs (P < 0.001). In the validation phase, there were direct and indirect effects of miR214-3 and MCC DNAm on GA. In an adjusted SEM model, mediation of the association between arsenic and GA by miR124-3 was borderline significant (P = 0.061). This study therefore identified DNAm at specific loci in cord blood that mediated the effect of arsenic exposure on GA. Specifically, prenatal arsenic exposure was associated with lower methylation of miR124-3 that mediated the exposure-response of arsenic on GA. Future research should evaluate if these epigenetic changes are persistent and associated with disease risk.

BACKGROUND:Globally adolescents continue to have an upward trend in HIV incidence and AIDS-related mortality. The interplay between the rapid physical growth, sexual maturation, and enormous albeit slow-evolving cognitive and psychological changes in adolescence may partly explain this trend. Our main purpose was to highlight key psychosocial characteristics of HIV-infected adolescents and explore if these characteristics are associated with depression symptoms. METHODS:From August to December 2016 after obtaining informed consent, adolescents living with HIV at Kenyatta National Hospital were interviewed using the Home environment, Education and Employment, Activity, Sexuality, Suicide and depression traits (HEADSS) tool combined with the Patient Health Questionnaire (PHQ-9) to elucidate which key symptoms of depression and link with psychosocial characteristics mapped on HEADSS. In order to determine which psychosocial characteristics were linked with risk of depression, the traits of adolescents who were symptomatic were compared to those who were not using univariate and multivariate regression analysis. RESULTS: = 0.06]. CONCLUSION/CONCLUSIONS:One in two of the adolescents interviewed had depression symptoms which were significantly associated with lack of school fees, missing meals, non-adherence to medication, and substance abuse.

Background: Little research has evaluated the social and sexual network-related health outcomes of young black transgender women (TGW) or compared these outcomes with those of black men who have sex with men (MSM). Social network analysis offers one potent means of understanding the dynamics driving the broad spectrum of adverse outcomes experienced by these subgroups. Methods: We examined the social and sexual health network traits of 618 black individuals assigned male at birth who have sex with men, 47 (7.6%) of whom identified as TGW. Using respondent-driven sampling, data collection occurred over three waves between 2013 and 2016, in Chicago, Illinois. Univariate, logistic regression, and confidant and sexual network analyses were conducted to characterize dynamic network features. Results: TGW's mean age was 22.1 (standard deviation ±2.6). TGW's sexual networks were significantly less stable (stability ratio of 0.175 vs. 0.278 among MSM, p=0.03) and had greater network turnover (turnover ratio of 0.825 vs. 0.735, p=0.04). TGW also had significantly more sex partners (7.6 vs. 4.0, p=0.0002) and exchange sex (odds ratio=2.97; 95% confidence interval: 1.66-5.32, p<0.001), lower rates of employment (39.6% vs. 71.1%, p<0.001), and more reported an income <$20,000 (93.5% vs. 80.8%, p=0.029). Within confidant networks, TGW had a borderline significantly higher network turnover ratio (0.703 vs. 0.625, p=0.06). Furthermore, both TGW and MSM had high, but similar, HIV rates (42.3% vs. 30.6%, respectively; p=0.17). There were no significant structural network differences vis-à-vis mean degree (p=0.46), betweenness centrality (p=0.40), closeness centrality (p=0.18), or average shortest path length (borderline statistically significant at p=0.06). Conclusion: Using data from a representative sample of younger black individuals, we observed black TGW have less sexual network stability in contrast to black MSM but comparable structural network features. We further observed that both groups, and black TGW especially, possess considerable system-level, socioeconomic, and sexual health burdens.