Androgen receptor (AR) CAG repeat length (RL) might modify the relationship between endogenous testosterone (T) and depressive symptoms in men on average over age 50 years. We hypothesized that CAG RL modifies the association between T and depressive symptoms in 525 black and 721 white men under age 40 years participating in the CARDIA Male Hormone Study. We assessed cross-sectional associations of quartiles of total and bioavailable T and tertiles of CAG RL with depressive symptoms, defined as Center for Epidemiologic Studies Depression Scale (CES-D) score > or=16, in 1995-1996. The interaction of CAG RL and total T on depressive symptoms was statistically significant for blacks, whites, and both groups combined. In the combined analysis, the odds ratios (OR) (95% confidence intervals (CI)) across the quartiles of total T were 1.00, 0.17 (95% CI=0.07-0.43), 0.31 (95% CI=0.14-0.70), and 0.49 (95% CI=0.22-1.09) for the shortest RL group. The interaction of CAG RL and bioavailable T on depressive symptoms was statistically significant for black men only, and nonsignificant in a combined analysis. For black men in the shortest RL group, the ORs for the quartiles of bioavailable T were 1.00, 0.41 (95% CI=0.16-1.05), 0.10 (95% CI=0.03-0.38), and 0.35 (95% CI=0.14-0.90). In other CAG groups, there were no relationships of total or bioavailable T with depressive symptoms. CAG RL might modify the association between endogenous total and bioavailable T and depressive symptoms in younger black men. Clinical trials assessing the effects of T replacement therapy on depressive symptoms in hypogonadal men should consider including CAG RL in their design and/or analysis.

Several studies have shown a positive association between acculturation and obesity in Hispanics. We sought to examine the association in a sample of urban Hispanic women. Using data collected in the Chicago Breast Health Project, we used logistic regression to examine the association of obesity (BMI ≥ 30 kg/m 2 ) with language acculturation and years in the US in a sample of 388 Hispanic women. Women self-reported the number of years they had lived in the US (mean 17.6) as well as their preferred language across several domains, which was used to calculate a language acculturation score. Nearly all the women (98%) were born outside the US with the majority (65%) born in Mexico and the majority of women (69%) had low language acculturation, i.e., answered "only Spanish" in every domain. Over half of the women were obese (56%). In multivariable analysis, odds of obesity was twice as high among women living in the US for greater than 20 years compared to those in the US for 10 years or less (OR/year = 2.07, 95% CI 1.25-3.42). In contrast, low language acculturation was not associated with odds of obesity (OR = 1.14, 95% CI 0.70-1.86). While greater years in the US increased odds of obesity among Hispanic women, no association of obesity with language acculturation was found. These results suggest that mechanisms other than language contribute to the immigration effect.

Selection and genetic drift can create genetic differences between populations. Cytokines and chemokines play an important role in both hematopoietic development and the inflammatory response. We compared the genotype frequencies of 45 SNPs in 30 cytokine and chemokine genes in two healthy Chinese populations and one Caucasian population. Several SNPs in IL4 had substantial genetic differentiation between the Chinese and Caucasian populations (F ST approximately 0.40), and displayed a strikingly different haplotype distribution. To further characterize common genetic variation in worldwide populations at the IL4 locus, we genotyped 9 SNPs at the IL4 gene in the Human Diversity Panel's (N = 1056) individuals from 52 world geographic regions. We observed low haplotype diversity, yet strikingly different haplotype frequencies between non-African populations, which may indicate different selective pressures on the IL4 gene in different parts of the world. SNPs in CSF2, IL6, IL10, CTLA4, and CX3CR1 showed moderate genetic differentiation between the Chinese and Caucasian populations (0.15 < F ST < 0.25). These results suggest that there is substantial genetic diversity in immune genes and exploration of SNP associations with immune-related diseases that vary in incidence across these two populations may be warranted.

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