Publications

BACKGROUND

Childhood asthma prevalence and morbidity varies among Latinos in the United States, with Puerto Ricans having the highest and Mexicans the lowest.

OBJECTIVE

To determine whether genetic ancestry is associated with the odds of asthma among Latinos, and secondarily whether genetic ancestry is associated with lung function among Latino children.

METHODS

We analyzed 5493 Latinos with and without asthma from 3 independent studies. For each participant, we estimated the proportion of African, European, and Native American ancestry using genome-wide data. We tested whether genetic ancestry was associated with the presence of asthma and lung function among subjects with and without asthma. Odds ratios (OR) and effect sizes were assessed for every 20% increase in each ancestry.

RESULTS

Native American ancestry was associated with lower odds of asthma (OR = 0.72, 95% CI: 0.66-0.78, P = 8.0 × 10(-15)), while African ancestry was associated with higher odds of asthma (OR = 1.40, 95% CI: 1.14-1.72, P = .001). These associations were robust to adjustment for covariates related to early life exposures, air pollution, and socioeconomic status. Among children with asthma, African ancestry was associated with lower lung function, including both pre- and post-bronchodilator measures of FEV1 (-77 ± 19 mL; P = 5.8 × 10(-5) and -83 ± 19 mL; P = 1.1 x 10(-5), respectively) and forced vital capacity (-100 ± 21 mL; P = 2.7 × 10(-6) and -107 ± 22 mL; P = 1.0 x 10(-6), respectively).

CONCLUSION

Differences in the proportions of genetic ancestry can partially explain disparities in asthma susceptibility and lung function among Latinos.

African American adults are disproportionately affected by HIV in the United States, underscoring the need for additional research on barriers to condom use. Guided by the theory of gender and power, this experimental study used a series of vignettes to test causal hypotheses regarding the influence of event-level alcohol use (present and absent), partner type (serious and casual), and relationship power (low and equal) on perceived difficulty implementing condom use. A total of 299 (151 women and 148 men) heterosexual African American adults indicated how "difficult" it would be to use a condom after reading 8 hypothetical sexual encounters, presented in a random order. A 2 × 2 × 2 × 2 repeated measures analysis of covariance with one between subjects factor (gender) and one covariate (condom use self-efficacy) was used to estimate the effects of these variables on an index of perceived difficulty. The women in the study reported significantly higher ratings of difficulty implementing condom use in vignettes characterized by low relationship power (p < .001) and presence of alcohol use (p < .001); the manipulated independent variables did not produce any main effects for men. Both men and women's ratings of perceived difficulty decreased as condom use self-efficacy increased (p < .001). This is the first study to use an experimental methodology to test hypotheses about barriers to condom use among a community-based sample of African American adults. These data can be used to enhance existing HIV prevention interventions.