Original article Asthma, body mass, gender, and Hispanic national origin among 517 preschool children in New York City Since 1980, asthma prevalence has increased by 60% in the USA. Among the many puzzling features of this increase are its associations with socioeconomic status, age, race/ethnicity, and national origin. Asthma has become, in the past quarter-century, a major burden on children and their families in low-income urban areas in the USA (1). Asthma appears to be especially prevalent among children of African or Hispanic descent (2) and, among Hispanics, especially prevalent among children of Puerto Rican background (3), whether they live in the continental United States or in Puerto Rico (4) and whether they live in high- or low-income neighborhoods (5). Although some studies have controlled for lifestyle and health care utilization and found that they do not account for the association of Puerto Rican background with asthma (6), the findings are not consistent (7). Among Hispanic adults in the USA, Puerto Ricans are reported to have the highest and Mexicans the lowest asthma prevalence (8) and mortality (9). Similar patterns are observed among children (6). These differences have been attributed to genetic factors (10, 11), gene–environ- ment interactions (12), acculturation (1, 13, 14), insurance coverage (15), and patterns of interpersonal communica- tion within families and with providers (16). Asthma is thought to be associated with sensitivity to indoor allergens, and the prevalence of sensitization to cock- roach and other indoor allergens (but not of asthma) has been reported to be higher among children of Mexican and of African descent than other children (17). Obesity has been associated with asthma among adults [reviewed in (18)] and children (reviewed in (19, 20) including children in Mexico (21), but not in all studies (22). Hispanic children are reported to be at high risk of both obesity and asthma (23). The temporal relationship between asthma and obesity in both children and adults is not well understood (24). A common genetic basis for both conditions has been suggested but not confirmed (25), and would not, in any case, account fully for the Background: Striking differences in asthma prevalence have been reported among Hispanic adults and children living in different cities of the USA. Prev- alence is highest among those of Puerto Rican and lowest among those of Mexican origin. We hypothesized that body size would mediate this association. Methods: Parents of children in New York City Head Start programs completed a questionnaire including demographic factors, health history, a detailed history of respiratory conditions, lifestyle, and home environment. ChildrenÕs height and weight were measured in home visits. Logistic regression was used to model the association of asthma with body mass index percentile (<85th percentile, gen- der/age specific vs ‡85th percentile, gender/age specific), national origin, and other factors. Results: Of 517 children at mean age of 4.0 ± 0.6 years, 34% met the study criteria for asthma, and 43% were above the 85th percentile. Asthma was strongly associated with non-Mexican national origin, male gender, allergy symptoms, and maternal asthma, and marginally with body size. The odds of asthma among boys of non-Mexican origin was 5.9 times that among boys of Mexican origin [95% confidence interval (CI): 2.9–12.2]; the comparable odds ratio (OR) among girls was 1.8 (95% CI: 0.9–3.6). Body mass was associated with asthma among girls [OR = 2.0 (95% CI: 1.1–3.7)], but not boys [OR = 1.4 (95% CI: 0.8–2.6)]. Conclusions: The association of asthma with both body mass and national origin was gender-specific among the children in our study. Ours is one of the first studies to report on pediatric asthma in different Hispanic populations in the same city, by gender. J. S. Jacobson, R. B. Mellins, R. Garfinkel, A. G. Rundle, M. S. Perzanowski, G. L. Chew, H. F. Andrews, I. F. Goldstein Departments of Epidemiology, Biostatistics, and Environmental Health Sciences, Mailman School of Public Health, and Department of Pediatrics, College of Physicians and Surgeons, Columbia University, New York, NY, USA Key words: asthma; body size; Hispanic; overweight; urban. Judith S. Jacobson, DrPH, MBA Mailman School of Public Health Columbia University 722 West 168th Street Room R736 New York NY 10032 USA Accepted for publication 13 July 2007 Allergy 2008: 63: 87–94 Ó 2008 The Authors Journal compilation Ó 2008 Blackwell Munksgaard DOI: 10.1111/j.1398-9995.2007.01529.x 87