The changing distribution and determinants of obesity in the neighborhoods of New York City, 2003-2007.

Obesity (body mass index >or=30 kg/m(2)) is a growing urban health concern, but few studies have examined whether, how, or why obesity prevalence has changed over time within cities. This study characterized the individual- and neighborhood-level determinants and distribution of obesity in New York City from 2003 to 2007. Individual-level data from the Community Health Survey (n = 48,506 adults, 34 neighborhoods) were combined with neighborhood measures. Multilevel regression assessed changes in obesity over time and associations with neighborhood-level income and food and physical activity amenities, controlling for age, racial/ethnic identity, education, employment, US nativity, and marital status, stratified by gender. Obesity rates increased by 1.6% (P < 0.05) each year, but changes over time differed significantly between neighborhoods and by gender. Obesity prevalence increased for women, even after controlling for individual- and neighborhood-level factors (prevalence ratio = 1.021, P < 0.05), whereas no significant changes were reported for men. Neighborhood factors including increased area income (prevalence ratio = 0.932) and availability of local food and fitness amenities (prevalence ratio = 0.889) were significantly associated with reduced obesity (P < 0.001). Findings suggest that policies to reduce obesity in urban environments must be informed by up-to-date surveillance data and may require a variety of initiatives that respond to both individual and contextual determinants of obesity.