Analyses of nationally representative longitudinal data—the National Longitudinal Survey of Youth (Strauss and Knight, 1999; Strauss and Pollack, 2001) and the National Longitudinal Study of Adolescent Health (NLSAH) (Goodman, 1999)—have suggested that family SES is inversely related to obesity prevalence in children and that the effects of SES and race/ethnicity are independent of other variables. A more recent analysis of a nationally representative sample of adolescents enrolled in the NLSAH examined trends in racial/ethnic disparities for leading health indicators from Healthy People 2010 (Harris et al., 2006) across multiple domains from adolescence to young adulthood. The results revealed that the health risk increased for 15 of 20 indicators among racially/ethnically diverse adolescents. Access to health care decreased from the teen to the adult years for most U.S. racial/ethnic groups, and the disparity was particularly high for American Indians (Harris et al., 2006).
Analyses of nationally representative cross-sectional data reveal additional findings that can help to provide an understanding of the relationship between SES and obesity. An examination of the 1988 to 1994 NHANES data showed that the prevalence of obesity in white adolescents was higher for those in low-income families, but there was no clear relationship between family income and obesity in individuals in other age or racial/ethnic subgroups (Ogden et al., 2003; Troiano and Flegal, 1998). A more recent analysis of trends in the association between poverty and adolescents’ obesity risk was conducted for four cross-sectional NHANES surveys conducted from 1971 to 2004 (Miech et al., 2006). Although the obesity prevalence did not differ by SES or family poverty status for teens through age 14 years, a widening disparity was observed for 15- to 17-year-olds, especially boys, girls, non-Hispanic whites, and non-Hispanic African Americans. There was a 50 percent higher risk of obesity among adolescents in poor families compared with that among adolescents in non-poor families. Possible mechanisms that contributed to the obesity risk for adolescents were physical inactivity, higher levels of consumption of sweetened beverages, and skipping breakfast (Miech et al., 2006).