Changes in overweight in youth over a period of 7 years: impact of ethnicity, gender and socioeconomic status.

Objective: To examine changes in overweight in youth over a period of 7 years, within the context of ethnicity, gender, and socioeconomic status (SES).

Methods: Participants in a longitudinal study of cardiovascular (CV) risk factor development were evaluated on 2 occasions an average of 7.2 +/- 0.5 years apart. There were 253 subjects (121 Blacks, 132 Whites, 130 females) with a mean age of 8.8 +/- 2.0 years at the initial visit. SES was determined by Hollingshead Social Status Index and was categorized as low, middle (+/-1 standard deviation from mean), and high. Overweight was defined as >85th percentile in Body Mass Index (BMI) for age and gender (National Health and Nutrition Examination Survey [NHANES] norms).

Results: Standardized BMI increased significantly over the course of the study (P<.001). The increase was not significantly different by ethnicity or by gender (both P values>.05) but did significantly differ by SES (P<.001). Overall, the prevalence of overweight increased from 31% to 40% (P<.001); however, for those with low SES, the prevalence increased from 37% to 67% (P<.001).

Conclusion: Lower SES youth, regardless of ethnicity or gender, exhibited extremely large increases in general adiposity over time and are at particular risk for development of a number of obesity-related problems, such as hypertension. Primary prevention of obesity is needed in youth, particularly among those from low SES backgrounds.