Racial and ethnic differences in secular trends for childhood BMI, weight, and height.

OBJECTIVES The prevalence of childhood overweight in the United States has markedly increased over the last 30 years. We examined differences in the secular trends for BMI, weight, and height among white, black, and Mexican-American children. RESEARCH METHODS AND PROCEDURES Analyses were based on nationally representative data collected from 2 to 17 year olds in four examinations (1971-1974 through 1999-2002). RESULTS Overall, black children experienced much larger secular increases in BMI, weight, and height than did white children. For example, over the 30-year period, the prevalence of overweight increased approximately 3-fold (4% to 13%) among 6- to 11-year-old white children but 5-fold (4% to 20%) among black children. In most sex-age groups, Mexican-American children experienced increases in BMI and overweight that were between those experienced by blacks and whites. Race/ethnicity differences were less marked among 2 to 5 year olds, and in this age group, white children experienced the largest increase in overweight (from 4% to 9%). In 1999-2002, the prevalence of extreme BMI levels (> or =99th percentile) reached 6% to 7% among black girls and Mexican-American boys. DISCUSSION Because of the strong tracking of childhood BMI levels into adulthood, it is likely that the secular increases in childhood overweight will greatly increase the burden of adult disease. The further development of obesity interventions in different racial/ethnic groups should be emphasized.