Trends in abdominal obesity in young people: United States 1988-2002.

OBJECTIVE To determine the prevalence and trends of abdominal obesity from 1988-1994 to 1999-2002 in American White, Black, and Hispanic youths. METHODS Data (N = 5020) from the 1988-1994 and 1999-2002 US National Health and Nutrition Examination Surveys were used for this analysis. Abdominal obesity was defined as sex-specific values > or = 95th percentile for waist circumference. Prevalence of abdominal obesity was compared across study periods, race/ ethnicity, socioeconomic status (SES), and age groups 6-11 years. RESULTS Between 1988-1994 and 1999-2002, increases in waist circumference exceeded those of body mass index in White, Black, and Hispanic young people. The prevalence of abdominal obesity was higher in the 1999-2002 than the 1988-1994 study periods. In 1988-1994, prevalences of abdominal obesity in White, Black, and Hispanic boys were 3.0%, 3.2%, and 6.2% compared with 5.6%, 5.0%, and 9.1% in 1999-2002. The values in girls were 3.9%, 2.9%, and 4.9% in 1988-1994 and 6.0%, 8.1%, and 8.5% in 1999-2002, respectively. Prevalences of abdominal obesity increased with decreasing level of SES in 1988-1994 and 1999-2002 for Whites, Blacks, and Hispanics. At same levels of SES, prevalences of abdominal obesity were higher in Blacks and Hispanic children compared to White children. CONCLUSION The trend toward increasing obesity among White, Black, and Hispanic American youths is compounded by an unequal increase in abdominal fat accumulation. Further studies are needed to determine the long-term significance of these trends, particularly in Hispanic youths who have greater tendencies for abdominal obesity compared with White and Black youths. The higher increase in the anthropometric markers (waist circumference) of abdominal obesity compared to body mass index suggests that body mass index may be inadequate in estimating changes in generalized adiposity in young people. Health promotion programs in the United States including education, nutrition, and appropriate physical activity targeted at children may help to ameliorate obesity epidemics. Emphasis should be placed on reducing abdominal obesity through physical activity and nutrition, both in school and at home for all children.