Obesity development during adolescence in a biracial cohort: the NHLBI Growth and Health Study

The National Heart, Lung, and Blood Institute Growth and Health Study (NGHS) is a 10-year study to investigate the development of obesity in black and white girls during adolescence and its environmental and psychosocial correlates. The purpose of this report was to examine changes in the annual prevalence rates of overweight and obesity in the NGHS cohort from ages 9 to 19 years.

A total of 2379 black and white girls, aged 9 to 10 years, were recruited from schools in Richmond, California, and Cincinnati, Ohio, and from families enrolled in a health maintenance organization in the Washington, DC area. Participant eligibility was limited to girls and their parents who declared themselves as being either black or white and who lived in racially concordant households. DESIGN AND STATISTICAL ANALYSIS: The NGHS is a multicenter prospective study of a biracial cohort followed annually from ages 9 to 10 years through 18 to 19 years. The prevalence of overweight and obesity was based on age-specific > or =85th and > or =95th percentile values, respectively, for body mass index based on the 1960-1965 National Health Examination Survey reference population.

The main outcome measures were body mass index (weight in kilograms divided by height in meters, squared) and proportions of girls who were "overweight" and "obese" by age and race.

The prevalence of overweight was 37% higher in blacks as compared with whites (30.6% vs 22.4%) even by age 9. The rate of overweight almost doubled in both groups during the 10-year period. By age 19, the rate of overweight was 56.9% in black and 41.3%, in white girls. The prevalence of obesity was 17.7% in black and 7.7% in white girls at 9 years old, and the rates also doubled during the study period.

The doubling in the prevalence of overweight and obesity during adolescence in black and white NGHS girls was surprising. By age 19, more than half of black girls were overweight and more than one third were obese. Almost half of white girls were overweight and almost 1 of 5 girls were obese. These findings should sound an alarm for all primary care physicians and public health professionals to take heed of what is happening to our youth.