Weight status in childhood as a predictor of becoming overweight or hypertensive in early adulthood

Nutrition Research Newsletter, April, 2005

Obesity is a serious public health problem. During the past 2 decades, the prevalence of overweight has more than doubled among children and adolescents in the United States. According to the 1999 to 2000 National Health and Nutrition Examination Survey, approximately 30% of adolescents are overweight or at risk of being overweight. The period of late adolescence and early adulthood may be particularly important in the maintenance of healthy weight. Weight status tracks with age, and the risk of an overweight child becoming an obese adult rises with age. Less is known about the relationship between childhood and adolescent weights in the normal weight range (that is, children not classified as underweight, at risk for overweight, or overweight) and subsequent changes in weight and blood pressure. To investigate these issues, the researchers analyzed data from a prospective cohort study based in an urban population in the Northeast.

The researchers conducted a prospective study of 314 children, who were 8 years to 15 years old at baseline, and were followed up 8 years to 12 years later. Weight, height, and blood pressure were measured by trained research staff. Incident overweight was defined as BMI greater than or equal to 25 kg/[m.sup.2] among participants who had not been overweight as children.

More male subjects (48.3%) than female subjects (23.5%) became overweight or obese between their first childhood visit and the young adult follow-up. Being in the upper one-half of the normal weight range (that is, BMI between the 50th and 84th percentiles for age and gender in childhood) was a good predictor of becoming overweight as a young adult. Compared with children with a BMI <50th percentile, girls and boys between the 50th and 74th percentiles of BMI were approximately 5 times more likely, and those with a BMI between the 75th and 84th percentiles were up to 20 times more likely to become overweight. The incidence of high blood pressure was greater among the male subjects (12.3% vs. 1.9%). Compared with boys who had childhood BMI below the 75th percentile, boys between the 75th and 85th percentiles of BMI as children were four times more likely and those at above the 85th percentile were five times more likely to become hypertensive.

Among this urban sample of young people, weight status at the first childhood visit was strongly predictive of becoming overweight or obese. Not only were children already in the categories of overweight or at risk for overweight (greater than or equal to 85th percentile of BMI) at increased risk, but also children in the upper part of the normal or healthy weight range (that is, children between the 50th and 84th percentiles of BMI for age and gender) were at increased risk for becoming overweight or obese adults.

The findings of this study underscore the potential seriousness of the increasing prevalence of pediatric obesity in the United States. Although very lean children are unlikely to become overweight adults, the researchers of the present study observed that children in the upper end of the healthy weight range (for example, 50th to 84th percentiles) are at an elevated risk of becoming overweight or obese. Furthermore, boys in the upper end of the healthy weight range are at an increased risk of becoming hypertensive. These findings suggest that future interventions to prevent adult obesity and its complications should include not only overweight children but also children and adolescents as low as the 50th percentile of BMI for age and gender.

A. Field, N. Cook, M. Gillman. Weight status in childhood as a predictor of becoming overweight or hypertensive in early adulthood. Obes Res 13:163-169 (January 2005) [Correspondence: Alison E. Field, Children's Hospital Boston, Division of Adolescent Medicine, 300 Longwood Avenue Boston, MA 02115. E-mail: Alison.Field@childrens.harvard.edu]