Prevalence of extreme obesity in a multiethnic cohort of children and adolescents

Abstract

Objective: To estimate the prevalence of extreme obesity in a large, multiethnic contemporary cohort of children and adolescents.

Study design: In a cross-sectional study, measured weight and height were extracted from electronic medical records of 710,949 patients aged 2 to 19 years (87.8% of eligible patients) who were enrolled in an integrated prepaid health plan in 2007 and 2008. Prevalence of extreme obesity was defined as body mass index (BMI)-for-age>or=1.2 times 95th percentile or BMI>or=35 kg/m2.

Results: Extreme obesity was observed in 7.3% of boys and 5.5% of girls. The prevalence peaked at 10 years of age in boys and at 12 years of age with a bimodal distribution in girls (second peak at 18 years; P value for sex x age interaction=.036). The prevalence of extreme obesity varied in ethnic/racial and age groups, with the highest prevalence in Hispanic boys (as high as 11.2%) and African-American girls (as high as 11.9%).

Conclusion: Extreme obesity in Southern California youth is frequently observed at relatively young ages. The shift toward extreme body weights is likely to cause an enormous burden of adverse health outcomes once these children and adolescents grow older.

Figure 1

Comparison of the percentiles of BMI for boys from CDC growth charts with empiric percentiles of Southern California patients aged 2 to 19 years.

Figure 2

Comparison of the percentiles of BMI for girls from 2000 CDC growth charts empiric percentiles of Southern California patients aged 2 to 19 years.

Figure 3

Percentage of extremely obese boys and girls according to age. In boys, extreme obesity develops at an earlier age than in girls, but girls catch up later, with a similar prevalence at age 18 to 19 years (P for sex × age interaction = .036).