Prevalence of Overweight and Obesity, 1999–2004.

Context:

The prevalence of overweight in children and adolescents and obesity in adults in the United States has increased over several decades.

Objective:

To provide current estimates of the prevalence and trends of overweight in children and adolescents and obesity in adults.

Design, Setting, and Participants:

Analysis of height and weight measurements from 3958 children and adolescents aged 2 to 19 years and 4431 adults aged 20 years or older obtained in 2003–2004 as part of the National Health and Nutrition Examination Survey (NHANES), a nationally representative sample of the US population. Data from the NHANES obtained in 1999–2000 and in 2001–2002 were compared with data from 2003–2004.

Main Outcome Measures:

Estimates of the prevalence of overweight in children and adolescents and obesity in adults. Overweight among children and adolescents was defined as at or above the 95th percentile of the sex-specific body mass index (BMI) for age growth charts. Obesity among adults was defined as a BMI of 30 or higher; extreme obesity was defined as a BMI of 40 or higher.

Results:

In 2003–2004, 17.1% of US children and adolescents were overweight and 32.2% of adults were obese. Tests for trend were significant for male and female children and adolescents, indicating an increase in the prevalence of overweight in female children and adolescents from 13.8% in 1999–2000 to 16.0% in 2003–2004 and an increase in the prevalence of overweight in male children and adolescents from 14.0% to 18.2%. Among men, the prevalence of obesity increased significantly between 1999–2000 (27.5%) and 2003–2004 (31.1%). Among women, no significant increase in obesity was observed between 1999–2000 (33.4%) and 2003–2004 (33.2%). The prevalence of extreme obesity (body mass index more than or equal to 40) in 2003–2004 was 2.8% in men and 6.9% in women. In 2003–2004, significant differences in obesity prevalence remained by race/ethnicity and by age. Approximately 30% of non-Hispanic white adults were obese as were 45.0% of non-Hispanic black adults and 36.8% of Mexican Americans. Among adults aged 20 to 39 years, 28.5% were obese while 36.8% of adults aged 40 to 59 years and 31.0% of those aged 60 years or older were obese in 2003–2004.

Conclusions:

The prevalence of overweight among children and adolescents and obesity among men increased significantly during the 6-year period from 1999 to 2004; among women, no overall increases in the prevalence of obesity were observed. These estimates were based on a 6-year period and suggest that the increases in body weight are continuing in men and in children and adolescents while they may be leveling off in women.

COMMENT

These estimates from the NHANES conducted in 2003–2004 provide the most recent prevalence estimates of overweight and obesity in the United States. Among children and adolescents aged 2 to 19 years, 17.1% were overweight and 32.2% of adults aged 20 years or older were obese. The prevalence of overweight among children and adolescents and obesity among men increased significantly between 1999 and 2004. No increase in overall obesity prevalence among women was observed over the 6-year period.

Multivariable model results indicate that the only statistically significant trends were those noted overall for men and for children and adolescents. Trends did not differ significantly by age or racial/ethnic group. Although differences in point estimates may appear large in some subgroups, the differences are not statistically significant. Subgroup estimates by sex, age, and race/ethnicity are less precise than the overall estimates. This is due to smaller sample sizes and fewer degrees of freedom than for the overall estimates. Future data from NHANES 2005–2006 should provide more information about changes in subgroups.

Increases in prevalence of overweight and obesity among both adults and children have been observed in many countries throughout the world. For example, the prevalence of obesity among adults in Great Britain almost tripled between 1980 and 2002. Among preschool children in urban areas of China, the prevalence of obesity increased from 1.5% in 1989 to 12.6% in 1997.

Similar to previous analyses, there continues to be differences in overweight and obesity prevalence by racial/ethnic group among women and among children and adolescents. Among women, almost 58% of non-Hispanic black women aged 40 to 59 years were obese in 2003–2004 compared with about 38% of non-Hispanic white women of the same age. Among men, however, the prevalence of obesity did not differ by racial/ethnic group. Among children and adolescents, differences by racial/ethnic group exist for both sexes. These racial/ethnic group differences in female children and adolescents were observed in 1988–1994 but these differences were not observed among male adolescents in 1988–1994.

The prevalence of overweight and obesity in the United States remains high. The prevalence of obesity has continued to increase in men and the prevalence of overweight has continued to increase in children and adolescents between 1999 and 2004. However, no significant increases were observed among women. There is little indication that the prevalence is decreasing in any subgroup of the population. These prevalence estimates, based on a 6-year period (1999–2004), suggest that the increases in body weight may be leveling off in women.