The prevalence of obesity and extreme obesity among young U.S. children seems to be on the decline, according to government researchers.
In a study of almost 27 million children ages 2 to 4 living in low-income families, obesity prevalence fell slightly between 2003 and 2010, from 15.21% to 14.94%, after steadily increasing since 1998, Liping Pan, MD, MPH, of the CDC, and colleagues reported in a research letter in the Journal of the American Medical Association.
The prevalence of extreme obesity -- having a body mass index (BMI) above 120% of the 95th percentile -- fell from 2.22% to 2.07% during that time.
This is the "first national study to show that the prevalence of obesity and extreme obesity among young U.S. children may have begun to decline," Pan and colleague wrote.
They noted that few studies have focused on extreme obesity because of its relatively low prevalence in national data, so Pan and colleagues looked at data from the Pediatric Nutrition Surveillance System, on 26.7 million children in 30 states and Washington, D.C., who were eligible for federally funded maternal and child health and nutrition programs.
All had consistently reported height and weight between 1998 and 2010.
They measured obesity and extreme obesity; the former was defined as being above the 95th percentile for BMI for age and sex.
The researchers found that the prevalence of obesity rose from about 13% in 1998 to 15.21% in 2003, and extreme obesity rose from 1.75% to 2.22% during that time.
But that started to fall after 2003, with obesity prevalence dropping to 14.94% in 2010 and extreme obesity declining to 2.07% at that time.
Specifically with regard to extreme obesity, its prevalence increased overall and in all groups except Asians/Pacific Islanders between 1998 and 2003, they reported.
The greatest average annual increases were among 4-year-olds and non-Hispanic whites, they found. For instance, the prevalence among 4-year-olds was up from 2.4 in 1998 to 3.21 in 2003, and from 1.17 to 1.64 in whites during that time.
But extreme obesity fell between 2003 and 2010 overall and in all groups except American Indians/Alaska Natives (adjusted odds ratio 0.983), they found, with the greatest decreases among those ages 2 and under and among Asians/Pacific Islanders.
Study limitations included the lack of data from every U.S. state.
The results suggest "modest recent progress of obesity prevention among young children," Pan and colleagues concluded, but pointed out that that they still "may have important public health implications because of the lifelong health risks of obesity and extreme obesity in early childhood."