Obesity in Preschoolers May Be Declining, Analysis Suggests

Jenni Laidman

February 10, 2015

Trends from multiple studies suggest preschoolers in the United States may be bridging a caloric gap, researchers report in a commentary published online February 9 in Pediatrics. The results suggest the recent decline in obesity rates in 2- to 5-year-olds may continue.

The caloric gap estimates how many calories children must eliminate from their daily diet to bring obesity rates down to the 1970s pre–obesity epidemic levels. Among children aged 2 to 5 years, the gap is about 30 kcal daily.

Such a calorie reduction may be behind the findings from two national surveys that showed declining obesity rates among preschoolers in recent years, note William H. Dietz, MD, PhD, director of the Sumner M. Redstone Global Center for Prevention and Wellness at the Milken Institute School of Public Health, George Washington University, Washington, DC, and Christina D. Economos, PhD, director of the John Hancock Research Center on Physical Activity, Nutrition, and Obesity Prevention, Tufts University, Medford, Massachusetts.

Dr Dietz and Dr Economos considered both the most recent report of the National Health and Nutrition Examination Survey (NHANES) and the Pediatric Nutrition Surveillance System (PedNSS) annual state-based survey of 2- to 4-year-old low-income children. Both surveys showed a trend toward declining obesity among preschool-age children.

The NHANES database demonstrated a statically significant 5.5% decrease in obesity prevalence among 2- to 5-year-olds between 2003 to 2004 and 2011 to 2012, after declines in 2008 and 2009, the authors note. No change in obesity rates occurred in other age groups. In 2008 and 2011, PedNSS found a significant decrease in the absolute prevalence of obesity, averaging 0.7% (range, 0.3% - 1.6%) in 18 states in 2008 and 2011.

Supporting these data, studies from 6 states and 14 communities also reported a decline in childhood obesity prevalence similar to that seen in PedNSS, the authors report.

"I continue to be encouraged," Sarah E. Barlow, MD, MPH, told Medscape Medical News, when asked about the new analysis.

"I have my fingers crossed that we'll continue to see this with the next round of NHANES results," continued Dr Barlow, who is an associate professor of pediatrics at Baylor College of Medicine and director of the Center for Childhood Obesity at Texas Children's Hospital, Houston.

The authors report, "If current trends in decreased fast food and sugar drink consumption continue, and as the current cohort of 2- to 5-year-old children ages, we might anticipate further declines in the prevalence of childhood obesity. However, the greater declines observed in white children compared with other ethnic groups emphasize that intensified efforts to identify and implement effective strategies to address ethnic disparities are essential."

The authors point to a number of trends that may have contributed to the decline in obesity prevalence in the younger set and helped toddlers bridge the caloric gap. For instance, the authors cite a 2013 report published in the American Journal of Clinical Nutrition estimating that between 1990 to 2000 and 2009 to 2010, the daily intake of sugary beverages fell by 68 kcal in 2- to 5-year olds. In addition, between 2003 to 2004 and 2007 to 2008, children aged 2 to 11 years reduced the number of calories they consumed at fast food restaurants by 64 calories.

Although children in other age groups also reduced calories in those time frames, they faced larger gaps. Those aged 6 to 11 years old need to cut consumption by 150 kcal daily to lower obesity rates to 1970s levels, and 12- to 19-year-olds have a 180-kcal gap to close. Children aged 6 to 11 years cut sugary drink consumption by 71 kcal, and children aged 12 to 19 years reduced sugary beverages by 84 kcal. Children aged 12 to 19 years reduced fast food consumption by only 14 kcal, the authors report.

The authors also note that another contributor to the preschooler weight loss could be the inclusion of fruits and vegetables in the Supplemental Nutrition Program for Women, Infants and Children food packages, which began in 2009. The program also now includes whole grains and 2% milk. Another possible contributor is a reduction in the calorie supply. Last year, the Healthy Weight Commitment Foundation announced a 6.4 trillion calorie reduction by companies that supply 36% of the calories sold in the United States, which adds up to nearly 80 kcal per person per day, the authors report.

Although praising the commentary and calling the recent decline in pediatric obesity "encouraging," Youfa Wang, MD, PhD, told Medscape Medical News that it is important to remember the limitations of the cited studies, including sample size. Dr Wang is a professor in the Department of Epidemiology and Environmental Health in the State University of New York at Buffalo and chair of the Department of Social and Preventive Medicine in the School of Public Health and Health Professions.

"Mainly, the decline is just observed in preschool age children, but not in older children. Most of the data used are collected from very small samples," he said, noting at although the studies were designed to provide a nationally representative estimate, "it's of doubt how nationally representative the related estimates are, in fact."

Further, Dr Wang said, declining obesity in low-income populations could be a result of an increase in the number of children from minority and immigrant groups. "Some of them may be likely to have lower weight than other groups of children," he noted.

He said First Lady Michele Obama's efforts addressing childhood obesity also may have mobilized some parents. "Such efforts have drawn more parents' attention, and may have affected their parenting regarding their children," he said. "Likely young kids, but not the older ones, are more responsive to such efforts by the parents."

The authors, Dr Barlow, and Dr Wang have disclosed no relevant financial relationships.

Pediatrics. Published online February 9, 2015.


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