From 2008 to 2011, small but significant decreases in obesity rates were observed for low-income preschoolers in 19 U.S. states and territories, according to the CDC.
The absolute decrease in obesity prevalence ranged from 0.3 to 2.6 percentage points, whereas relative decreases ranged from 1.8% to 19.1%, Ashleigh May, PhD, of the CDC in Atlanta, and colleagues reported in Morbidity & Mortality Weekly Report.
Despite the declines, obesity prevalence is still high — one-in-eight low-income preschoolers in the United States is obese, the researchers found.
CDC director Thomas Frieden, MD, MPH, was cautiously optimistic about the study, calling the findings “a bright spot for our nation’s young kids,” in a telephone briefing, but also acknowledged “the fight is very far from over.”
Obesity rates are high across the board for American youths, but the disease is especially prevalent in black (18.9% of 2 to 5 year olds) and Hispanic children (16.2%). A variety of negative mental and physical health consequences stem from childhood obesity, including high blood sugar, high cholesterol, asthma and a greater likelihood of being obese as an adult.
For this study, May and colleagues analyzed height and weight data from 11.6 million low-income children aged 2 to 4 years from 40 states, the District of Columbia and two U.S. territories that participated in the Pediatric Nutrition Surveillance System (PedNSS) from 2008 to 2011. Puerto Rico had the highest incidence of obesity at 17.9%, whereas Hawaii had the lowest at 9.2%.
During the study period, statistically significant downward trends in obesity prevalence were observed in 18 states and the U.S. Virgin Islands, the researchers found.
The greatest declines occurred in the U.S. Virgin Islands, where prevalence fell from 13.6% in 2008 to 11.0% in 2011, for an absolute decrease of 2.6 percentage points (adjusted odds ratio 0.92, 95% CI 0.87-0.97).
Florida, Georgia, Missouri, New Jersey and South Dakota also saw significant decreases in obesity prevalence of at least 1%. Among the 24 other states and territories, 21 saw no significant difference in obesity prevalence and three experienced an upward trend, with a maximum absolute increase in prevalence of 0.7%.
An additional statistical analysis also adjusted for household income, but the effects of this factor were only seen in one state, Montana, which went from experiencing no significant trend to showing a decrease in obesity prevalence (aOR 0.97, CI 0.94-1.00).
In the previous examination of this data in 2009, only nine states saw declines in obesity prevalence, while 24 experienced increases. “We’re going in the right direction for the first time in a generation,” Frieden said.
The researchers were unable to definitively pinpoint the exact cause of the declines, but they suggested several possible contributing factors, “such as local and state initiatives that focus on the implementation of nutrition and physical activity standards for early care and education programs and efforts to improve healthier food options and physical activity offerings in communities.”
In particular, First Lady Michelle Obama has championed efforts to reduce obesity in U.S. children with the “Let’s Move” campaign, and the White House issued the Childhood Obesity Task Force Report in February 2011.
Upward trends in breastfeeding, along with decreases in sugar intake and overall calorie counts for children were also cited as potential contributing factors.
The study results may indicate that the obesity epidemic in this country has been somewhat curtailed, but the researchers called for more efforts, including initiatives to identify and improve local play spaces to give kids’ better opportunities to exercise, and expanding the availability of grocery markets in underserved communities.
Study limitations include the incomplete nature of the data, as not all 50 states participated. The economic recession in recent years might also have caused more children to qualify as low income, the researchers noted, although they did not know how this shift may have altered the findings.