Childhood obesity has become a public health concern over the past three decades. Overweight children and adolescents are now beginning to present with obesity-related chronic diseases, such as hypercholesterolemia, hypertension, and diabetes. Earlier onset of these chronic conditions and resultant disabilities will have long-term ramifications for society and public policy. Lifestyle behaviors, including dietary intakes and physical activity habits, have been identified as primary contributors to increasing obesity rates in the United States. Nutrient-poor, high-fat, energy-dense diets, which are linked to chronic disease development, are common among those with limited incomes. Research is needed to examine the potential of food assistance programs to reduce risk for obesity and resultant chronic diseases in families with limited resources. The primary goal of this project is to investigate the impact of food assistance on the risk of early development of obesity and metabolic syndrome among U.S. adolescents (12-18 years of age) across levels of eligibility and participation in Federal food assistance programs.
A secondary data analysis of adolescents ages 12-18 from the 1999-2006 National Health and Nutrition Examination Survey was conducted to examine the differences in obesity, central adiposity, and metabolic syndrome across levels of food assistance participation. Adolescents were classified into income eligibility and participation/nonparticipation categories for the Food Stamp Program (FSP) (now the Supplemental Nutrition Assistance Program, SNAP), School Breakfast Program (SBP), and National School Lunch Program (NSLP). Further, to elucidate the impact of nonparticipation, income-eligible adolescents were categorized as “participating” or “eligible, not participating.”
Rates of obesity and metabolic syndrome were classified based on anthropometric assessments and laboratory data collected during the mobile examination center visit. Body mass index (BMI)-for-age percentiles were generated based on age and gender to assess body weight. Weight status was categorized based on the 2000 Centers for Disease Control and Prevention (CDC) Growth Charts. The International Diabetes Federation (IDF) definition of metabolic syndrome for children and adolescents was used to identify adolescents with central adiposity (>90th percentile) and metabolic syndrome. The IDF defines metabolic syndrome as the presence of central obesity plus one of four additional risk factors: elevated blood pressure, glucose, and triglycerides and low high-density lipoprotein (HDL).
FSP: Of the sample, 9.1 percent (n=1,031) were participating in FSP, while 21.5 percent (n=2,108) and 69.4 percent (n=4,184) of the nonparticipants were eligible and not eligible, respectively. FSP participants had a significantly higher mean BMI-for-age percentile than those not participating (P=0.003), but there were no significant mean differences in central obesity (P=0.067). FSP participants were significantly more likely to be overweight (17.1 percent) or obese (23.3 percent, P=0.001). Eligible nonparticipants exhibited higher rates of overweight (17.4 percent) and obesity (17.8 percent) than nonparticipants. Also, nearly a quarter of participants (24.8 percent) exhibited a waist circumference in the >90th percentile (P=0.001) in contrast to 17.8 percent of those not eligible, not participating.
Significant differences (P=0.002) in waist circumference existed across categories of FSP participation, with those “participating” (24.8 percent) and “eligible, not participating” (21.8 percent) having the greatest proportion displaying the risk factor. The most prevalent risk factor in all groups was low HDL, with rates highest in the “eligible, not participating” group (35.4 percent, P<0.001). Similar patterns of the presence of the blood pressure risk factor were seen across all groups at nearly 5 percent. The triglyceride risk factor was most prevalent among those “eligible, not participating” (7.1 percent, P=0.009), while those participating in the FSP had the lowest rate of elevated triglycerides. The rates of metabolic syndrome were higher among children “participating” (3.3 percent) or “eligible, not participating” (3.6 percent), but the differences were not significant.
NSLP: Nearly a quarter (n=1,711, 23.0 percent) of children participated in the free or reduced-price breakfast program. Another 1,435 children (20.0 percent) were income eligible but did not participate. Participation in the School Lunch Program was more frequent, with 32.4 percent (n=3,064) receiving free or reduced-price lunches and an additional 41.1 percent (n=1,810) paying full price. No significant differences existed in BMI percentiles or waist circumference by school breakfast participation. Rates of obesity (P<0.001) and central adiposity (P<0.001) were highest among adolescents receiving free or reduced-price lunches (21.6 percent and 24.3 percent) or “eligible, not participating” (21.2 percent and 20.4 percent).
SBP: No significant differences were evident for metabolic syndrome across levels of participation in the SBP. Similar trends existed regarding the most prevalent risk factors, where the waist circumference and HDL risk factors were greatest in each group. Rates of metabolic syndrome were highest in the “eligible, not participating” group (3.7 percent), but the differences among the groups were not significant. Differences in the rates of central obesity were more pronounced for those eligible for participation in the NSLP. Presence of the waist circumference risk factor was 50 percent more likely in the “participating” (24.3 percent) and the “eligible, not participating” (20.4 percent) groups compared with those “participating, paying full price” (18.2 percent) or “not participating” (15.5 percent, P<0.001). The HDL (34.1 percent) and triglyceride (8.7 percent) risk factors were most common in the “eligible, not participating” category, but the differences were not significant.
More information is needed to explain the differences noted in these analyses. Differences in dietary habits and food procurement habits may identify correlates of weight status in these adolescents, which would provide valuable information for targeted nutrition education and policy development for food assistance programs.
Direct inquiries about this study to the Project Contact listed above.