"Two lifestyle behaviors associated with obesity, insulin resistance, and metabolic syndrome are (1) high levels of sugar-sweetened beverage...intake and (2) low levels of physical activity," write Andrew A. Bremer, MD, PhD, from the University of California Davis School of Medicine in Sacramento, and colleagues.
"Dietary modifications and consistent exercise are thus 2 recommendations typically given by pediatricians to children and adolescents either at risk for or currently diagnosed with these disorders. Experimental studies support the hypothesis that [sugar-sweetened beverages] may increase energy intake and induce weight gain via their reduced satiety response, the promotion of a positive energy balance by liquid calories relative to isoenergetic solid calories, and their dysregulation of energy homeostasis."
The goal of this study was to examine the association between insulin resistance-associated metabolic parameters and anthropometric measurements with sugar-sweetened beverage intake and physical activity levels, using a nationally representative sample of 6967 US adolescents participating in NHANES during the years 1999 to 2004. Age range was 12 to 19 years.
Sugar-sweetened beverages were defined as caloric soft drinks, colas, sugar-sweetened fruit drinks, and any other sugar-sweetened drinks.
The exposure of interest was sugar-sweetened beverage consumption and physical activity levels, and the main endpoints were glucose and insulin concentrations; a homeostasis model assessment of insulin resistance (HOMA-IR); total, high-density lipoprotein, and low-density lipoprotein cholesterol concentrations; triglyceride concentrations; systolic and diastolic blood pressure; waist circumference; and body mass index percentile for age and sex. Body mass index was calculated as weight in kilograms divided by height in meters squared.
Increased sugar-sweetened beverage intake was independently associated with increased HOMA-IR, systolic blood pressure, waist circumference, and body mass index percentile for age and sex and decreased high-density lipoprotein cholesterol concentrations, based on multivariate linear regression analyses. Increased physical activity levels were independently associated with reduced HOMA-IR, low-density lipoprotein cholesterol concentrations, and triglyceride concentrations and increased high-density lipoprotein cholesterol concentrations.
"Low sugar-sweetened beverage intake and high physical activity levels appear to modify each others' effects of decreasing HOMA-IR and triglyceride concentrations and increasing high-density lipoprotein cholesterol concentrations," the study authors write. "Sugar-sweetened beverage intake and physical activity levels are each independently associated with insulin resistance-associated metabolic parameters and anthropometric measurements in adolescents."
Limitations of this study include cross-sectional design precluding determination of causality, inability to adjust for the subjects' degree of sexual maturation, and use of questionnaire data with inherent limitations.
"Although prospective studies are needed to directly test the effects of dietary modification and consistent exercise on the development of obesity, insulin resistance, and metabolic syndrome in the pediatric population, pediatricians should continue promoting these lifestyle modifications in efforts to improve overall health," the study authors conclude.
The National Center for Research Resources, a component of the National Institutes of Health (NIH), and NIH Roadmap for Medical Research supported this study. The authors have disclosed no relevant financial relationships.
Arch Pediatr Adolesc Med. 2009;163:328-335.