CME Author: Penny Murata, MD
June 2, 2008 — Teens who were obese and overweight had a higher risk for chronic diseases such as type 2 diabetes, cardiovascular disease, and fatty liver disease, according to the results of an Australian cross-sectional study reported in the June issue of the Archives of Pediatrics & Adolescent Medicine.
"Several studies have shown that obese children and adolescents have an increased prevalence of metabolic risk factors for cardiovascular disease, type 2 diabetes, and, more recently, fatty liver disease," write Elizabeth Denney-Wilson, PhD, MPH, BN, from the University of Sydney in Sydney, Australia, and colleagues. "Although morbidity could be expected to increase in parallel with the prevalence of obesity, little is known about chronic disease risk factors in the general adolescent population. Most studies of comorbidities either have been conducted in clinic-based groups of severely obese adolescents or have not studied the full range of metabolic complications."
The goal of this study was to evaluate the association between measures of adiposity (body mass index [BMI] and waist circumference) and risk factors for heart disease, type 2 diabetes, and fatty liver disease as well as the clustering of risk factors in middle adolescence.
At secondary schools in Sydney, 496 grade 10 students were categorized as overweight or obese by the International Obesity Task Force cutoff points and the UK waist circumference cutoff points. Mean age was 15.4 ± 0.4 years; 58.4% were boys. Blood samples were tested for high-density lipoprotein (HDL) and low-density lipoprotein (HDL) cholesterol, triglycerides, insulin, glucose, alanine aminotransferase (ALT), gamma-glutamyltransferase (GGT), and high-sensitivity C-reactive protein (CRP) levels. Published guidelines were used to categorize these results as normal or abnormal. Logistic regression helped define associations between overweight and obesity and risk factors, and clustering of risk factors within individuals was also examined.
In adolescent boys, factors significantly associated with overweight and obesity were insulin levels (P <.001), ALT (P <.001), GGT (P = .005), HDL cholesterol levels (P < .001), high-sensitivity CRP levels (P <.001), and blood pressure (P <.001). Factors significantly associated with overweight and obesity in adolescent girls were insulin, HDL cholesterol (P <.001) and high-sensitivity CRP levels (P < .001).
Compared with adolescents who were not overweight, obese adolescent boys and girls were significantly more likely to have 2 or more risk factors (boys: 73.5% vs 7.6%; girls: 44.4% vs 5.4%; P < .001 for both).
"Overweight and obese adolescents, especially boys, are at substantial risk for chronic conditions," the study authors write. "Waist circumference is not a better predictor of metabolic risk factors than is . . . BMI."
Limitations of this study include lack of data on family history of cardiovascular disease and lack of reporting of the consumption of alcohol and other drugs.
"The propensity of adiposity, behaviors, and risk factors to track from adolescence through adulthood would suggest that health care systems can expect a greater burden of disease from obesity-related conditions when today's young people achieve adulthood," the study authors conclude.
Pearls for Practice
- In adolescent boys, overweight and obesity are linked with abnormal values of insulin, ALT, GGT, HDL cholesterol, high sensitivity CRP, and blood pressure. In adolescent girls, overweight and obesity are linked with abnormal values of insulin, HDL cholesterol, and high sensitivity CRP.
- Obese adolescents, especially boys, are more likely to have at least 2 risk factors for heart disease, type 2 diabetes, and fatty liver disease than nonobese adolescents.
The New South Wales Department of Health supported this study. The study authors have disclosed no relevant financial relationships.
Arch Pediatr Adolesc Med. 2008;162:566-573.