News Author: Laurie Barclay, MD
CME Author: Penny Murata, MD
Penny Murata, MD
Brande Nicole Martin





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.
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.

Clinical Context

According to Freedman and colleagues in the June 1999 issue of Pediatrics, the prevalence of risk factors for cardiovascular disease is greater in overweight children. Berenson and colleagues reported in the June 4, 1998, issue of the New England Journal of Medicine that having more than 1 risk factor in childhood increases the risk for adult cardiovascular disease.
In the September 2005 issue of the Journal of Science in Medicine and Sport/Sports Medicine Australia, Booth and colleagues described the New South Wales Schools Physical Activity and Nutrition Survey (SPANS 2004), a population survey of students in kindergarten and grades 2, 4, 6, 8, and 10 from 45 primary and 48 secondary schools.
This biomarker substudy of the SPANS 2004 adolescent population is a cross-sectional evaluation to evaluate the association between BMI and waist circumference and risk factors for diabetes, cardiovascular disease, and fatty liver disease and whether risk factors are clustered according to BMI.

Study Highlights

2 classes from each school were randomly selected.
Exclusion criteria were attendance at special schools, school enrollment of less than 180 students, and geographically remote location.
Fasting blood samples were obtained from 500 students in grade 10 (mean age, 15.4 years).
4 blood samples were excluded because of preexisting type 1 diabetes and lack of anthropometric data.
58.4% of the subjects were boys.
Subjects self-reported pubertal development and menarche.
Subjects were categorized as nonoverweight, overweight, or obese based on the International Obesity Task Force criteria for BMI or waist circumference at 91st percentile for overweight and 98th percentile for obese.
Overweight and obese categories were combined because of a small number of subjects for some biomarkers.
Boys had combined overweight and obese prevalence of 27.6% based on BMI and 20.0% based on waist circumference.
Girls had combined overweight and obese prevalence of 19.4% based on BMI and 18.0% based on waist circumference.
BMI and waist circumference correlated well for both boys and girls (r = 0.89; P <.001).
Biomarkers for cardiovascular disease, diabetes, and fatty liver disease and reported prevalences in study population were as follows:
Systolic or diastolic blood pressure greater than 90th percentile adjusted for height, age, and sex (22.1% of boys; 10.8% of girls)
HDL cholesterol levels less than 40 mg/dL (10.7% of boys; 3.9% of girls)
LDL cholesterol levels more than 131 mg/dL (4.5% of boys; 6.3% of girls)
High-sensitivity CRP levels greater than 3.0 mg/L (7.5% of boys; 8.6% of girls); 6 subjects with levels greater than 10.0 mg/L were excluded
Triglyceride levels greater than 199 mg/dL (1.0% of boys; 0.5% of girls)
Glucose levels greater than 110 mg/dL (0.7% of boys; no girls)
Insulin levels at 75th percentile or higher (90.28 µIU/mL in boys; 97.23 µIU/mL in girls)
ALT levels of 30 U/L or greater
GGT levels of 30 U/L or greater (3.5% of boys; 2.4% of girls)
Obesity in boys was significantly linked with abnormal values of insulin (P < .001), ALT (P < .001), GGT (P = .005), HDL cholesterol (P < .001), high-sensitivity CRP (P < .001), and blood pressure (P < .001).
Multivariable analysis showed a persistent link for abnormal values of insulin, ALT, HDL cholesterol, and blood pressure in boys.
Obesity in girls was significantly linked with abnormal values of insulin (P < .001), HDL cholesterol (P < .001), and high-sensitivity CRP (P < .001).
Multivariable analysis showed a persistent link for values insulin, HDL cholesterol, and high-sensitivity CRP in girls based on BMI, but only insulin levels were linked with waist circumference.
Obese vs nonobese boys were more likely to have at least 2 risk factors for chronic conditions (73.5% vs 7.6%; odds ratio [OR], 34.0; 95% confidence interval [CI], 12.6 - 91.7; P<.001).
Obese vs nonobese girls were more likely to have at least 2 risk factors for chronic conditions (44.4% vs 5.4%; OR, 14.0; 95% CI, 4.1 - 47.5; P < .001).
Limitations of the study included difficulty in determining abnormal cutoff points for biomarkers, lack of testing for other causes of liver disease, and lack of information on alcohol and drug use and family history of cardiovascular disease.

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.

Bron : Medscape