The increased prevalence of obesity in childhood is of concern because of the strong association between obesity and cardiovascular disease risk, hypertension, dyslipidemia, and T2D that begins in childhood and continues into adulthood.
Cardiovascular disease (CVD) is the leading cause of death and disability in the U.S., responsible for some 500,000 deaths a year. Most CVD is the result of the process of atherosclerosis whereby plaque builds up in blood vessels. About 50 percent of CVD is related to coronary artery disease. Although the clinical effects of the process do not usually show up until middle age, atherosclerosis begins in childhood and the extent of atherosclerotic change in childhood and young adulthood is correlated with elevated risk in adults (Rodriguez et al., 2006; Williams et al., 2002).
Risk factors for CVD, such as elevated serum cholesterol and blood pressure occur with increased frequency in obese children and adolescents compared to children with a normal weight. In a population-based sample, approximately 60 percent of obese children aged 5 to 10 years had at least one physiological CVD risk factor, such as elevated total cholesterol, triglycerides, insulin, or blood pressure, and 25 percent had two or more CVD risk factors (Freedman et al., 1999). These risk factors are related in some degree to lifestyle factors such as diet and physical activity. The American Heart Association concludes that existing evidence indicates that primary prevention of atherosclerotic disease should begin in childhood (Williams et al., 2002).
Hypertension contributes substantially to CVD, renal failure, and premature death. The diagnosis of hypertension in children and adolescents is based on the distribution of blood pressure measurement in healthy children. Those with an average systolic or diastolic blood pressure above the 95th percentile for age, gender, and height on three separate occasions are considered to be hypertensive, while those between the 90th and 95th percentile are considered high normal or prehypertensive and are at increased risk for hypertension (AAP, 2004a). NHANES 1999–2000 found that 8 percent of children and adolescents aged 12 to 19 years had hypertension. Recent studies with participants who were predominantly minority and, on average, higher in weight, have shown around 20 to 25 percent of children with hypertension or prehypertension. The rates increase with higher BMIs,