Childhood obesity predicts cardiovascular disease in adults

February 2008

Childhood overweight has increased at an alarming rate over the past two decades, with 17% of children and adolescents having BMI > 95% and approximately one-third of all youth having BMI > 85%.

Obesity is associated with increased secretion of leptin, IL-6, and TNF-α by adipocytes.

These adipokines are associated with insulin resistance and decreased secretion of the insulin sensitizer adiponectin. Insulin resistance, in turn, leads to dyslipidemia, hypertension, abnormal carbohydrate tolerance, and a pro-thrombotic state, a cluster of cardiovascular disease risk factors.

Thus, it would be expected that the epidemic of obesity in children and adolescents would result in earlier onset of cardiovascular disease, with increased morbidity and mortality that would incur a huge cost to society, both as a financial burden to the health care system and in personal cost to the individual as decreased quality of life and decreased productivity, with absenteeism and unemployment.

Until recently, no studies had demonstrated early coronary artery disease in young adults and middle-aged individuals who had been obese as adolescents, although several studies have shown obese youth to have increased surrogate markers of cardiovascular disease, including increased carotid intima media thickening (CIMT) and decreased brachial artery reactivity. Two longitudinal studies of 22 years’ duration have found increased risk of surrogate markers of cardiovascular disease in adults who were overweight as children.

The Bogalusa Heart Study found high childhood BMI and LDL-C correlated with CIMT in adults aged 25 to 37 years. Similarly, the Cardiovascular Risk In Young Finns study of 2,200 adults initially studied when they were aged 3 to 18 years found correlates of adult CIMT included childhood BMI, LDL-C, systolic BP, and smoking.

This latter study is of particular concern because increased CIMT persisted in adulthood if the child had high BMI during adolescence, independent of adult BMI, indicating that blood vessel changes are likely already irreversible at a young age.

Baker et al recently reported that BMI in Danish children aged 7 to 13 years was positively associated with risk of coronary heart disease when they were young adults or middle-aged. The risk increased linearly with increased BMI and the association became stronger as the children in this age range got older, consistent with the Finnish data indicating more of an effect of obesity in the pubertal ages and less of an effect of overweight during the pre-pubertal years.

Bibbins-Domingo et al estimated the prevalence of obese 35-year-old adults in 2020 based on the prevalence of adolescent obesity in 2000 and estimated that the prevalence of CHD would increase 5% to 16% by 2035, translating to more than 100,000 excess cases of CHD due to obesity in the United States alone.

Reversing obesity-related increases in blood pressure and LDL-C could blunt the increase in CHD events in this model, especially at younger ages.

Counsel patients early

These studies are sobering. Unless we commit the resources necessary to provide an environment that encourages physical activity and healthy eating, provides adequate reimbursement for obesity treatment programs, and invests in obesity prevention initiatives, this problem will not diminish.

Pediatricians must be proactive in identifying and counseling patients early if they notice an increase in BMI percentile or SDS for age and sex, especially if the parents are obese. They should counsel parents of children at high risk for obesity (children of mothers who had gestational diabetes, were either SGA or LGA at birth, had early adiposity rebound, etc.) to initiate healthy lifestyle habits early.

And, finally, blood pressure and fasting lipid profiles should be obtained in all children who are overweight and, if abnormal, be treated aggressively. If a three- to six-month trial of lifestyle modification is unsuccessful in lowering blood pressure and hyperlipidemia, pharmacologic intervention is appropriate.

Until we can prevent obesity, we need to treat it and its co-morbidities aggressively if we are to diminish early heart disease in these children.

For more information:

• Janet H. Silverstein, MD is the Chief of the Department of Pediatrics, Division of Endocrinology, University of Florida, Gainesville.
• Baker JL, Olsen LW, Sørensen TIA. Childhood body-mass index and the risk of coronary heart disease in adulthood. N Engl J Med.2007;357:2329-2337.
• Bibbins-Domingo K, Coxson P, Fletcher MJ, et al. Adolescent overweight and future adult coronary heart disease. N Engl J Med.2007;357:2371-2379.
• Iannuzzi A, Licenziati MR, Acampora C, et al. Increased carotid intima-media thickness and stiffness in obese children. Diabetes Care. 2004;27:2506-8.
• Li S, Chen W, Srinivasan SR, et al. Childhood cardiovascular risk factors and carotid vascular changes in adulthood: the Bogalusa Heart Study. JAMA. 2003;290:2271-2276.
• Meyer AA, Kundt G, Steiner M, et al. Impaired flow-mediated vasodilation, carotid artery intima-media thickening, and elevated endothelial plasma markers in obese children: the impact of cardiovascular risk factors. Pediatrics. 2006;117:1560-1567.
• Raitakari OT, Juonala M, Kähönen M, et al. Cardiovascular risk factors in childhood and carotid artery intima-media thickness in adulthood: the Cardiovascular Risk in Young Finns Study. JAMA.2003;290:2277-2283.