Risk of heart disease from childhood obesity reversible

Obese children who lose weight as adults have the same risk for developing heart disease as people who were never obese at all, results from a meta-analysis indicate.

There were no differences between these two groups in terms of several cardiovascular disease parameters including type 2 diabetes, hypertension and dyslipidemia, Markus Juonala, MD, PhD, of the University of Turku, in Turku, Finland, and colleagues, reported in the New England Journal of Medicine.

The researchers examined data from 6,328 patients enrolled in four prospective studies that assessed cardiovascular disease risk using childhood and adult BMI: the Bogalusa Heart Study, the Muscatine Study, the Childhood Determinants of Adult Health Study, and the Cardiovascular Risk in Young Finns Study.

Patients were followed from childhood to adulthood for a mean 23 years; 774 patients were overweight or obese as children, of which 64.6% remained obese as adults.

The researchers found that patients who were consistently heavy from childhood to adulthood had a greater risk of several markers of cardiovascular disease (P≤0.002 for all) compared with children whose BMI remained normal through adulthood:

  • Type 2 diabetes: RR 5.4 (95% CI: 3.4-8.5)
  • Hypertension: RR 2.7 (95% CI: 2.2-3.3)
  • Elevated LDL: (RR 1.8, 95% CI: 1.4-2.3)
  • Reduced HDL: (RR 2.1, 95% CI: 1.8-2.5)
  • Elevated triglycerides: (RR 3.0: 95% CI 2.4-3.8)
  • Carotid artery atherosclerosis: (RR 1.7: 95% CI 1.4-2.2)

But these risks did not remain for those who were heavy as children but lost weight as adults. The effects of childhood adiposity on the risk of type 2 diabetes, dyslipidemia and carotid atherosclerosis became nonsignificant when adult obesity was taken into account, the researchers noted.

Only the association between childhood obesity and hypertension remained significant, suggesting that childhood adiposity may have “a residual effect on the risk of hypertension,” the researchers wrote.

Obese adults, however, had significantly increased risk for all outcomes regardless of childhood adiposity.

In light of the findings, Juonala and colleagues suggested that efforts to reduce in overweight and obese children and adolescents could help reduce their cardiovascular risk.

"If this hypothesis is correct, primary care physicians should not take the pessimistic view that once childhood obesity is established, cardiovascular risk is also determined," they wrote, "but should recognize that cardiovascular risk may be substantially reduced if childhood obesity is successfully treated."

The researchers warned that the findings might lack generalizability as the studies involved mostly white participants. Other limitations included inability to compare the effect of certain variables, such as socioeconomic status, across cohorts, and inability to establish causality due to the study's observational nature.

Juonala M et al. N Eng J Med. 2011; 365:1876-1885.

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