A new study suggests people who are overweight or obese early in life may not be more likely to have heart disease or stroke as adults.

However, the study’s authors point out that the population data used in their analysis were collected many years ago, and more precise investigations in today’s children are necessary to fully answer to the question of whether childhood obesity or being overweight increases the risk of future cardiovascular disease risk.

The prevalence of obesity has tripled in most of the developed world during the past 20 years, Dr. Debbie A. Lawlor of the University of Bristol in the UK and colleagues note, raising fears of a future epidemic of heart disease.

But studies investigating whether childhood overweight is related to later heart disease risk have not uniformly supported this concern.

To investigate, the researchers evaluated the relationship of early body mass index (BMI) and the risk of heart disease or stroke in three groups of individuals who had been followed for decades. All of the subjects were born between 1922 and 1950. The height and weight of participants in each group had been checked in childhood, adolescence or young adulthood. The groups included nearly 24,000 people in total.

The researchers’ analysis found no strong statistical evidence for any association between early-life BMI and future heart disease or stroke risk, according to their report in the American Journal of Clinical Nutrition.

While the average BMIs in each of the three groups were similar to those seen today, childhood obesity and overweight in the three groups were much less common. For example, “almost none” of the individuals in the study were categorized as obese and 4 percent to 6 percent were overweight, compared to roughly 1% obesity and 10% overweight seen in studies of children done between 1978 and 1993.

“The relatively low levels of overweight or obesity in our cohorts may explain the lack of strong statistical evidence for associations between early life overweight or obesity and CVD outcomes,” Lawlor and her team write.

It’s also possible, they suggest, that childhood obesity or overweight do not increase future heart disease or stroke risk if other risk factors are well controlled. Finally, they note, BMI may not be the most accurate measure of excess fat for children.

“In the future, results from studies of contemporary children that have direct measurements of lean and fat mass will be able to provide a more definitive assessment of the effect of early life adiposity and its distribution on future CVD risk,” they conclude.

SOURCE: American Journal of Clinical Nutrition, April 2006.