Preventing children from accumulating too much body fat between adolescence and young adulthood could help protect their heart health, a new study suggests.

Individuals who showed the highest gains in body mass index (BMI), a measure of weight in relation to height, between the ages of 13 and 27, also showed the greatest gains in mass of the heart’s main pumping chamber, the left ventricle (LV), Dr. Julia Steinberger of the University of Minnesota Medical School in Minneapolis and colleagues found. Greater LV mass has been tied to an increased risk of heart disease, heart failure and stroke.

Whether a person was thin or heavy at the study’s outset had no effect on the link between greater BMI gain and LV mass.

“This finding suggests that strategies to limit excessive weight gain between childhood and adulthood may prevent unwarranted increases in LV mass,” Steinberger and her team write in the American Journal of Cardiology.

To investigate how excess weight might influence LV mass, the researchers assessed BMI, LV mass in 132 healthy children, average age 13, and then reassessed them at age 27.

An individual’s BMI at both time points were strongly correlated, as were LV mass measurements, while BMI and LV mass also were associated with one another. The BMI-LV mass relationship became stronger over time.

The researchers also found that people who gained 5.5 or more points in BMI during the course of the study showed a proportionately larger increase in LV mass than those who experienced lower BMI gains, regardless of whether they were thin or heavy at the beginning of the study.

People who showed the largest increases in BMI were more likely to have risk factors for the metabolic syndrome, a constellation of factors including insulin resistance that boosts heart disease and diabetes risk.

“These results reaffirm the important role of obesity and the rate of weight gain at the transition between adolescence and young adulthood in the development of increased LV mass and cardiovascular risk factors,” the researchers conclude.

SOURCE: The American Journal of Cardiology, August 1, 2006.