Childhood and adolescent overweight are associated with an increased risk of coronary heart disease in young and middle-aged adults, researchers in two separate studies reported.

Given the current surge in pediatric weight gain worldwide, these findings indicate that there will be substantial

In the first study, Jennifer L. Baker, Ph.D., of the Institute for Health and Society, Copenhagen, and her associates analyzed data from a cohort of people born between 1930 and 1976 who had initially been examined as schoolchildren. The study sample included "virtually every schoolchild in Copenhagen" during that interval.

The investigators calculated the subjects' body mass index from these records, then used national databases to track CHD diagnoses and deaths that occurred in 280,678 of the subjects in adulthood.

There were 10,235 CHD events in men and 4,318 in women during follow-up. The risk of an event rose significantly and in a linear fashion for every 1-U increase in BMI z score at every age from 7 to 13 years.

The CHD risk rose with increasing child age, so that the risk in adults who had had a high BMI at age 13 was twice as high as that for adults who had had a high BMI at age 7. "We speculate that ... increases in BMI z scores at these later ages could reflect a greater accumulation of fat, in particular intraabdominal fat, which increases the risk of CHD," the investigators said.

"In comparison with an average-size 13-year-old boy, a boy of the same age and height weighing 11.2 kg more had a 33% higher risk of having a CHD event" before age 60. Similar results were observed for girls, Dr. Baker and her associates said (N. Engl. J. Med. 2007;357:2329-37).

This pattern held true for both fatal and nonfatal CHD events, even after the data had been adjusted to account for the subjects' birth weight. Moreover, the pattern held true regardless of whether subjects were born before or during the current obesity epidemic.

"Currently, children are typically classified as being at risk only if their BMI values are above cutoff points such as the 85th or 95th percentile on growth charts. Our results do not support this approach. The linearity of the associations we identified between childhood BMI and adult CHD implies that even a surprisingly small amount of weight gain will increase the risk of CHD," they noted.

In the second study, Kirsten Bibbins-Domingo, Ph.D., of the University of California, San Francisco, and her associates used computer simulation models to estimate the potential effect of adolescent overweight on future adult CHD. The models incorporated data from the U.S. Census, the National Center for Health Statistics, Medicare, the Framingham Heart Study, and the National Health and Nutrition Examination Surveys to project the proportion of obese 35-year-old men and women in successive cohorts from 2020 to 2035.

The prevalence of adolescent overweight in 2000 was 17% in boys and 15% in girls. "By the time these adolescents turn 35 years old in 2020, the proportion of obese 35-year-olds is projected to be 30%-37% in men (as compared with 25% now) and 34%-44% in women (as compared with 32% now)," the investigators said.

They projected a steep rise in total CHD events, "with 550 absolute excess events in 2020 (an excess of 10%) increasing to 33,000 excess events in 2035 (an excess of 14%).

"The annual excess in the incidence of CHD is projected to rise from 1,600 in 2000 to 40,000 in 2035, an excess of 15% over the incidence that would have been expected without the increase in future obesity." Similarly, the number of excess CHD deaths is projected to rise from 59 in 2020 to 3,600 in 2035, Dr. Bibbins-Domingo and her associates said (N. Engl. J. Med. 2007;357:2371-9).

Although projections into the future "are notoriously unreliable," analyses of current treatments and trends "suggest that barring a major advance in the treatment of either excessive weight gain itself or its associated alterations in blood pressure, lipid levels, and glucose metabolism, current adolescent overweight will have a substantial effect on public health far into the future," they noted.

BY MARY ANN MOON

Contributing Writer