Reversal of Childhood Overweight May Prevent Later CHD Risks

People who were overweight as children but achieve a normal weight by young adulthood appear to have a long-term risk of coronary heart disease (CHD) similar to what’s seen in people who were never overweight as youth, a population-based cohort study from Sweden suggests.

On the other hand, those who develop overweight during the onset of puberty carry even greater risks of future CHD compared with their peers with persistent overweight early in life, researchers led by Claes Ohlsson, MD, PhD (University of Gothenburg, Sweden), report in a study published online this week in JAMA Pediatrics.

“The clinical implications are that we should identify and treat childhood unhealthy weight,” senior author Jenny Kindblom, MD, PhD (University of Gothenburg), told TCTMD. “We believe that our findings lend some support to the fact that it might actually improve the prognosis, improve the risk situation, for this child, at least concerning CHD.”

Though parents and young people themselves should be involved in addressing overweight and obesity in childhood, there’s also a “societal responsibility” to support this, she added.

Childhood overweight and obesity have been associated with the development of CHD in adulthood, and Kindblom said her group has been researching whether the long-term health risks of excess adiposity vary depending on when it occurs and whether it persists into adulthood.

From Kids to Adolescents to Adults

In this study, the investigators turned to the BMI Epidemiology Study (BEST), which enrolled individuals born between 1945 and 1968 in Gothenburg, Sweden’s second largest city. Child and school health records were linked to nationwide registries to enable the tracking of changes in body mass index (BMI) and the long-term risk of CHD.

Overweight/obesity in childhood (age 7 years for females and 8 years for males) was defined according to cutoffs from the International Obesity Task Force. In young adulthood (age 18 years for females and 20 years for males), overweight was defined by a BMI of 25 to < 30 kg/m² and obesity by a BMI of 30 kg/m² or greater. Long-term follow-up started when participants were 22 years old, lasting for an average of 37.8 years.

The analysis included 103,232 people (44.5% women). Mean childhood BMI was 15.6 kg/m2, with 6.3% of individuals being overweight or obese. In young adulthood, mean BMI was 21.1 kg/m², with 6.6% being overweight or obese. The prevalence of obesity was low (0.8%) at both time points.

During long-term follow-up, 5.6% of individuals had a CHD event, including 0.9% that were fatal. Childhood overweight (HR 1.15; 95% CI 1.02-1.28) and overweight/obesity in young adults (HR 1.71; 95% CI 1.56-1.86) each were associated with a greater risk of CHD.

Changes in BMI between childhood and young adulthood influenced risk, however. Individuals who were overweight as children but not as young adults had a CHD risk similar to that seen in those who maintained a normal weight at both time points (HR 0.98; 95% CI 0.84-1.14), with similar results for males and females.

Persistent overweight while young and pubertal onset of overweight were both associated with a greater risk of adult CHD compared with maintenance of normal weight from childhood to young adulthood, although there was excess risk associated with pubertal onset versus persistent overweight (HR 1.23; 95% CI 1.03-1.49).

This study wasn’t designed to answer why that would be, but it likely has something to do with sex hormones, Kindblom indicated, adding that the finding is not necessarily surprising. “We have previous findings that the pubertal BMI change is very tightly linked to the risk of different kinds of cardiovascular disease, like stroke, heart failure, cardiovascular death, coronary atherosclerosis, and more,” she said.

Overall, the findings suggest childhood overweight should be treated as soon as it’s identified, the researchers say. “These findings have implications for public health planning, emphasizing the importance of early detection and treatment of overweight during childhood and adolescence,” they write.

The authors acknowledge that the findings are limited by the inability to account for lifestyle factors like smoking, the possibility of residual confounding, the inclusion of mostly white individuals, and the very low rate of severe obesity in the cohort.

Commenting for TCTMD, Sheldon Litwin, MD (Medical University of South Carolina, Charleston), said the study is challenging to interpret since it’s missing information on various risk factors.

“It’s hard to really interpret whether the changes [in BMI] from childhood to puberty to adulthood are what matters or whether it’s changes in risk factors or whether it’s a cumulative effect of obesity,” Litwin said. “It’s probably more the latter if I had to guess.”

Either way, “clearly, obesity is driving all kinds of risk factors in children and that’s a problem,” Litwin said, agreeing that excess adiposity in children should be treated and, more importantly, prevented. “We need to work on trying to keep this from happening at any point throughout the human lifespan.”