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Rate of change in childhood BMI predicts adult obesity risk

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February 13, 2019

The rate of change in BMI at different ages during childhood, particularly during and after puberty, is differentially associated with adult obesity, independent of absolute BMI values at corresponding ages, according to findings from a longitudinal analysis published in Pediatric Obesity.

“Previous studies have examined different characteristics of BMI growth patterns in early life, such as early rebound, period growth velocity and group membership of modelled trajectories, for their relevance to adult obesity and cardiometabolic health,” Wei Chen, MD, PhD, a research professor and genetic epidemiologist at Tulane University School of Public Health and Tropical Medicine in New Orleans, and colleagues wrote in the study background. “Yet the relevance of rate of change at different ages during childhood for adult obesity risk had not been reported.”

Chen and colleagues analyzed data from 2,732 adults who participated in the Bogalusa Heart Study, which included a series of long-term observations conducted every 2 to 3 years between 1973 and 2010 (44.9% men; mean follow-up, 28.4 years). Participants underwent repeated BMI measurements in childhood (aged 4-19 years) and adulthood (aged 20-51 years). Researchers used a random-effects model to construct BMI growth curves by race and sex, and model-estimated levels and linear growth rates were linked to adult obesity in separate logistic regression models at individual childhood age points.

The overall prevalence of adult obesity in the cohort was 34%, with a between-sex difference observed among black adults (44.7% in women vs. 30% in men; P < .001) and a between-race difference among women (44.7% in black women vs. 30.3% in white women).

Researchers found that BMI levels were correlated with rates of change in BMI at different ages during childhood (P < .001 for all). The BMI growth curves for adults with and without obesity separated in early childhood, according to the researchers, and linear growth rates during childhood were greater for adults with obesity vs. adults without obesity.

In multiple regression analyses, researchers found that a higher rate of change in BMI during childhood tended to be associated with increased odds for developing obesity in adulthood. The association was weakest at age 6 to 8 years and peaked at age 14 years (OR = 3.1; 95% CI, 2.7-3.5), before gradually decreasing; however, the OR remained more than 2 at age 19 years, according to researchers.

“In contrast, the BMI levels-adult obesity associations did not show a similar trend, although higher BMI levels at childhood ages were all significantly associated with adult obesity; the strength of the association decreased from [age] 5 to 10 years and remained relatively stable after age 11 [years],” the researchers wrote.

The researchers noted that the growth curve model did not fit well with the observed data from age 4 to 6 years, due to the small number of observations and adiposity rebound during this period, and any associations for that age should be interpreted with caution.

“Our observations support early prevention and intervention of childhood obesity,” the researchers wrote. “It remains to be determined, however, whether specifically targeting critical periods during childhood is more efficient and effective in reducing adult obesity burden. Further studies are needed to explore the underlying mechanisms, such as hormonal changes during puberty, for the observed differential associations between rate of change in BMI during childhood and adult obesity risk.” – by Regina Schaffer

Disclosures: The authors report no relevant financial disclosures.

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