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Early adiposity rebound increases risk for PCOS in adulthood
Women who experience a second rise in childhood BMI before age 5 years are more likely to develop polycystic ovary syndrome in adulthood than women who followed a more typical BMI trajectory, according to findings published in the International Journal of Obesity.
Early timing of the adiposity rebound, defined as the second rise in BMI after a nadir occurring in early childhood, has been associated with increased obesity risk and metabolic derangements in adolescence and adulthood, Terhi T. Piltonen, MD, PhD, associate professor and senior consultant in the department of obstetrics and gynecology, reproductive endocrinology and IVF unit at the Medical Research Centre, University of Oulu, Finland, and colleagues wrote in the study background. According to population-based BMI trajectories, mean age at adiposity rebound occurs at age 5 to 6 years, with early adiposity rebounds defined as occurring before age 5 years.
“In this study we found that childhood growth patterns, namely early adiposity rebound and high BMI at menarche, may present as early signs for the woman for having PCOS later in adulthood,” Pilotnen told Endocrine Today. “In clinical practice, childhood growth patterns offer a tool to assess the risk for adulthood obesity. Moreover, adolescent girls with early adiposity rebound and persisting obesity should be screened for PCOS symptoms, such as persistent irregular cycles and hirsutism.”
In a prospective, population-based study, Piltonen and colleagues analyzed data from 1,853 women, using data from the Northern Finland Birth Cohort. Data on weight and height from early infancy to adolescence were gathered from welfare clinic records collected as part of a national child-health screening program in Finland. As part of the study, women completed mailed questionnaires at ages 31 and 46 years on health, lifestyle, occupation and living environment; provided fasting blood samples; and underwent anthropometric measurements. PCOS was identified via two questions asked during the 31-year follow-up assessing menstrual cycle regularity and the presence of hirsutism (n = 280).
“This was a population-based study that utilized questionnaire data to identify cases with PCOS,” Piltonen said. “There was a small validation cohort and several other studies showing that, with these two questions, women with PCOS can be identified.”
Researchers used binary logistic regression analysis to estimate the association between adiposity rebound timing and PCOS.
Researchers found that women with PCOS had a lower birth weight vs. controls (mean, 3,357 g vs. 3,445 g; P < .001), an earlier age at adiposity rebound (mean, 5.2 years vs. 5.6 years; P < .001) and a higher BMI beginning at the point of adiposity rebound onward when compared with controls. Independent of BMI, early timing of adiposity rebound was associated with PCOS diagnosis (OR = 1.62; 95% CI, 1.37-1.92).
The researchers found that age at menarche was not different between women with PCOS and controls; however, women with PCOS had a higher BMI at menarche.
“Interestingly, serum testosterone levels at age 31 or 46 [years] were not associated with timing of [adiposity rebound], even though hyperandrogenism has been associated with a more severe BMI outcome in women with PCOS,” the researchers wrote.
As the BMI trajectories appear to deviate early on from the time of adiposity rebound, the researchers wrote, early adiposity rebound may be the first sign of a developmental process toward a PCOS phenotype.
“Growth patterns in children should be monitored and more studies should be established to see if early interventions targeting BMI in childhood could alleviate the risk for having PCOS later in life,” Piltonen said. “All in all, studies investigating early life triggers for PCOS are warranted.”– by Regina Schaffer
For more information:
Terhi T. Piltonen, MD, can be reached at the PEDEGO Research Unit, Medical Research Center, University of Oulu, P.O. Box 8000, FI-90014, Oulu, Finland; email: terhi.piltonen@oulu.fi.
Disclosures: The Academy of Finland, the Finnish Medical Association, the Novo Nordisk Foundation and the Sigrid Juselius Foundation supported this study. The authors report no relevant financial disclosures.