Timing of Puberty Determines Serum Insulin-Like Growth Factor-I in Late Adulthood

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Abstract
Context: IGFs may play an important role in disease etiology, especially cancer. Changes in diet can alter acute levels, but little is known about life course influences on IGF levels. Objective: The objective of the study was to examine the association between timing of puberty and adulthood serum IGFs (IGF-I and IGF binding protein-3). Design: This was a retrospective cohort study. Setting: Male pupils who attended a single school in Southern England were part of the study. Participants: Participants in the study were a cohort of 1028 men born between 1927 and 1956 with anthropometric measures between 9 and 18 yr and adulthood serum IGF levels. Main Outcome Measure: The study measured serum IGF-I and IGF binding protein-3 at mean age 63 yr. Results: Age at peak height velocity (APHV) was inversely associated with adult IGF-I levels. IGF-I decreased by 3.7 ng/ml (95% confidence interval 1.0–6.4, P = 0.007) for each sd increase in APHV. Prepubertal childhood height and body mass index were both inversely associated with APHV (P trend < 0.001). APHV was positively associated with adult height and inversely associated with adult body mass index. Adjustment for childhood, adult anthropometry, and other lifestyle factors did not substantially alter the association between APHV and adult IGF-I. Conclusions: This is the first study to document an association between timing of puberty and adult IGF-I levels. A better understanding of life course determinants of the IGF system may provide new insights into disease etiology and primary prevention.