Maternal age at childbirth is associated with offspring insulin sensitivity: a cross-sectional study in adult male siblings

Objective Maternal age at childbirth is increasing worldwide, but studies investigating the consequences of this trend on offspring metabolic health are scarce. We investigated the associations of maternal age at childbirth with metabolic outcomes in adult male siblings. Methods We used data from 586 men aged 25-45 participating in a cross-sectional, population-based sibling-pair study, including maternal age at childbirth and offspring birthweight, adult weight, height, dual-energy X-ray absorptiometry (DXA)-derived body composition, blood pressure, and total cholesterol, glucose and insulin levels from fasting serum samples. Insulin sensitivity was evaluated using the homeostasis model assessment of insulin resistance (HOMA-IR). Results Maternal age at childbirth was 27.1 +/- 4.7 years and was inversely associated with glucose levels (beta = -0.10, P = 0.022) and HOMA-IR (beta = -0.06, P = 0.065) in age-and body composition-adjusted analyses. Moreover, sons of younger (aged <25 and 25-29) and older (aged >= 35) mothers had higher HOMA-IR values than sons of mothers aged 30-34 (1.39, 1.35 and 1.42 vs 1.19, P = 0.028). Additional adjustment for birthweight did not substantially alter these results. Maternal age was inversely associated with cholesterol levels in unadjusted (beta = -0.09, P = 0.032), but not in age-and body composition-adjusted analyses. No associations of maternal age were observed with blood pressure, leptin, or adiponectin levels or with any of the body composition measurements. Conclusions Increasing maternal age at childbirth is associated with lower fasting glucose levels and higher insulin sensitivity in adult male offspring. However, this association might not hold true in offspring of women aged >= 35 years at childbirth.