No effect of maternal calcium intake and bone resorption during pregnancy on offspring bone mineral density at age 5 years

Summary Maternal nutrition during pregnancy plays a role in offspring bone health. In a prospective cohort study, offspring bone mineral density at 5 years was not associated with maternal calcium intake or maternal bone resorption during pregnancy. Purpose Suboptimal bone mineral density in childhood can result in osteoporosis later in life. We reported previously that lower calcium intake during pregnancy was associated with higher maternal bone resorption during pregnancy and that lower maternal dietary calcium and higher maternal bone resorption in pregnancy were associated with lower maternal bone mineral density (BMD) 5 years later. The current study sought to investigate the effect of both maternal dietary calcium intake and maternal bone resorption during pregnancy on offspring BMD at 5 years. Methods Data collected as part of the ROLO longitudinal cohort study ( n = 103, mother-child dyads) were used in the current analysis. ROLO started as a randomised controlled trial of a low glycemic index diet during second pregnancy in women with macrosomia in first pregnancy in order to prevent recurrence of macrosomia. Maternal dietary intakes were assessed using 3-day food diaries completed during each trimester of pregnancy. Bone resorption in early and late pregnancy was calculated through urinary excretion of cross-linked N-telopeptides (uNTX). Offspring whole-body BMD at 5 years was measured using dual-energy X-ray absorptiometry. Results Offspring BMD at 5 years correlated with offspring body mass index ( r = .385; p < .001) and offspring BMD was higher in boys than girls ( t = 2.91; p = .004). Offspring BMD at 5 years was not associated with either maternal calcium intake or uNTX during pregnancy, after controlling for offspring body mass index and offspring sex. Conclusion Offspring BMD at 5 years is not associated with either maternal calcium intake or maternal bone resorption during pregnancy.