Relation of maternal prepregnancy body mass index with offspring bone mass in childhood: is there evidence for an intrauterine effect?

摘要

>Background: Evidence indicates that intrauterine skeletal development has implications for bone mass in later life and that maternal fat stores in pregnancy are important for fetal bone mineral accrual.>Objective: We investigated whether childhood bone mass is influenced by maternal body mass index (BMI) via an intrauterine mechanism by comparing parental associations.>Design: We conducted a multivariable regression analysis of 7121 children in the Avon Longitudinal Study of Parents and Children. Total body less head (TBLH) and spine bone measures were derived from dual-energy X-ray absorptiometry scans at a mean age of 9.9 y. Maternal and paternal BMI values were derived from self-reported weight and height during pregnancy.>Results: Maternal prepregnancy BMI (SD score) was positively associated with offspring TBLH bone mineral content and bone mineral density (SD scores) [mean difference (95% CI): boys, 0.19 (0.16, 0.23) and 0.15 (0.12, 0.19), respectively; girls, 0.23 (0.19, 0.26) and 0.19 (0.16, 0.23), respectively] and spine bone mineral content and bone mineral density [boys, 0.20 (0.16, 0.24) and 0.18 (0.14, 0.22), respectively; girls, 0.22 (0.18, 0.26) and 0.21 (0.17, 0.25), respectively] and with TBLH and spine bone area–and spine area–adjusted bone mineral content. Associations of paternal BMI with these outcomes were similar, with no statistical evidence of a difference between maternal and paternal effects. Maternal associations were partly explained by offspring birth weight and gestational age and attenuated to the null after adjustment for offspring height and weight.>Conclusion: The positive relation between maternal prepregnancy BMI and offspring bone mass is likely due to shared familial, genetic, and environmental characteristics rather than to an intrauterine mechanism.