Bone Abstracts

Background: Advancing maternal age at childbirth has been associated with a higher risk of pregnancy complications and with adverse short-term and long-term offspring health outcomes, but little is known about the effects of increasing maternal age on offspring bone acquisition.

Objective: To investigate associations of maternal age at childbirth with offspring bone parameters in healthy men at the age of peak bone mass.

Methods: We used cross-sectional data from 689 subjects participating in a population-based sibling pair study including healthy men aged 25–45 years. Data include maternal age at childbirth, offspring birth weight, adult weight and height, and offspring DXA and pQCT-derived areal and volumetric bone parameters and cortical bone geometry. Cross-sectional associations were investigated using linear mixed-effects modeling with adjustment for offspring age, height and weight.

Results: Maternal age at childbirth was 27.0±4.7 years and correlated inversely with areal bone mineral density (aBMD) and bone mineral content (BMC) at the lumbar spine (ß=-0.09, P= 0.011 and ß=-0.01, P= 0.017), as well as with trabecular volumetric BMD (vBMD) at the distal radius (ß=-0.10, P= 0.014). No associations of maternal age were found with aBMD or BMC at the total hip or femoral neck, nor with cortical vBMD at the proximal radius or tibia. However, increasing maternal age was associated with smaller cortical thickness (ß=-0.13, P= 0.002), cortical area (ß=-0.08, P= 0.024), and cortical over total bone area ratio (ß=-0.11, P= 0.010) as well as with larger endosteal circumference (ß=0.10, P= 0.010) at the tibia. No associations of maternal age with cortical bone geometry were observed at the radius.

Conclusions: Advancing maternal age at childbirth might adversely affect the acquisition of peak bone mass and geometry in male offspring, with in particular less favourable trabecular bone mineral density and tibial cortical bone geometry. Whether this results from altered placental function or from epigenetic changes due to lifestyle factors remains to be established.