Bone Abstracts

Women suffer more fragility fractures in old age and have a higher incidence of fractures at the femoral neck region compared to men who have higher incidence of trochanteric femoral fractures. The purpose of this cross-sectional study was to analyze associations between physical activity (PA) and bone mass distribution at the femoral neck (FN) and trochanter (TR) in young adults. A left hip DXA scan was used to measure bone mineral density (BMD) at the integral, superolateral (SL) and inferomedial (IM) FN, and TR sub-regions in 38 women (age: 23.5±2.9 years; BMI: 22.3±3.3 kg/m²) and 31 men (age: 24.2±3.6 years; BMI: 23.1±2.3 kg/m²). These sub-regions were used to represent bone mass distribution via two BMD ratios – FN:TR and IMFN:SLFN. PA was evaluated with the Actigraph GT1M accelerometers over 7 days. Partial correlation analyses adjusted for body mass revealed in males associations of FN:TR BMD ratio with sedentary (r=0.449) and active time (r=−0.467) (P<0.05) and associations of IMFN:SLFN BMD ratio with light PA (r=−0.463). In females it was not found significant associations between BMD ratios and PA variables, despite a trend in the association of FN:TR BMD ratio with sedentary time (r=−0.330, P=0.53) and steps/day (r=0.304, P=0.075). In conclusion, PA seems to be related with bone mass distribution in males with a more active lifestyle (independent of PA intensity) to favor the BMD of the TR sub-region and a light PA to favor the SL sub-region of the FN. Potential associations in females appear however to have a contrary relationship with a more active lifestyle to promote the FN compared to the TR sub-region.