Cumulative Lifestyle Score and Osteoporotic Fracture Risk by Bone Mineral Density Category in a Nationwide Korean Cohort of 66- Year-Old Women

Abstract We aimed to evaluate the association between a cumulative lifestyle score and osteoporotic fracture risk by baseline bone mineral density (BMD) category using retrospective cohort data from the Korean National Health Insurance Service. We studied 541,770 women aged 66 years who underwent dual-energy X-ray absorptiometry through the NHIS life-transition health screening program between 2010 and 2016. A cumulative lifestyle score ranging from 0 to 3 was constructed by assigning one point each for regular exercise, non- or ex-smoking status, and non-drinking status. Cox proportional hazards models were used to estimate the risk of any, vertebral, hip, and other osteoporotic fractures across normal BMD, osteopenia, and osteoporosis groups. Higher lifestyle scores were consistently associated with lower fracture risk across BMD categories. For any fracture, the adjusted hazard ratios for score 3 versus score 0 were 0.746 (95% confidence interval [CI], 0.564–0.987) in normal BMD, 0.747 (95% CI, 0.630–0.885) in osteopenia, and 0.786 (95% CI, 0.668–0.924) in osteoporosis. No significant interaction was observed between lifestyle score and BMD category for any fracture outcome. Absolute risk differences were larger among women with osteopenia or osteoporosis, reflecting their higher baseline fracture risk. These findings suggest that cumulative lifestyle profiles are associated with osteoporotic fracture risk across skeletal risk categories, with greater absolute risk differences in women with lower BMD.