The Osteoporotic Fractures in Men study (MrOS): a 25-yr landmark study of skeletal health in older men

The Osteoporotic Fractures in Men study (MrOS) is amongst the largest and longest running prospective cohort studies of older men. MrOS determined how fracture risk was related to bone mass, bone geometry, lifestyle, anthropometric and neuromuscular measures, comorbidity, biomarkers, and fall propensity. The cohort consisted of 5994 community-dwelling, ambulatory U.S. men aged 65 years or older recruited at 6 US academic clinical centers in 2000-2002 and followed through November 2024. After enrollment, men were contacted by mail/phone every 4 months to ascertain information on incident falls, fractures and deaths/loss to follow-up. All fractures were confirmed by imaging reports. Over the 25-year study, 95% of active surviving participants had complete follow-up. The MrOS study had 5 major clinic visits; while an ancillary sleep study had 2 additional clinic visits. MrOS has provided a comprehensive analysis of factors associated with areal (a) and volumetric (v) bone mineral density (BMD) and clinical risk factors for aBMD loss among men. Further analyses identified risk factors for hip, all non-spine, rib, wrist and vertebral fractures. MrOS was the largest single cohort to estimate associations of aBMD with incident fractures in men and results indicated stronger associations in men than women. MrOS also analyzed other structural features from dual x-ray absorptiometry (DXA) and both central and peripheral quantitative computed tomography in relationship to fractures in men. Serum, urine and DNA were collected at clinic visits and extensive analyses have been performed with respect to sex steroid and calciotropic hormones, bone turnover and other novel measures of bone health. Several analyses evaluated the performance of formal tools in estimating the absolute risk of fractures in older men; findings indicated that better fracture prediction tools are needed. MrOS encourages outside investigators to make use of the publicly available data and to access the biospecimen bank. https://mrosonline.ucsf.edu.