Purpose: This study assessed osteoporosis, sarcopenia and osteosarcopenia as risk factors for fractures and mortality during 19-year follow-up.

Methods: We analyzed 2506 individuals aged ≥ 55 from the Finnish Health 2000 Survey. Probable sarcopenia was defined as grip strength < 27 kg for men and < 16 kg for women. Osteoporosis was identified by a bone density T-score < -2,5 via ultrasound or a self-reported diagnosis. Participants were categorized in four groups: reference group with no sarcopenia and no osteoporosis, probable sarcopenia only, osteoporosis only, or osteosarcopenia. Fractures and deaths were identified from national registers until 2019. Four adjustment models were used, adjusting for age, sex, smoking, education, physical activity, and mobility limitation.

Results: Over a mean follow-up of 19.1 years, 580 (23.1%) participants sustained a low-energy fracture of any type and 1,375 (54.9%) died. Osteosarcopenia, probable sarcopenia and osteoporosis were all associated with increased risk of any fracture and mortality compared to the reference group. Osteoporosis alone was associated with lower mortality than osteosarcopenia (HR 0.69, 95% CI 0.50-0.95), but mortality did not differ between probable sarcopenia and osteosarcopenia (HR 0.79, 95% CI 0.59-1.06). No differences in the fracture risk between osteosarcopenia, sarcopenia and osteoporosis were observed.

Conclusion: While both sarcopenia and osteoporosis increase fracture and mortality risks, their combination does not seem to additively elevate fracture risks. Osteoporosis is a stronger predictor for future fractures, whereas probable sarcopenia is more closely linked to mortality. Further research is warranted to determine the best ways to incorporate sarcopenia assessment into comprehensive fracture risk evaluation.

Keywords: Fracture; Mortality; Older adults; Osteoporosis; Osteosarcopenia; Risk; Sarcopenia.