IMPACT OF OSTEOSARCOPENIA ON DISABILITY AND MORTALITY AMONG JAPANESE OLDER ADULTS

H. Shimada¹, T. Doi¹, K. Tsutsumimoto¹, S. Nakakubo¹, K. Makino¹, O. Katayama¹, K. Tomida¹, K. Fujii¹, Y. Kiuchi¹, K. Nishimoto¹, R. Yamaguchi¹, S. Lee¹

¹National Center for Geriatrics and Gerontology, Obu, Japan

Background: Osteoporosis and osteopenia (OP), along with associated fragility fractures, pose huge current and future public healthcare burden. Multiple channels of communication exist between bone and muscle, including mechanical and chemical pathways. This direct mutual communication is the physiological basis for the biological link between OP and muscle wasting that constitutes the musculoskeletal syndrome. Sarcopenia (SP), the age-related loss of muscle mass and physical performance, is increasingly becoming a medical and financial concern, such as functional disability, hospitalization, and all-cause mortality, in aging patients and in those with OP. The pathophysiologies of OP and SP reveal overlapping features and a mechanically and biochemically intensive and complicated interaction. Due to these interactions between the muscle and bone, individuals with SP and OP are classified to have osteosarcopenia (OS). In clinical settings, muscle mass and bone mineral density assessments are usually performed using dual-energy x-ray absorptiometry (DXA), the gold standard technique. However, DXA is often unavailable in community settings.

Purpose: This study aimed to determine whether OP and SP identified by simplified instruments are associated with the future incidence of disability and mortality and evaluate the validity of these instruments as community screening tools. We also examined OS, defined as the coexistence of OP and SP, as a new indicator of geriatric syndromes to determine whether it has an additive effect on adverse outcome incidence compared to OP and SP alone.

Methods: In total, 8,995 older adults participated in the study (average age: 73.5 ± 5.4 years). We determined OP based on T-scores generated based on the speed of sound, which is the time taken for ultrasound waves to go through a determined distance in the calcaneus bone. Skeletal muscle mass was evaluated using a bioimpedance analysis device. Handgrip strength and walking speed were measured as physical performance indicators. Incidences of disability and mortality were prospectively determined for 5 years.

Results: The prevalence of OP, SP, and OS was 45.5%, 3.9%, and 7.4%, respectively. The incidence of disability in the healthy, OP, SP, and OS groups was 6.5%, 14.9%, 20.5%, and 33.5%, respectively. The incidence of mortality in the healthy, OP, SP, and OS groups was 4.0%, 4.9%, 10.3%, and 10.2%, respectively. Participants with OP (hazard ratio [HR]: 1.45, 95% confidence interval [CI]: 1.25–1.68), SP (HR: 1.38, 95% CI: 1.08–1.76), and OS (HR: 1.73, 95% CI: 1.43–2.09) had a higher risk of disability than healthy participants. Participants with OP (HR: 1.31, 95% CI: 1.04–1.64) and OS (HR: 1.45, 95% CI: 1.05–2.00) had a higher risk of mortality than healthy participants. SP was not significantly related to mortality (HR: 1.14, 95% CI: 0.90–1.45).

Conclusions: This study revealed that OS defined by bioimpedance analysis and quantitative ultrasound assessments was associated with an increased risk of disability and mortality among older adults.

Implications: Healthcare providers are advised to perform both muscle and bone assessments to evaluate disability and mortality risks and provide suitable interventions to high-risk individuals, particularly older adults with OS.

Funding acknowledgements: This work received financial support via Health Labour Sciences Research Grant, Research Funding Longevity Sciences, and Strategic Basic Research Programs.

Keywords:
Osteopenia
Sarcopenia
Osteosarcopenia

Topics:
Older people
Musculoskeletal
Health promotion & wellbeing/healthy ageing/physical activity

Did this work require ethics approval? Yes

Institution: National Center for Geriatrics and Gerontology

Committee: Ethics Committee of NCGG

Ethics number: 1067-3