Olfaction and muscle strength in older adults: a longitudinal study

Abstract

Background: Olfactory impairment is common in older adults and has been linked to weight loss and functional decline. This study aimed to examine whether olfactory impairment is associated with an accelerated decline in muscle strength among older adults.

Methods: We analyzed data from 2348 participants (aged 71-82 years; 48.0% men; 37.5% Black) in the Health, Aging, and Body Composition Study. Olfactory function was assessed using the Brief Smell Identification Test at the Year 3 clinical visit (1999-2000) and categorized as good (scores 11-12), moderate (9-10), hyposmia (7-8), or anosmia (0-6). Participants were followed for up to 7 years. Grip strength and quadriceps strength were measured at clinical visits in Years 4, 6, 8, and 10.

Results: During follow-up, participants with anosmia experienced a faster decline in grip strength than those with good olfaction. The annual difference in decline was -0.19 kg/year (95% confidence interval [CI], -0.37 to -0.01) for men and -0.21 kg/year (95% CI, -0.37 to -0.05) for women. For quadriceps strength, men with anosmia had a greater annual decline (-1.26 Nm/year; 95% CI, -2.26 to -0.26), whereas no statistically significant association was observed in women.

Conclusions: Anosmia in older adults is associated with accelerated decline in muscle strength. These findings suggest that olfactory impairment may serve as an early marker of neuromuscular aging. Further research is warranted to investigate the underlying mechanisms.

Keywords: Aging; Epidemiology; Longitudinal study; Muscle strength; Olfactory impairment.