Neither Leg Muscle Strength Nor Balance Is Associated With the Incidence of Falls in Middle-Aged Women: A 5-Year Population-Based Prospective Study

BACKGROUND: Muscle strength and balance are major modifiable factors of falls in older adults, but their associations with falls in middle-aged adults are underinvestigated. We aimed to examine the association of baseline and change in leg muscle strength (LMS) and balance with the incidence of falls in a cohort of middle-aged women. METHODS: This was a 5-year follow-up of a population-based sample of 273 women aged 36-57 years at baseline (2011-2012). Data on LMS (by dynamometer) and balance (timed up and go test, step test, functional reach test, and lateral reach test) were obtained at baseline and 5 years later (2017-2018). After 5 years, falls were recorded monthly for 1 year by questionnaire (2017-2019). Negative binomial/Poisson and log-binomial regressions were used as appropriate to assess associations of baseline and change in LMS and balance with any falls, injurious falls, and multiple falls. RESULTS: Over 1 year, 115 participants (42%) reported at least one fall. Neither baseline nor 5-year change in LMS and balance measures was associated with the risk of any falls, injurious falls, or multiple falls 5 years later, with or without adjusting for confounders at baseline (incidence rate ratio/relative risk ranging from 0.85 to 1.19, 0.90 to 1.20, and 0.82 to 1.36, respectively; p > .05 for all). CONCLUSIONS: Baseline or change in LMS and balance measures are not associated with incident falls among middle-aged women. The contributions of environmental and other intrinsic factors such as chronic conditions and gait/mobility problems need to be investigated.