Physical activity, physical function limitation, and falls from mid-life to older age in Australian women

Background: The World Health Organization recommends adults to undertake 150-300 minutes/week of moderate-intensity physical activity (PA). PA positively affects balance, strength and bone health, which could prevent physical function limitation or fall-related injuries. However, physical function limitation, fall-related injuries could lessen PA participation.

Purpose: To examine bi-directional prospective relationships between PA and physical function limitation, and PA and falls.

Methods: Women born 1946-51 in the Australian Longitudinal Study on Women’s Health; self-reported physical activity, physical function limitation (Short-Form-36 physical functioning subscale), and falls every three years between 1996 (mean age: 48 years) and 2019 (71 years). Generalised estimating equations examined bi-directional population-averaged prospective associations between PA and physical function limitation, and PA and falls at multiple timepoints with three-year intervals (n=13,714).

Results: Compared with women who reached recommended levels of PA, women without the recommended levels of PA had a higher odds of subsequent physical function limitation (Odds ratios(OR)0min: 3.3, 95% CI 3.08-3.53; OR1-<150min:1.44, 95%CI 1.36-1.54). Women who reported ≥300 minutes/week of PA had lower odds of developing physical function limitation. Women who reported physical function limitation had higher odds of undertaking no activity (OR 3.32, 95% CI 3.1-3.55) or some PA (1-<150 minutes/week,1.42, 95% CI 1.33-1.51) and lower odds of undertaking 300+ minutes/week of physical activity.

Participation in recommended levels of PA was associated with reduced injurious falls risk (OR:0.73, 95% CI 0.67-0.80), compared to no physical activity. However, compared to women without falls, women who had injurious falls were less likely to undertake PA of 1-<150 (OR:0.75, 95% CI 0.68-0.82), 150-<300 (OR:0.69, 95% CI 0.63-0.75) or ≥300 minutes/week (OR:0.64, 95% CI 0.59-0.70).

Conclusions: Prospective associations between PA and physical function, and PA and falls are bi-directional.

Practical implications: Programmes and strategies are needed to ameliorate the cycle of physical function limitation, falls and low physical activity participation.

Funding:not-applicable