Physical function trajectory after wrist or lower arm fracture in postmenopausal women: results from the Women’s Health Initiative Study

Summary: Long-term physical functioning trajectories following distal forearm fracture are unknown. We found that women with versus those without distal forearm fracture were more likely to experience a 5-year decline in physical functioning, independent of initial physical functioning level. This association was most evident among women 80 years and older. Introduction: Physical functioning trajectory following lower arm or wrist fracture is not well understood. Purpose: This study is to evaluate physical functioning trajectory before vs. after lower arm or wrist fracture, stratified by age. Methods: We performed a nested case–control study of prospective data from the Women’s Health Initiative Study (n = 2097 cases with lower arm or wrist fracture, 20,970 controls). Self-reported fractures and the physical functioning subscale of the RAND 36-item Short-Form Health Survey were assessed annually. We examined three physical functioning trajectory groups: stable, improving, and declining. Results: Mean (SD) number of physical functioning measurements was 5.2 (1.5) for cases and 5.0 (1.4) for controls. Declining physical functioning was observed among 20.4% of cases and 16.0% of controls. Compared to women without lower arm or wrist fracture, women with lower arm or wrist fracture were 33% more likely to experience declining physical functioning (adjusted odds ratio [aOR] 1.33 95% confidence interval [CI] 1.19–1.49, reference group stable or improving physical functioning trajectory). Associations varied by age: age ≥ 80 years aOR 1.56 (95% CI 1.29–1.88); age 70–79 years aOR 1.29 (95% CI 1.09–1.52); age < 70 years aOR 1.15 (95% CI 0.86–1.53) (p_interaction = 0.06). Associations between lower arm or wrist fracture and odds of declining physical functioning did not vary by baseline physical functioning or physical activity level. Conclusions: Women with lower arm or wrist fracture, particularly those aged 80 and older, were more likely to experience declines in physical functioning than women without such fractures, independent of baseline physical functioning level.