Higher Fatigue Prospectively Increases the Risk of Falls in Older Men.

BACKGROUND AND OBJECTIVES: Fatigue is a common complaint and shares many risk factors with falls, yet the independent contribution of fatigue on fall risk is unclear. This study's primary aim was to assess the association between fatigue and prospective fall risk in 5642 men aged 64-100 enrolled in the Osteoporotic Fractures in Men Study (MrOS). The secondary aim was to examine the association between fatigue and recurrent fall risk. RESEARCH DESIGN AND METHODS: Fatigue was measured at baseline using the Medical Outcomes Study (short form) single-item question "During the past four weeks, how much of the time did you feel energetic?" Responses were then classified: higher fatigue = "none," "a little," or "some" of the time and lower fatigue = "a good bit," "most," or "all" of the time. We assessed falls using triannual questionnaires. Fall risk was examined prospectively over 3 years; recurrent falling was defined as at least 2 falls within the first year. Generalized estimating equations and multinomial logistic regression modeled prospective and recurrent fall risk as a function of baseline fatigue status, adjusted for demographics, medications, physical activity, and gait speed. RESULTS: Men with higher (26%) versus lower baseline fatigue were older (75.1 ± 6.2 vs 73.2 ± 5.7 years), 24% less active, and had worse physical function (gait speed = 1.09 ± 0.24 vs 1.24 ± 0.21 m/s), all p < .0001. Within 1 year, 25.4% (n = 1409) had fallen at least once, of which 47.4% (n = 668) were recurrent fallers. Men with higher versus lower fatigue had 25% increased fall risk (relative risk = 1.25, 95% CI: 1.14-1.36) over 3 years follow-up, but had 50% increased odds of recurrent falling (odds ratio = 1.50, 95% CI: 1.22-1.85) within the first year. DISCUSSION AND IMPLICATIONS: Fatigue is an important risk factor of falling independent of established risk factors. Reductions in fatigue (ie, increased energy) may lessen the burden of falls in older men and provide a novel avenue for fall risk intervention.