Peak Expiratory Flow and the Risk of Injurious Falls in Older Adults : The Role of Physical and Cognitive Deficits

Objectives: Previous studies showed that peak expiratory flow (PEF) is associated with health-related outcomes in advanced age, but the extent to which it may be related to falls risk remains unclear. We aimed to detect the association between PEF and injurious falls in older adults and to explore the role of cognitive and physical deficits in this association. Design: Prospective study with a 6-year follow-up. Setting and Participants: The study involves 2234 community-dwelling older adults with no history of pulmonary disease. Methods: For each study participant, we assessed the PEF at baseline, expressed as standardized residual (SR) percentile and derived from the normalization of residuals between the measured and predicted PEF values (based on individual age, sex, and body height); incident injurious falls over 6 years, from Hospital Discharge Diagnosis; and physical and cognitive functioning at the baseline and at 3- and 6-year followups by evaluating walking speed, balance, chair stand, and Mini-Mental State Examination, respectively. Results: Over the follow-up, 232 individuals experienced injurious falls. Cox models indicated 7% higher risk of falls per each 10th reduction in PEF SR-percentile. The risk of injurious falls increased by more than twice for those who had PEF SR-percentile <10th as for values of 80th-100th (hazard ratio = 2.31, 95% confidence interval: 1.41-3.76). Physical deficits mediated 63% of the total effect of PEF on falls risk. Conclusions and Implications: Our findings suggest that low PEF is associated with higher risk of injurious falls in older adults, and most of this association is explained by balance or muscular strength deficits.