Back pain and decline in lower extremity physical function among community-dwelling older persons.

BACKGROUND Little is known regarding the longitudinal effects of back pain on physical function among older persons. We sought to determine whether back pain leading to activity restriction (i.e., restricting back pain) is associated with decline in lower extremity physical function among community-dwelling older persons. METHODS In this prospective study with an 18-month follow-up period, participants (N = 659) were aged 70 years or older and independent in bathing, dressing, transferring, and walking at baseline. Restricting back pain, defined as staying in bed for at least one-half day or cutting down on one's usual activities due to back pain, was ascertained during monthly telephone interviews. Lower extremity physical function was assessed using three timed, performance-based tests (rapid gait, chair stands, and foot taps) at baseline and 18 months. Decline in lower extremity physical function was defined as an increase in timed scores on these tests between the baseline and 18-month assessments. RESULTS The mean (standard deviation) number of months with restricting back pain was 1.3 (2.3); 364 (55%) participants reported 0 months, 209 (32%) reported 1-3 months, and 86 (13%) reported 4 or more months. After adjustment for baseline performance score and other covariates, the number of months with restricting back pain was independently associated with worsening rapid gait (p <.001), chair stand (p =.030), and foot tap (p <.001) performance. The deleterious effects of the "exposure" were limited to participants with 4 months of restricting back pain. CONCLUSIONS Restricting back pain is independently associated with decline in lower extremity physical function among community-dwelling older persons. Treatment of restricting back pain may help to decrease functional decline in this population.