Association of Back Pain with All-Cause and Cause-Specific Mortality Among Older Women: a Cohort Study.

<bold>Background: </bold>The impact of back pain on disability in older women is well-understood, but the influence of back pain on mortality is unclear.<bold>Objective: </bold>To examine whether back pain was associated with all-cause and cause-specific mortality in older women and mediation of this association by disability.<bold>Design: </bold>Prospective cohort study.<bold>Setting: </bold>The Study of Osteoporotic Fractures.<bold>Participants: </bold>Women aged 65 or older.<bold>Measurement: </bold>Our primary outcome, time to death, was assessed using all-cause and cause-specific adjusted Cox models. We used a four-category back pain exposure (no back pain, non-persistent, infrequent persistent, or frequent persistent back pain) that combined back pain frequency and persistence across baseline (1986-1988) and first follow-up (1989-1990) interviews. Disability measures (limitations of instrumental activities of daily living [IADL], slow chair stand time, and slow walking speed) from 1991 were considered a priori potential mediators.<bold>Results: </bold>Of 8321 women (mean age 71.5, SD = 5.1), 4975 (56%) died over a median follow-up of 14.1 years. A higher proportion of women with frequent persistent back pain died (65.8%) than those with no back pain (53.5%). In the fully adjusted model, women with frequent persistent back pain had higher hazard of all-cause (hazard ratio [HR] = 1.24 [95% CI, 1.11-1.39]), cardiovascular (HR = 1.34 [CI, 1.12-1.62]), and cancer (HR = 1.33, [CI 1.03-1.71]) mortality. No association with mortality was observed for other back pain categories. In mediation analyses, IADL limitations explained 47% of the effect of persistent frequent back pain on all-cause mortality, slow chair stand time, and walking speed, explained 27% and 24% (all significant, p < 0.001), respectively.<bold>Limitations: </bold>Only white women were included.<bold>Conclusion: </bold>Frequent persistent back pain was associated with increased mortality in older women. Much of this association was mediated by disability. [ABSTRACT FROM AUTHOR]