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

J Gen Intern Med. 2019 Jan;34(1):90-97. doi: 10.1007/s11606-018-4680-7. Epub 2018 Oct 22.

Abstract

Background: The impact of back pain on disability in older women is well-understood, but the influence of back pain on mortality is unclear.

Objective: To examine whether back pain was associated with all-cause and cause-specific mortality in older women and mediation of this association by disability.

Design: Prospective cohort study.

Setting: The Study of Osteoporotic Fractures.

Participants: Women aged 65 or older.

Measurement: 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.

Results: 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.

Limitations: Only white women were included.

Conclusion: Frequent persistent back pain was associated with increased mortality in older women. Much of this association was mediated by disability.

Keywords: back pain; disability; mediation; mortality.

Publication types

  • Multicenter Study
  • Research Support, N.I.H., Extramural

MeSH terms

  • Adult
  • Aged
  • Aged, 80 and over
  • Back Pain / etiology
  • Back Pain / mortality*
  • Back Pain / rehabilitation
  • Cause of Death / trends
  • Disability Evaluation*
  • Disabled Persons / statistics & numerical data*
  • Female
  • Follow-Up Studies
  • Humans
  • Middle Aged
  • Osteoporotic Fractures / complications*
  • Osteoporotic Fractures / mortality
  • Osteoporotic Fractures / rehabilitation
  • Prospective Studies
  • Risk Factors
  • Survival Rate / trends
  • United States / epidemiology