Association of Back Pain with All-Cause and Cause-Specific Mortality Among Older Women: a Cohort Study
The impact of back pain on disability in older women is well-understood, but the influence of back pain on mortality is unclear.
To examine whether back pain was associated with all-cause and cause-specific mortality in older women and mediation of this association by disability.
Prospective cohort study.
The Study of Osteoporotic Fractures.
Women aged 65 or older.
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.
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.
Only white women were included.
Frequent persistent back pain was associated with increased mortality in older women. Much of this association was mediated by disability.
KEY WORDSback pain mortality disability mediation
We thank the participants and staff of the Study of Osteoporotic Fractures and Tuhina Neogi MD PhD for her thoughtful review of this manuscript.
Drs. Roseen and Fredman had full access to all of the data in the study and take responsibility for the integrity of the data and the accuracy of the data analysis.
Study concept and design: Roseen, LaValley, Saper, Felson, and Fredman.
Acquisition, analysis, or interpretation of data: Roseen, LaValley, Saper, Li, Felson, and Fredman.
Drafting of the manuscript: Roseen and Fredman.
Critical revision of the manuscript for important intellectual content: Roseen, LaValley, Saper, Li, Felson, and Fredman.
Statistical analysis: Roseen, LaValley, Li, and Fredman.
Obtained funding: n/a.
Administrative, technical, or material support: Roseen and Fredman.
Study supervision: Roseen and Fredman.
The Study of Osteoporotic Fractures (SOF) is supported by National Institutes of Health funding. The National Institute on Aging (NIA) provides support under the following grant numbers: R01 AG005407, R01 AR35582, R01 AR35583, R01 AR35584, R01 AG005394, R01 AG027574, R01 AG027576, and R01 AG026720. Dr. Roseen is supported by a Ruth L. Kirschstein National Research Service Award (1F32AT009272) from the National Center for Complementary and Integrative Health (NCCIH) and by the Boston University Clinical and Translational Science Institute (CTSI) Clinical Research Training Program (1UL1TR001430).
Compliance with Ethical Standards
This study was approved by the Institutional Review Boards at each SOF clinical site and at Boston University Medical Campus.
Conflict of Interest
The authors declare that they do not have a conflict of interest.
The funding sources had no role in the design and conduct of the study; collection, management, analysis, and interpretation of the data; preparation, review, or approval of the manuscript; and decision to submit the manuscript for publication. The contents of this manuscript are solely the responsibility of the authors and do not necessarily represent the official views of NIA or NCCIH.
- 1.GBD 2015 Disease and Injury Incidence and Prevalence Collaborators. Global, regional, and national incidence, prevalence, and years lived with disability for 310 diseases and injuries, 1990-2015: a systematic analysis for the Global Burden of Disease Study 2015. Lancet. 2016;388:1545–1602.CrossRefGoogle Scholar
- 8.Astrand NE, Isacsson SO. Back pain, back abnormalities, and competing medical, psychological, and social factors as predictors of sick leave, early retirement, unemployment, labour turnover and mortality: A 22 year follow up of male employees in a Swedish pulp and paper company. Br J Ind Med. 1988; 45(6):387–395.PubMedPubMedCentralGoogle Scholar
- 23.Allison PD. Survival Analysis Using SAS: A Practical Guide, Second Edition. Crary, NC. SAS Institute Inc. 2010.Google Scholar
- 24.Vanderweele TJ. Explanation in Causal Inference: Methods for Mediation and Interaction. New York, NY: Oxford University Press. 2015.Google Scholar
- 46.Qaseem A, Wilt TJ, McLean RM, Forciea MA; Clinical Guidelines Committee of the American College of Physicians. Noninvasive treatments for acute, subacute, and chronic low back pain: a clinical practice guideline from the American College of Physicians. Ann Intern Med. 2017;166:514–530.CrossRefGoogle Scholar