Impact of Competing Risk of Mortality on Association of Weight Loss With Risk of Central Body Fractures in Older Men: A Prospective Cohort Study

Kristine E. Ensrud, Stephanie L. Harrison, Jane A. Cauley, Lisa Langsetmo, John T. Schousboe, Deborah M. Kado, Margaret L. Gourlay, Jennifer G. Lyons, Lisa Fredman, Nicolas Napoli, Carolyn J. Crandall, Cora E. Lewis, Eric Orwoll, Marcia L. Stefanick, Peggy M. Cawthon

Research output: Contribution to journalArticle

9 Scopus citations

Abstract

To determine the association of weight loss with risk of clinical fractures at the hip, spine, and pelvis (central body fractures [CBFs]) in older men with and without accounting for the competing risk of mortality, we used data from 4523 men (mean age 77.5 years). Weight change between baseline and follow-up (mean 4.5 years between examinations) was categorized as moderate loss (loss ≥10%), mild loss (loss 5% to <10%), stable (<5% change) or gain (gain ≥5%). Participants were contacted every 4 months after the follow-up examination to ascertain vital status (deaths verified by death certificates) and ask about fractures (confirmed by radiographic reports). Absolute probability of CBF by weight change category was estimated using traditional Kaplan-Meier method and cumulative incidence function accounting for competing mortality risk. Risk of CBF by weight change category was determined using conventional Cox proportional hazards regression and subdistribution hazards models with death as a competing risk. During an average of 8 years, 337 men (7.5%) experienced CBF and 1569 (34.7%) died before experiencing this outcome. Among men with moderate weight loss, CBF probability was 6.8% at 5 years and 16.9% at 10 years using Kaplan-Meier versus 5.7% at 5 years and 10.2% at 10 years using a competing risk approach. Men with moderate weight loss compared with those with stable weight had a 1.6-fold higher adjusted risk of CBF (HR 1.59; 95% CI, 1.06 to 2.38) using Cox models that was substantially attenuated in models accounting for competing mortality risk and no longer significant (subdistribution HR 1.16; 95% CI, 0.77 to 1.75). Results were similar in analyses substituting hip fracture for CBF. Older men with weight loss who survive are at increased risk of CBF, including hip fracture. However, ignoring the competing mortality risk among men with weight loss substantially overestimates their long-term fracture probability and relative fracture risk.

Original languageEnglish (US)
JournalJournal of Bone and Mineral Research
DOIs
StateAccepted/In press - 2016

Keywords

  • CENTRAL BODY FRACTURES
  • MORTALITY
  • OLDER MEN
  • WEIGHT CHANGE

ASJC Scopus subject areas

  • Endocrinology, Diabetes and Metabolism
  • Orthopedics and Sports Medicine

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    Ensrud, K. E., Harrison, S. L., Cauley, J. A., Langsetmo, L., Schousboe, J. T., Kado, D. M., Gourlay, M. L., Lyons, J. G., Fredman, L., Napoli, N., Crandall, C. J., Lewis, C. E., Orwoll, E., Stefanick, M. L., & Cawthon, P. M. (Accepted/In press). Impact of Competing Risk of Mortality on Association of Weight Loss With Risk of Central Body Fractures in Older Men: A Prospective Cohort Study. Journal of Bone and Mineral Research. https://doi.org/10.1002/jbmr.3020