Association of body mass index with all-cause and cardiovascular disease mortality in the elderly

PLoS One. 2014 Jul 11;9(7):e102589. doi: 10.1371/journal.pone.0102589. eCollection 2014.

Abstract

Objectives: To evaluate the associations of body mass index (BMI) with all-cause, cardiovascular disease (CVD), and expanded CVD mortality in the elderly.

Design: Observational cohort study.

Setting: Annual physical examination program for the elderly from 2006 to 2010.

Participants: We included 77,541 Taipei residents aged ≥ 65 years (39,365 men and 38,176 women).

Measurements: BMI was categorized as underweight (BMI<18.5), normal weight (18.5 ≤ BMI<25), overweight (25 ≤ BMI<30), grade 1 obesity (30 ≤ BMI<35), or grade 2-3 obesity (BMI ≥ 35). Mortality was ascertained by national death files.

Results: Underweight (hazard ratios [HRs] of all-cause, CVD, and expanded CVD mortality: 1.92, 1.74, and 1.77, respectively), grade 2-3 obesity (HRs: 1.59, 2.36, and 2.22, respectively), older age, male sex, smoking, and high fasting blood sugar were significant predictors of mortality. Meanwhile, being married/cohabitating, higher education, alcohol consumption, more regular exercise, and high total cholesterol were inversely associated with mortality. Multivariate stratified subgroup analyses verified smokers (HRs of all-cause, CVD, and expanded CVD mortality: 3.25, 10.71, and 7.86, respectively, for grade 2-3 obesity), the high triglyceride group (HRs: 5.82, 10.99, and 14.22, respectively for underweight), and patients with 3-4 factors related to metabolic syndrome (HRs: 4.86, 12.72, and 11.42, respectively, for underweight) were associated with mortality.

Conclusion: The associations of BMI with all-cause, CVD, expanded CVD mortality in the elderly are represented by U-shaped curves, suggesting unilateral promotions or interventions in weight reduction in the elderly may be inappropriate. Heterogeneous effects of grades 1 and 2-3 obesity on mortality were observed and should be treated as different levels of obesity.

Publication types

  • Observational Study
  • Research Support, Non-U.S. Gov't

MeSH terms

  • Aged
  • Aged, 80 and over
  • Body Composition
  • Body Mass Index*
  • Cardiovascular Diseases / etiology
  • Cardiovascular Diseases / mortality*
  • Cardiovascular Diseases / physiopathology
  • Cause of Death / trends
  • Cohort Studies
  • Exercise
  • Female
  • Humans
  • Male
  • Overweight / complications
  • Overweight / mortality*
  • Overweight / physiopathology
  • Risk Factors
  • Smoking
  • Socioeconomic Factors
  • Survival Rate
  • Taiwan
  • Thinness / complications
  • Thinness / mortality*
  • Thinness / physiopathology

Grant support

This study was supported by the Taiwan Ministry of Education through its “Aim for the Top University Plan,” by the Department of Health of the Taipei City Government (Grant 10301-62-001), and by Taiwan's National Science Council (Grant 98-2314-B-010-015-MY2). This study is based on data from the Taipei City Public Health Database provided by the Department of Health of the Taipei City Government and managed by the Databank for Public Health Analysis. The funders had no role in study design, data collection and analysis, decision to publish, or preparation of the manuscript.