Socioeconomic position, type 2 diabetes and long-term risk of death

PLoS One. 2015 May 5;10(5):e0124829. doi: 10.1371/journal.pone.0124829. eCollection 2015.

Abstract

Background: Both socioeconomic position (SEP) and type 2 diabetes have previously been found to be associated with mortality; however, little is known about the association between SEP, type 2 diabetes and long-term mortality when comorbidity is taken into account.

Methods: We conducted a population-based cohort study of all Danish citizens aged 40-69 years with no history of diabetes during 2001-2006 (N=2,330,206). The cohort was identified using nationwide registers, and it was followed for up to 11 years (mean follow-up was 9.5 years (SD: 2.6)). We estimated the age-standardised mortality rate (MR) and performed Poisson regression to estimate the mortality-rate-ratio (MRR) by educational level, income and cohabiting status among people with and without type 2 diabetes.

Results: We followed 2,330,206 people for 22,971,026 person-years at risk and identified 139,681 individuals with type 2 diabetes. In total, 195,661 people died during the study period; 19,959 of these had type 2 diabetes. The age-standardised MR increased with decreasing SEP both for people with and without diabetes. Type 2 diabetes and SEP both had a strong impact on the overall mortality; the combined effect of type 2 diabetes and SEP on mortality was additive rather than multiplicative. Compared to women without diabetes and in the highest income quintile, the MRR's were 2.8 (95%CI 2.6, 3.0) higher for women with type 2 diabetes in the lowest income quintile, while diabetes alone increased the risk of mortality 2.0 (95%CI 1.9, 2.2) times and being in the lowest income quintile without diabetes 1.8 (95%CI 1.7,1.9) times after adjusting for comorbidity. For men, the MRR's were 2.7 (95%CI 2.5,2.9), 1.9 (95%CI 1.8,2.0) and 1.8 (95%CI 1.8,1.9), respectively.

Conclusion: Both Type 2 diabetes and SEP were associated with the overall mortality. The relation between type 2 diabetes, SEP, and all-cause mortality was only partly explained by comorbidity.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Adult
  • Aged
  • Cause of Death
  • Comorbidity
  • Denmark / epidemiology
  • Diabetes Mellitus, Type 2 / epidemiology*
  • Diabetes Mellitus, Type 2 / mortality
  • Female
  • Follow-Up Studies
  • Humans
  • Male
  • Middle Aged
  • Mortality
  • Population Surveillance
  • Registries
  • Socioeconomic Factors

Grant support

This work was supported by the Danish Council for Strategic Research. MV is supported by an unrestricted grant from the Lundbeck Foundation. The funders had no role in study design, data collection andanalysis, decision to publish, or preparation of manuscript.