The Association Between Air Pollution and Type 2 Diabetes in a Large Cross-Sectional Study in Leicester: The CHAMPIONS Study

Environ Int. 2017 Jul;104:41-47. doi: 10.1016/j.envint.2017.03.027. Epub 2017 Apr 13.

Abstract

Background: Observational evidence suggests there is an association between air pollution and type 2 diabetes; however, there is high risk of bias.

Objective: To investigate the association between air pollution and type 2 diabetes, while reducing bias due to exposure assessment, outcome assessment, and confounder assessment.

Methods: Data were collected from 10,443 participants in three diabetes screening studies in Leicestershire, UK. Exposure assessment included standard, prevailing estimates of outdoor nitrogen dioxide and particulate matter concentrations in a 1×1km area at the participant's home postcode. Three-year exposure was investigated in the primary analysis and one-year exposure in a sensitivity analysis. Outcome assessment included the oral glucose tolerance test for type 2 diabetes. Confounder assessment included demographic factors (age, sex, ethnicity, smoking, area social deprivation, urban or rural location), lifestyle factors (body mass index and physical activity), and neighbourhood green space.

Results: Nitrogen dioxide and particulate matter concentrations were associated with type 2 diabetes in unadjusted models. There was no statistically significant association between nitrogen dioxide concentration and type 2 diabetes after adjustment for demographic factors (odds: 1.08; 95% CI: 0.91, 1.29). The odds of type 2 diabetes was 1.10 (95% CI: 0.92, 1.32) after further adjustment for lifestyle factors and 0.91 (95% CI: 0.72, 1.16) after yet further adjustment for neighbourhood green space. The associations between particulate matter concentrations and type 2 diabetes were also explained away by demographic factors. There was no evidence of exposure definition bias.

Conclusions: Demographic factors seemed to explain the association between air pollution and type 2 diabetes in this cross-sectional study. High-quality longitudinal studies are needed to improve our understanding of the association.

Keywords: Air pollutants; Cross-sectional studies; Diabetes mellitus, type 2.

MeSH terms

  • Aged
  • Air Pollutants / analysis
  • Air Pollution / analysis*
  • Body Mass Index
  • Cross-Sectional Studies
  • Diabetes Mellitus, Type 2 / epidemiology*
  • Exercise
  • Female
  • Humans
  • Life Style
  • Male
  • Middle Aged
  • Nitrogen Dioxide / analysis
  • Particulate Matter / analysis
  • Residence Characteristics
  • Smoking
  • United Kingdom / epidemiology

Substances

  • Air Pollutants
  • Particulate Matter
  • Nitrogen Dioxide