Exposure to Ambient Air Pollution and the Risk of Inflammatory Bowel Disease: A European Nested Case-Control Study

Dig Dis Sci. 2016 Oct;61(10):2963-2971. doi: 10.1007/s10620-016-4249-4. Epub 2016 Jul 26.

Abstract

Background: Industrialization has been linked to the etiology of inflammatory bowel disease (IBD).

Aim: We investigated the association between air pollution exposure and IBD.

Methods: The European Prospective Investigation into Cancer and Nutrition cohort was used to identify cases with Crohn's disease (CD) (n = 38) and ulcerative colitis (UC) (n = 104) and controls (n = 568) from Denmark, France, the Netherlands, and the UK, matched for center, gender, age, and date of recruitment. Air pollution data were obtained from the European Study of Cohorts for Air Pollution Effects. Residential exposure was assessed with land-use regression models for particulate matter with diameters of <10 μm (PM10), <2.5 μm (PM2.5), and between 2.5 and 10 μm (PMcoarse), soot (PM2.5 absorbance), nitrogen oxides, and two traffic indicators. Conditional logistic regression analyses were performed to calculate odds ratios (ORs) with 95 % confidence intervals (CIs).

Results: Although air pollution was not significantly associated with CD or UC separately, the associations were mostly similar. Individuals with IBD were less likely to have higher exposure levels of PM2.5 and PM10, with ORs of 0.24 (95 % CI 0.07-0.81) per 5 μg/m(3) and 0.25 (95 % CI 0.08-0.78) per 10 μg/m(3), respectively. There was an inverse but nonsignificant association for PMcoarse. A higher nearby traffic load was positively associated with IBD [OR 1.60 (95 % CI 1.04-2.46) per 4,000,000 motor vehicles × m per day]. Other air pollutants were positively but not significantly associated with IBD.

Conclusion: Exposure to air pollution was not found to be consistently associated with IBD.

Keywords: Air pollution; Crohn’s disease; Inflammatory bowel disease; Particulate matter; Ulcerative colitis.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Adult
  • Air Pollution / statistics & numerical data*
  • Case-Control Studies
  • Colitis, Ulcerative / epidemiology*
  • Crohn Disease / epidemiology*
  • Denmark / epidemiology
  • Environmental Exposure / statistics & numerical data*
  • Europe / epidemiology
  • Female
  • France / epidemiology
  • Humans
  • Incidence
  • Inflammatory Bowel Diseases / epidemiology
  • Logistic Models
  • Male
  • Middle Aged
  • Netherlands / epidemiology
  • Odds Ratio
  • Particulate Matter*
  • United Kingdom / epidemiology
  • Vehicle Emissions

Substances

  • Particulate Matter
  • Vehicle Emissions