Vitamin D intake associated with reduced risk for Crohn’s disease

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Increased intake of vitamin D may significantly reduce the risk for Crohn’s disease (CD) in women, according to an article published online December 12 and in the March issue of the journal Gastroenterology.

  • This study involved 72,719 women who returned the 1986 questionnaire. They had data on both vitamin D intake and physical activity and did not have a history of CD or UC.
  • Diagnosis of CD was based on a typical history of 4 weeks or longer and was confirmed by radiologic, endoscopic, or surgical evaluation.
  • The diagnosis of ulcerative colitis (UC) was based on typical clinical presentation of 4 weeks or more and endoscopic, radiologic, or surgical evaluation.
  • Mean age of the participants at baseline was 53 years, mean body mass index (BMI) was 25.4 kg/m2, mean physical activity was 13.2 metabolic hours per week, 94.5% were white and 36.6% never smoked.
  • A documented 122 cases of CD and 123 cases of UC were recorded during 1,492,811 person–years of follow–up. The median predicted 25(OH)D level was 27.6 ng/mL.
  • Women in the lowest quartile of predicted 25(OH)D level compared with those in the highest quartile had a higher body mass index, were less active, tended to reside in the Northern or Midwestern regions of the United States, and had lower intake levels of dietary or supplemental vitamin D. The median age of diagnosis of CD was 64.0 years; for UC, it was 63.5 years.
  • The median interval between assessment of plasma 25(OH) D levels and disease diagnosis was 12 years for UC and 10 years for CD.
  • For every 1 ng/mL increase in predicted 25(OH)D level, the risk for CD was reduced by 6%.
  • For UC, there was also a reduction in risk, but it was non–significant at 4%.
  • Women in the highest two quartiles of 25(OH)D levels had multivariate HRs of 0.50 and 0.55, respectively, for CD
  • Each 100 IU/day increase in total intake resulted in a 10% reduction in UC risk and a 7% reduction in CD risk.
  • For vitamin D intake from diet and supplements based on quartile distribution, there was a significant linear inverse trend for vitamin D intake and UC risk, but this trend was weaker for CD.
  • Intakes of 800 IU/day or higher resulted in greater reductions in the risks for UC and CD
  • Vitamin D intake was inversely associated with the risks for CD and UC, vitamin D insufficiency or deficiency was an important mediator in the pathogenesis of UC and CD, and assessment of vitamin D status should be a part of the assessment of inflammatory bowel diseases.