1. GUT 2012;61:1533–1537. R4 Kim Dong Hyun / Fellow Kim Jung Wook Higher Predicted Vitamin D Status Is Associated With Reduced Risk of Crohn’s Disease

2. INTRODUCTION Inflammatory Bowel Disease  Chronic, immunologically mediated disorders.  Pathogenic mechanism  An inappropriate immune response to intestinal microbial flora in a genetically susceptible host N Engl J Med 2009;361:2066 –2078. Nearly 100 genetic loci associated with IBD (less than 25%)  Undefined genetic and environmental factors

3. INTRODUCTION Vitamin D  First, Increased incidence of IBD at higher latitudes.  lower levels of vitamin D associated with less UV radiation Nat Clin Pract Gastroenterol Hepatol 2005;2:308 –315.  Second, SNP in the vit D receptor (VDR) to increased susceptibility to CD and UC J Gastroenterol Hepatol 2008;23:1816 –1822.  Third, deficiency of 1,25(OH) 2 D 3 and VDR knockout in mouse models increases the severity of dextran sodium sulfate– induced colitis J Nutr 2000;130:2648 –2652.

4. INTRODUCTION Goal  To examine the association between vitamin D status among women enrolled in a large prospective cohort, the Nurses’ Health Study (NHS)

5. METHODS Study Population  NHS, prospective cohort that began in 1976  72,719 women in 1986  Data on dietary intake and physical activity  No prior history of CD, UC or cancer.

6. METHODS  Assessment of predicted plasma 25(OH)D status by a previously published and validated regression model. J Natl Cancer Inst 2006;98:451– 459..

7. METHODS

8. Statistical Analysis  Primary analysis  The hazard ratio (HR) by dividing the incidence rate in each exposure category  Secondary analysis  Individual contributions of dietary vitamin D (from food) and supplemental vitamin D intake on risk of CD & UC

9. RESULTS

10. Baseline characteristics of the study population

11. Risk of CD and UC According to Quartiles of Predicted Plasma 25(OH)D Level Each 1ng/mL Increase in plasma 25(OH)D level, CD : 6% relative reduction (multivariate HR, 0.94; 95% CI, 0.89-0.99;P=.03) UC : non-significant 4% reduction (multivariate HR, 0.96; 95% CI,0.91-1.02).

12. Risk of CD and UC According to Quartiles of Dietary and Supplemental Vitamin D Intake Each 100 IU/day Increase in total vitamin D intake, CD : non significant 7% reduction (multivariate HR, 0.93; 95% CI, 0.86-1.01;P=.09) UC : 10% reduction (multivariate HR, 0.90; 95% CI,0.83-0.98;P=.02).

13. Conclusion Higher predicted plasma levels of 25(OH)D significantly reduce the risk for incident CD and non-significantly reduce the risk for UC in women.