PTH-097 Dietary antioxidants and the risk of developing ulcerative colitis: a nested-case-control study within EPIC-Norfolk

Introduction Oxidative stress may be involved in ulcerative colitis (UC) aetiology. Here we investigate, for the first time using a prospective study design, whether the dietary antioxidants vitamins C, E and zinc are associated with a decreased risk of developing UC, using 7-day food diaries, the most accurate dietary methodology. Methods A cohort of 23,658 participants, aged 40–74 years, enrolled in the European Prospective Investigation of Cancer-Norfolk between 1993–1997. At recruitment participants completed 7-day food diaries that recorded food intake including frequency, brands and portion sizes. Nutrient intakes were computed using a specifically designed nutrient database of 11,000 food items. The cohort was monitored to 2004 to identify incident UC cases. Conditional logistic regression analysis calculated odds ratios (OR) of developing UC across tertiles of intake. Adjustments were made for smoking status and energy intake. Results During follow-up 26 individuals (42% female) developed UC, 35% of whom had left-sided disease. Multivariable analyses showed no associations between any of vitamin C, vitamin E and zinc and the odds of UC, with no trends across tertiles (For vitamin C: 3rd vs 1st tertile OR=2.03, 95% confidence interval (CI)=0.67–6.20; trend OR=1.42, 95% CI=0.82–2.45; For vitamin E 3rd vs 1st tertile OR=1.04, 95% CI=0.27–4.07; trend OR=1.10, 95% CI=0.57–2.14; For zinc 3rd vs 1st tertile OR=2.00, 95% CI=0.42–9.53; trend OR=1.38, 95% CI=0.69–2.78). Conclusions The data does not support a role for any of vitamin C, vitamin E and zinc in preventing UC. Further follow-up of the cohort is continuing to make estimates with better precision.