Low hygiene and exposure to infections may be associated with increased risk for ulcerative colitis in a North Indian population

BACKGROUND: Previous studies have attempted to link hygiene hypothesis with IBD. However most of these studies come from developed countries where the level of hygiene is high and universal. Very little data is available from developing countries. The present study explores the truth of hygiene hypotheses and other risk factors for ulcerative colitis (UC) in a North Indian population where the prevalence of UC has been increasing. METHODS: A total of 518 patients diagnosed with UC and 188 age-matched controls were included in the study. A structured questionnaire concerning socio-demographics and level of hygiene was completed by all participants. Logistic regression analysis was used to study the association between hygiene-related factors and the risk for UC. Odds ratios and 95% confidence intervals were estimated. RESULTS: There was a higher proportion of females (P<0.001), and a higher educational status (P=0.01) in UC patients compared with controls. A family history of IBD was present in 7.2% of cases and non-existent in controls. On multivariate analysis, after accounting for potential confounders, having a private bed (P<0.001), and having better toilet facilities [(RCA versus none, P=0.01; Flush toilet versus none, P=0.01), (RCA LATRINE as a toilet technology used in rural areas where no flush facility exists. It was developed under RCA project)] were inversely associated with risk for UC whereas owning a pet (P=0.01) and stressful events like a death in the family (P=0.01) were associated with greater risks for UC. CONCLUSION: Our study does not provide definitive evidence to support hygiene hypothesis and rather suggests that the rising incidence of UC in North India may be attributable to inadequate sanitary measures or other as yet unidentified factors.