Modern life' in the epidemiology of inflammatory bowel disease: a case-control study with special emphasis on nutritional factors.

OBJECTIVE: The rising incidence of inflammatory bowel disease (IBD) since the Second World War coincides with profound changes of the dietary pattern. The aim of the study was to investigate the possible pathogenic role of some characteristic 'modern life' dietary factors in IBD.

DESIGN: Case-control, studying risk factors in recently diagnosed cases, 290 with Crohn's disease and 398 with ulcerative colitis, compared with 616 population controls. Smoking, age, gender and education were taken into account by using logistic regression analysis.

SETTING: Hospital cases and population controls.

INTERVENTIONS: Questionnaires.

MAIN OUTCOME MEASURES: Logistic regression-derived odds ratios.

RESULTS: A positive association with cola drinks [OR: 2.2 (95% CI 1.5-3.1)], chewing gum [OR: 1.5 (95% CI: 1.1-2.1)] and chocolate consumption [OR: 2.5 (95% CI: 1.8-3.5)] and a negative association with citrus fruit consumption [OR: 0.5 (95% CI 0.3-0.7)] and the development of Crohn's disease were found. Consumption of cola drinks [OR: 1.6 (95% CI 1.1-2.3)] and chocolate consumption [OR: 2.5 (95% CI 1.8-3.5)] were positively associated with developing ulcerative colitis. There was a negative association between the intake of citrus fruits [OR: 0.5 (95% CI 0.4-0.8)] and 'having a stuffed pet' for a period longer than 5 years [OR: 0.6 (95% CI 0.4-0.9)] and developing the disorder. No association with the frequency of tooth brushing and developing IBD was found.

CONCLUSION: All the nutritional items mentioned may be true risk factors or they just might be the expression of a modern life-style also involving other risk factors for the development of IBD which at the present are still unknown.