Epidemiological Survey on Chronic Inflammatory Bowel Disease Developed during Childhood in Japan, and a Case-Control Study on Nutrition during Infancy

An epidemiological survey was performed from 1979 to 1993 on Japanese patients who developed ulcerative colitis (UC) or Crohn's disease (CD) during childhood. A case-control study was also conducted concurrently in order to assess whether artificial feeding during infancy (up to 4 months after birth) could be a risk factor for these diseases. The cumulative number of patients until 1993 was 578 cases for UC (sex ratio, 1.1:1.0) and 260 cases for CD (sex ratio, 1.4:1.0). There was almost no change in the number of new cases of UC and CD per year after 1978, showing cases of around 32 (mean ± SD; 32.1 ± 6.8) per year for UC and 16 (15.7 ± 6.3) per year for CD. A case-control study was performed on 133 cases of UC and 42 cases of CD. The 2 × 2 contingency tables were prepared to calculate the odds ratio, significance and 95% confidence interval. Comparison between the group fed exclusively by breast milk or mixed, and the group fed by artificial (bottle) feeding alone for the development of inflammatory bowel disease, showed the following results: in UC, the odds ratio was 0.53 and the 95% confidence interval was 0.31 to 0.89; and in CD, the odds ratio was 0.30 and the 95% confidence interval was 0.13 to 0.70. These results indicated that breast feeding during infancy until postnatal 4 months might decrease the development of chronic inflammatory bowel disease.