Akane Higashi

Prevalence and mortality of ulcerative colitis and Crohn's disease in Japan.

SummaryA descriptive epidemiological study of ulcerative colitis and regional enteritis or Crohn’s disease in the general population in Japan was conducted. Mortality rates were based on death certificate records and prevalence rates on the statistics of public aid patients with intractable diseases. Between 1969 and 1985, age-adjusted mortality rates from ulcerative colitis gradually decreased. For regional enteritis, these rates did not change.The prevalence of ulcerative colitis in Japan from April 1, 1984 to March 31, 1985 was 7.85 per 100,000 (6.44 for males, 9.22 for females). The prevalence of Crohn’s disease was 1.86 (2.25 for males, 1.48 for females). These figures are one fourth to one fortieth of the rates in Western countries.

Validity of Observed Differences in Dietary Surveys by Two Self-Administered Questionnaires Over a 5-year Period: Concordance with Self-Reported Change

Differences observed by comparing the responses to two surveys taken 5 years apart were compared with self-reported changes in dietary habits in the second survey to examine the construct validity of dietary change. That is, when an observed difference about a certain food was consistent with a self-reported change, these two methods seemed to show a high validity regarding dietary change. Both surveys used the same self-administered food intake frequency questionnaire, and subjective changes in food intake were evaluated at the second survey (self-reported change). Eight hundred fifty-five males and one thousand females aged 30-69 years were analyzed. Since results by both methods showed a higher frequency of increased intake of green-yellow vegetables in general, pale- colored vegetables in general, carrots, and squash, these results were thought to be of high validity. However, cabbage, lettuce, and seaweeds showed inconsistent results regarding higher frequencies of intake. Changes among quintiles of lower frequency seemed to show lower validity because the results obtained by the two methods were often inconsistent for dairy foods and some other foods. Thus, self-reported changes may reflect respondents’ attitudes toward foods, not their actual behavior.