To reduce the overall mortality rate and to prolong life expectancy in Japan, measures must be taken to reduce those mortality rates associated with seasonal differences, especially those causes of death which show a strong correlation with seasonal change: respiratory, heart, cerebrovascular, diabetes and infectious diseases.

A good deal of data are available on the bowel habits of pre-climacteric females during menstruation. Few studies have examined the same subject in females of climacteric age but who are still menstruating, so the present study was undertaken to examine the bowel habits in menstruating females in this age group. Subjects (n = 246) were residents of a city in northern Japan, aged from 45 to 55 years old and who were still menstruating. Their every-day state of defecation and fecal characteristics were assessed with regard to four parameters: bowel movement frequency, defecation state, fecal appearance and fecal consistency. Based on a perfect match to these four criteria, the subjects were assigned to two groups, the normal group and the constipation group, and changes were assessed by enquiring how their bowel habits differed immediately before and during menses compared with their usual state. Immediately before menstruation, in the constipation group feces became harder and looser in 22.1% and 13.7%, respectively, compared with 8.7% and 9.5% in the normal group. On the other hand, during menstruation in the constipation group, feces became harder and looser in 11.6% and 16.8%, respectively, compared with 5.7% and 8.9% in the normal group. In other words, the constipation group showed a greater change immediately before and during menstruation compared with the normal group, though the differences were not significant. Our data thus suggest that the changes in the bowel habits of women of climacteric age at menstruation are greater for those suffering from constipation than those who are not.

The report of Fuchs et al. in 1999 on the protective effects of dietary fiber (DF) against colon carcinogenesis has led many researchers to question the benefits of DF. We analyzed the relationship between dietary intake and mortality from colon cancer in Japan cross-sectionally. Dietary data were taken from the National Nutrition Survey. The standardized mortality ratio (SMR) was calculated using data from "Vital Statistics" and "the Population Census in Japan." Multiple regression analysis (stepwise variable selection method) was performed with the SMR of colon cancer as the objective variable and intake of DF, nutrients, and food groups in 1966 as the explanatory variables. The beta regression coefficient was significantly positive for intakes of fat, protein, and vitamin C and significantly negative for intakes of calcium and vitamin A to the SMR of colon cancer. However, no significant correlation was observed for DF or for any of the various food groups analyzed. In conclusion, our data do not demonstrate any protective effect of DF on colon cancer in subjects with a low fat intake (Japanese subjects), which supports Fuchs' findings in subjects with high fat intake (U.S. subjects).

We examined the defecatory conditions in a population of Japanese subjects and analyzed the measured parameters as a means for self-evaluation of defecation. Subjects (n=1195) were residents of northern Japan and were all aged over 40 years. The state of defecation and fecal characteristics were assessed with regard to nine parameters including "self-reported bowel habit" and "bowel movement frequency." Logistic regression analysis was carried out to analyze the association between the complaint of constipation and other eight parameters. A higher tendency for constipation was noted in women than in men. The highest value of the odds ratio was "bowel movement frequency"; especially the value "once per three days or more" was noted in both genders (odds ratio: 13.38 and 42.46 in men and women, respectively). In addition, "stool appearance", "length of time for bowel movement", "straining after bowel movement", "alternating diarrhea/constipation/ disorder" and "travel-related changes in bowel movements" were significantly related with the complaint of constipation ("self-reported bowel habits") in both genders. In conclusion, the study elucidated that personal and subjective evaluation of bowel habits in normal subjects consisted of various factors under the heading of "bowel movement frequency". defecation; self-reported bowel habits; bowel movement frequency; general population; logistical regression analysis

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