Cerebral apoplexy death problems in recent Iwate Prefecture has been statistically studied using the statistics of the Prefecture of 1951 to 1957. Calculating the auto-correlation coefficient according to G.U. Yule (1926) and making correlograms of each districts of the Prefectures the following results have been obtained:
1) Death due to cerebral apoplexy was noted to have a typical definite connection with the seasons regardless of age. With an annual periodical cycle, the number of death due to cerebral apoplexy increases in the winter season while decreasing in the summer season. This typical periodical seasonal change in the number of death of apoplexy was noted to be conspicuous after 50, particularly after 60 years of age.
2) This seasonal change in the apoplexy death number was noted to be varied somewhat with the districts: Morioka, Kamaishi, Hanamaki, Ichinoseki, and Daito, which are divided according to the existance of the health center, are the districts with an apparant typical seasonal change in the death number, while destricts of Iwate, Kuji, Iwaizumi, TOno show no noticeable seasonal change in the same.
3) Corrected death rate of cerebral apoplexy in each of the health center districts made known that there are an apparant difference among the districts, being, as a rule, higher in the inland plains and lower in the coast districts. There is a trend that the greater the proportion of aged people after 65 years of age among the apoplexy dead people is, the lowler is the corrected death rate of apoplexy. Concerning the relationship between the ratio of aged people in the number of apoplexy death and the corrected death rate of apoplexy, there are noticeable differences in the relationship among the following three districts: the inland plains, the coast districts, and the districts between the mountains of the Kitakami mountain system, however, there is still a district accumulation character. These trends are also noted to exist in other prefectures throughout Japan.
4) Atmospheric pressure and temperature were the two factors of the weather picked out to might have some connection with the death of apoplexy. With both the multiple and partial correlation method, statistically studying the relationship between these two atmospheric factors and the death rate of apoplexy, it was found that temperature had more influence on the death rate of apoplexy than the pressure.
