[Changes of nutritional factors related to regional differences in the mortality of cardiovascular disease between 1966 and 1985 in Japan].

Cardiovascular disease has been the leading cause of death since 1946 in Japan. In this paper, the relationship between mortality and nutritional factors was analyzed by 12 different regions in Japan during the period 1966-1985. Data in the Reports of the National Nutritional Survey in Japan were used as the nutritional factors, and calculation was made of age-adjusted mortality from ischemic heart disease (IHD), cerebral hemorrhage (CH) and cerebral infarction (CI). The results obtained were as follows: 1. Correlation coefficients were calculated based on the average value of 20 years in each 12 different regions. Correlation coefficients between the mortality from IHD and intake of total fat and n3-polyunsaturated fatty acids were positively significant for both sexes. Between the mortality from CH and vegetable protein and salt, they were positively significant (p < 0.01) while cholesterol was negatively significant (p < 0.01). Between the mortality from CI and vegetable protein, salt and carbohydrate, they were positively significant (p < 0.01). 2. Correlation coefficients between slopes of CH and slopes of nutrients intakes, indicated cholesterol to be negatively significant (p < 0.05) for women from 1966-1970, and salt to be positively significant for men (p < 0.01) and women (p < 0.05) from 1974-1985. In the period 1966-1970, the correlation coefficient between slopes of IHD and those of Keys' factor was positively significant (p < 0.05) for women. 3. To clarify changes in the relationship between mortality and nutrients, correlation coefficients were calculated each year from 1966 to 1985. Significant positive correlation coefficients for IHD were found with animal protein and saturated fat starting from about 1975. Salt was associated with IHD in the 1960s but not following 1970. Those of nutrients for CH and CI did not change markedly during 18 years. 4. Multiple regression analysis with intake of salt and Keys' factor indicated that the influence of salt on cardiovascular disease to decreased and that that of low serum cholesterol on CH declined. Multiple correlation coefficients with salt and Keys' factor decreased for IHD (men) and CH (women).