Recently, cardiovascular diseases have increased in Japan by the westernized diet habit and the increase of elderly people. Community survey on cardiovascular diseases was performed in the mountainous area (Shichikawa) and the seaboard area (Ohshima) in Wakayama Prefecture from 1975 to 1977 to estimate the effect of the differences in the life environment on the occurence of hypertension and the ischemic heart disease. Total 731 subjects were examined, aged 20 to 90 years. The average blood pressure levels in both areas were slightly lower compared to the average in Japan, and there was no significant difference in the blood pressure levels between the two areas. The incidence of ECG abnormalities was higher in Shichikawa than Ohshima, corresponding to the higher rough mortality rate from the cardiovascular diseases from 1971 to 1975 in the former than the latter. The aggravation of ECG findings during two years was more frequently found in the subjects with high serum cholesterol levels than those with normal serum cholesterol. The serum cholesterol level was significantly higher in the seaboard area than in the mountainous area and the nutritional survey performed in part in 1976 also showed the higher lipid intake in the former than the latter. Although the serum cholesterol levels in the hypertensives were higher than in the normotensives, it may be due to 10 years older mean age in the former than the latter. The hypertensive changes in ocular fundi were marked in the subjects with severe hypertension, and the arteriosclerotic changes were increased with age. The present study showed that the incidence of ECG abnormalities and the rough mortality rate from cardiovascular diseases were higher in the mountainous area than the seaboard area, though the serum cholesterol level was lower in the former than in the latter, suggesting that the difference in the incidence of the cardiovascular diseases in these two areas is probably due to the environmental life factors other than serum cholesterol. Therefore, it is concluded that the differences of serum cholesterol levels in some extent might not so influence on the occurence of ischemic heart disease.
The incidence of radiologically visible carotid calcification sharply increased after the age of 60 and showed a significant sex difference. Postero-anterior films of the cervical spine, routine chest films and abdominal lateral films were reviewed on 983 consecutive Japanese patients over the age of 40. The incidence of carotid calcification was none of 90 males and none of 46 females in the age group of 40 to 49, 2 (1.2%) of 168 males and 3 (2.3%) of 128 females in the age group of 50 to 59, 45 (19.3%) of 233 males and 5 (3.8%) of 130 females (p<0.001) in the age group of 60 to 69, and 35 (27.3%) of 128 males and 10(16.7%) of 69 females in the age group of 70 to 79. Carotid calcification developed about 10 years later than aortic calcification. Most of the patients with carotid calcification had calcification of the aortic arch or the abdominal aorta. Clinical abnormalities such as hypertension, glucose intolerance and stroke were more frequently found in patients with carotid calcification than in those without it. These results indicate that the carotid calcification is one of the important signs of severe generalized atherosclerosis.