We examined the mean blood preasure levels (MBPL) and prevalence rates of hypertension by sex and age in the people of Okinawa. The number of subjects studies was 16.759. Of which 6.352 were male and 10.407 were female over 10 years old. We estimated the volume of salt intake per person per day. We found that MBPL and pevalence rates of hypertension were significantly lower in Okinawan people than in mainland Japanese people. The main cause of a lower MBPL and lower prevalence rates of hypertension in Okinawan people results from the warm climate of the subtropical zone and a low salt intake (9.6 g). This may influence the low prevalence rates of ischemic heart disease and cerebrovascular disease in Okinawa, diseases which are number two and three respectively among the three main causes of death in Japan.
As obesity is the most prevalent, chronic risk in aged population, a much more accurate method is needed in order to assess obesity which is not satisfied by current methods and machines. As to those background, A-mode type Ultrasonic Device is able to assess directly subcutaneous fat thickness and also to estimate more exactly mass of body fat so that it will be able to test etiological relationship between fat mass and diseases. Authors studied the subcutaneous fat thickness of clients who had medical data of health examination respectively at three districts which were Hase village of Nagano, Nerima and Kashiwa of metropolitan area, and analyzed statistically the relationship between subcutaneous fat thickness and data of medical examination. The results are following: 1. Subcutaneous fat layers were thinner in Hase of rural mountainous area than in both metropolitan subjects of the urban area, even though there were not any different value of Body Mass Index (BMI) among them. 2. After measuring four abdominal location of suprailiac, three abdominal location of supra-, mid- and infra-rectum abdominal, it was more clear that males were more thick than females in supra-rectum abdominal area, and adversely females were more thick than males in infra-rectum abdominal area. 3. When subjects of all were divided into five degrees according to the levels of T-cholesterol, triglyceride and HDL-cholesterol, by Hata's classification of hyperlipidemia, subcutaneous fat thickness increases in accordance with severity of hyperlipidemia. This relationships were most typical in the level of trigryceride. 4. According to the occupational activities, the harder workers got the thinner subcutaneous fat thickenss especially in male.