[The comparison of blood pressure of community-dwelling elderly subjects in Okinawa and Shikoku].

In Japan hypertension is frequent, but the prevalence of hypertension in Okinawa has been known to be lower than in other areas in Japan. Now it has been almost 30 years since Okinawa reverted to Japan. So we investigated to know whether the prevalence of hypertension was still lower today or not. We compared the differences of prevalence of hypertension and blood pressure (BP) levels between the two community-dwelling elderly subjects aged 75 years or more: 305 in Ie in Okinawa (M:F = 107:198, mean age: 81 years old), and 99 in Omogo in Ehime, Shikoku (M:F = 45:54, mean age: 81 years old). We visited the homes of the elderly and measured their BP twice in a sitting position and asked them whether they were taking medicine for hypertension or not. According to the 1999 revised guidelines on the treatment of hypertension in the elderly by the Japanese Society of Geriatrics, we defined hypertension as systolic BP (SBP) > or = 160 mmHg or diastolic BP (DBP) > or = 90 mmHg or taking medicine for hypertension, and normotension as SBP < 160 mmHg and DBP < 90 mmHg and not taking medicine for hypertension. Hypertension rates were 52% in Ie, and 59% in Omogo, indicating no significant difference. However, in Ie only 54% of the elderly with hypertension were taking medicine for hypertension, as opposed to 74% in Omogo. These results suggest the possibility that in Okinawa hypertension is thought to be less important than in other districts in Japan.