HYPERINSULINEMIA AND BLOOD-PRESSURE IN A GENERAL JAPANESE POPULATION - THE HISAYAMA STUDY

Objectives: To study the relationship between serum insulin and blood pressure, as well as the prevalence of hypertension according to the i nsulin level in a general Japanese population. Design: In 1988 a cross -sectional community survey was conducted among Hisayama residents age d 40-79 years. Methods: A total of 1073 males and 1407 females (72.5 a nd 80.5% of the total population, respectively) underwent comprehensiv e investigation, including a 75-g oral glucose-tolerance test. Fasting and 2-h serum insulin levels were measured by radioimmunoassay. Resul ts: The sum of the fasting and 2-h postloading insulin levels was sign ificantly correlated with the systolic blood pressure (SBP; r=0.18 and 0.26 for males and females, respectively) and the diastolic blood pre ssure (DBP; r=0.24 and 0.19, respectively) in the subjects not receivi ng antihypertensive drugs. In multiple regression analysis the correla tion with blood pressure remained significant in both sexes even after controlling for age, body mass index, alcohol intake, smoking, a fami ly history of hypertension, serum total cholesterol and fasting plasma glucose. The age- and sex-adjusted prevalence of hypertension (SBP gr eater than or equal to 160mmHg or DBP greater than or equal to 95 mmHg , or both, or receiving drug treatment) increased significantly with a h increase in the sum of fasting and 2-h postload insulin levels in bo th the non-obese subjects (body mass index <25 kg/m(2)) and the obese subjects (body mass index greater than or equal to 25kg/m(2)). Multipl e logistic regression showed that the sum of fasting and 2-h postload insulin levels was a significant factor with an independent relationsh ip to hypertension, even after taking the other risk factors into acco unt. Conclusion: The present study suggests that hyperinsulinaemia is related to hypertension in a general Japanese population.