Blood pressure, insulin, and haematocrit values in Japanese subjects over 60 years of age

Many studies have suggested an association between blood pressure (BP) and both insulinaemia and haematocrit values in Western populations. However, relatively few data regarding such associations for the Japanese population are available. We investigated the relationship between BP and various parameters, including insulin and haematocrit, in 269 healthy Japanese individuals (113 men and 156 women) over 60 years of age. The data were analysed by stepwise multiple regression analysis. In men, the most important determinant of systolic BP (SBP) and diastolic BP (DBP) was the plasma insulin concentration (β = 0.32, F = 12.4, P < 0.001 and β = 0.32, F = 13, P < 0.001, respectively), and haematocrit was found to be associated with DBP (β = 0.21, F = 5.3, P < 0.05). In women, fasting insulins were unrelated to BP, but fasting plasma glucose and triglyceride concentrations and age were associated with SBP (β = 0.29, F = 15.5, P < 0.001, β = 0.27, F = 14.3, P < 0.001, and β = 0.2, F = 7.8, P < 0.01, respectively), and haematocrit, fasting plasma glucose concentration and age were associated with DBP (β = 0.29, F = 14, P < 0.001, β = 0.2, F = 6.9, P < 0.01 and β 0.2, F = 6.3, P < 0.05, respectively). These results suggest that the insulin-BP associations in healthy Japanese subjects over 60 years of age differ according to sex, and that haematocrit is an important determinant of DBP in both sexes in our population.