The Interrelationships between Fasting Serum Insulin Level, Obesity and Blood Pressure in Women: Results from a Cross-Sectional Population Study of Women in Gothenburg, Sweden

This study is based on a representative population sample of women in Gothenburg, Sweden. Three hundred and thirty-six 50-year-old nondiabetic women, not taking any antihypertensive medication, were included in the study. They underwent a comprehensive examination programme, where body weight, body height, waist and hip circumferences, systolic and diastolic blood pressures and fasting serum insulin concentration were measured. Fasting serum insulin concentration was significantly correlated with systolic and diastolic blood pressures. After controlling for both body mass index (BMI) and waist to hip circumference ratio (WHR), fasting serum insulin concentration remained independently associated with blood pressure (P =0.001 for systolic blood pressure, P =0.06 for diastolic blood pressure). When stratified for BMI or WHR the correlations between fasting serum insulin concentration and blood pressure remained significant only in the upper 50th precentiles of BMI and WHR. When relating pressure to different levels of fasting serum insulin concentration there seems to be a threshold at an insulin concentration corresponding to the upper quartile limit (at approximately 17 μU/ml), above which level the blood pressure rises more obviously. The same phenomenon was seen for systolic and diastolic blood pressures.