Fasting plasma insulin levels in an unselected Prague suburban population.
OBJECTIVE: The aim of the study was to determine the levels of fasting plasma insulin in an unselected population of a Prague suburban community and correlate the levels of insulin with other metabolic and anthropometric parameters which could be directly or indirectly associated with insulin levels. RESEARCH DESIGN AND METHODS: A total of 835 adult inhabitants, the Prague suburban community, were examined. Mean age of examined people was 44.9 +/- 16.9 years, the group included 370 men and 465 women, 189 of the latter were in the menopause. The parameters examined included the fasting plasma levels of insulin, glycaemia, total cholesterol, HDL cholesterol and triacylglycerols; LDL cholesterol and, using the basic anthropometric data, the body mass index (BMI) and the waist/hip ratio (WHR) were calculated. RESULTS: The levels of all parameters were divided in ten-year groups of men and women. The average levels of fasting plasma insulin in all ten-year groups of men and women were normal. We found in the men small but constant rise of fasting insulinaemia in the decades. This was not observed in women, where the insulin levels were similar up to the time after menopause, then the level of average plasma insulin rose significantly. We found the positive correlation of plasma insulin levels with triacylglycerol levels (p < or = 0.001), BMI (p < or = 0.001) and WHR (p < or = 0.001) and a negative correlation with plasma HDL cholesterol (p < or = 0.001) in the whole group of probands. No significant correlation was demonstrated between fasting insulinaemia and total or LDL cholesterol. When dividing the group by age and sex, the strongest positive correlations were seen between insulin and triacylglycerols, glycaemia, BMI, and WHR, and negative correlations between insulin and HDL cholesterol. CONCLUSION: Fasting plasma insulin levels in an unselected population were within the normal range, but follow a continuous and steady upward course in men while did not change until after the menopause when they bounce in women; compared to insulin levels in younger women, insulinaemia does not increase up to 55 years of age. The strongest positive correlations were demonstrated between plasma insulin and triacylglycerols, and between insulin and BMI and WHR in men and postmenopausal but not premenopausal women whereas a negative correlation was observed between fasting plasma insulin and HDL cholesterol.