Serum insulin and lipoprotein(a) concentrations. The Jichi Medical School Cohort Study

To examine the relationship between serum insulin and lipoprotein (a) [Lp(a)] concentrations in both sexes in a large population.

The authors conducted a cross-sectional investigation of fasting serum concentrations of insulin and Lp(a), other blood tests, blood pressures, anthropological measurements, physical activity index, smoking habit, alcohol consumption, and menopause. The subjects were 1,121 men and 1,480 women, ranging between 30 and 90 years of age, who were voluntary participants in the Jichi Medical Cohort Study and who resided in one of five rural communities in Japan.

In men, insulin, age, BMI, LDL cholesterol, triglycerides, glucose, and fibrinogen were significantly correlated with Lp(a). In women, insulin, age, LDL cholesterol, fibrinogen, and activated coagulation factor VII were significantly correlated with Lp(a). However, all correlations were weak in either sex. Insulin was inversely correlated with Lp(a) in both sexes. However, the coefficients were weak (r = -0.16 in mean and r = -0.06 in women). In the partial correlation analyses, Lp(a) was not significantly associated with insulin in either sex. The result was not influenced by selecting the subjects on the basis of detectable values of insulin and Lp(a) and stratifying them by serum glucose level.

There was no significant relationship found between serum insulin and Lp(a) concentrations in either sex of the cohort, which indicates that Lp(a) does not play a role in the increased risk of cardiovascular disease in hyperinsulinemic subjects.