Plasma Total Homocysteine Concentrations Are Unrelated to Insulin Sensitivity and Components of the Metabolic Syndrome in Healthy Men1

Plasma homocysteine levels are lowered by insulin and can be elevated in insulin-resistant states. However, it is uncertain whether homocysteine and insulin resistance or components of the metabolic (insulin resistance) syndrome are related in healthy individuals. Total homocysteine concentrations were measured by gas chromatography-mass spectrometry in samples from 100 male participants in the second follow-up cohort of the Heart Disease and Diabetes Risk Indicators in a Screened Cohort Study. Members of this cohort have each undergone an iv glucose tolerance test with measurement of insulin sensitivity by minimal model analysis. Age ranged from 31–62 yr (mean, 46.8), body mass index from 20.6–36.5 kg/m2 (mean, 26.3), insulin sensitivity from 0.0–9.6 min/mU·L (mean, 2.32), and homocysteine concentrations from 7.5–30.6 μmol/L (mean, 12.2). In univariate correlation, homocysteine concentrations were unrelated to insulin sensitivity or to components of the metabolic syndrome, including fasting serum triglycerides, high density lipoprotein cholesterol, high density lipoprotein subfraction 2 cholesterol, blood pressure, uric acid, systolic blood pressure, or body mass index. These measures were, nevertheless, highly intercorrelated. These findings strengthen the possibility that in healthy humans, homocysteine metabolism is not substantially affected by insulin action.