Homocysteine plasma levels are independently associated with insulin resistance in normal weight, overweight and obese pre-menopausal women.

OBJECTIVES: The aim of the present study was to examine the relationship of homocysteine (Hcy) plasma levels to insulin resistance (IR).

DESIGN: A cross-sectional study in a primary care setting.

SUBJECTS AND METHODS: Fasting Hcy levels were measured in the plasma of 44 pre-menopausal women [17 normal weight (body mass index BMI 20.0-24.9 kg/m2), 7 overweight (BMI 25.0-29.9 kg/m2), 20 obese (BMI> or =30.0 kg/m2)], aged 18-45 yr. Other measurements included: central fat accumulation, as evaluated by waist circumference; IR, as calculated by homeostatic model assessment (HOMAIR); systolic and diastolic blood pressure; and fasting concentrations of glucose, insulin and lipids (total cholesterol, HDL-cholesterol, triglycerides).

RESULTS: Hcy was positively correlated with insulin concentrations (p<0.01), HOMAIR (p<0.01), and systolic and diastolic blood pressure (p<0.01 and p<0.05, respectively). After multivariate analysis, only HOMAIR maintained an independent association with Hcy (p<0.05), irrespective of age and other anthropometric and biochemical variables. Lastly, we observed a gradual increase in Hcy plasma levels across the age- and BMI-matched quartiles in which the whole population was divided according to HOMAIR levels (F: 2.73, p<0.05 for linear trend).

CONCLUSIONS: Our study shows that Hcy plasma levels are independently associated with IR in apparently healthy normal weight, overweight and obese pre-menopausal women, thus suggesting a possible role of IR and/or hyperinsulinaemia in increasing Hcy plasma levels. Since Hcy is a well-known cardiovascular risk factor, higher Hcy plasma levels may well be a further mechanism explaining the higher risk of coronary heart disease in patients affected by IR.