Study aim: To evaluate plasma homocysteine (Hcy), insulin and glucose levels in blood and the insulin resistance index (FIRI) in young, healthy non-obese men and women.

Material and methods: A total of 152 young, healthy, non-obese (BMI<30) men (n = 81) and women (n = 71) participated in the study. The following substances were assayed in blood using commercial kits: total plasma homocysteine by fluorescence polarisation immunoassay, plasma glucose - by the oxidase method, and insulin by radioimmunoassay using monoclonal antibodies. From the latter two, the index of insulin resistance (FIRI) was computed.

Results: Mean plasma homocysteine concentration in men was significantly (p<0.001) higher than in women (10.3 ± 3.0 and 8.4 ± 2.4 μmol/l, respectively) and that of FIRI was significantly (p<0.001) lower than in women (1.310 ± 0.483 and 1.437 ± 0.420, respectively). Neither in men nor in women were plasma homocysteine concentrations correlated with FIRI.

Conclusions: Although no association between circulating homocysteine and FIRI was found in young, non-obese men and women, the existence of such association in Type 2 diabetes cannot be ruled out.