Background. Mild hyperhomocysteinaemia (MHHcy) is a significant and independent risk factor for vascular diseases, however, its causality has not yet been unequivocally confirmed. The total homocysteine (Hcy) blood level is considered a product of genetic and lifestyle interactions, mainly folates, vitamin B 12 and pyridoxine intake. In this paper we estimated the influence of these factors on MHHcy in the population. Methods and Results. The population sample included 292 males a 251 women, mean age 53.4 years, selected from the population study PILS II. All subjects were examined by a standard protocol for clinical, anthropometrical and laboratory examination. Hcy levels were examined by ion exchange chromatography, all other factors by commercial kits. Statistical analysis was done in quartiles of distribution by Kruskal-Wallis ANOVA, Wilcoxon’s un-paired test and multiple logistic regression (stepwise). Serum total Hcy levels were in significant positive associations with age in both sexes, with BMI in males only. Negative associations of Hcy were found with plasma folates and B 12 concentrations in both sexes, with alcohol consumption again only in males. Smoking and physical activity and serum methionine concentration were not associated with Hcy levels. The established associations remained significant when adjusted by multiple logistic regression. About 40% of subjects with MHHcy had low folates and/or B 12 levels and a deficiency in both vitamins was found in 17% of subjects. In contrast, MHHcy also was assessed in 14% of subjects with high folates and in 17% with high B 12 concentration and in as few as in 3.7% of subjects with high concentrations of both vitamins as well. Conclusions. Nutritional factors, i.e. folates and B 12 intake, seem to be the most important ones responsible for Hcy levels. A predominating influence of genetic factors may be assumed in less than one fifth of subjects with MHHcy.

        Key words: homocysteine, folates, B 12 , alcohol intake, lifestyle, population.