MAJOR LIFE-STYLE DETERMINANTS OF PLASMA TOTAL HOMOCYSTEINE DISTRIBUTION - THE HORDALAND HOMOCYSTEINE STUDY

We report on the location and skewness of the distribution of plasma t otal homocysteine (tHcy) according to lifestyle indexes in 11 941 appa rently healthy participants of the Hordaland Homocysteine Study. Most subjects were in two age groups: 9165 subjects were aged 40-42 y and 2 351 subjects were aged 65-67 y. The remaining 425 subjects were of int ermediate ages. In multivariate analysis, sex, age, folate intake, smo king status, and coffee consumption were the strongest determinants of tHcy concentration. The combined effect of the three modifiable facto rs was larger than the effect from each factor alone. A lifestyle prof ile characterized by low folate intakes, smoking, and coffee consumpti on was associated with a high median tHcy concentration and a pronounc ed skewness toward high tHcy values. In subjects characterized by a co ntrasting lifestyle profile [high folate intakes, nonsmoking status, a nd low coffee consumption (<1 cup/d)], tHcy values were almost normall y distributed and the median concentration was 3.0-4.8 mu mol/L lower. Among all 40-42-y-old subjects, the 95% reference ranges based on geo metric mean tHcy concentrations were 5.1-16.5 mu mol/L for women and 6 .2-18.7 (mu,mol/L for men. The corresponding ranges for subjects chara cterized by high folate intakes, nonsmoking status, and low or moderat e coffee consumption (<5 cups/d) were 4.8-12.8 mu mol/L and 6.2-14.7 m u mol/L. These findings are relevant for establishing adequate referen ce ranges for tHcy and emphasize folate intake, smoking status, and co ffee consumption as major acquired determinants of tHcy concentration in this general population.