The material was analyzed with SPSS 14 quantitative data using Student’s t-tests. Ordinal data and variables not normally distributed were analyzed by the Mann–Whitney U-test, the Kruskal Wallis test and the z-test for comparison of population proportions. Hardy-Weinberg equilibrium was assessed for each SNP by χ2 analyses. The findings in univariate analyses were furthermore investigated in multivariate models adjusted for age and sex.
