5. All data are given as means ± standard deviation (SD). The SAS 9.1 program (SAS Institute, Cary, NC) was used for all data processing. Demographic data and baseline characteristics were checked for normal distribution with Kolmogorov-Smirnov goodness-of-fit tests. Significant differences were evaluated in contingency tables using either Fisher’s exact tests or χ2-tests. Continuous variables were compared between groups using Student’s t tests or
Mann-Whitney rank sum tests. Two-sided P < 0.05 were considered significant, unless previous studies indicated that lower or higher values were to be expected; then, one-sided tests were performed. Pearson’s correlation coefficient was used to evaluate univariate associations between the sitosterol:lathosterol and campesterol: lathosterol PD0325901 clinical trial ratios and different ethnic groups, age, BMI and gender. Analysis of covariance was performed to obtain estimates selleck kinase inhibitor of sitosterol:lathosterol and campesterol: lathosterol ratios between ethnic groups adjusted for age,
BMI and gender. The area under the receiver operating characteristic curve (AUC) was calculated for each serum surrogate marker of cholesterol synthesis and absorption as well as the specified ratios; the P-values for the AUC indicate significance in comparison to 0.5. For ABCG5/8 genotypes, Hardy-Weinberg equilibrium was checked using exact tests (http://ihg.gsf.de/cgi-bin/hw/hwa1.pl).14 Potential associations between gene variants
and cholelithiasis were tested in contingency tables (genotypes: Armitrage’s trend tests; alleles: χ2-tests). Table 1 presents the baseline demographic data of the study cohorts. In Germans and Chilean Hispanics, cases and matched controls are similar in age, gender, and BMI distribution. Compared with the Chilean Hispanic cohort, the German patients are older, leaner, and include more men. The small Amerindian Chilean cohort (Mapuche) was composed only of women who were relatively younger than the Hispanics and Germans. Of note, serum total cholesterol and low-density lipoprotein (LDL) cholesterol concentrations were Succinyl-CoA lower in Mapuches compared with Hispanics independently of gallstone status. Serum lipids are similar in cases and controls in the German cohort. In contrast, in the Chilean Hispanic cohort total and LDL cholesterol levels are significantly lower in cases compared with controls. In the Chilean Hispanic and Amerindian cohorts, fasting glucose and insulin levels were also determined, yielding comparable results between cases and controls. As shown in Table 1, the IR-HOMA indexes are high and in the range of insulin resistance for both cases and controls, but they do not differ between groups.