👤 M Fiegenbaum

APOC3 polymorphisms were associated with lipid parameters and coronary artery disease in several populations but not all. Considering the multifactorial inheritance and environmental factors that underlie the determination of triglyceride (TG) and HDL-C levels, the aims of the present study were to perform association analyses of APOC3 polymorphisms and these lipids in a southern Brazilian population of European descent to investigate possible interactions with other genetic and/or environmental factors. Six hundred and seventy-three subjects participated in the study. -482C>T, -455T>C and 3238C>G polymorphisms genotyping were carried out by PCR followed by restriction enzyme digestion. In female subjects the APOC3-APOE genotype combinations had a significant effect on triglyceride levels (ANOVA, P=0.009). Post hoc analysis showed that the observed differences were between APOC3 S(*)2 carriers and S(*)1S(*)1 homozygotes in individuals with an APOE(*)3/3 genotype (Tukey HSD post hoc test, P=0.027). In APOE(*)3/(*)3 subjects, the raising effect of APOC3 S(*)2 allele on TG concentrations was more pronounced in female smokers (+59.4%) than in nonsmokers (+18.8%, P of S(*)2-smoking interaction=0.009). Among APOE(*)3/(*)3 subjects, male carriers of the less common alleles -482T and -455C had significant lower levels of HDL-C compared to homozygotes -482C/C and -455T/T (P=0.02 and P=0.006, respectively). APOC3 polymorphisms were associated with lipid variables, but the magnitude of these associations was modulated by additional genetic, biologic and/or environmental factors. Show less

To investigate associations and gene-environment interactions of APOA-IV gene polymorphisms with obesity-related phenotypes in a Brazilian population. A total of 391 individuals (171 men and 220 women) were genotyped for Xbal, Thr347Ser and Gln360His polymorphisms by PCR-RFLP methods. Adjusted body mass index (BMI) and waist circumference (WC) were compared among genotypes/haplotypes by unpaired t-test or analysis of variance. Gene-environment interactions were tested by analysis of variance using a general linear model. Analysis of the APOA-IV gene variants separately showed that X*2 and 347Ser alleles were associated with higher BMI (P=0.02 for both polymorphisms). Haplotype analysis confirmed this association. For these polymorphisms, the effect on BMI appeared to depend on smoking status (test for interaction, P=0.007 and 0.02, respectively), the Thr347Ser variant was associated with a BMI increase in smokers only (P=0.002). At the single-locus level no association was observed between 360His allele and BMI; however, haplotype analyses showed an association of this gene variant and higher BMI. A trend for association with WC (P=0.05) was observed in male carriers of the 360His allele. The effect of this polymorphism also depended on smoking status (test for interaction, P=0.018). Nonsmoker male carriers of the 360His allele had a larger waist circumference than homozygotes for the Gln allele (P=0.003). Our data suggest that the APOA-IV gene polymorphisms investigated are associated with obesity-related traits. The effects of X*2 and 347Ser variants on BMI and the 360His variant on waist circumference depended on smoking status. Show less