The Relation between Erythrocyte Trans Fat and Triglyceride, VLDL- and HDL-Cholesterol Concentrations Depends on Polyunsaturated Fat

<div><h3>Background</h3><p>Trans fatty acids (TFA) lower HDL and increase triglyceride concentrations while polyunsaturated fatty acids (PUFA) lower triglycerides and may decrease HDL concentrations. The effect of the interaction between trans fat and PUFA on lipids is uncertain.</p> <h3>Methods</h3><p>Men and women (n = 1032) in the Genetics of Lipid-Lowering Drugs and Diet Network (GOLDN) study were included. Fatty acids in erythrocyte membranes were measured with gas chromatography while data on potential confounders were obtained from questionnaires. To test the interaction between total erythrocyte PUFA (ePUFA) and TFA (eTFA) on lipid concentrations we distributed eTFA into tertiles and dichotomized ePUFA at the median concentration.</p> <h3>Results</h3><p>For the 1^st, 2^nd and 3^rd tertiles of eTFA, multivariate-adjusted means±s.e.m for HDL were 46.2±1.1, 46.3±1.1 and 45.5±1.0 mg/dL among those with low ePUFA, respectively, while they were 50.0±1.1, 46.9±1.1 and 44.7±1.1 mg/dL among those with high ePUFA, respectively (<em>P</em> for interaction = 0.01). For the 1^st, 2^nd and 3^rd tertiles of eTFA, multivariate-adjusted means±s.e.m for triglycerides were 178.6±11.3, 144.7±10.9 and 140.8±10.6, respectively, among those with low ePUFA, while they were 133.8±11.3, 145.7±10.9 and 149.3±11.5, respectively, among those with high ePUFA (<em>P</em> for interaction = 0.005). Results for VLDL were similar to those for triglycerides. No significant interactions were observed for LDL or total cholesterol.</p> <h3>Conclusions</h3><p>The relation between trans fat and HDL, VLDL and triglycerides may depend on PUFA. The benefit of avoiding trans fat may be greater among individuals with higher PUFA intake. Supplementation with PUFA among individuals with relatively high trans fat intake may have limited benefits on lipid profiles.</p> </div

Relation between trans fat (distributed in tertiles) and HDL (panel A), LDL (panel B), triglycerides (panel C) and VLDL (panel D) in analyses stratified by polyunsaturated fat content in erythrocyte membranes.

<p>Lipid values are means ± s.e.m and are adjusted for study site, age, sex, body mass index, physical activity, alcohol intake status, smoking status, erythrocyte monounsaturated fat, erythrocyte saturated fat and pedigree as a random effect.</p

Characteristics of the study population by polyunsaturated fat and trans fat content, both measured in erythrocyte membranes.

<p>Values are means±SD or %. PUFA = Polyunsaturated fat; MUFA = Monounsaturated fat; Sat = Saturated; Trans = Total trans fat in erythrocyte membranes; BP = Blood pressure; FFQ = Food frequency questionnaire.</p

Parameter estimates from linear regression models looking at the effects of <i>LRP-1</i> I10701 SNP and <i>ApoE</i> isoforms on BMI in the GOLDN study population.

a<p><i>P</i>-values were derived from mixed linear models, specifying a Kenward Rogers correction on the estimator, with <i>LRP-1</i> I10701 SNP and <i>ApoE</i> genotype frequency, an interaction between ApoE and LRP-1 genotype frequency, age and age², sex, smoking, total alcohol and center of data collection as predictors, and BMI (logarithmically transformed) as the outcome.</p

ApoE genotypes by LRP-1 <i>I10701</i> genotype.

<p>ApoE genotypes by LRP-1 <i><u>I10701</u></i> genotype.</p

N, mean age (standard deviation) and percentage of males and ApoE ε3 carriers, in the GOLDN study population by LRP-1 genotype group.

†<p>a = minor allele; A = major allele.</p>‡<p><i>P</i>-values were derived from tests of null hypothesis that no group is different, using a 1-way ANOVA for continuous traits or the χ² test for categorical variables.</p

Adjusted hazard ratios for mortality at 12 weeks (baseline variables).

<p>There is little evidence that the association between phosphate and the hazard of death is non-linear based on a likelihood ratio test (p = 0.27). Similarly, there is little evidence that the association between any continuous variable and the hazard of death is non-linear (p>0.20 for each).</p

Study procedures and cohort status by study visit.

<p>Study procedures and cohort status by study visit.</p

Baseline participant characteristics.

<p>Abbreviations: ART, antiretroviral therapy; BMI, body mass index; BUN, blood urea nitrogen; hsCRP, high sensitivity C-reactive protein; IQR, interquartile range.</p><p>Among the 142 cases included in the multivariable analysis, values were missing for the following measurements: 8 (6%) baseline serum phosphate, 31 (22%) week one serum phosphate, 29 (20%) baseline hemoglobin (because either blood or assay reagents could not be obtained), 2 age (birth dates unknown), and one BMI (participant could not stand for height measurement).</p><p>*Normal creatinine range: females 44–80, males 53–106 µmol/L; normal albumin range: females 41–53, males 40–50 g/L; normal ferritin range: females 10–150, males 29–248 µg/L.</p

Characteristics of study participants in the participating cohorts.

<p>Characteristics of study participants in the participating cohorts.</p