The PNPLA3 Ile148Met interacts with overweight and dietary intakes on fasting triglyceride levels

The Ile148Met (rs738409, G-allele) in the patatin-like phospholipase domain-containing protein 3 gene (PNPLA3) associates with liver fat content and may lead to loss-of-function (hydrolysis) or gain-of-function (CoA-dependent lysophosphatidic acid acyltransferase) defects. PNPLA3 is up-regulated by dietary carbohydrates, and interactions between rs738409 and carbohydrates, and sugar and omega 6:omega 3-polyunsaturated fatty acid (PUFA) ratio on hepatic fat accumulation have been reported. We examined interaction between rs738409 and overweight, and between rs738409 and dietary intakes (carbohydrates, sucrose and omega 6:omega 3-PUFA ratio), on fasting triglyceride levels. From the Malmo Diet and Cancer Study-Cardiovascular Cohort, 4,827 individuals without diabetes aged 58 +/- 6 years, 2,346 with BMI <= 25 kg/m(2) and 2,478 with BMI > 25 kg/m(2), were included in cross-sectional analyses. Dietary data were collected by a modified diet history method. Overweight modified the association between rs738409 and fasting triglyceride levels (P-interaction = 0.003). G-allele associated with lower triglycerides only among overweight individuals (P = 0.01). Nominally, significant interaction on triglyceride levels was observed between rs738409 and sucrose among normal-weight individuals (P-interaction = 0.03). G-allele associated with lower triglycerides among overweight individuals in the lowest tertiles of carbohydrate and omega 6:omega 3-PUFA ratio (P = 0.04 and P = 0.001) and with higher triglycerides among normal-weight individuals in the highest tertile of sucrose (P = 0.001). We conclude that overweight and dietary sucrose may modify the association between rs738409 and fasting triglyceride levels.