PNPLA3 rs738409, environmental factors and liver-related mortality in the U.S. Population

Background & aims: Little is known about the interplay between patatin-like phospholipase domain protein 3 (PNPLA3 rs738409 C>G), environmental factors, and the risk of liver-related death (LRD).

Methods: 4,361 adults were selected from NHANES III, 1991-1994. All participants were linked to the National Death Index until 2019 (mean follow-up: 23.2 years). LRD was the study outcome. Associations of PNPLA3, diet, light alcohol intake, smoking, and BMI (kg/m²) with LRD were examined using competing risk regression models.

Results: PNPLA3 G-allele was significantly associated with LRD (adjusted subhazard ratio [adj.sHR]: 2.9, 95% CI: 1.4-5.8). Non-heavy alcohol intake (adj.sHR: 2.2, 95% CI: 1.1-4.5), top quartiles of monounsaturated fat (MUFA) (adj.sHR: 0.43, 95% CI: 0.12-0.99), and cholesterol (adj.sHR: 2.6, 95% CI: 1.00-8.8) and coffee intake ≥3 cups/day (adj.sHR: 0.05, 95% CI: 0.06-0.10), former/current smoking (adj.sHR: 1.8, 95% CI: 1.2-2.6), BMI (adj.sHR: 1.1, 95% CI: 1.03-1.2), and healthy eating index (HEI) (adj.sHR: 0.96, 95% CI: 0.93-0.98) were associated with LRD. Joint effects between PNPLA3 and environmental factors showed that the risk of LRD was significantly increased in carriers of the G-allele with non-heavy alcohol intake (adj.sHR: 3.7), higher consumption (top quartile) of cholesterol (adj.sHR: 4.1), former (adj.sHR: 4.3) or current (adj.sHR: 3.5) smoking, or BMI ≥30 (adj.sHR: 4.0) kg/m². The effects of the G-allele on the risk of LRD were significantly attenuated in those with top quartile consumption of MUFA (adj.sHR: 0.5) or ≥3 cups/day of coffee (adj.sHR: 0.09). HEI was inversely associated with LRD across all PNPLA3 genotypes (adj.sHR: 0.94, 0.96, and 0.97 for CC, CG, and GG, respectively).

Conclusions: PNPLA3 is associated with LRD and this relationship is significantly modified by anthropometric and environmental factors.