Background and aims: To examine whether the association between the −514 C/T polymorphism of the hepatic lipase gene and myocardial infarction (MI) is modified by history of hypercholesterolemia and increased waist circumference.

Methods and results: A total of 1940 pairs of nonfatal MI cases and population-based controls were genotyped. Multiple conditional logistic regression was used for data analyses. The −514T variant was not associated with MI in the whole population. However, among people with history of hypercholesterolemia the T allele increased MI risk for heterozygous and homozygous carriers, respectively [OR = 1.25 (95%CI = 0.92–1.70) and OR = 1.59 (95%CI = 1.09–2.32). In contrast, the T allele decreased MI risk among people with no history of hypercholesterolemia [OR = 0.85 (95%CI = 0.70–1.03) and OR = 0.76 (95%CI = 0.60–0.97)], p for interaction = 0.004. Among subjects with normal waist circumference there was no association between the −514T allele and MI for heterozygous and homozygous carriers, respectively [OR = 1.04 (95%CI = 0.86–1.25) and OR = 0.96 (95%CI = 0.77–1.21)], while among subjects with waist circumference above the limits of the metabolic syndrome definition there was a protective association [OR = 0.63 (95%CI = 0.45–0.90) and OR = 0.81 (95%CI = 0.53–1.25) p for interaction = 0.04].

Conclusion: The −514 T allele is associated with MI in opposite directions depending on the background of the studied population. This could explain what seem like inconsistent results across studies.