['Single nucleotide polymorphisms in the APOA5-A4-C3-A1 gene complex are associated with elevated plasma triglycerides and elevated vascular risk in healthy populations. In patients with clinically manifest vascular disease, hypertriglyceridemia and metabolic syndrome are frequently present, but the contribution of these single nucleotide polymorphisms to plasma triglycerides, effect modification by obesity and risk of recurrent vascular events is unknown in these patients.', 'Prospective cohort study of 5547 patients with vascular disease. Rs964184 (APOA5-A4-C3-A1 gene complex) was genotyped, and we evaluated the relation with plasma lipid levels, presence of metabolic syndrome and the risk for new vascular events.', 'The minor allele of rs964184 was strongly associated with log plasma triglycerides (β 0.12; 95%CI 0.10-0.15, p\u200a=\u200a1.1*10(-19)), and was also associated with 0.03 mmol/L lower high-density lipoprotein-cholesterol (95%CI 0.01-0.04), and 0.14 mmol/L higher non-high-density lipoprotein-cholesterol (95%CI 0.09-0.20). The minor allele frequency increased from 10.9% in patients with plasma triglycerides <1 mmol/L to 24.6% in patients with plasma triglycerides between 4 and 10 mmol/L. The relation between rs964184 and plasma triglycerides was modified by body mass index in patients with one minor allele (β 0.02; (95%CI -0.04-0.09) if body mass index <24 kg/m2, β 0.17 (95%CI 0.12-0.22) if body mass index >27 kg/m2, p for interaction\u200a=\u200a0.02). The prevalence of the metabolic syndrome increased from 52% for patients with two copies of the major allele to 62% for patients with two copies of the minor allele (p\u200a=\u200a0.01). Rs964184 was not related with recurrent vascular events (HR 0.99; 95%CI 0.86-1.13).'] Is rs964184 ( APOA5-A4-C3-A1 ) related to elevated plasma triglyceride levels , but not to an increased risk for vascular events in patients with clinically manifest vascular disease?