Aims: Myocardial infarction (MI) in very young individuals is a rare disease associated with an unfavourable prognosis. Familial-combined hyperlipidaemia (FCHL) increases the risk for MI in individuals below 60 years; however, its role in very young MI patients below 40 years is not as well established. We investigated the prevalence and impact of FCHL in these very young MI patients.
Methods and results: We prospectively enrolled 102 consecutive MI survivors (< or =40 years) from two high-volume cardiac catheterization centres. Patients were frequency-matched for age, gender, and centre to 200 hospital controls free from coronary heart disease. Myocardial infarction patients were invited to send family members for FCHL screening. Overall, 37 families were screened. Familial-combined hyperlipidaemia was diagnosed using a nomogram, which takes into account total cholesterol, triglycerides, and Apo B(100) levels. Thirty-eight acute myocardial infarction (AMI) patients (38%) and five controls (2.5%) displayed the FCHL phenotype, 21 of these MI patients sent family members for screening, and FCHL was confirmed in 16 families (76%). The FCHL phenotype was associated with a 24-fold increased adjusted risk for MI (95% CI 7.5-81, P < 0.001). Of all lipid parameters, VLDL-cholesterol, and non-HDL-cholesterol were most strongly associated with MI.
Conclusions: The present study suggests that the FCHL phenotype seems to be a major risk factor for the occurrence of MI at a very young age. It remains to be determined whether this excessively increased risk can be favourably modified by therapeutic interventions.