A Case-Control Study of Lipoprotein Particles in Two Populations at Contrasting Risk for Coronary Heart Disease

The incidence of coronary heart disease (CHD) in middle-aged men is more than three times higher in Northern Ireland than in France. The ECTIM study, which is based on WHO MONICA centers in Belfast (Northern Ireland), Strasbourg (eastern France), Toulouse (southwestern France), and Lille (northern France), has been established to investigate this striking difference. Male patients aged 25-64 years with myocardial infarction (MI) and control subjects sampled from the general population were recruited in the four centers. Hypolipidemic drug treatment was much more frequent in France than in Belfast. "Hypercholesterolemia" denned by the presence of hypolipidemic drug treatment or a low density liproprotein cholesterol level >200 mg/dl was more frequent in cases than in controls in both countries but was similar in both control groups. An in-depth study of lipid variables, including measurements of cholesterol fractions, triglycerides, apolipoproteins (apo), and lipoprotein particles (Lp), was performed in nonhypercholesterolemic subjects. In Northern Ireland and France, patients in comparison with controls had lower levels of high density lipoprotein cholesterol, apo A-I, apo A-II, Lp A-I, and Lp A-II: A-I and higher levels of Lp E:B and Lp(a):B. The levels of triglycerides, very low density lipoprotein cholesterol, apo B, and Lp C-III:B were higher in cases than in controls only in Belfast. In control subjects, the mean levels of cholesterol fractions and apolipoproteins were similar in Northern Ireland and France; however, the level of Lp A-I was lower and the levels of Lp E: B and Lp(a): B were higher in Northern Ireland than in France. A high-risk profile, characterized by a low Lp A-I level and by high levels of Lp E: B and Lp(a): B, was thus more frequent in the population of Northern Ireland. Further studies are needed to determine the contribution of environmental and genetic factors to this risk profile and to investigate its predictive value within populations. (Arteriosclerosis and Thrombosis 1992;12:701-707)