Prevalence of dyslipidaemias in a representative sample of the French population Hypercholesterolaemia is a major factor of risk of coronary atherosclerosis. The prevalence of other types of dyslipidaemia in the general population remains poorly defined. This study was performed to measure the prevalence of various dyslipidaemias in the French population. A representative sample of 3508 men and women between the ages of 35 and 64 years was recruited by the "Multinational MONItoring of trends and determinants in CArdiovascular disease" centres of Lille, Strasbourg and Toulouse. We excluded 162 patients suffering from known cardiovascular disorders, and 409 individuals treated with lipid-lowering drugs. The prevalence of pure hypercholesterolaemia, defined as a total cholesterol concentration >6.2 mmol/l (2.4 g/l) and triglyceride concentration <2.3 mmol/l (2 g/l), was 30% (29-32%). The prevalence of HDL cholesterol concentration <1 mmol/l (0.4 g/l) in men, or <1.3 mmol/l (0.5 g/l) in women, was 12% (11-13%). The prevalence of mixed hyperlipidaemia, defined as a total cholesterol concentration >6.2 mmol/l (2.4 g/l) and triglyceride concentration >2.3 mmol/l (2 g/l) was 5% (4-6%). The prevalence of hypertriglyceridaemia, defined as a total cholesterol concentration <6.2 mmol/l (2.4 g/l) and triglyceride concentration >2.3 mmol/l (2 g/l) was 4% (3-5%). Low HDL cholesterol concentrations were associated with smoking, obesity, and absence of either regular physical exercise or alcohol consumption. This study confirmed the high prevalence of pure hypercholesterolaemia, and revealed an important prevalence of low HDL cholesterol concentration, which represents a major cardiovascular risk factor.