Summary:In a study designed to measure lipoprotein(a), cholesterol, cholesterol fractions and triacylglycerols in serum 4004 hospitalised individuals aged between 18 and 100 years were examined. Lipoprotein(a) was determined in 1313 patients (438 males, 875 females) aged 18-59 years and 489 patients (234 males, 255 females) aged 60-100 years. Cholesterol, cholesterol fractions and triacylglycerols were determined in a further 2037 patients (1084 males, 953 females) aged 18 to 100 years, for whom a lipid-status request had been made. Lipoprotein(a) concentrations in 619 females measured directly postpartum were not significantly different from aged-matched female in-patients (n = 104) and age-matched female hospital staff (n = 114). Lipoprotein(a) concentrations in women (n = 77) aged 30-74 undergoing chronic haemodialysis were significantly higher (p < 0.001) than in men (n = 95) of the corresponding age group. Median lipoprotein(a) serum concentrations showed a peak between 60-69 years in both men and women, i. e. at times of reported increased cardiovascular disease in both sexes. The lipoprotein(a) levels found in old age are comparable with those found in children and adolescents. The lipoprotein(a) patient group was assessed according to age and clinic. Eight groups of patients were analysed. The maternity patients were significantly younger (median age 26 a) than the other seven groups (p < 0.05-< 0.01), the hospital employees (median age 31 a) attending the annual check-up being younger than the remaining six groups (p < 0.01). Lipoprotein(a) concentrations were marginally higher (p = 0.05) in the dialysis patients, when compared with those on internal medical wards. Of the 'traditional' lipid analytes, the ratio LDL-cholesterol : HDL-cholesterol was of interest, being significantly higher in males aged 70-79 years of age, when compared with males under 30 years of age. Triacylglycerols were higher in men aged between 30 and 59 years (p = 0.05-< 0.01). The relationship between median analyte concentration and age was different for lipoprotein(a) than for the ratio LDL-cholesterol : HDL-cholesterol and triacylglycerols, thus further supporting the fact that lipoprotein(a) may be an independent risk factor for the development of atherosclerotic disease.