Background Preliminary studies have suggested that microalbuminuria — a slightly increased urinary excretion of albumin — is a risk factor for atherosclerosis. The aim of this study was to examine whether an association exists between urinary excretion of albumin and a history of acute myocardial infarction, in a major population sample.

Methods The study was performed as a part of the 3rd Copenhagen City Heart Study, Denmark, 1992-1994, and included 2613 participants aged 30-70 years, and without diabetes mellitus, renal or urinary tract disease or haematuria. The study programme included measurement of urinary albumin excretion rate, acquisition of information regarding previous acute myocardial infarction (verified by the Danish Hospital Register) and tobacco and alcohol consumption, 12-lead resting electrocardiogram, and measurement of blood pressure, body mass index, waist: Hip ratio, plasma concentrations of total cholesterol, HDL cholesterol and fibrinogen, serum albumin concentration and glomerular filtration rate.

Results Among the participants, 3.6% presented with a history of acute myocardial infarction. There was a positive association between urinary albumin excretion rate (logarithmically transformed) and acute myocardial infarction (odds ratio 1.35, 95% confidence interval 1.08 to 1.70, n = 2613; P= 0.01), which was independent of age, sex, conventional atherosclerotic risk factors, and glomerular filtration rate. The odds ratio for acute myocardial infarction associated with microalbuminuria (urinary albumin excretion rate exceeding the upper decile in the entire study population) was 2.06 (95% confidence interval 1.20 to 3.55, n = 2613; P= 0.009).

Conclusion There exists a positive and independent association between urinary excretion of albumin and a history of acute myocardial infarction. Follow-up analyses should determine the time sequence of this association.