This study aimed at identifying factors influencing aortic valve calcification in old age. Echocardiographic and Doppler characteristics of the aortic valve were compared with possible clinical and biochemical predictors in 501 people aged 75-86 years and in 76 aged 55-71. Slight calcification was seen in 222 people (40%) and severe calcification in 72 (13%); 21 people had moderate or severe aortic stenosis. Age (P = 0.000) and serum parathyroid hormone (P = 0.015) were higher and body mass index lower (P = 0.002) in the presence of aortic valve calcification. In multivariate analysis, age (P = 0.000), hypertension (P = 0.005) and body mass index (P = 0.005) were independent predictors of aortic valve calcification, and age (P = 0.022) and serum ionized calcium (P = 0.037) of valve stenosis. The odds ratio (95% confidence interval) for valve calcification was 1.89 (1.42-2.50) for a 10-year increase in age, 1.74 (1.19-2.55) in the presence of hypertension, and 1.39 (1.10-1.76) for a 5 kg.m-2 decrease in body mass index. Sex, smoking, diabetes, serum lipids and insulin were unrelated to valvular calcification. These data suggest that leanness and a history of hypertension increase the likelihood of senile aortic valve calcification. Calcium metabolism may also be of significance. The mechanisms of these associations deserve further study.