PAI-1 was measured in citrated plasma with a two-site immunoassay sensitive to free active and latent PAI-1 but not to PAI-1 complexed with tissue plasminogen activator (1). The coefficient of variation was 14%. Fibrinogen was measured in citrated plasma with a modified clot-rate assay, using a Diagnostica STAGO ST4 instrument (Diagnostica, Parsippany, NJ) with a coefficient of variation of 3.0%. Plasma lipid concentrations were determined at the central laboratory following Lipid Research Clinics methodology. Height, waist circumference, and weight were measured in duplicate and recorded to the nearest 0.5 cm and 0.1 kg, respectively. BMI was calculated as weight in kilograms divided by the square of height in meters.