Methods. Men ages 40-70, selected from state census lists, were interviewed in 1987-1989 and reinterviewed in 1995-1997. Data were collected and blood was drawn in participants' homes. ED was assessed from responses to a privately self-administered questionnaire. Analysis was restricted to 513 men with no ED at baseline and no diabetes, heart disease, or related medications at either time.

Results. Cigarette smoking at baseline almost doubled the likelihood of moderate or complete ED at followup (24% vs 14%, adjusted for age and covariates, P = 0.01). Cigar smoking and passive exposure to cigarette smoke also significantly predicted incident ED, as did overweight (body-mass index greater than or equal to 28 kg/m(2)) and a composite coronary risk score. Weaker prospective associations were seen for hypertension and dietary intake of cholesterol and unsaturated fat.

Conclusions. Erectile dysfunction and coronary heart disease share some behaviorally modifiable determinants in men who, like our sample, are free of manifest ED or predisposing illness. Open questions include whether modification of coronary risk factors can prevent ED and whether ED may serve as a sentinel event for coronary disease. (C) 2000 American Health Foundation and Academic Press.