Serum estradiol and risk of stroke in elderly men

To determine if levels of serum estradiol and testosterone can predict stroke in a population-based sample of elderly men.

Serum 17beta estradiol and testosterone were measured in 2,197 men aged 71 to 93 years who participated in the Honolulu-Asia Aging Study from 1991 to 1993. All were free of prevalent stroke, coronary heart disease, and cancer. Participants were followed to the end of 1998 for thromboembolic and hemorrhagic events.

During the course of follow-up, 124 men developed a stroke (9.1/1,000 person-years). After age adjustment, men in the top quintile of serum estradiol (> or =125 pmol/L [34.1 pg/mL]) experienced a twofold excess risk of stroke vs men whose estradiol levels were lower (14.8 vs 7.3/1,000 person-years, p < 0.001). Among the lower quintiles, there were little differences in the risk of stroke. Findings were also significant and comparable for bioavailable estradiol and for thromboembolic and hemorrhagic events. After additional adjustment for hypertension, diabetes, adiposity, cholesterol concentrations, atrial fibrillation, and other characteristics, men in the top quintile of serum estradiol continued to have a higher risk of stroke vs those whose estradiol levels were lower (relative hazards = 2.2; 95% CI = 1.5 to 3.4, p < 0.001). Testosterone was not related to the risk of stroke.

High levels of serum estradiol may be associated with an elevated risk of stroke in elderly men.