Endogenous estradiol levels indicated stroke risk in older postmenopausal women

  • February 12, 2010

Older postmenopausal women with high endogenous free estradiol levels had 2.3-fold greater odds of stroke, particularly women with greater central adiposity, according to new study results.

“Potential mediators, including atherogenic dyslipidemia, insulin resistance and inflammation, might underlie this association,” researchers wrote in the study. “Whether estradiol, independent of atherogenic adiposity, influences such mediators and stroke risk needs to be determined.”

Researchers conducted a prospective, case-control study of the Study of Osteoporotic Fractures. They compared baseline serum levels of endogenous estradiol in 196 postmenopausal women who had a subsequent first-ever atherogenic stroke with 219 randomly selected women who did not. Women did not take estrogen at baseline.

The main outcome measure, free estradiol index, was calculated by dividing total estradiol by sex hormone-binding globulin concentrations measured in baseline serum.

Postmenopausal women who experienced a first-ever stroke tended to be older, were more likely to smoke and drink alcohol and had a greater mean waist circumference.

After a median eight years of follow-up, the odds of atherogenic stroke increased with increasing free estradiol index quartiles, independent of age (P=.007). Women with free estradiol index levels in the highest quartile had an age-adjusted OR of 2.31 (95% CI, 1.28-4.17) for stroke, compared with levels in the lowest quartile. When the researchers excluded women who did not take estrogen therapy during the eight-year follow-up (53 incident stroke; 11 controls), those in the highest free estradiol index quartile had an age-adjusted OR of 2.38 (95% CI, 1.29-4.42).

Moreover, this association between estradiol levels and stroke was even stronger in women with greater central adiposity (P=.08). Women with a waist circumference that measured >88 cm (78 incident stroke; 73 controls) and free estradiol index levels in the highest quartile had an OR of 6.27 (95% CI, 1.10-35.6), compared with those in the lowest quartile. In contrast, women with a waist circumference <88 cm (117 incident stroke; 146 controls) and the highest estradiol levels had an OR of 1.4 (95% CI, 0.64-3.06).

Type 2 diabetes, C-reactive protein levels and atherogenic dyslipidemia were deemed potential biological mediators of the relationship between endogenous estradiol levels and stroke.

“Estrogen-altering agents might be harmful or beneficial depending on endogenous estradiol levels, especially in women with greater central adiposity,” the researchers said.

Lee JS. Arch Neurol. 2010;67:195-201.

More In the Journals summaries>>

TwitterFollow EndocrineToday.com on Twitter.

Comments

Healio is intended for physician use and all comments will be posted at the discretion of the editors. We reserve the right not to post any comments with unsolicited information about medical devices or other products. At no time will Healio be used for medical advice to patients.