Total estrogen exposure time not independently associated with CVD

Researchers found no independent association between the amount of time women were exposed to estrogen and angiographic coronary artery disease or major adverse cardiovascular events in a group of postmenopausal women evaluated for potential ischemia.

The researchers set out to examine the association between detailed measurements of endogenous and exogenous estrogen exposure time with angiographic CAD and major adverse cardiac events. Participants included 646 postmenopausal women undergoing coronary angiography for evaluation of ischemia in the Women’s Ischemia Syndrome Evaluation (WISE) study.

Data indicated that the timing of postmenopausal exogenous hormone therapy use was associated with reduced CAD. Women who never used HT had the highest prevalence and severity of CAD (P<.0001), followed by women with up to 5.5 years of HT use (P<.0001). Women using HT for more than 5.5 years had the lowest prevalence and severity of CAD (P=.002).

The researchers also calculated total estrogen exposure time, accounting for exposure to endogenous and exogenous estrogen. Initial findings revealed that women with the highest years of estrogen exposure had the lowest age-adjusted CAD prevalence and severity. However, when the researchers adjusted for years of HT use, all differences became nonsignificant, which the researchers said suggests that HT is the major driving variable in total estrogen time compared with CAD.

The researchers also found no association between total estrogen time and major adverse cardiovascular events.

“Our results suggest that the paradigm of estrogen protection from CAD in women may be more complex than estrogen exposure duration,” the researchers wrote. “The current analysis sheds light on prior data discrepancies and may be useful for prospective HT clinical trial planning.”

Bairey Merz CN et al. J Womens Health. 2009; doi:10.1089/jwh.2008.1063.