Lifetime estrogen exposure linked to stroke after menopause
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Women in China may be at greater risk for stroke events following menopause, according to a study published in Neurology.
“Lifetime cumulative estrogen exposure due to reproductive factors could potentially be a useful indicator of patients’ risk of stroke events following menopause,” Leying Hou, PhD, of Zhejiang University School of Medicine in China, and colleagues wrote. “However, further research is needed on the underlying biological, behavioral and social mechanisms linking estrogen exposure with stroke risk across female patients’ lifespans.”
Researchers conducted a population-based, longitudinal, prospective cohort study using data from the China Kadoorie Biobank study to evaluate the link between lifetime cumulative estrogen exposure and stroke. They included 122,939 postmenopausal women, aged 40 to 79 years, without prior history of stroke from 2004 to 2008.
Hou and colleagues assessed cumulative estrogen exposure using reproductive lifespan (RLS), endogenous estrogen exposure (EEE) and total estrogen exposure (TEE).
During a median follow-up of 8.9 years, researchers identified 15,139 new-onset stroke cases, subcategorized as 12,853 ischemic stroke (IS), 2,580 intracerebral hemorrhage (ICH) and 269 subarachnoid hemorrhage (SAH), using health insurance data and a disease registry system.
According to results, compared with the lowest quartile of RLS, the highest quartile had a lower risk for total stroke (adjusted HR = 0.95; 95% CI, 0.92-0.98), IS (aHR = 0.95; 95% CI, 0.92-0.98) and ICH (aHR = 0.87; 95% CI, 0.81-0.94).
Further, when comparing the highest quartile with the lowest, EEE and TEE showed a graded association with descending risk for total stroke (EEE: aHR = 0.85; 95% CI, 0.82-0.89; TEE: aHR = 0.87; 95% CI, 0.84-0.9), IS (aHR = EEE: 0.86; 95% CI, 0.83-0.9; TEE: aHR = 0.86; 95% CI, 0.83-0.89) and ICH (EEE: aHR = 0.73; 95% CI, 0.65-0.81; TEE: aHR = 0.83; 95% CI, 0.76-0.91).
“Lifetime cumulative estrogen exposure due to reproductive factors, as indicated by RLS, EEE and TEE, is associated with stroke events among postmenopausal patients,” Hou and colleagues wrote. “For RLS, those in the highest quartile were found to have a lower risk of total stroke, IS and ICH. As for EEE and TEE, higher quartiles were found to have a graded association with a descending risk of total stroke, IS and ICH.”