Risk Factors for Atrial Fibrillation and Their Population Burden in Postmenopausal Women: The Women’s Health Initiative Observational Study

Study Questions:

What are risk factors for atrial fibrillation among postmenopausal women?

Methods:

Data used for this analysis were collected as part of the Women’s Health Initiative (WHI) Observational Study, a prospective observational study of postmenopausal women between the ages of 50 and 79 at baseline. Women with prevalent atrial fibrillation and/or incomplete data were excluded. The main outcome of interest was incident atrial fibrillation identified by WHI-ascertained hospitalization records and diagnosis codes from Medicare claims. Women were followed for an average of 9.8 years for cardiovascular outcomes.

Results:

A total of 81,892 postmenopausal women were included in this study. On average, participants were 63 years of age, 42.4% had a history of hypertension, 2.0% reported peripheral arterial disease, 3.9% were self-reported diabetic, and 0.6% had a history of heart failure. Rates of atrial fibrillation increased significantly with age and were higher for women with coronary heart disease (CHD) in all age groups. The rate of incident atrial fibrillation in women between 75 and 80 years of age was ∼2.8%/year in the absence of CHD, and 4.9%/year in women with CHD. Age, hypertension, obesity, diabetes, myocardial infarction, and heart failure were independently associated with incident atrial fibrillation. Hypertension and overweight status accounted for 28.3% and 12.1%, respectively, of the population-attributable risk. Hispanic and African-American participants had lower rates of incident atrial fibrillation (hazard ratio [HR], 0.58; 95% confidence interval [CI], 0.47-0.70 and HR, 0.59; 95% CI, 0.53-0.65, respectively) than Caucasians.

Conclusions:

The investigators concluded that Caucasian ethnicity, traditional cardiovascular risk factors, and peripheral arterial disease were independently associated with higher rates of incident atrial fibrillation in postmenopausal women. Hypertension and overweight status accounted for a large proportion of population-attributable risk. Measuring burden of modifiable atrial fibrillation risk factors in older women may help target interventions.

Perspective:

These data suggest that traditional CHD risk factors are associated with incident atrial fibrillation. Improving blood pressure control and reducing rates of obesity may result in reduced rates of atrial fibrillation among postmenopausal women; further investigations will be needed to answer such questions.

Clinical Topics: Heart Failure and Cardiomyopathies, Prevention, Vascular Medicine, Acute Heart Failure, Hypertension

Keywords: Myocardial Infarction, Overweight, Women's Health, Coronary Disease, Transcription Factors, Peripheral Arterial Disease, Risk Factors, Blood Pressure, Hispanic Americans, Estrogen Replacement Therapy, Postmenopause, Heart Failure, Obesity, Confidence Intervals, Hospitalization, Hypertension, United States, Diabetes Mellitus


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