Pre-Pregnancy Obesity and Associations with Stroke and Myocardial Infarction in Women in the Years after Childbirth: A Nationwide Cohort Study
Background—Cardiovascular events (stroke or myocardial infarction) are often associated with poorer prognosis in younger, compared with older individuals. We examined the associations between obesity and the risks of myocardial infarction and stroke in young, healthy women.
Methods and Results—All Danish women giving birth during 2004-2009 without a history of renal disease or cardiovascular disease were identified from national registers and followed for a median time of 4.5 years (interquartile range=2.9-5.8). They were grouped according to pre-pregnancy body mass index (BMI) in underweight (BMI<18.5 kg/m2), normal weight (BMI=18.5-<25 kg/m2), overweight (BMI=25-<30 kg/m2), and obese (BMI≥30 kg/m2). The hazard ratios of myocardial infarction, stroke, and a composite outcome (myocardial infarction, ischemic stroke, cardiovascular death) were assessed using multivariable Cox regression models. We included 273,101 women with a median age of 30.4 years (interquartile range=27.2-33.8). A total of 68 women experienced a myocardial infarction, and 175 women experienced an ischemic stroke. The adjusted hazard ratios of myocardial infarction compared to normal weight were 2.50 (95% confidence interval [95%CI]=0.97-6.50) in underweight, 1.68 (95%CI=0.92-3.06) in overweight, and 2.63 (95%CI=1.41-4.91) in obese women. For ischemic stroke the adjusted hazard ratios were 1.06 (95%CI=0.44-2.28) in underweight, 1.27 (95%CI=0.87-1.85) in overweight, and 1.89 (95%CI=1.25-2.84) in obese women, respectively. For the composite outcome, hazard ratios were 1.34 (95% CI=0.81-2.20), 1.43 (95% CI=1.11-1.84) and 1.76 (95% CI=1.31-2.34) for underweight, overweight, and obese women.
Conclusions—In apparently healthy women of fertile age, obesity was associated with increased risks of ischemic stroke and myocardial infarction.
- Received April 16, 2013.
- Revision received September 24, 2013.
- Accepted October 1, 2013.