Obesity, Oral Contraceptives Factors in Rare Stroke Risk

Both the authors and the writer of an editorial said obese women should be warned of potential risks, but that with absolute stroke risk low, they should not be denied access to contraception.

A study published today in JAMA Neurology finds that obese women taking oral contraceptives are at higher risk of a rare type of stroke than normal weight women who did not take the medication.

The obese women were found to be at increased risk for cerebral venous thrombosis (CVT), a condition that primarily afflicts young adults and children. Researchers from the Academic Medical Center in Amsterdam studied 186 patients with CVT and 6134 healthy controls and found that those with CVT were typically younger, female, more likely to use oral contraceptives and more likely to have a history of cancer than the controls.1

Of note, the researchers found a 30-fold increased risk of CVT among the obese women taking oral contraceptives, compared with women of normal weight not taking birth control pills. There was some increased risk of CVT among overweight women; however, there was no link between obesity and CVT among women (or men) who did not use oral contraceptives.

The researchers found that while the increased risk of CVT was noteworthy, the overall incidence was small, and not prescribing birth control pills to obese women would have other consequences that could be more severe.

“Nevertheless,” they wrote, “Obese women should be informed about the increased risk of thrombosis if they use oral contraceptives, especially if other risk factors are present. Alternative methods of contraception that are not associated with thrombosis, such as an intrauterine device, might be offered to these women.”

An accompanying editorial concurred. Use of oral contraception has also been linked with increased risk of arterial ischemic stroke in obese women, wrote Chirantan Banerjee, MD, MPH, of the Medical University of South Carolina in Charleston.2

“Better counseling and education of obese women informing them of the increased risk would be prudent, as would be consideration of alternate nonhormonal … options,” Banerjee writes.

Also recommended are future studies that examine the effect of inherited thrombophilia on the association between obesity and CVT, as well as such factors as sleep apnea and anemia.

References

1. Zuurbier SM, Arnold Middeldorp S, et al. Risk of cerebral venous thrombosis in obese women [published online March 14, 2016]. JAMA Neurol. doi:10.1001/jamaneuro.2016.0001

2. Banerjee C. Obesity, oral contraceptive use, and cerebral venous thrombosis in women [published online March 14, 2016]. JAMA Neurol. doi:10.1001/jamaneurol.2015.5107.