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Long-term use of hormonal contraceptives – increased risk of brain tumors?

A new study published in the British Journal of Clinical Pharmacology reports on the possible increased risk for young women of developing glioma after taking a hormonal contraceptive for 5 years or more.

Use of hormonal contraceptives, which contain female sex hormones, is widespread among women all over the world. Although the etiology of glioma and other brain tumors is poorly understood, there is some evidence suggesting that female sex hormones may increase risk of certain cancer types; however, there is also evidence suggesting that use of contraceptives may reduce risk in certain age groups.

“This prompted us to evaluate whether using hormonal contraceptives might influence the risk of gliomas in women of the age range who use them,” commented research team leader David Gaist of the Odense University Hospital and University of Southern Denmark (both Denmark).

In the study, the team collected data from Denmark’s national and administrative health registries and identified all women aged 15–49 years who had a first-time diagnosis of glioma between 2000 and 2009. A total of 317 cases were identified and hormonal contraceptive use among these women was compared with eight age-matched women without gliomas.

“It is important to keep this apparent increase in risk in context,” remarked Gaist. “In a population of women in the reproductive age, including those who use hormonal contraceptives, you would anticipate seeing five in 100,000 people develop a glioma annually, according to the nationwide Danish Cancer Registry.”

“While we found a statistically significant association between hormonal contraceptive use and glioma risk, a risk–benefit evaluation would still favor the use of hormonal contraceptives in eligible users,” commented Gaist. He advises that continuing to evaluate long-term contraceptive use is important, in order for women to be able to make informed decisions about which is the best contraception for them.

Gaist emphasizes in the paper that the study’s findings should be interpreted with care. “Despite that, we feel our study is an important contribution and we hope that our findings will spark further research on the relationship between female hormonal agents and glioma risk,” he remarked.

Source: Wiley press release