If you scour a vast amount of data from various inputs versus various outcomes, you will eventually find some statistically significant linkage in the test sample but that often does not indicate any real connection, but merely pure chance. That may explain how researchers led by Dr. David Gaist, a neurologist at Odense University Hospital and the University of Southern Denmark came to the conclusion that taking hormonal contraceptives specifically those containing estrogen, progestin or a combination of both is associated with higher rates of a brain tumor known as glioma. The incidence of glioma is about 2 to 3 per 100,000 people in the United States and Europe and mostly affect adults ages 45 to 75 years.
Researchers conducted a case-control study using data from Denmark s national registries of health records, cancer cases and prescriptions from women aged 15 to 49 years diagnosed with glioma and found 317 cases. They found that using a hormonal contraceptive was associated with a 50 percent increased risk of developing glioma compared to those women who had not used hormonal contraceptives.
However, researchers caution that glioma is very rare; among women in Denmark, that number is just five in 100,000. And Dr. Santosh Kesari, director of neuro-oncology at University of California San Diego adds that we have not seen increased rates of glioma since women started using hormonal contraceptives.
The bottom line, according to Dr. Gaist is this: With the present knowledge we have, I would still favor using contraception in eligible women.
ACSH s Dr. Gilbert Ross adds, Given that the total burden of glioma among Danish women amounts to 317 cases, I find it unbelievable that detecting such a slight variance with use of BCPs can possibly reflect a causal relationship. The other issue that the researchers have not brought up is the consequences of advising women to stop using hormonal contraceptives. In the case of fear of glioma, it can be said that the benefits of taking birth control outweigh the risks and study authors are right to caution women that this study does not indicate that they should stop taking contraceptives.