Researchers from the University of Oxford say that the use of progestogen contraceptives is associated with an increased risk of have breast cancer. Specifically, consuming these products could pose between 20 and 30% more risk of disease than a person who does not use them.
To reach this conclusion, scientists analyzed data from 9,498 women who developed invasive breast cancer between the ages of 20 and 49 and 18,171 women closely related but no breast cancer. He study has been published in ‘PLOS Medicine’.
The collected data were used to calculate the association between the use of each type of hormonal contraceptive and the risk of breast cancer. In addition to these calculations, the researchers took into account risk factors such as each woman’s body mass index or when she gave birth. They also combined their results with those of previous studies.
Specifically, the results offered that the 44% of women with breast cancer and 39% of the women without breast cancer included in the study had a prescription for a hormonal contraceptive. The participants had taken the drug for about three years before diagnosis, according to the Oxford University.
In addition, the scientists recorded a significantly increased risk of breast cancer, who associated it with the use of hormonal contraceptives. It was independent of whether the contraceptive was oral estrogen plus progestin (23% increased risk), progestin-only (26%), injected progestin (25%), or a progestin-releasing intrauterine device (32 %).
On the other hand, the researchers showed that the increase in risk of breast cancer was reduced by discontinuing use of contraceptives. In one year it was reduced by 33%, if it was taken two to four years ago by 17% and more than five years by 15%.
Finally, the scientists calculated what risk there was of develop breast cancer in the next 15 years if a woman had used contraceptives for five years. Estimates ranged from eight in 100,000 women aged 16 to 20 to 265 in 100,000 between 35 and 39, according to the Oxford University results.
