A new study suggests that the intake of oral contraceptives may increase the risk of breast cancer in women.
The nested case-control study has been funded by the National Cancer Institute and researchers from the Fred Hutchinson Cancer Research Center in Seattle, Washington observed 1,102 women who had breast cancer. These women were aged between 29 to 45 years.
Based on the data published in the Cancer Research journal, women who consumed birth control pills that had "high-dose estrogen" as well as some other formulations were more prone to contracting breast cancer when compared to women who used alternative formulations.
"Our results suggest that use of contemporary oral contraceptives [birth control pills] in the past year is associated with an increased breast cancer risk relative to never or former oral contraceptive use, and that this risk may vary by oral contraceptive formulation," said Elisabeth F. Beaber, PhD, MPH, a staff scientist.
Upon diagnosis of their medical records, the researchers found that women who took birth control pill within the previous year had a 50 percent higher chance of getting cancer when compared to women the same age who did not take oral birth control contraceptives. The diagnosis was conducted between 1990 and 2009.
Per the study's findings, oral birth control contraceptives that have "high-dose estrogen" increase the risk of breast cancer 2.7 fold. Pills which have "moderate-dose estrogen" increase the risk by 1.6 fold. An alarming finding is that triphasic combination oral contraceptives that contain 0.75 milligrams of norethindrone on an average increase the risk of contracting breast cancer 3.1 fold.
Interestingly, oral contraceptives that contained "low-dose estrogen" did not contribute to breast cancer risk.
While the findings raise concerns, Beaber cautioned that the results needed "confirmation" and it would warrant better if they were "interpreted cautiously." She also highlighted the innumerable health benefits like menses regulation and decreases dysmenorrhea that were associated with oral contraceptives.
The researchers, however, caution against the limitations of the study owing to restricted exposure.
The study has been published on Friday, August 1 in the journal Cancer Research.
