Contraceptives Contribute to Risk of Getting Breast Cancer in
A 2009 study reports that oral contraceptive use contributes to
younger women developing breast cancer particularly a type called
triple-negative that is aggressive, more difficult to treat and has
higher mortality rates. Among women < 40 years of age, the
risk for breast cancer overall, and the risk of non-triple-negative
breast cancer increased with younger age at first use.
Triple-Negative Breast Cancer, an understudied and aggressive type
of breast cancer associated with high mortality, occurs more
frequently in younger women and in African American women. This
study showed that a strong association exists between oral
contraceptive use and the risk for triple-negative breast cancer.
The study was done to assess risk for this type of cancer among
women age 45 or younger in relation to demographic/lifestyle
factors, reproductive history, land oral contraceptive use. Known
and suspected breast cancer risk factors were examined separately as
potential confounders for the main effects of all other risk factors
in age-adjusted models. These were: age (at reference), race,
education, annual incomes, family history of breast cancer, body
mass index(1 year before reference), smoking history, alcohol
consumption, age at menarche, number of live births, age at first
birth (still or live), lactation history, abortion history, and oral
contraceptive use. The risk factors of older age, family history of
breast cancer, earlier menarche age, induced abortion, and oral
contraceptive use were associated with an increased risk for breast
cancer. Oral contraceptive use > 1 year was associated with
a 2.5 –fold increased risk for triple-negative breast cancer. Among
oral contraceptive users only, earlier age at first use further
elevated the risk of breast cancer. Risk was decreased in relation
to greater number of births and younger age at first birth.
Multivariate-adjusted odds ratios for examined risk factors were
consistent with the effects observed in previous studies on younger
women. In women < 40 years of age, oral contraceptive use
> 1 year was associated with a > 4-fold increased risk
for triple-negative breast cancer and no increased risk for
non-triple-negative breast cancer. Among women < 40 years of
age, the risk for breast cancer overall, and the risk of
non-triple-negative breast cancer increased with younger age at
Jessica M. and Daling, Janet R. Risk Factors for Triple-Negative
Breast Cancer in Women Under the Age 45 Years.
Epidemiology, Biomarkers & Prevention 2009; 18(4) April 2009, pp.