Tubal sterilization and risk of breast cancer mortality in US women.
OBJECTIVE
To investigate the hypothesis that tubal sterilization is associated with a reduced risk of breast cancer.


METHODS
We examined this hypothesis in a large prospective study of US adults. After 14 years of mortality follow-up, 3837 deaths from breast cancer were observed in a cohort of 619,199 women who were cancer-free at study entry in 1982.


RESULTS
Cox proportional hazards models (adjusted for multiple breast cancer risk factors) showed a significant inverse association between tubal sterilization and breast cancer mortality (adjusted rate ratio (RR) = 0.82, 95% confidence interval (CI) 0.70-0.96). Women who were sterilized before age 35 had a lower risk (adjusted RR = 0.69, 95% CI 0.53-0.88) than women who were sterilized at 35 years of age or older (adjusted RR = 0.92, 95% CI 0.75-1.13). Also, sterilizations performed before 1975 resulted in a lower risk (RR = 0.75, 95% CI 0.62-0.91) than those performed during or after 1975 (RR = 0.98, 95% CI 0.74-1.29), possibly reflecting the likelihood of greater tissue damage with earlier procedures.


CONCLUSIONS
These results suggest that tubal sterilization may lower subsequent risk of breast cancer, especially among women who are sterilized at a relatively young age. Additional studies are needed to confirm or refute these findings.
Calle
E E
EE
Department of Epidemiology and Surveillance Research, American Cancer Society, Atlanta, GA 30329, USA. jcalle@cancer.org
Rodriguez
C
C
Walker
K A
KA
Wingo
P A
PA
Petrelli
J M
JM
Thun
M J
MJ
D000328:Adult; D017677:Age Distribution; D000368:Aged; D001943:Breast Neoplasms / Q000209:etiology / Q000401:mortality*; D002423:Cause of Death; D015331:Cohort Studies; D016001:Confidence Intervals; D005260:Female; D006801:Humans; D015994:Incidence; D008875:Middle Aged; D016016:Proportional Hazards Models; D011446:Prospective Studies; D018570:Risk Assessment; D012307:Risk Factors; D013246:Sterilization, Tubal / Q000009:adverse effects / Q000706:statistics & numerical data*; D014481:United States / Q000453:epidemiology