TY - JOUR
T1 - Prepregnancy exposure to cigarette smoking and subsequent risk of postmenopausal breast cancer
AU - Olson, Janet E.
AU - Vachon, Celine M.
AU - Vierkant, Robert A.
AU - Sweeney, Carol
AU - Limburg, Paul J.
AU - Cerhan, James R.
AU - Sellers, Thomas A.
N1 - Funding Information:
This work was supported by a grant from the National Cancer Institute (R01 CA39742).
PY - 2005/11
Y1 - 2005/11
N2 - OBJECTIVE: To examine the association of cigarette smoking before first pregnancy with risk of postmenopausal breast cancer in a large population-based cohort. PATIENTS AND METHODS: The Iowa Women's Health Study is a prospective cohort study of 55- to 69-year-old women at baseline in 1986. In January 1986, a questionnaire was mailed to 99,826 postmenopausal women to identify risk factors for cancer and other chronic diseases; 41,836 women responded (42.7% response rate). The primary analyses examined the associations among smoking, parity, age at first birth, and postmenopausal breast cancer. RESULTS: Of the 37,105 women in the cohort at risk, 7095 (19%) and 4186 (11%) initialed smoking before and after first pregnancy, respectively, and 2017 breast cancers were identified before December 31, 1999. Compared with parous women who never smoked, women who began smoking after their first full-term pregnancy were not at increased risk of postmenopausal breast cancer (multivariate-adjusted risk ratio, 1.03; 95% confidence interval, 0.83-1.21). However, women who began smoking before their first pregnancy had a slightly elevated risk of breast cancer (risk ratio, 1.21; 95% confidence interval, 1.07-1.37). Results were not attenuated by adjustment for age at first pregnancy or number of live births. CONCLUSION: These data suggest that cigarette smoking is associated with a slightly greater risk of postmenopausal breast cancer for women who started smoking before their first full-term pregnancy.
AB - OBJECTIVE: To examine the association of cigarette smoking before first pregnancy with risk of postmenopausal breast cancer in a large population-based cohort. PATIENTS AND METHODS: The Iowa Women's Health Study is a prospective cohort study of 55- to 69-year-old women at baseline in 1986. In January 1986, a questionnaire was mailed to 99,826 postmenopausal women to identify risk factors for cancer and other chronic diseases; 41,836 women responded (42.7% response rate). The primary analyses examined the associations among smoking, parity, age at first birth, and postmenopausal breast cancer. RESULTS: Of the 37,105 women in the cohort at risk, 7095 (19%) and 4186 (11%) initialed smoking before and after first pregnancy, respectively, and 2017 breast cancers were identified before December 31, 1999. Compared with parous women who never smoked, women who began smoking after their first full-term pregnancy were not at increased risk of postmenopausal breast cancer (multivariate-adjusted risk ratio, 1.03; 95% confidence interval, 0.83-1.21). However, women who began smoking before their first pregnancy had a slightly elevated risk of breast cancer (risk ratio, 1.21; 95% confidence interval, 1.07-1.37). Results were not attenuated by adjustment for age at first pregnancy or number of live births. CONCLUSION: These data suggest that cigarette smoking is associated with a slightly greater risk of postmenopausal breast cancer for women who started smoking before their first full-term pregnancy.
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U2 - 10.4065/80.11.1423
DO - 10.4065/80.11.1423
M3 - Article
C2 - 16295021
AN - SCOPUS:27644436388
SN - 0025-6196
VL - 80
SP - 1423
EP - 1428
JO - Mayo Clinic proceedings
JF - Mayo Clinic proceedings
IS - 11
ER -