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Home > Understanding Breast Cancer > Breast Cancer Research > Table 22: Smoking and breast cancer risk


Table 22: Smoking and breast cancer risk

This summary table contains detailed information about research studies. Summary tables offer an informative look at the science behind many breast cancer guidelines and recommendations. However, they should be viewed with some caution. In order to read and interpret research tables successfully, it is important to understand some key concepts. Learn how to read a research table.

Introduction: Smoking increases the risk of many types of cancer (including cancers of the lung, kidney and pancreas). Although findings on a possible link to breast cancer remain mixed, there is growing evidence that smoking may slightly increase the risk of breast cancer. More research is needed before solid conclusions can be made about a potential link between smoking and breast cancer.  

Some studies have shown smoking before a first childbirth may increase the risk of breast cancer [1-3]. Others have found no link between the two [4].  

Find information on secondhand smoke exposure (also called passive smoking) and the risk of breast cancer.

Learn more about smoking and breast cancer risk.

Learn about the strengths and weaknesses of different types of studies

See how this risk factor compares with other risk factors for breast cancer.   


 Komen Perspectives 

Read our perspective on smoking and breast cancer risk
(November 2012).*

*Please note, the information provided within Komen Perspectives articles is only current as of the date of posting. Therefore, some information may be out of date at this time.  


Study selection criteria: Prospective cohort studies with at least 200 breast cancer cases and meta-analyses.

Table note: Relative risk above 1 indicates increased risk. Relative risk below 1 indicates decreased risk.  


Study Population
(number of participants)


Relative Risk of Breast Cancer in
Current Smokers Compared to
Never Smokers,
RR (95% CI)

Prospective cohort studies 

Nurses' Health Study [5]

(8,772 cases)


1.09 (1.02-1.17)

Bjerkaas et al. [3]

(7,490 cases)


1.14 (1.08-1.20)

NIH-AARP Diet and Health Study [6]

(7,841 cases)


1.19 (1.10-1.28)

Canadian National Breast Screening Study [7]

(4,445 cases)


 1.18 (1.09-1.27)

Cancer Prevention Study II (CPS-II) [2]

(3,721 cases)


1.24 (1.07-1.42) 

Women’s Health Initiative Observational Study [8]

(3,520 cases)


1.16 (1.00-1.34)

California Teachers Study [9]

(2,005 cases)


 1.32 (1.10-1.57)

Iowa Women's Health Study [10]

(1,995 cases)


 1.19 (1.03-1.37) 

Norwegian-Swedish Cohort Study [11]

(1,130 cases)


 1.17 (0.95-1.45)

Nurses' Health Study II [12]

(1,007 cases)†


 1.12 (0.92-1.37)

Ha et al. [13]

(906 cases)


 1.13 (0.96-1.32)

Norwegian study [14]

(603 cases)


 1.0 (0.8-1.2)

Japan Collaborative Cohort Study for Evaluation of Cancer Risk [15]

(208 cases)


 0.67 (0.32-1.38)


Collaborative Group on Hormonal Factors in Breast Cancer [16]

48 studies



Gaudet et al. [2]

15 studies


1.12 (1.08-1.16)

NS = No statistically significant increase or decrease in risk  

† Most participants were premenopausal

‡ Estimated from person-years of follow-up time 


  1. DeRoo LA, Cummings P, Mueller BA. Smoking before the first pregnancy and the risk of breast cancer: a meta-analysis. Am J Epidemiol. 174(4):390-402, 2011.
  2. Gaudet MM, Gapstur SM, Sun J, Diver WR, Hannan LM, Thun MJ.Active smoking and breast cancer risk: original cohort data and meta-analysis. J Natl Cancer Inst. 105(8):515-25, 2013.
  3. Bjerkaas E, Parajuli R, Weiderpass E, et al. Smoking duration before first childbirth: an emerging risk factor for breast cancer? Results from 302,865 Norwegian women. Cancer Causes Control. 24(7):1347-56, 2013.
  4. Lawlor DA, Ebrahim S, Davey Smith G. Smoking before the birth of a first child is not associated with increased risk of breast cancer: findings from the British Women's Heart and Health Cohort Study and a meta-analysis. Br J Cancer. 91(3):512-8, 2004.
  5. Xue F, Willett WC, Rosner BA, Hankinson SE, Michels KB. Cigarette smoking and the incidence of breast cancer. Arch Intern Med. 171(2):125-133, 2011.
  6. Nyante SJ, Gierach GL, Dallal, et al. Cigarette smoking and postmenopausal breast cancer risk in a prospective cohort. Br J Cancer. 2014 Mar 18 [Epub ahead of print].
  7. Cui Y, Miller AB, Rohan TE. Cigarette smoking and breast cancer risk: update of a prospective cohort study. Breast Cancer Res Treat. 100(3):293-9, 2006.
  8. Luo J, Margolis KL, Wactawski-Wende J, et al. Association of active and passive smoking with risk of breast cancer among postmenopausal women: a prospective cohort study. BMJ. 342:d1016, 2011.
  9. Reynolds PR, Hurley S, Goldberg DE, et al. Active smoking, household passive smoking, and breast cancer: evidence from the California Teachers Study. J Natl Cancer Inst. 96(1):29-37, 2004.
  10. Olson JE, Vachon CM, Vierhant RA, et al. Prepregnancy exposure to cigarette smoking and subsequent risk of postmenopausal breast cancer. Mayo Clin Proc. 80(11):1423-8, 2005.
  11. Gram IT, Braaten T, Terry PD, et al. Breast cancer risk among women who start smoking as teenagers. Cancer Epidemiol Biomarkers Prev. 14(1):61-6, 2005.
  12. Al-Delaimy WK, Cho E, Chen WY, Colditz GA, Willet WC. A prospective study of smoking and risk of breast cancer in young adult women. Cancer Epidemiol Biomarkers Prev. 13(3):398-404, 2004.
  13. Ha M, Mabuchi K, Sigurdson AJ, et al. Smoking cigarettes before first childbirth and risk of breast cancer. Am J Epidemiol. 166(1):55-61, 2007.
  14. Engeland A, Andersen A, Haldorsen T, Tretli S. Smoking habits and risk of cancers other than lung cancer: 28 years' follow-up of 26,000 Norwegian men and women. Cancer Causes Control. 7(5):497-506, 1996.
  15. Lin L, Kikuchi S, Tamakoshi K, et al. for the Japan Collaborative Cohort Study Group for Evaluation of Cancer Risk. Active smoking, passive smoking, and breast cancer risk: findings from the Japan Collaborative Cohort Study for Evaluation of Cancer Risk. J Epidemiol. 18(2):77-83, 2008.
  16. Hamajima N, Hirose K, Tajima K, et al. for the Collaborative Group on Hormonal Factors in Breast Cancer. Alcohol, tobacco and breast cancer--collaborative reanalysis of individual data from 53 epidemiological studies, including 58,515 women with breast cancer and 95,067 women without the disease. Br J Cancer. 87(11):1234-45, 2002.

Updated 04/08/14