The Who, What, Where, When and Sometimes, Why.

Smoking and breast cancer risk

This summary table contains detailed information about research studies. Summary tables are a useful way to look at the science behind many breast cancer guidelines and recommendations. However, to get the most out of the tables, it’s 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’s growing evidence 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 having your first child may increase the risk of breast cancer [1-5]. Others have found no link between the two [6-7].

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 smoking and breast cancer survival.

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.*

*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 Therefore, some information may be out of date.


Study selection criteria: Prospective cohort studies with at least 1,000 breast cancer cases, pooled analyses 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

EPIC [4]

(9,822 cases)


1.06 (1.00-1.12)

Nurses’ Health Study [8]

(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 [9]

(7,841 cases)


1.19 (1.10-1.28)

Canadian National Breast Screening Study [10]

(6,549 cases)


1.17 (1.10-1.25)

Multiethnic Cohort Study [5]

(4,230 cases)


1.11 (1.00-1.22)

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

(3,721 cases)


1.24 (1.07-1.42) 

Women’s Health Initiative Observational Study [11]

(3,520 cases)


1.16 (1.00-1.34)

California Teachers Study [12]

(2,005 cases)


1.32 (1.10-1.57)

Iowa Women’s Health Study [13]

(1,995 cases)


1.19 (1.03-1.37) 

National Institute of Environmental Health Sciences Sister Study [14] 

(1,843 cases)


1.03 (0.85-1.26)

Generations Study [7]

(1,815 cases)


1.12 (0.89-1.39)

Danish Nurse Cohort [15]

(1,407 cases)


1.19 (1.05-1.36)

Black Women’s Health Study [16]

(1,377 cases)


1.05 (0.83-1.31)

Norwegian-Swedish Cohort Study [17]

(1,130 cases)


1.17 (0.95-1.45)

Nurses’ Health Study II [18]

(1,007 cases)†


1.12 (0.92-1.37)

Prospective Family Study Cohort [19]

(1,006 cases)‡


1.02 (0.85-1.23)

Pooled and meta-analyses

Gaudet et al. [20]

(36,060 cases)


1.07 (1.04-1.10)

Collaborative Group on Hormonal Factors in Breast Cancer [21]

48 studies



Macacu et al. [22]

27 studies


1.13 (1.09-1.17)

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.

‡ Study population included many women at higher risk of breast cancer due to family history, or a BRCA1 or BRCA2 inherited gene mutation. Results similar for these higher risk women and other women in the study (findings were not statistically significant in either group of women).


  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. Dossus L, Boutron-Ruault MC, Kaaks R, et al. for the European Prospective Investigation into Cancer and Nutrition (EPIC) cohort. Active and passive cigarette smoking and breast cancer risk: results from the EPIC cohort. Int J Cancer. 134(8):1871-88, 2014.
  5. Gram IT, Park SY, Maskarinec G, Wilkens LR, Haiman CA, Le Marchand L. Smoking and breast cancer risk by race/ethnicity and oestrogen and progesterone receptor status: the Multiethnic Cohort (MEC) study. Int J Epidemiol. 48(2):501-511, 2019.
  6. 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.
  7. Jones ME, Schoemaker MJ, Wright LB, Ashworth A, Swerdlow AJ. Smoking and risk of breast cancer in the Generations Study cohort. Breast Cancer Res. 19(1):118, 2017. 
  8. 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.
  9. Nyante SJ, Gierach GL, Dallal, et al. Cigarette smoking and postmenopausal breast cancer risk in a prospective cohort. Br J Cancer. 110(9):2339-47, 2014.
  10. Catsburg C, Miller AB, Rohan TE. Active cigarette smoking and risk of breast cancer. Int J Cancer. 136(9):2204-9, 2015.
  11. 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.
  12. 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.
  13. 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.
  14. White AJ, D’Aloisio AA, Nichols HB, DeRoo LA, Sandler DP. Breast cancer and exposure to tobacco smoke during potential windows of susceptibility. Cancer Causes Control. 28(7):667-675, 2017.
  15. Heberg J, Simonsen MK, Danielsen AK, Klausen TW, Zoffmann V, Thomsen T. Joint tobacco smoking and alcohol intake exacerbates cancer risk in women- the Danish nurse cohort. Eur J Oncol Nurs. 43:101675, 2019.
  16. Rosenberg L, Boggs DA, Bethea TN, Wise LA, Adams-Campbell LL, Palmer JR. A prospective study of smoking and breast cancer risk among African-American women. Cancer Causes Control. 24(12):2207-15, 2013.
  17. 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.
  18. 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.
  19. Zeinomar N, Knight JA, Genkinger JM, et al. Alcohol consumption, cigarette smoking, and familial breast cancer risk: findings from the Prospective Family Study Cohort (ProF-SC). Breast Cancer Res. 21(1):128, 2019.
  20. Gaudet MM, Carter BD, Brinton LA, et al. Pooled analysis of active cigarette smoking and invasive breast cancer risk in 14 cohort studies. Int J Epidemiol. 46(3):881-893, 2017.  
  21. 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.
  22. Macacu A, Autier P, Boniol M, Boyle P. Active and passive smoking and risk of breast cancer: a meta-analysis. Breast Cancer Res Treat. 154(2):213-24, 2015.

Updated 02/29/20


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