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

Research table: 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: Women who smoke for many years may have a slightly increased risk of breast cancer [1-3].

Women who are current smokers and have been smoking for more than 10 years appear to have about a 10% higher risk of breast cancer than women who’ve never smoked [1-3].

Women who are current smokers but have smoked for less than 10 years don’t appear to have an increased risk of breast cancer.

Whether women who smoked in the past have an increased risk of breast cancer is under study.

Learn more about smoking and breast cancer risk.

Learn about smoking and breast cancer survival.

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

Learn about the strengths and weaknesses of different types of studies.

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

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 [5]

(8,772 cases)


1.09 (1.02-1.17)

Bjerkaas et al. [1]

(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 [2]

(6,549 cases)


1.17 (1.10-1.25)

Multiethnic Cohort Study [7]

(4,230 cases)


1.11 (1.00-1.22)

Cancer Prevention Study II (CPS-II) [8]

(3,721 cases)


1.24 (1.07-1.42) 

Women’s Health Initiative Observational Study [9]

(3,520 cases)


1.16 (1.00-1.34)

California Teachers Study [10]

(2,005 cases)


1.32 (1.10-1.57)

Iowa Women’s Health Study [11]

(1,995 cases)


1.19 (1.03-1.37) 

National Institute of Environmental Health Sciences Sister Study [12]

(1,843 cases)


1.03 (0.85-1.26)

Generations Study [13]

(1,815 cases)


1.12 (0.89-1.39)

Danish Nurse Cohort [14]

(1,407 cases)


1.19 (1.05-1.36)

Black Women’s Health Study [15]

(1,377 cases)


1.05 (0.83-1.31)

Norwegian-Swedish Cohort Study [16]

(1,130 cases)


1.17 (0.95-1.45)

Nurses’ Health Study II [17]

(1,007 cases)†


1.12 (0.92-1.37)

Prospective Family Study Cohort [18]

(1,006 cases)‡


1.02 (0.85-1.23)

Pooled and meta-analyses

Gaudet et al. [19]

(36,060 cases)


1.07 (1.04-1.10)

Collaborative Group on Hormonal Factors in Breast Cancer [20]

48 studies



Scala et al. [21]

44 studies


1.10 (1.07-1.14)

Macacu et al. [3]

27 studies


1.13 (1.09-1.17)

Gaudet et al. [8]

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 women at higher risk and other women in the study (findings were not statistically significant in either group of women).


  1. 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.
  2. Catsburg C, Miller AB, Rohan TE. Active cigarette smoking and risk of breast cancer. Int J Cancer. 136(9):2204-9, 2015.
  3. 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.
  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. 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. 110(9):2339-47, 2014.
  7. 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.
  8. 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.
  9. 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.
  10. 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.
  11. 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.
  12. 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.
  13. 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.
  14. 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.
  15. 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.
  16. 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.
  17. 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.
  18. 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.
  19. 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.
  20. 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.
  21. Scala M, Bosetti C, Bagnardi V, et al. Dose-response relationships between cigarette smoking and breast cancer risk: a systematic review and meta-analysis. J Epidemiol. 2023 Mar 25 [Online ahead of print].

Updated 11/08/23