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

Research table: Secondhand smoke 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: Most large prospective cohort studies have found no link between breathing secondhand smoke (breathing the smoke from other people’s cigarettes, also called passive smoking) and breast cancer.

However, findings from some case-control studies have shown a small increased risk of breast cancer, especially among premenopausal women.

More research is needed to draw solid conclusions about a possible link between secondhand smoke and breast cancer risk.

Learn more about secondhand smoke and breast cancer risk.

Find a summary of research studies on smoking and 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 and case-control studies with at least 900 breast cancer cases, and meta-analyses of cohort and nested case-control studies.

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


Study Population
(number of participants)


Secondhand Smoke Exposure

Relative Risk of Breast Cancer in Women Exposed to Secondhand Smoke Compared to Women Not Exposed to Secondhand Smoke,
RR (95% CI)

Prospective cohort studies

EPIC [1]

(6,264 cases)


Exposure in childhood or at home or at work

1.10 (1.01-1.20)

Nurses’ Health Study [2]

(2,890 cases)


Exposure in home or at work

0.97 (0.81-1.16)

Million Women Study [3]

(2,518 cases)


Exposure in home

1.02 (0.86-1.16)

California Teachers Study [4]

(2,005 cases)


Exposure in home

0.94 (0.82-1.07)*

Women’s Health Initiative Observational Study [5]

(1,660 cases)


Exposure in home or at work

1.11 (0.92-1.34)

Black Women’s Health Study [6]

(1,377 cases)


Exposure in home

1.18 (0.98-1.42)

National Institute of Environmental Health Sciences Sister Study [7] 

(985 cases)


Exposure in childhood or at home or at work

0.98 (0.81-1.18)†

Case-control studies





Young et al. [8]




Exposure in home or at work

0.97 (0.88-1.08)

Ontario Women’s Diet and Health Study [9]




Exposure in home, at work or in social settings

Premenopausal women:
1.61 (0.74-3.52)

Postmenopausal women:
1.03 (0.69-1.55)

Lissowska et al. [10]




Exposure in home or at work

1.11 (0.85-1.46)

Johnson et al. [11]




Exposure in home or at work

Premenopausal women:
2.6 (1.1-6.0)

Postmenopausal women:
1.1 (0.6-1.8)

Slattery et al. [12]




Exposure in home, at work or outside of home

Premenopausal women:
1.2 (0.6-2.7)‡ 

Postmenopausal women:
1.0 (0.6-1.7)‡

Shrubsole et al. [13]




Exposure in home or at work

1.1 (0.8-1.4)*


Macacu et al. [14]

11 cohort and nested case-control studies


Exposure in home, at work or outside of home

1.07 (1.01-1.13)

Yang et al. [15]

10 cohort studies


Exposure in home, at work or outside of home

1.01 (0.96-1.06)

Pirie et al. [3]

8 cohort studies


Exposure in home or at work

0.99 (0.93-1.05)

* Results were similar when premenopausal and postmenopausal women were examined separately.

† Results were similar when childhood and adult exposure to secondhand smoke were examined separately.

‡ Results are for non-Hispanic white women in this study.


  1. 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.
  2. 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.
  3. Pirie K, Beral V, Peto R, Roddam A, Reeves G, Green J for the Million Women Study Collaborators. Passive smoking and breast cancer in never smokers: prospective study and meta-analysis. Int J Epidemiol. 37(5):1069-79, 2008.
  4. Reynolds P, 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.
  5. 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.
  6. 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.
  7. 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. 
  8. Young E, Leatherdale ST, Sloan M, Kreiger N, Barisic A. Age of smoking initiation and risk of breast cancer in a sample of Ontario women. Tob Induc Dis. 5(1):4, 2009.
  9. Anderson LN, Cotterchio M, Mirea L, Ozcelik H, Kreiger N. Passive cigarette smoke exposure during various periods of life, genetic variants, and breast cancer risk among never smokers. Am J Epidemiol. 175(4):289-301, 2012.
  10. Lissowski J, Brinton LA, Zatonski W, et al. Tobacco smoking, NAT2 acetylation genotype and breast cancer risk. Int J Cancer. 119(8):1961-9, 2006.
  11. Johnson KC, Hu J, Mao Y and The Canadian Cancer Registries Epidemiology Research Group. Passive and active smoking and breast cancer risk in Canada, 1994-97. Cancer Causes Control. 11(3):211-21, 2000.
  12. Slattery ML, Curtin K, Giuliano AR, et al. Active and passive smoking, IL6, ESR1, and breast cancer risk. Breast Cancer Res Treat. 109(1):101-11, 2008.
  13. Shrubsole MJ, Gao YT, Dai Q, et al. Passive smoking and breast cancer risk among non-smoking Chinese women. Int J Cancer. 110(4):605-9, 2004.
  14. 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.
  15. Yang Y, Zhang F, Skrip L, Wang Y, Liu S. Lack of an association between passive smoking and incidence of female breast cancer in non-smokers: evidence from 10 prospective cohort studies. PLoS One. 8(10):e77029, 2013. 

Updated 11/08/23