ArticleCancer causes & control : CCC2013
Smoking duration before first childbirth: an emerging risk factor for breast cancer? Results from 302,865 Norwegian women.
Article in Cancer causes & control : CCC, 2013. The graph could read no effect estimate from its abstract, so it casts no vote on the map. Cited by 33 papers, 1 of them a synthesis that pooled it.
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33 citing papers in PubMed, 1 synthesis or guideline pooled it, 60 citations in OpenAlex.
- Genetic variants of genes in the NER pathway associated with risk of breast cancer: A large-scale analysis of 14 published GWAS datasets in the DRIVE study.International journal of cancer · 2019Pooled it
- Real-World Evidence for Breast Cancer Risk Stratification: Insights from the P.I.N.K. Study.Cancers · 2026Article
- Childhood exposure to second-hand smoke (SHS) and risk of breast cancer in postmenopausal never smokers: the Multiethnic Cohort (MEC) study.Breast cancer research : BCR · 2025Article
- Development and validation of a risk prediction model for premenopausal breast cancer in 19 cohorts.Breast cancer research : BCR · 2025Article
- Aromatics from fossil fuels and breast cancer.iScience · 2025Review
- Current trends in breast cancer genetics, risk factors, and screening strategies.Journal of biological methods · 2025Review
- Alcoholic beverage consumption and female breast cancer risk: A systematic review and meta-analysis of prospective cohort studies.Alcohol, clinical & experimental research · 2024Review
- Smoking history and breast cancer risk by pathological subtype: MCC-Spain study.Tobacco induced diseases · 2023Article
- Breast Cancer Incidence Patterns in the Saudi Female Population: A 17-Year Retrospective Analysis.Medicina (Kaunas, Lithuania) · 2022Article
- Health effects associated with smoking: a Burden of Proof study.Nature medicine · 2022Article
- Never-smokers and the fraction of breast cancer attributable to second-hand smoke from parents during childhood: the Norwegian Women and Cancer Study 1991-2018.International journal of epidemiology · 2022Article
- Causal Effects of Lifetime Smoking on Breast and Colorectal Cancer Risk: Mendelian Randomization Study.Cancer epidemiology, biomarkers & prevention : a publication of the American Association for Cancer Research, cosponsored by the American Society of Preventive Oncology · 2021Article
- A Step Forward in Breast Cancer Research: From a Natural-Like Experimental Model to a Preliminary Photothermal Approach.International journal of molecular sciences · 2020Article
- Smoking and breast cancer risk by race/ethnicity and oestrogen and progesterone receptor status: the Multiethnic Cohort (MEC) study.International journal of epidemiology · 2019Article
- Epidemiological characteristics of and risk factors for breast cancer in the world.Breast cancer (Dove Medical Press) · 2019Review
- Awareness and Misconceptions of Breast Cancer Risk Factors Among Laypersons and Physicians.Current oncology reports · 2018Observational
- Smoking and risk of breast cancer in the Generations Study cohort.Breast cancer research : BCR · 2017Article
- Article
- Breast cancer and exposure to tobacco smoke during potential windows of susceptibility.Cancer causes & control : CCC · 2017Article
- Smoking and risk of ovarian cancer by histological subtypes: an analysis among 300 000 Norwegian women.British journal of cancer · 2017Article
Corrections and comments
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Authors and funding
7 authors at 4 institutions in 4 countries.
Funding
No grant is acknowledged in the PubMed record.
Abstract
purposeRecently, The International Agency for Research on Cancer classified cigarette smoking as possibly carcinogenic to the human breast. Since some new cohort studies have suggested that this risk is confined to women who started to smoke before first childbirth, we wanted to examine the association between smoking and breast cancer, with a focus on time of smoking initiation in relation to the first childbirth.
methodsWe followed 302,865 Norwegian women born between 1899 and 1975, recruited from 1974 to 2003, by linkage to national registries through December 2007. We used Cox proportional hazard models to estimate hazard ratios (HR) and 95% confidence intervals (CI).
resultsDuring more than 4.1 million person-years of follow-up, we ascertained 7,490 cases of primary invasive breast cancer. Compared with never smokers, ever smokers had a 15% (HR = 1.15, 95% CI 1.10-1.21) increased risk of breast cancer overall and also a significantly increased risk of breast cancer in the three most exposed categories of age at smoking initiation (parous women), number of cigarettes smoked per day, years of smoking duration and number of pack-years. Ever smokers who started to smoke more than 1 year after the first childbirth had not an increased risk (HR = 0.93, 95% CI 0.86-1.02), while those who initiated smoking more than 10 years before their first childbirth had a 60% (HR = 1.60, 95% CI 1.42-1.80) increased risk of breast cancer, compared with never smokers.
conclusionSmoking initiation before the first childbirth increases the risk of breast cancer.
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