Mendelian randomisation study of smoking exposure in relation to breast cancer risk
- PMID: 34341517
- PMCID: PMC8505411
- DOI: 10.1038/s41416-021-01432-8
Mendelian randomisation study of smoking exposure in relation to breast cancer risk
Abstract
Background: Despite a modest association between tobacco smoking and breast cancer risk reported by recent epidemiological studies, it is still equivocal whether smoking is causally related to breast cancer risk.
Methods: We applied Mendelian randomisation (MR) to evaluate a potential causal effect of cigarette smoking on breast cancer risk. Both individual-level data as well as summary statistics for 164 single-nucleotide polymorphisms (SNPs) reported in genome-wide association studies of lifetime smoking index (LSI) or cigarette per day (CPD) were used to obtain MR effect estimates. Data from 108,420 invasive breast cancer cases and 87,681 controls were used for the LSI analysis and for the CPD analysis conducted among ever-smokers from 26,147 cancer cases and 26,072 controls. Sensitivity analyses were conducted to address pleiotropy.
Results: Genetically predicted LSI was associated with increased breast cancer risk (OR 1.18 per SD, 95% CI: 1.07-1.30, P = 0.11 × 10-2), but there was no evidence of association for genetically predicted CPD (OR 1.02, 95% CI: 0.78-1.19, P = 0.85). The sensitivity analyses yielded similar results and showed no strong evidence of pleiotropic effect.
Conclusion: Our MR study provides supportive evidence for a potential causal association with breast cancer risk for lifetime smoking exposure but not cigarettes per day among smokers.
© 2021. The Author(s).
Conflict of interest statement
U.Me. has reported a conflict of interest outside of the submitted work (owing stocks in Abcodia awarded to her by University College London). P.H., R.M.T. and A.Cox. are subject editors for the
References
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- Centers for Disease C, Prevention, National Center for Chronic Disease P, Health P, Office on S, Health. Publications and reports of the surgeon general. in How Tobacco Smoke Causes Disease: The Biology and Behavioral Basis for Smoking-Attributable Disease: A Report of the Surgeon General Centers for Disease Control and Prevention (US): Atlanta (GA) (2010). - PubMed
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Grants and funding
- MR/M012190/1/MRC_/Medical Research Council/United Kingdom
- P30 ES010126/ES/NIEHS NIH HHS/United States
- MR/N003284/1/MRC_/Medical Research Council/United Kingdom
- 29186/CRUK_/Cancer Research UK/United Kingdom
- G1000143/MRC_/Medical Research Council/United Kingdom
- P50 CA058223/CA/NCI NIH HHS/United States
- P30 CA008748/CA/NCI NIH HHS/United States
- 14136/CRUK_/Cancer Research UK/United Kingdom
- G0401527/MRC_/Medical Research Council/United Kingdom
- P30 CA015083/CA/NCI NIH HHS/United States
- 16563/CRUK_/Cancer Research UK/United Kingdom
- 16561/CRUK_/Cancer Research UK/United Kingdom
- 16565/CRUK_/Cancer Research UK/United Kingdom
- MC_UU_00004/02/MRC_/Medical Research Council/United Kingdom
