title: Active and passive smoking and the risk of breast cancer in women aged 36-45 years: a population based case-control study in the UK.
abstract: Active smoking has little or no effect on breast cancer risk but some investigators have suggested that passive smoking and its interaction with active smoking may be associated with an increased risk. In a population based case-control study of breast cancer in women aged 36-45 years at diagnosis, information on active smoking, passive smoking in the home, and other factors, was collected at interview from 639 cases and 640 controls. Women were categorised jointly by their active and passive smoking exposure. Among never smoking controls, women who also reported no passive smoking exposure were significantly more likely to be nulliparous and to be recent users of oral contraceptives. Among those never exposed to passive smoking, there was no significant association between active smoking and breast cancer, relative risk (RR) of 1.12 (95% confidence interval (CI) 0.72-1.73) for past smokers and RR of 1.19 (95% CI 0.72-1.95) for current smokers, nor was there an association with age started, duration or intensity of active smoking. Compared with women who were never active nor passive smokers, there was no significant association between passive smoking in the home and breast cancer risk in never smokers, RR of 0.89 (95% CI 0.64-1.25), in past smokers, RR of 1.09 (95% CI 0.75-1.56), or in current smokers, RR of 0.93 (95% CI 0.67-1.30). There was no trend with increasing duration of passive smoking and there was no heterogeneity among any of the subgroups examined. In this study, there was no evidence of an association between either active smoking or passive smoking in the home and risk of breast cancer.
authors.affiliation: Cancer Research UK Epidemiology Unit, Richard Doll Building, University of Oxford, Old Road Campus, Headington, Oxford OX3 7LF, UK. andrew.roddam@ceu.ox.ac.uk
authors.forename: A W
authors.initials: AW
authors.lastname: Roddam
authors.forename: K
authors.initials: K
authors.lastname: Pirie
authors.forename: M C
authors.initials: MC
authors.lastname: Pike
authors.forename: C
authors.initials: C
authors.lastname: Chilvers
authors.forename: B
authors.initials: B
authors.lastname: Crossley
authors.forename: C
authors.initials: C
authors.lastname: Hermon
authors.forename: K
authors.initials: K
authors.lastname: McPherson
authors.forename: J
authors.initials: J
authors.lastname: Peto
authors.forename: M
authors.initials: M
authors.lastname: Vessey
authors.forename: V
authors.initials: V
authors.lastname: Beral
mesh_terms: D000328:Adult; D001943:Breast Neoplasms / Q000453:epidemiology*; D016022:Case-Control Studies; D005260:Female; D006801:Humans; D008875:Middle Aged; D011159:Population Surveillance; D012907:Smoking / Q000009:adverse effects*; D014028:Tobacco Smoke Pollution / Q000009:adverse effects*; D006113:United Kingdom / Q000453:epidemiology
chemical_list: D014028:Tobacco Smoke Pollution