Show simple item record

dc.contributor.authorBjerkaas, Eivind
dc.contributor.authorParajuli, Ranjan
dc.contributor.authorWeiderpass, Elisabete
dc.contributor.authorEngeland, Anders
dc.contributor.authorGertraud, Maskarinec
dc.contributor.authorSelmer, Randi
dc.contributor.authorGram, Inger Torhild
dc.date.accessioned2014-03-18T12:51:57Z
dc.date.available2014-03-18T12:51:57Z
dc.date.issued2013
dc.description.abstractPurpose: Recently, 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. Methods: We 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). Results: During 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.en
dc.descriptionThis article is part of Eivind Bjerkaas' doctoral thesis which is available in Munin at <a href=http://hdl.handle.net/10037/6799>http://hdl.handle.net/10037/6799</a>en
dc.identifier.citationCancer Causes and Control 24(2013) nr. 7 s. 1347-1356 (http://dx.doi.org/10.1007/s10552-013-0213-1)en
dc.identifier.cristinIDFRIDAID 1028604
dc.identifier.doihttp://dx.doi.org/10.1007/s10552-013-0213-1
dc.identifier.issn0957-5243
dc.identifier.urihttps://hdl.handle.net/10037/5955
dc.identifier.urnURN:NBN:no-uit_munin_5647
dc.language.isoengen
dc.publisherSpringerLinken
dc.rights.accessRightsopenAccess
dc.subjectVDP::Medical disciplines: 700::Clinical medical disciplines: 750::Oncology: 762en
dc.subjectVDP::Medisinske Fag: 700::Klinisk medisinske fag: 750::Onkologi: 762en
dc.titleSmoking duration before first childbirth: an emerging risk factor for breast cancer? Results from 302,865 Norwegian womenen
dc.typeJournal articleen
dc.typeTidsskriftartikkelen
dc.typePeer revieweden


File(s) in this item

Thumbnail
Thumbnail

This item appears in the following collection(s)

Show simple item record