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Night work and breast cancer in women: a Swedish cohort study

OBJECTIVES: Recent research has suggested a moderate link between night work and breast cancer in women, mainly through case–control studies, but non-significant studies are also common and cohort studies are few. The purpose of the present study was to provide new information from cohort data throu...

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Autores principales: Åkerstedt, Torbjörn, Knutsson, Anders, Narusyte, Jurgita, Svedberg, Pia, Kecklund, Göran, Alexanderson, Kristina
Formato: Online Artículo Texto
Lenguaje:English
Publicado: BMJ Publishing Group 2015
Materias:
Acceso en línea:https://www.ncbi.nlm.nih.gov/pmc/articles/PMC4401866/
https://www.ncbi.nlm.nih.gov/pubmed/25877283
http://dx.doi.org/10.1136/bmjopen-2015-008127
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author Åkerstedt, Torbjörn
Knutsson, Anders
Narusyte, Jurgita
Svedberg, Pia
Kecklund, Göran
Alexanderson, Kristina
author_facet Åkerstedt, Torbjörn
Knutsson, Anders
Narusyte, Jurgita
Svedberg, Pia
Kecklund, Göran
Alexanderson, Kristina
author_sort Åkerstedt, Torbjörn
collection PubMed
description OBJECTIVES: Recent research has suggested a moderate link between night work and breast cancer in women, mainly through case–control studies, but non-significant studies are also common and cohort studies are few. The purpose of the present study was to provide new information from cohort data through investigating the association between the number of years with night work and breast cancer among women. DESIGN: Cohort study of individuals exposed to night shift work in relation to incidence of breast cancer in women. SETTING: Individuals in the Swedish Twin registry, with follow-up in the Swedish Cancer Registry. PARTICIPANTS: 13 656 women from the Swedish Twin Registry, with 3404 exposed to night work. OUTCOME MEASURES: Breast cancer from the Swedish Cancer Registry (463 cases) during a follow-up time of 12 years. RESULTS: A Cox proportional hazards regression analysis with control for a large number of confounders showed that the HR was HR=1.68 (95% CI 0.98 to 2.88) for the group with >20 years of night work. When the follow-up time was limited to ages below 60 years, those exposed >20 years showed a HR=1.77 (95% CI 1.03 to 3.04). Shorter exposure to night work showed no significant effects. CONCLUSIONS: The present results, together with previous work, suggest that night work is associated with an increased risk of breast cancer in women, but only after relatively long-term exposure.
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spelling pubmed-44018662015-04-29 Night work and breast cancer in women: a Swedish cohort study Åkerstedt, Torbjörn Knutsson, Anders Narusyte, Jurgita Svedberg, Pia Kecklund, Göran Alexanderson, Kristina BMJ Open Occupational and Environmental Medicine OBJECTIVES: Recent research has suggested a moderate link between night work and breast cancer in women, mainly through case–control studies, but non-significant studies are also common and cohort studies are few. The purpose of the present study was to provide new information from cohort data through investigating the association between the number of years with night work and breast cancer among women. DESIGN: Cohort study of individuals exposed to night shift work in relation to incidence of breast cancer in women. SETTING: Individuals in the Swedish Twin registry, with follow-up in the Swedish Cancer Registry. PARTICIPANTS: 13 656 women from the Swedish Twin Registry, with 3404 exposed to night work. OUTCOME MEASURES: Breast cancer from the Swedish Cancer Registry (463 cases) during a follow-up time of 12 years. RESULTS: A Cox proportional hazards regression analysis with control for a large number of confounders showed that the HR was HR=1.68 (95% CI 0.98 to 2.88) for the group with >20 years of night work. When the follow-up time was limited to ages below 60 years, those exposed >20 years showed a HR=1.77 (95% CI 1.03 to 3.04). Shorter exposure to night work showed no significant effects. CONCLUSIONS: The present results, together with previous work, suggest that night work is associated with an increased risk of breast cancer in women, but only after relatively long-term exposure. BMJ Publishing Group 2015-04-15 /pmc/articles/PMC4401866/ /pubmed/25877283 http://dx.doi.org/10.1136/bmjopen-2015-008127 Text en Published by the BMJ Publishing Group Limited. For permission to use (where not already granted under a licence) please go to http://group.bmj.com/group/rights-licensing/permissions This is an Open Access article distributed in accordance with the Creative Commons Attribution Non Commercial (CC BY-NC 4.0) license, which permits others to distribute, remix, adapt, build upon this work non-commercially, and license their derivative works on different terms, provided the original work is properly cited and the use is non-commercial. See: http://creativecommons.org/licenses/by-nc/4.0/
spellingShingle Occupational and Environmental Medicine
Åkerstedt, Torbjörn
Knutsson, Anders
Narusyte, Jurgita
Svedberg, Pia
Kecklund, Göran
Alexanderson, Kristina
Night work and breast cancer in women: a Swedish cohort study
title Night work and breast cancer in women: a Swedish cohort study
title_full Night work and breast cancer in women: a Swedish cohort study
title_fullStr Night work and breast cancer in women: a Swedish cohort study
title_full_unstemmed Night work and breast cancer in women: a Swedish cohort study
title_short Night work and breast cancer in women: a Swedish cohort study
title_sort night work and breast cancer in women: a swedish cohort study
topic Occupational and Environmental Medicine
url https://www.ncbi.nlm.nih.gov/pmc/articles/PMC4401866/
https://www.ncbi.nlm.nih.gov/pubmed/25877283
http://dx.doi.org/10.1136/bmjopen-2015-008127
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