Outdoor Light at Night and Breast Cancer Incidence in the Danish Nurse Cohort
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Outdoor Light at Night and Breast Cancer Incidence in the Danish Nurse Cohort. / Clarke, Rebecca B.; Amini, Heresh; James, Peter; von Euler-Chelpin, My; Jørgensen, Jeanette T; Mehta, Amar; Cole-Hunter, Tom; Westendorp, Rudi; Mortensen, Laust H; Loft, Steffen; Brandt, Jørgen; Hertel, Ole; Ketzel, Matthias; Backalarz, Claus; Andersen, Zorana J; Lim, Youn-Hee.
In: Environmental Research, Vol. 194, 110631, 2021.Research output: Contribution to journal › Journal article › Research › peer-review
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TY - JOUR
T1 - Outdoor Light at Night and Breast Cancer Incidence in the Danish Nurse Cohort
AU - Clarke, Rebecca B.
AU - Amini, Heresh
AU - James, Peter
AU - von Euler-Chelpin, My
AU - Jørgensen, Jeanette T
AU - Mehta, Amar
AU - Cole-Hunter, Tom
AU - Westendorp, Rudi
AU - Mortensen, Laust H
AU - Loft, Steffen
AU - Brandt, Jørgen
AU - Hertel, Ole
AU - Ketzel, Matthias
AU - Backalarz, Claus
AU - Andersen, Zorana J
AU - Lim, Youn-Hee
N1 - Copyright © 2020 Elsevier Inc. All rights reserved.
PY - 2021
Y1 - 2021
N2 - BACKGROUND: Knowledge of the role of melatonin, xenograft experiments, and epidemiological studies suggests that exposure to light at night (LAN) may disturb circadian rhythms, possibly increasing the risk of developing breast cancer.OBJECTIVES: We examined the association between residential outdoor LAN and the incidence of breast cancer: overall and subtypes classified by estrogen (ER) and progesterone (PR) receptor status.METHODS: We used data on 16,941 nurses from the Danish Nurse Cohort who were followed-up from the cohort baseline in 1993 or 1999 through 2012 in the Danish Cancer Registry for breast cancer incidence and the Danish Breast Cancer Cooperative Group for breast cancer ER and PR status. LAN exposure data were obtained from the U.S. Defense Meteorological Satellite Program (DMSP) available for 1996, 1999, 2000, 2003, 2004, 2006, and 2010 in nW/cm2/sr unit, and assigned to the study participants' residence addresses during the follow-up. Time-varying Cox regression models were used to calculate the hazard ratios (HRs) and 95% confidence intervals (CIs) for the association between LAN and breast cancer, adjusting for individual characteristics, road traffic noise, and air pollution.RESULTS: Of 16,941 nurses, 745 developed breast cancer in total during 320,289 person-years of follow-up. We found no association between exposure to LAN and overall breast cancer. In the fully adjusted models, HRs for the highest (65.8-446.4 nW/cm2/sr) and medium (22.0-65.7 nW/cm2/sr) LAN tertiles were 0.97 (95% CI: 0.77, 1.23) and 1.09 (95% CI: 0.90, 1.31), respectively, compared to the lowest tertile of LAN exposure (0-21.9 nW/cm2/sr). We found a suggestive association between LAN and ER-breast cancer.CONCLUSION: This large cohort study of Danish female nurses suggests weak evidence of the association between LAN and breast cancer incidence.
AB - BACKGROUND: Knowledge of the role of melatonin, xenograft experiments, and epidemiological studies suggests that exposure to light at night (LAN) may disturb circadian rhythms, possibly increasing the risk of developing breast cancer.OBJECTIVES: We examined the association between residential outdoor LAN and the incidence of breast cancer: overall and subtypes classified by estrogen (ER) and progesterone (PR) receptor status.METHODS: We used data on 16,941 nurses from the Danish Nurse Cohort who were followed-up from the cohort baseline in 1993 or 1999 through 2012 in the Danish Cancer Registry for breast cancer incidence and the Danish Breast Cancer Cooperative Group for breast cancer ER and PR status. LAN exposure data were obtained from the U.S. Defense Meteorological Satellite Program (DMSP) available for 1996, 1999, 2000, 2003, 2004, 2006, and 2010 in nW/cm2/sr unit, and assigned to the study participants' residence addresses during the follow-up. Time-varying Cox regression models were used to calculate the hazard ratios (HRs) and 95% confidence intervals (CIs) for the association between LAN and breast cancer, adjusting for individual characteristics, road traffic noise, and air pollution.RESULTS: Of 16,941 nurses, 745 developed breast cancer in total during 320,289 person-years of follow-up. We found no association between exposure to LAN and overall breast cancer. In the fully adjusted models, HRs for the highest (65.8-446.4 nW/cm2/sr) and medium (22.0-65.7 nW/cm2/sr) LAN tertiles were 0.97 (95% CI: 0.77, 1.23) and 1.09 (95% CI: 0.90, 1.31), respectively, compared to the lowest tertile of LAN exposure (0-21.9 nW/cm2/sr). We found a suggestive association between LAN and ER-breast cancer.CONCLUSION: This large cohort study of Danish female nurses suggests weak evidence of the association between LAN and breast cancer incidence.
U2 - 10.1016/j.envres.2020.110631
DO - 10.1016/j.envres.2020.110631
M3 - Journal article
C2 - 33345898
VL - 194
JO - Environmental Research
JF - Environmental Research
SN - 0013-9351
M1 - 110631
ER -
ID: 253611838