Details:

Alternative Title:
Environ Health Perspect
Publisher's site:
http://dx.doi.org/10.1289/EHP935
Personal Author:
James, Peter ; Bertrand, Kimberly A. ; Hart, Jaime E. ; Schernhammer, Eva S. ; Tamimi, Rulla M. ; ... More +
James, Peter ; Bertrand, Kimberly A. ; Hart, Jaime E. ; Schernhammer, Eva S. ; Tamimi, Rulla M. ; Laden, Francine Less -
Description:
Background:

Animal and epidemiologic studies suggest that exposure to light at night (LAN) may disrupt circadian patterns and decrease nocturnal secretion of melatonin, which may disturb estrogen regulation, leading to increased breast cancer risk.

Objectives:

We examined the association between residential outdoor LAN and breast cancer incidence using data from the nationwide U.S.-based Nurses’ Health Study II cohort.

Methods:

We followed 109,672 women from 1989 through 2013. Cumulative LAN exposure was estimated using time-varying satellite data for a composite of persistent nighttime illumination at ∼1 km2 scale for each residence during follow-up. Incident invasive breast cancer cases were confirmed by medical record review. We used Cox proportional hazard models to calculate hazard ratios (HRs) and 95% confidence intervals (CIs), adjusting for anthropometric, reproductive, lifestyle, and socioeconomic risk factors.

Results:

Over 2,187,425 person-years, we identified 3,549 incident breast cancer cases. Based on a fully adjusted model, the estimated HR for incident breast cancer with an interquartile range (IQR) (31.6 nW/cm2/sr) increase in cumulative average outdoor LAN was 1.05 (95% CI: 1.00, 1.11). An association between LAN and breast cancer appeared to be limited to women who were premenopausal at the time of a case [HR=1.07 (95% CI: 1.01, 1.14) based on 1,973 cases vs. HR=1.00 (95% CI: 0.91, 1.09) based on 1,172 cases in postmenopausal women; p-interaction=0.08]. The LAN–breast cancer association was observed only in past and current smokers at the end of follow-up [HR=1.00 (95% CI: 0.94, 1.07) based on 2,215 cases in never smokers; HR=1.10 (95% CI: 1.01, 1.19) based on 1,034 cases in past smokers vs. HR=1.21 (95% CI: 1.07, 1.37) for 300 cases in current smokers; p-interaction=0.08].

Conclusions:

Although further work is required to confirm our results and to clarify potential mechanisms, our findings suggest that exposure to residential outdoor light at night may contribute to invasive breast cancer risk. https://doi.org/10.1289/EHP935


Subject:
[+]
Adult
Breast Neoplasms
Environmental Exposure
Female
Humans
Incidence
Lighting
Middle Aged
Prospective Studies
Research
Risk Factors

Source:
Environ Health Perspect. 125(8).
Pubmed ID:
28886600
Pubmed Central ID:
PMC5783660
Document Type:
Journal Article
Funding:
K99 CA201542/CA/NCI NIH HHS/United States ; R01 OH009803/OH/NIOSH CDC HHS/United States ; R00 CA201542/CA/NCI NIH HHS/United States ; T32 HL098048/HL/NHLBI NIH HHS/United States ; UM1 CA176726/CA/NCI NIH HHS/United States
K99 CA201542/CA/NCI NIH HHS/United States ; R01 OH009803/OH/NIOSH CDC HHS/United States ; R00 CA201542/CA/NCI NIH HHS/United States ; T32 HL098048/HL/NHLBI NIH HHS/United States ; UM1 CA176726/CA/NCI NIH HHS/United States Less -
Collection(s):
CDC Public Access
Main Document Checksum:
[+]
urn:sha256:23d876d88a1cc0c3df2bf14fd68e86a072e948e9ba312c613dcf217fbaaa089e
File Type:

Supporting Files

• 	EHP935.nxml	xml
  	EHP935.s001.acco.pdf	pdf
  	EHP935_f1.gif	gif
  	EHP935_f1.jpg	jpeg

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