# Indoor and outdoor light at night: Associations with sleep and breast cancer

> **NIH NIH F31** · UNIV OF NORTH CAROLINA CHAPEL HILL · 2021 · $34,833

## Abstract

PROJECT SUMMARY
Applicant. The goal of this F31 fellowship application is to support and promote the training of Marina
Sweeney, who is currently a pre-doctoral student in the Department of Epidemiology at the University of North
Carolina, Chapel Hill. Her long-term research interests focus on elucidating the role of the environment on
cancer risk. The applicant will be mentored by Drs. Hazel Nichols and Alexandra White during the F31 training
period. Significance. Breast cancer is the most common malignancy diagnosed in women in the US, and
known risk factors are estimated to explain only half of incident cases. Risk of breast cancer may be increased
by poor quality or insufficient sleep through mechanisms of inflammation and obesity. Outdoor and indoor light
at night (LAN) are proposed to disrupt circadian rhythms and thereby negatively impact sleep and possibly
increase the risk of breast cancer. Prior studies suggest that outdoor LAN increases breast cancer risk, while
studies of indoor LAN have been mixed. Outdoor and indoor LAN have been shown to disrupt sleep, but few
large-scale epidemiologic studies have been conducted. Assessments of outdoor or indoor LAN individually
may misclassify LAN exposure, and no studies have assessed combined outdoor and indoor LAN exposure in
relation to either breast cancer or sleep characteristics. The overall goal of the proposed study is to further our
knowledge of the role of LAN in breast carcinogenesis and sleep disruption. Aim 1. Examine the association
between outdoor, indoor, and combined LAN and risk of incident breast cancer. Aim 2. Examine the
association between outdoor, indoor, and combined LAN and sleep duration and quality. Approach. The Sister
Study prospective cohort includes 50,884 women who had a sister with breast cancer but who themselves
were breast-cancer free at baseline. Outdoor LAN will be determined from satellite data and linked to baseline
geocoded addresses. Indoor LAN was self-reported at baseline. Aim 1 will use Cox proportional hazards
models to calculate hazard ratios and 95% confidence intervals for the associations between indoor and
outdoor LAN and breast cancer risk. Aim 2 will use weighted log binomial models to calculate prevalence ratios
and 95% confidence intervals for associations between LAN and characteristics of sleep duration and quality.
Innovation. The proposed project capitalizes on existing data within the Sister Study and will incorporate
existing and new geospatial variables (outdoor LAN, neighborhood SES index, area deprivation index, fine
particulate matter, green space, noise) in a prospective cohort of >50,000 US women. This will be the first
study to assess joint outdoor and indoor LAN in relation to either breast cancer or sleep characteristics.
Impact. The proposed study will provide the applicant with further training in epidemiologic methods, including
the integration of both geographic and individual exposure data, and provide high-quality mentor...

## Key facts

- **NIH application ID:** 10230773
- **Project number:** 1F31ES033062-01
- **Recipient organization:** UNIV OF NORTH CAROLINA CHAPEL HILL
- **Principal Investigator:** Marina Rose Sweeney
- **Activity code:** F31 (R01, R21, SBIR, etc.)
- **Funding institute:** NIH
- **Fiscal year:** 2021
- **Award amount:** $34,833
- **Award type:** 1
- **Project period:** 2021-08-01 → 2022-06-05

## Primary source

NIH RePORTER: https://reporter.nih.gov/project-details/10230773

## Citation

> US National Institutes of Health, RePORTER application 10230773, Indoor and outdoor light at night: Associations with sleep and breast cancer (1F31ES033062-01). Retrieved via AI Analytics 2026-05-23 from https://api.ai-analytics.org/grant/nih/10230773. Licensed CC0.

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