Outdoor light at night and postmenopausal breast cancer risk in the NIH‐AARP diet and health study

Jun 4, 2020International journal of cancer

Outdoor light at night and breast cancer risk after menopause in the NIH-AARP diet and health study

AI simplified

Circadian Biology on OpenScience ↗PubMed ↗DOI ↗

Abstract

Women in the highest quintile of outdoor light at night exposure had a 10% increase in postmenopausal breast cancer risk compared to those in the lowest quintile.

The study followed 186,981 postmenopausal women over approximately 16 years, identifying 12,318 cases of breast cancer.
A 10% increase in risk was observed for postmenopausal breast cancer with higher outdoor light at night exposure (hazard ratio 1.10).
The association was stronger for estrogen receptor positive breast cancer, with a hazard ratio of 1.12 compared to 1.07 for estrogen receptor negative cancer.
Individual factors like smoking, alcohol consumption, sleep duration, BMI, and neighborhood environment may influence the relationship between light exposure and breast cancer risk.

AI simplified

Circadian disruption may play a role in breast carcinogenesis. Previous studies reported relationships between outdoor light at night (LAN) and the breast cancer risk, but their findings are mixed. There is also a need to examine LAN and breast cancer incidence according to different individual and environmental characteristics to identify subpopulations at greater risk associated with LAN exposure. We studied residential outdoor LAN estimated from satellite imagery at baseline (1996) in relation to postmenopausal breast cancer incidence over ~16 years of follow-up in 186 981 postmenopausal women including 12 318 incident postmenopausal breast cancer cases in the NIH-AARP Diet and Health Study. We used Cox proportional hazards models to estimate hazard ratios (HR) and two-sided 95% confidence intervals (CI) of the relationship between quintiles of LAN and postmenopausal breast cancer risk, overall and by hormone receptor status and cancer stage. We found that when compared to women in the lowest quintile of baseline LAN, those in the highest quintile had a 10% increase in postmenopausal breast cancer risk (HR (95% CI), 1.10 (1.02, 1.18), P-trend, .002). The association appeared to be stronger for estrogen receptor (ER) positive breast cancer (1.12 [1.02, 1.24], .007) than for ER-negative cancer (1.07 [0.85, 1.34], .66). Our findings also suggested that the relationship between LAN and breast cancer risk may differ by individual characteristics, such as smoking, alcohol drinking, sleep duration and BMI, and neighborhood environment. In conclusion, our study suggests that higher outdoor LAN exposure may be a risk factor for postmenopausal breast cancer.

Full Text

Full text is available at the source.

View full text (PDF) ↗View full text (XML) ↗View full text ↗

Outdoor light at night and postmenopausal breast cancer risk in the NIH‐AARP diet and health study

Abstract

Full Text

You found one interesting study. We’ll send the next 7.

what lands in your inbox each week:

Recent issues from the circadian biology brief

Abstract

Full Text

Related papers

You found one interesting study. We’ll send the next 7.

what lands in your inbox each week:

Recent issues from the circadian biology brief