Association between Outdoor Light at Night and Prostate Cancer in the Health Professionals Follow-up Study

Abstract

Background: Circadian disruption is a potential risk factor for advanced prostate cancer, and light at night (LAN) exposure may disrupt circadian rhythms. We evaluated whether outdoor LAN increases the risk of prostate cancer. Methods: We prospectively followed 49,148 participants in the Health Professionals Follow-up Study from 1986 through 2016. We estimated baseline and cumulative time-varying outdoor LAN with ~1 km2 resolution using data from the US Defense Meteorological Satellite Program’s Operational Linescan System, which was assigned to participants’ geocoded addresses. Participants reside in all 50 US states and reported a work or home address. We used multivariable Cox models to estimate hazard ratios (HR) and 95% confidence intervals (CI) for the association between outdoor LAN and risk of overall (7,175 cases) and fatal (915 cases) prostate cancer adjusting for individual and contextual factors. Results: There was no association between the interquartile range increase in cumulative LAN and total (HR:1.02, 95% CI 0.98, 1.06) or fatal (HR: 1.05, 95% CI: 0.96, 1.15) prostate cancer in adjusted models. However, there was a positive association between baseline LAN and total prostate cancer among non-movers (HR: 1.06, 95% CI:1.00,1.14) including among highly screened participants (HR: 1.11, 95% CI:1.01,1.23). Conclusions: There was a suggestive positive association between baseline outdoor LAN and total prostate cancer. Additional studies with different measures of outdoor LAN and in more diverse populations are necessary. Impact: To our knowledge, this is the first longitudinal cohort study exploring the relationship between outdoor LAN and prostate cancer.

Risk of prostate cancer with increasing years of night shift work: A two-stage dose-response meta-analysis with duration of night shift work as exposure dose

“…However, several studies have suggested no statistically significant association between ALAN exposure and prostate cancer. Chowdhury-Paulino et al reported no association between the interquartile range increase in cumulative light exposure at night and total and fatal prostate cancer incidence [ 49 ].…”