Higher Daytime Light Exposure Predicts Lower Risk of Gastrointestinal Cancer Incidence and Mortality

Area of Science:

• Chronobiology
• Cancer Epidemiology
• Public Health

Background:

• Daytime light exposure synchronizes circadian rhythms, essential for physiological health.
• Insufficient light exposure can disrupt circadian alignment, potentially increasing cancer risk.
• Gastrointestinal cancers represent a significant global health burden.

Purpose of the Study:

• To investigate the association between objectively measured daytime light exposure and the incidence and mortality of gastrointestinal cancers.
• To specifically examine the impact of light exposure on pancreatic cancer risk.
• To compare the predictive power of light exposure metrics against other lifestyle factors.

Main Methods:

• Prospective cohort study of 89,069 participants.
• Objective measurement of daytime light intensity and duration.
• Cox proportional hazards models to assess cancer incidence and mortality risks.

Main Results:

• Higher mean daytime light intensity was associated with a lower risk of gastrointestinal cancer incidence (HR: 0.87) and mortality (HR: 0.76).
• Significantly lower risks were observed for pancreatic cancer incidence (HR: 0.58) and mortality (HR: 0.47) with higher light exposure.
• Daytime light metrics demonstrated greater predictive ability than sleep quality, diet, depression, or alcohol consumption.

Conclusions:

• Increased daytime light exposure is associated with reduced risks of gastrointestinal and pancreatic cancer incidence and mortality.
• Daytime light may exert a protective effect against gastrointestinal cancers, particularly pancreatic cancer.
• These findings highlight the potential role of light exposure in cancer prevention and prognosis.