Exposure to bright light at night significantly increases the risk of developing type 2 diabetes by disrupting circadian rhythms and affecting insulin Glucose secretion and metabolism, according to a study by Flinders University.
A study from Flinders University suggests that avoiding bright light at night may be an easy way to reduce your risk of diabetes.
The study published in the prestigious journal The Lancet Regional Health – Europe reveals the compelling relationship between light exposure and the risk of developing type 2 diabetes.
Type 2 (acquired) diabetes is a chronic disease that affects how the body uses insulin. It develops over many years, is difficult to treat, and is usually linked to lifestyle factors, such as inactivity and obesity.
Main results of the study
“We found that exposure to brighter light at night was associated with a higher risk of developing type 2 diabetes,” said lead author Associate Professor Andrew Phillips from the College of Medicine and Public Health.
In a large-scale modeling study, the research team examined whether patterns of personal light exposure predicted diabetes risk using data from about 85,000 people and about 13 million hours of light sensor data.
Participants, who did not have type 2 diabetes, wore devices on their wrists for a week to track their light levels throughout the day and night.
They were then followed over the next nine years to see if they developed type 2 diabetes.
Impact of light exposure on circadian rhythms
“Exposure to light at night can disrupt our circadian rhythms, leading to changes in insulin secretion and glucose metabolism,” he explains.
“Changes in insulin secretion and glucose metabolism caused by disrupted circadian rhythms affect the body’s ability to regulate blood sugar, which can ultimately lead to the development of type 2 diabetes.”
Increased exposure to light at night (between 12:30 a.m. and 6:00 a.m.) was associated with a higher risk of developing type 2 diabetes, and this was true regardless of the amount of light people were exposed to during the day.
Importance of reducing exposure to nighttime light
The study took into account other factors associated with type 2 diabetes, such as lifestyle habits, sleep patterns, shift work, diet and mental health.
Even after taking these factors into account, the results showed that having more light at night was still a strong predictor of developing diabetes.
“The results showed that exposure to brighter light at night is associated with a higher risk of developing diabetes, with a dose-dependent relationship between light exposure and risk,” says Associate Professor Phillips.
“Our results suggest that reducing your exposure to light at night and maintaining a dark environment may be a simple and inexpensive way to prevent or delay the development of diabetes,” he adds.
Reference: “Personal light exposure patterns and incidence of type 2 diabetes: analysis of 13 million hours of light sensor data and 670,000 person-years of prospective observation” by Daniel P. Windred, Angus C. Burns, Martin K. Rutter, Chris Ho Ching Yeung, Jacqueline M. Lane, Qian Xiao, Richa Saxena, Sean W. Cain and Andrew JK Phillips, June 4, 2024, The Lancet Regional Health – Europe.
DOI: 10.1016/j.lanepe.2024.100943
This research was conducted using data from UK Biobank (Project ID: 6818). We thank the participants for their time and the UK Biobank team for the ongoing development and maintenance of this resource. This research was conducted with financial support from the Australian Government Research Training Program, the National Heart, Lung, and Blood Institute (R21HL165369) and the Australian Research Council (DP210102924 and DP220102812).
