Exposure to bright light at night significantly increases the risk of developing type 2 diabetes because it disrupts the circadian rhythm and insulin Secretion and glucose metabolism, according to a study by Flinders University.
A study from Flinders University suggests that avoiding bright light at night may be a simple way to reduce the risk of diabetes.
The study was published in the renowned journal The Lancet Regional Health – Europe reveals the compelling link between light exposure and the risk of developing type 2 diabetes.
Type 2 diabetes (acquired diabetes) is a chronic disease that affects the body’s ability to use insulin. The disease develops over many years, is difficult to treat, and is usually associated with lifestyle factors such as lack of exercise and obesity.
Key findings of the study
“We found that exposure to brighter light at night is associated with a higher risk of developing type 2 diabetes,” says lead author and Associate Professor Andrew Phillips of the College of Medicine and Public Health.
In the large model study, the research team used data from around 85,000 people and around 13 million hours of light sensor data to investigate whether personal light exposure patterns predict diabetes risk.
The participants – who did not have type 2 diabetes – wore devices on their wrists for a week to monitor their light intensity throughout the day and night.
They were then followed over the next nine years to see if they later developed type 2 diabetes.
Influence of light exposure on the circadian rhythm
“Exposure to light at night can disrupt our circadian rhythm and lead to changes in insulin secretion and glucose metabolism,” he says.
“Changes in insulin secretion and glucose metabolism caused by disrupted circadian rhythms impair the body’s ability to regulate blood sugar levels, which can ultimately lead to the development of type 2 diabetes.”
Greater 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, regardless of how much light people were exposed to during the day.
Importance of reducing nighttime light exposure
The research 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 more light at night is 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 light exposure 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 the 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 funding from the Australian Government Research Training Program, National Heart, Lung, and Blood Institute (R21HL165369) and the Australian Research Council (DP210102924 and DP220102812).
