Can the light leaking into your bedroom at night raise your Type 2 diabetes risk more than moderately bad genetics?
This Lancet study (UK Biobank, 84,790 people, 13 million hours of wrist light sensor data) says yes it effing can.
Brighter nights = higher diabetes.
Here are the exact numbers (fully adjusted for age, sex, lifestyle, income and even polygenic risk score):
Darkest nights (0-50th percentile): baseline risk
50-70th: 29% risk (HR 1.29)
70-90th: 39% risk (HR 1.39)
Brightest nights 10%: 53% risk (HR 1.53)
Your circadian amplitude and phase mattered too. Unnatural light timing = higher diabetes.
The mind blowing part is that night light was independent of genetic risk.
The jump from dark to bright nights was roughly the same risk increase as going from low to moderate genetic risk for T2D.
What this means for you is that you can literally outrun bad genes by keeping your nights dark.
This is one of the main reasons the Blue Light Diet was created over a decade ago.
So here's a general protocol to get this done if you still want to live a modern, big city life......
→ Blackout curtains night coded light bulbs and red or flux filtered screens after sunset.
→ No blue light 3-4 hours before bed.
→ Phone in redshift mode.
(see all recs in replies below)
From the paper....."Avoidance of light at night is “a simple and cost-effective recommendation that mitigates risk of diabetes, even in those with high genetic risk.”