Last week YourLifeChoices highlighted the risks associated with going to bed at the wrong time. Not only was hitting the pillow too late a potential problem, even an early bedtime came with risks, research showed. Now, a different study has suggested there’s another potential night-time danger – light pollution.
For some people, the smallest amount of light can apparently affect their ability to get to sleep. I have a friend who claims the glow of the microwave oven two rooms away from her bedroom affects her!
That may sound somewhat extreme, but her attention to shutting out all night-time light pollution is likely a good thing. On the other hand, I have no trouble sleeping regardless of the level of light pollution. And while that may deliver short-term benefits, new research suggests it may increase my risk of developing Alzheimer’s disease.
The link between light pollution and Alzheimer’s
Researchers at Rush University Medical Centre, Chicago, have published a study that shows a link between light pollution and Alzheimer’s. As a starting point, the study’s authors acknowledged the already known health risks associated with light pollution. There’s no shortage of those, among them being sleep disruption, obesity, depression, anxiety, memory dysfunction, atherosclerosis and cancer.
But, as pointed out in the study’s introduction, “little is known about the impact of light pollution on Alzheimer’s disease”.
The authors – Robin M. Voigt, Bichun Ouyang and Ali Keshavarzian – set about addressing that lack of knowledge. Using data from multiple government sources across 48 US states, they “evaluated the relationship between AD prevalence and average night-time light intensity (light pollution)”.
States were ranked according to average night-time light intensity and divided into five groups from lowest to highest average intensity. Multiple comparisons found statistical differences between states with the darkest and brightest average night-time light intensity.
The comparison results were supported using a statistical technique known as Pearson correlation analysis. In short, the greater the intensity, the greater the risk of Alzheimer’s.
Is age a factor?
One interesting finding in the research was that age may well play a part in the level of risk. Perhaps surprisingly, it is comparatively younger people who appear to be at greater risk. Using age 65 as a boundary, the study found light pollution increased the risk in both younger and older participants.
Exposure to night-time light pollution in over-65s was a stronger risk factor for Alzheimer’s than chronic kidney failure, depression, heart failure, alcohol abuse and obesity. Each of these has a strong correlation to Alzheimer’s. On the other hand, the light pollution risk factor was lower than for diabetes, high blood pressure and stroke.
However, for those aged under 65, light pollution was a greater risk factor than all of the ones listed above.
Why the younger group appears to be at greater risk is not entirely clear, but genetics may play a part. Specifically, what’s known as the APOE gene could be a key contributor. The APOE gene is linked with greater risk of early onset Alzheimer’s and can affect how the body deals with stress.
As it turns out, younger people are more likely to carry the APOE gene. This in turn suggests under-65s might be less equipped to handle stressors like light pollution.
It’s time we saw the light (pollution)
As with many studies, the authors said further studies would help to untangle the various factors at play. Notwithstanding that caveat, evidence for light pollution as a risk factor for Alzheimer’s is mounting.
Last week’s revelations suggested we should try to head to bed between 10pm and midnight as a rule. To further enhance your chances of ageing healthily, try to block out as much light as possible when you do.
Does light pollution affect your sleep? What measures do you take to block out light at bedtime? Let us know via the comments section below.
Also read: Alzheimer’s: new studies could signal a revolution
Disclaimer: This article contains general information about health issues and is not advice. For health advice, consult your medical practitioner.
