Brighter daytime light is linked to a lower dementia risk

 Of course your competent? doctor has been using bright light therapy for almost a decade already! NO? So, incompetence? And your board of directors is so incompetent they don't know what competence is in their hospital!

• bright light therapy (8 posts to February 2017)

Brighter daytime light is linked to a lower dementia risk

People exposed to brighter daytime light were significantly less likely to develop dementia over eight years, with the strongest associations seen in those already at higher risk, highlighting light exposure as a promising avenue for future prevention research.A large prospective study published in the journal General Psychiatry found that greater exposure to bright daytime light was associated with a lower risk of developing dementia.

Circadian rhythms may influence dementia development

Dementia is the most common neurodegenerative disease worldwide and is rapidly increasing in prevalence with the aging of the global population. With limited effective treatments, prevention is a top priority.

The environmental light-dark cycle is key to aligning with natural circadian rhythms, which, in turn, are fundamental to normal physiological, behavioral, and cognitive functioning. People with dementia often show disrupted circadian rhythms, and conversely, these are linked to a higher risk of dementia.

More evidence of such associations comes from the promising use of bright light therapy (BLT) in patients with dementia to correct dysregulated circadian rhythms and improve cognitive symptoms. However, the modern lifestyle limits adequate exposure to natural bright light during the day, as most people spend this time indoors in buildings with insufficient lighting. This is worsened by excessive nighttime light exposure, which affects nearly 80% of the world’s population.

The current study aimed to investigate associations between daytime and nighttime light exposures and dementia risk.

Wearable devices tracked weekly light exposure patterns

Researchers measured daytime and nighttime light exposure using wrist-worn devices over seven days in a community cohort of 87,577 dementia-free adults (mean age 62 years). They then examined whether light exposure predicted future dementia diagnoses.

Brighter daytime light linked to lower dementia risk

Over a median follow-up period of eight years, 741 participants developed dementia. At baseline, participants who developed dementia were more likely to be older, male, less educated, less physically active, smokers, or to have hypertension, diabetes, or hearing loss.

The investigators found that exposure to daytime light levels brighter than 1,000 lux was associated with a 16% lower risk of dementia. Shorter durations of increasingly bright daytime light showed similar associations, suggesting a graded pattern across brighter-light thresholds.

Thus, 17% reductions in risk were observed with at least 1.4 hours of exposure to bright daytime light of 3000 lux or more, versus 0.7 hours at 5000 lux, and 0.45 hours at 7000 lux.

Greater effects among high-risk groups

The effects of higher average daytime light exposure and longer exposure to bright daytime light were most pronounced among certain groups. For instance, such exposures were associated with a 30% to 38% reduction in dementia risk among individuals exposed to higher nighttime light levels.

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