March 2, 2024

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Urban Night Lights Linked to 242% Higher Risk of Blindness

Urban Night Lights Linked to 242% Higher Risk of Blindness



Urban Night Lights Linked to 242% Higher Risk of Blindness

Light Pollution Linked to Increased Risk of Blindness! Urban Population Faces a 242% Higher Risk of Disease!

Light pollution is a new form of environmental pollution, including white light pollution (such as glare from glass curtain walls of tall buildings), nighttime artificial light pollution (such as neon lights, advertising screens, and electronic devices at night), and colored light pollution (such as colorful light sources, rotating lights, and laser lights).

Prolonged exposure to light pollution can not only damage the structures within the eyes and disrupt the body’s circadian rhythm but also increase the risk of sleep disorders, obesity, cardiovascular diseases, cancer, and mental disorders. However, compared to other environmental issues, light pollution is often overlooked.

Previous studies have indicated that nighttime artificial light can have a substantial impact on the human retina and optic nerve, causing direct or indirect damage to eye tissues.

A recent study published in JAMA Network Open confirms that nighttime artificial light is associated with one of the main causes of blindness, exudative age-related macular degeneration (EAMD).

Urban Night Lights Linked to 242% Higher Risk of Blindness

Compared to subjects with lower levels of nighttime outdoor artificial light exposure, those with higher exposure had a 117% increased risk of developing EAMD. The study emphasizes that the correlation between nighttime outdoor artificial light and the risk of EAMD is more significant in urban areas.

Age-related macular degeneration (AMD) is a chronic disease affecting the macular region of the retina, primarily caused by degenerative changes in retinal pigment epithelial cells and retinal degeneration, leading to distorted vision, central vision loss, or even blindness. AMD is the leading cause of irreversible vision impairment globally, and with the aging population and increased life expectancy, the number of AMD patients is expected to rise.

As of now, the mechanisms behind AMD are not fully understood. In recent years, environmental factors associated with an increased risk of AMD have become a research focus. This study, based on data from 126,418 EAMD patients, analyzed the correlation between nighttime outdoor artificial light and the risk of exudative AMD.

The study included 126,418 participants, comprising 4,078 newly diagnosed EAMD patients and 122,340 participants without EAMD. The average age of the participants was 66 years, with males accounting for 61.9%.

Researchers found that participants with higher levels of nighttime outdoor artificial light exposure tended to reside in areas with higher levels of PM10 (particulate matter with an aerodynamic diameter equal to or less than 10 micrometers) and nighttime traffic noise. Conversely, participants with lower levels of nighttime outdoor artificial light exposure generally had lower levels of physical activity.

The analysis results showed that as the level of nighttime outdoor artificial light exposure in participants’ residences increased, the risk of EAMD also increased (P=0.01). Compared to participants with lower levels of nighttime outdoor artificial light exposure, those with higher exposure had a 117% increased risk of developing EAMD.

Additionally, for every increase of 55.8 nW/cm2/sr in nighttime outdoor artificial light exposure, there was a 67% increased risk of EAMD. The analysis of the exposure-response curve showed a particularly pronounced association between higher levels of nighttime outdoor artificial light exposure (such as exposure values reaching 110 nW/cm2/sr) and the onset of EAMD.

It is noteworthy that overall analysis results indicated a more pronounced association between nighttime outdoor artificial light and the risk of EAMD in older individuals, males, those with a higher body mass index (BMI) (≥25.0 kg/m2), smokers, drinkers, urban residents, and individuals with hypertension or abnormal blood lipid levels.

Significantly Higher Risk of EAMD in Urban Areas

Subgroup analysis included 122,523 participants who had not relocated between urban and rural areas. Among them, 73,551 participants (60.0%) resided in urban areas, while 48,972 participants (40.0%) resided in rural areas. Statistical data showed that the average nighttime outdoor artificial light exposure value in urban areas was 61.2 nW/cm2/sr, compared to 20.6 nW/cm2/sr in rural areas. The nighttime outdoor artificial light exposure level in urban areas was nearly three times that in rural areas. In urban areas, 2,755 participants (3.7%) developed EAMD between 2010 and 2011, while in rural areas, 1,210 participants (2.5%) developed EAMD during the same period.

The analysis results indicated a significantly higher risk of EAMD in urban areas (P=0.005). In urban populations, compared to participants with lower levels of nighttime outdoor artificial light exposure, those with higher exposure had a 242% increased risk of developing EAMD. Furthermore, for every increase of 55.8 nW/cm2/sr in nighttime outdoor artificial light exposure, there was a 46% increased risk of EAMD in urban participants.

However, researchers did not find a significant association between nighttime outdoor artificial light and the risk of EAMD in rural areas (P=0.77). For every increase of 55.8 nW/cm2/sr in nighttime outdoor artificial light exposure, there was only a 1% increased risk of EAMD in rural participants.

In conclusion, the analysis results of this study suggest that nighttime outdoor artificial light may be a risk factor for EAMD. Moreover, the association between nighttime outdoor artificial light and EAMD may vary by region, with a significantly higher correlation observed in urban areas, where nighttime outdoor artificial light exposure levels are strongly linked to an increased risk of EAMD.

Urban Night Lights Linked to 242% Higher Risk of Blindness

References:

[1] Su Hwan Kim et al. Nighttime Outdoor Artificial Light and Risk of Age-Related Macular Degeneration. JAMA Netw Open. doi: 10.1001/jamanetworkopen.2023.51650

(source:internet, reference only)


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