Artificial light is as bad for the heart as fine particles

Artificial light is as bad for the heart as fine particles


Not only does it cause permanent changes to the ecosystem and animal behavior and prevents us from enjoying the spectacle of the night sky, light pollution is also harmful to our health. According to a new study published in the journal Strokes and conducted on residents of the Chinese metropolis of Ningbo, excessive exposure to artificial light at night is associated with an increase in the risk of developing cerebrovascular diseases.

The study, which also analyzed the effects ofpollution atmospheric pollution due to PM2.5, PM10 and NO2, has in fact highlighted how individuals most exposed to light pollution have a 43% higher probability of developing a stroke or suffering from cerebrovascular events compared to those less exposed.

“This is an innovative aspect because we almost never talk about light pollution from a health point of view and this study represents further evidence of how the environment around us influences the incidence of cerebrovascular diseases”, he commented Pasquale Perrone Filardipresident of the Italian Society of Cardiology (Sic).

The Chinese study

The team of researchers analyzed data relating to over 28 thousand individuals with an average age of 61 years and without a clinical history of cerebrovascular disease, followed from 2015 to 2021 or until the first manifestation of a cerebrovascular disease.

To evaluate the association between light pollution and diseases linked to alterations in brain blood circulation, the scholars compared exposure to night light measured through the analysis of images collected by the environmental monitoring satellite system Joint Polar Satellite System with data on health conditions obtained from the medical records and death certificates of the subjects taken into consideration.

The results

Taking into account age, gender, education, occupation, annual family income, body mass index, physical activity, smoking and alcohol consumption, hypertension, dyslipidemia, diabetes and other factors that could influence the results, the scientists found that individuals living in areas with the highest levels of light pollution have a 43% greater risk of developing cerebrovascular disease than those living in areas where there is less night-time lighting. Levels in line with those that researchers observed for exposure to particulate pollution and smog (41% for PM2.5, 50% for PM10 and 31% for NO2).

Light pollution is therefore turning out to be pollution in all respects, capable of causing alterations that are harmful to humans. A factor to keep under control, considering that the increasingly widespread use of street, building and sign lighting has led approximately 80% of the world population to live in environments “polluted” by light.

The effects of light pollution on health

“Intense exposure to artificial light during the night can lead to disturbances in the level of brain secretions, interfering above all with the production of melatonin, and this can be associated with a greater cerebrovascular risk”, said Perrone Filardi.

Light influences our internal clock by suppressing the natural release of the melatonin hormone during the night by the pineal gland, compromising sleep rhythms and shortening its duration, with consequent changes, as also underlined by the authors of the study, in physiological biological values. such as the increase in triglyceride levels, blood pressure and blood glucose, all key factors in the onset of cerebrovascular diseases.

“The type of light source is also relevant”, underlined President Sic. Cold lights, with a low wavelength, such as white LEDs and fluorescent bulbs have a more accentuated melatonin suppression effect with greater negative consequences for health.

Some limitations in the results

The study only took into consideration data from satellite images and did not evaluate the exposure of individuals to light sources inside homes and the presence of blackout curtains, shutters and windows capable of reducing the light coming from the outside during the night. Furthermore, the satellite images used do not provide a complete overview of light pollution as they hardly capture low-wavelength light sources.

These are factors which overall can lead to an underestimated association between light pollution and the incidence of cerebrovascular diseases.

Therefore, as underlined by the authors of the research, further studies will be necessary to confirm these results which nevertheless remain relevant and which open our eyes to an aspect that has so far been little considered.


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