2023-07-24 04:00:04
Many studies now report the harmful effects of air pollution on the central nervous system (neurodegenerative diseases in adults, neurodevelopmental disorders in children). Glaucoma, the second leading cause of blindness in the world, is a neurodegenerative disease of the optic nerve, the main characteristic of which is a thinning of the nerve fiber layer of the retina.
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In a study of a cohort made up of 683 elderly people from Bordeaux, whose follow-up lasted ten years, researchers from Inserm and the University of Bordeaux, at the Bordeaux Population Health research center, highlighted an accelerated thinning of the nerve fiber layer of the retina in people more exposed to pollution (Pollution is defined as what makes an environment unhealthy. The definition varies according to the …) atmospheric, in particular those which had a greater exposure to fine particles (particles with a diameter (In a circle or a sphere, the diameter is a line segment passing through the center…) less than 2.5 microns = PM2.5).
This study therefore suggests a possible increase in the risk of glaucoma for the inhabitants of areas polluted with fine particles, even at levels below the current regulatory thresholds of the European Union (25 micrograms/cubic meter). The results are published in the journal Environmental Research.
Air pollution is a global public health issue. The harmful effects of atmospheric pollutants on respiratory and cardiovascular functions have been widely documented in the scientific literature (A scientist is a person who is dedicated to the study of a science or sciences and who…). It is also increasingly evident that chronic exposure to air pollution has harmful effects on the central nervous system (The nervous system is a network system formed of the sense organs,…) with in particular an increased risk of neurodegenerative diseases in adults and neurodevelopmental disorders in children.
The retinal nerve fiber layer (RNFL) is part of the central nervous system, and its thinning is the hallmark of glaucoma[1], an eye disease associated with the progressive destruction of the optic nerve, most often caused by too much pressure inside the eye. This pathology (Pathology, a term from ancient Greek, is literally the speech, the…) is the second cause of blindness in developed countries (Developed countries with market economy (PDEM) are countries whose…).
Researchers from Inserm and the University of Bordeaux have studied the effect of exposure to higher concentrations of air pollutants (fine particles and nitrogen dioxide) on neurodegenerative processes at the ocular level. To do this, they followed a Bordeaux population for ten years (Bordeaux is a French bovine breed.) of 683 people aged over 75 at the time of their inclusion in the cohort. Eleanor. This is the first prospective study carried out on this subject.
In the study, people had eye exams every two years between 2009 and 2020 to measure changes in the thickness of the nerve fiber layer of their retina.
In addition, their exposure to air pollution over the previous 10 years was determined from their home address, using annual exposure maps for each pollutant. These detailed maps, with a resolution of 100 meters, were produced from measurements of control stations (The word control can have several meanings. It can be used as a synonym for examination, of…) of air quality and meteorological and geographical characteristics (proximity to a road, population density, distance from the sea, altitude…).
According to the results of this study, people who were exposed to higher concentrations of fine particles had more rapid thinning of the retinal nerve layer over time.
These results are shown in the figure above, in which we can see that participants exposed to a concentration of 25 µg/m3 to fine PM2.5 particles had a faster decrease in the thickness of this layer compared to those exposed to 20 µg/m3.
These results suggest that exposure to a high concentration of pollutants over time might increase the risk of glaucoma.
With regard to PM2.5 fine particles, the average exposure estimates over 10 years were below the regulatory annual threshold of the European Union (set at a maximum of 25 μg/m3) for all participants, but above the limit values ​​recommended by the WHO in 2005 (10 μg/m3) further lowered in 2021 (5 μg/m3).
“The results of this study confirm previous observations on the effects of atmospheric pollution on neurodegenerative processes, here at the ocular level. They constitute an additional argument in favor of lowering European regulatory thresholds, as recommended by the WHO, as well as reducing the effective exposure of the French population, which continues to exceed current regulatory thresholds in places”, explains Laure Gayraud, doctoral student in epidemiology and first author of the study.
“More generally, our study documents the effects of atmospheric pollutants on neurological aging. Taking the example of ocular aging, it suggests that exposure to high concentrations of pollutants over time might lead to an acceleration (Acceleration commonly refers to an increase in speed; in physics,…) of neurological aging, as has been observed in studies on brain aging”, explains CĂ©cile Delcourt, research director at Inserm, the last author of this work.
The objective is now for scientists to expand the field of study on a national scale, thanks to data from other French cohorts, in order to deepen knowledge on the effects of pollutants on ocular aging.
Diagram of the eye and the retina
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