[ad_1]
The effects of pollution on human health are often subtle but vast. As an example, a new study released Tuesday seems to show that a high exposure to certain auto fumes can increase the risk of developing a degenerative disease that gradually erodes eyesight.
The disease is known as age-related macular degeneration, or AMD. AMD is characterized by the progressive destruction of the macula, a part of the retina that allows us to see right in front of us with a sharp and clean focus. The progression of AMD can vary, with some people experiencing small vision problems for many years while others worsen rapidly. Although the disease does not cause complete blindness, it is one of the leading causes of irreversible vision loss in people over 50 years of age.
Like many degenerative diseases, AMD can be caused by several risk factors. Age obviously plays a major role, but genetics and the environment also play an important role. For example, white Americans over the age of 50 are twice as likely to have AMD (2.1% of people over 50) compared to all other races (0.9%) .
Even low levels of air pollution can damage your lungs as much as smoking a bag a day
Breathing polluted air can have an impact on a person's health as well as smoking a pack of cigarettes …
Read more
According to the authors of the new study published in the BMJ, there has been little or no study on the effects of air pollution on our chances of getting AMD. Some studies have shown that exposure to air pollution can increase the risk of eye problems such as conjunctivitis and dry eye. It is also thought that smoking doubles the risk of developing AMD.
The researchers, based in China, reviewed the country's national health data and compared it with data on air quality. Medical records of people over 50, in addition to determining whether they had previously been diagnosed with AMD over a period of eleven years to 2010, were used to approximate their place of residence, depending on where they have often received medical treatment. Regarding air quality, they focused on two main sources of air pollution often emitted by motor vehicles: nitrogen dioxide (NO2) and carbon monoxide (CO).
People were divided into four equal groups, based on their average daily NO2 and CO exposure level. The authors found that people living in the areas most affected by NO2 and CO were nearly twice as likely to be diagnosed with AMD as those living in the last quartile of NO2 and CO.
"This study indicates that exposure to air pollution is a risk factor for AMD," the authors wrote.
As usual, this study has some caveats. One is that population studies like this one can only show a correlation between two things, not that one causes the other. And while the authors explained other risk factors for AMD, such as age or high blood pressure, they were unable to trace people's smoking history.
Another important factor to consider is that China has much higher levels of air pollution on average than many other countries, including the United States. Since researchers have not found an increased risk of AMD for more moderate levels of exposure to NO2 or CO, the regions of the world where these results are not really relevant. The relative risk of contracting AMD was also low in the study, with only 0.036% of people in a sample of nearly 40,000 people developing the disease during the study period.
That said, China is obviously one of the largest countries in the world, with more than 1.3 billion inhabitants. Nor is it the only country concerned about high levels of air pollution: a large part of Asia, including India, which is more populated, also faces poor quality of air pollution. 'air. And even in countries where air quality is relatively good, as in the UK, it is thought that car exhaust gases contribute to thousands of preventable deaths every year.
As the retina is connected to the central nervous system, the effects of air pollution on the brain can extend beyond AMD – a study published by the authors in 2018, using much of the same data, has revealed an increased risk of dementia in the elderly. exposed to these pollutants.
[ad_2]
Source link