By Emily Stearn, Mailonline health reporter
14:09 Jul 10, 2024, updated 17:47 Jul 10, 2024
Living in a polluted, busy city could increase the risk of developing an autoimmune disease affecting 50,000 Britons, according to an alarming study.
Scientists have long tried to determine what exactly triggers the onset of systemic lupus erythematosus, more commonly known as lupus.
The condition, which also affects Selena Gomez, Lady Gaga and Nick Cannon, sees the body’s immune system mistakenly attack healthy tissue.
But Chinese researchers now believe that long-term exposure to air pollution “may increase the risk of developing lupus.”
Dr Yaohua Tian, an expert on air pollutants and chronic diseases at Huazhong University of Science and Technology and co-author of the study, said: “Our study provides crucial information on air pollution contributing to autoimmune diseases.
“These findings can inform the development of stricter air quality regulations to reduce exposure to harmful pollutants, thereby reducing the risk of lupus.”
Patients with this disease often experience flare-ups where symptoms such as joint and muscle pain, extreme fatigue, and skin rashes become worse.
These episodes can last for weeks or longer.
In the new study, Chinese researchers followed 460,000 patients and found that 399 people were diagnosed with lupus over a 12-year period.
Average levels of six pollutants close to their homes were also assessed.
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These included PM2.5 (particles less than 2.5 micrometers in diameter), nitrogen dioxide (NO2), nitric oxide (NOx) and sulfur dioxide (SO2).
All four have been linked to health problems such as heart disease and dementia.
These particles, emitted by car exhausts, cleaning products and wood stoves, among other things, can be so small that they penetrate deep into the lungs and bloodstream.
The researchers estimated that there was a 1 in 1,000 risk of developing lupus among people exposed to the highest levels of NO2, and a risk of just 0.075 in 1,000 among those exposed to the lowest levels.
This trend was reflected among the other three particles.
In a paper published in the journal Arthritis and Rheumatology, the scientists said the findings provide “crucial insights into environmental factors contributing to autoimmune diseases.”
They added: “The findings can inform the development of stricter air quality regulations to mitigate exposure to harmful pollutants, thereby reducing the risk of lupus.”
The researchers acknowledged, however, that the study had “some limitations,” including the fact that participants enrolled voluntarily.
This means they “may have been healthier, more health-conscious or more willing to participate in the study,” they added.
The World Health Organization has long called on countries to take tougher measures to combat the scourge of pollution, which is estimated to kill 7 million people worldwide each year.
The news comes as another study revealed today that US scientists have discovered a molecular defect they believe could trigger lupus.
These changes in the blood molecules of lupus patients mean that the aryl hydrocarbon receptor (AHR), which regulates the response of cells to pollutants and bacteria, is not activated properly.
Dr Deepak Rao, co-author of the study and assistant professor of medicine at Harvard Medical School, said: “We have identified a fundamental imbalance in the immune responses of patients with lupus, and we have defined specific mediators that can correct this imbalance to attenuate the pathological autoimmune response.”
According to Lupus UK, around one in 50,000 people in the UK have the condition.
There is no cure for lupus. Treatment is designed to help people manage their symptoms.
Lupus can be mild, causing skin or joint problems, or severe, which can be life-threatening.
Flares, periods when symptoms worsen, are another aspect of the disease that scientists are still trying to understand.
It is not yet clear what triggers them and what makes them disappear.
Further complicating the situation is that some patients do not experience any flare-ups.