Is there a link between pollution and autoimmune diseases? Researchers from AIIMS plan to undertake a detailed study in this regard.
Dr Uma Kumar, professor and head of rheumatology department at the institute told TOI the project was necessitated by shocking results of a pilot study conducted by them to assess correlation between flaring of symptoms in patients of rheumatoid arthritis (RA), an auto-immune disease that causes debilitating pain in joints, and pollutants.
“In 2013, we took out data of 500 RA patients seeking treatment at AIIMS. Retrospective analysis of their clinical history and the area they lived in revealed that frequency of joint pain was higher when the level of pollutants such as PM 2.5 and PM 10 peaked. Also, those living near main road had persistent pain in the joints,” Kumar said. She added that the same patients were followed prospectively–from 2014 to 2015–and the researchers found the same pattern in terms of link between pollution and aggravation of RA symptoms.
The AIIMS professor said nearly 18% of healthy individuals were found to have evidence of sub-clinical autoimmunity .Simply put, these people did not have autoimmune disease, but markers of autoimmune disease like rheumatoid factor, antinuclear antibody and antineutrophil cytoplasmic antibodies.
In the new study, for which government has approved over Rs 75 lakh, the researchers will try to explore cellular changes caused by pollutants that are leading to autoimmune diseases.”We will assess DNA changes and oxidative stress levels in 600 healthy individuals living in polluted and less-polluted areas. In Delhi, 400 people will be picked up from within 200 metres of monitoring stations that record high pollution levels. Another 200 people will be taken in Palampur in Himachal Pradesh where the air is cleaner,” Kumar added.
RA is a systemic autoimmune disease that primarily targets joints leading to progressive joint erosions. While 50%60% of the RA cases have family history, the rest don’t, which is why researchers are trying to explore other preventable causes. Pollution is one of them.
Globally , there have been multiple studies to find a link between pollution and RA, but no conclusion has been reached so far. A review published in the `Journal of Inflammation’ in 2015 looked at multiple studies on this which propounded that pollutants can trigger RA by causing local lung and systemic oxidative stress along with hypovitaminosis (vitamin deficiency) D.
“Traffic, a surrogate of air pollution, has been associated with incidence of RA. Whether this environmental factor is casually associated with RA across populations is still a matter of debate,” the review concluded. AIIMS researchers said they will be able to deliver that. The incidence of RA in India is estimated to be 0.75-1% of the total population. Kumar said till about a decade ago the rheumatology OPD had a waiting time of up to six weeks and it has now gone up to four months, reflecting the trend of increased incidence apart from more diagnosis.