Air pollution triggers respiratory diseases — this is well known. But did you know researchers are increasingly linking toxic air to diabetes and cardiovascular diseases?
One in four cases of Type II diabetes — a chronic condition where the body is unable to produce enough insulin, leading to a rise in sugar levels — in the world is found in the Indian subcontinent, which has 23% of the population. Recent estimates suggest 62.4 million Indians live with diabetes, another 4.6 million have tuberculosis (TB). In Mumbai, cardiovascular diseases, diabetes and TB are the top three killers, according to municipal records.
The concerns that air pollution’s effects are not limited to lung ailments has set off a host of studies. In Mumbai, the Foundation of Medical Research, a government-recognised institute, is planning a study to find out how pollutants play a role in causing and worsening tuberculosis and diabetes symptoms. “Air pollution can bring a dual set of epidemic of diabetes and TB,” said Dr N Mistry, director and trustee of the facility, which recently did a presentation on air pollutants and possible pathways that could make a person susceptible to developing diabetes and TB.
Head of department of medicine, Jaslok Hospital, Dr Altaf Patel, said there is enough evidence linking air pollution to non-communicable diseases, including diabetes and cardiovascular conditions. “The inflammation caused by air pollutants affects the heart’s arteries. The inflammation leads to thickening of blood vessels and causes a heart attack. People think air pollution can only affect the lungs and worsen respiratory conditions, but there is more to it,” said Dr Patel.
Researchers are trying to piece together the link between air pollution and cardiovascular deaths. The Expert Position Paper on Air Pollution and Cardiovascular Disease published in the European Heart Journal last year showed oxidative stress, a condition that impairs the body’s energy production and repair mechanism thesis, and inflammation caused by pollutants can affect heart rhythm, leading to arrhythmia that may result in a heart failure.
Calling air pollution a global public health concern, Dr Sanjay Rajgopalan, professor of medicine and physiology at University of Maryland School of Medicine, Baltimore, said, “Some studies show ambient air pollution can lead to insulin resistance, an underlying condition that causes diabetes.” Dr Rajgopalan has published scientific papers explaining this association. He said studies suggest air pollution aggravates heart conditions and appears to have a role in its development.
Echoing the view, Dr Patel said about 40 years ago, the incidence of diabetes was extremely low. “Suddenly, we are recording so many cases. Genetics alone cannot be responsible, as the genetic pool takes years to change. The role of pollutants should be probed,” said Dr Patel.
In fact, Dr Mistry’s team has designed a study to understand the impact of exposure to pollution on incidence of communicable and non-communicable diseases. “We will study changes in the internal biochemistry of an individual exposed to pollutants and the onset of diabetes and TB. Such changes are known to trigger conversion of latent to active TB,” said Dr Mistry.
Public health experts said air pollution is not just a matter of vehicular emissions. Small factories in slums and the way homes are built lead to exposure. To illustrate, a study in Govandi slums showed homes had only one to two air exchanges over 15 hours, against the ideal seven to eight. Air exchange is the replacement of air inside a building with fresh air from outside.
Hyderabad-based diabetologist, Dr PV Rao, said, “We know children born to mothers exposed to pollution can develop diabetes and thyroid. There are studies about emissions from common implements such as non-stick pans. We cannot ignore the role of pollution.” Dr Om Shrivastav, infectious disease consultant said, “In diabetes, the person’s body has an active inflammation, pollutants only aggravate this. This puts the person at risk of contracting other infections owing to lowered immunity.”