The ongoing air pollution crisis within the National Capital Region (NCR) has underlined a major burden borne by the Indian health system: the very air breathed within the country is bad for health.Such a situation creates an unavoidable risk factor to the health of many, not just in cities, but within rural regions as well. In fact, rural areas account for the majority of pollution-related deaths in the country. Mounting scientific research links air pollution to increased rates of noncommunicable diseases (NCDs). While previously only lung conditions were known as the obvious result of breathing polluted air, studies are now linking the phenomenon to conditions such as heart disease, diabetes, Alzheimer’s disease and mental health issues.
A recent study has further implicated air pollution as a risk to both heart disease and strokes. A team led by the Barcelona Institute for Global Health (ISGlobal) in Spain performed the study in a periurban area in Hyderabad, Telangana. The results indicated that people most exposed to fine particulate matter (such as PM2.5, a major by-product of motor vehicles) have a higher carotid intima-media thickness (CIMT) — a major marker of atherosclerosis or the thickening of the artery walls.
Thickening of the arteries is among the top risk factors of cardiovascular disease which can result in heart attacks, angina, and strokes. This is due to its capacity to limit blood flow in instances where blockages or partial obstructions occur in blood vessels. When this occurs within the brain, the result is a stroke.
The team measured CIMT, as well as the estimated exposure to air pollution using an algorithm called land use regression (LUR), a technique frequently used to predict the amount of particles such as PM2.5 in high-income countries. The participants also provided information on the type of cooking fuel they used.
Sixty per cent of participants in the study used biomass cooking fuel. “People using biomass fuel for cooking had a higher CIMT, particularly women who cooked in unventilated spaces,” Otavio Ranzani, ISGlobal researcher and first author of the study, explained.
Biomass fuel is commonly used in India, particularly in areas of rural India. While a rural village may not be the smog chamber that is Delhi at present, flooding an unventilated house with fumes from a cooking stove can have much the same effect on the health of the individual, delivering high concentrations of particulate matter over a shorter period of time. The study noted that women were found to have a higher CIMT than men, which the authors suggest is due to a larger amount of time spent in kitchens in close proximity to burning biomass fuel.
The study goes on to acknowledge India’s shift in disease demographics. While just a few decades ago India’s most common causes of death were infectious, perinatal, neonatal, and maternal diseases, the current list of the top causes of death within the nation are overwhelmingly occupied by NCDs, with heart disease at the top of the list.
Alongside heart disease, conditions such as cancer and asthma have surged in recent years. These changes coincide with a number of factors. India has seen an industrial revolution in the last few decades. With this, lifestyles have altered due to greater prosperity, whilst industrial activity has resulted in air pollution rising by vast margins.
Factors such as lower levels of physical activity and alterations to dietary habits will have made a considerable difference in increasing the risk factors of NCDs. Obesity has surged on account of a shift to office-based, sedentary lifestyles for many in India’s urban locales. Diets are now filled with calorie-dense, low-nutrient foods that are often processed and filled with fat, sugar, and salt. All these factors played a role in India’s NCD crisis. However, it is becoming ever more difficult to ignore the role pollution is playing.
Reports indicate that India is home to forty percent of the world’s heart failures, with heart disease in recent decades increasing by fifty percent. Alongside lifestyle changes, pollution may be a major driver in this increase.
One key factor links many NCDs with air pollution — the capacity for PM2.5 to be absorbed through the lungs (and in the process, damaging the lungs themselves) and into the bloodstream. From this point the PM2.5 has been linked to an inflammatory effect throughout both blood vessels, the heart itself, and potentially in other major organs.
As more data is uncovered implicating pollution in numerous diseases, the full extent of India’s pollution crisis on public health will be unveiled. More must be done to alleviate the pollution burden in the country or the increase in incidence seen in NCDs are likely to continue long into the future.