Amid rapid socioeconomic developments, harmful effects of air pollutants have emerged as a concern worldwide. As per the Global Burden of Disease, Injuries, and Risk Factors report, air pollution is the eighth leading risk factor for death as it fuels respiratory, cardiovascular and cerebrovascular diseases, and metabolic syndrome. Several epidemiological studies indicate the adverse effects of air pollution on diabetes, which is basically a metabolic disorder, says Dr Ankita Tiwari, consultant (diabetes and endocrinology) at Manipal Hospitals, Bhubaneswar, in conversation with Hemant Kumar Rout. Edited excerpts:
India has emerged as the diabetes capital of the world. What factors are responsible for it?
Changes in lifestyle and fast urbanisation, besides its genetic predisposition are to be blamed for India emerging as the diabetes capital. The consumption of processed foods, sugary drinks, and the transition to a more sedentary lifestyle have resulted in high obesity rates, which is an important risk factor for type 2 diabetes. The situation has been compounded by genetic disposition and late diagnosis. With expanding diagnosis facilities, the detection rate has increased manifold in recent years. The numbers would be more as many cases in rural parts still go unreported.
Why are more women affected by diabetes than men in India?
The percentage of growth in diabetes cases has increased more in women, from 11.9% to 23.7% in last three decades. In case of men, it has gone up from 11.3% to 21.4%. Women tend to have more insulin resistance, partly due to hormonal changes particularly after menopause. Women who also have conditions such as polycystic ovary syndrome (PCOS) and gestational diabetes are at greater risk. This situation is worsened by social factors like poor access to healthcare and sedentary lifestyle.
How does air pollution contribute to the development or exacerbation of diabetes?
A large number of epidemiological studies have found adverse effects of air pollution on diabetes. They suggest that diabetes related biomarkers increase with increasing exposure duration and concentration of air pollutants. The chemical constituents of the air pollutant mixture affect type-2 diabetes mellitus to varying degrees. The pollutants induce increased inflammation, oxidative stress, and endoplasmic reticulum stress. The systemic inflammation and oxidative stress caused by air pollution damage blood vessels and reduce insulin sensitivity, leading to diabetes.
Does air pollution cause hypertension?
Yes, there is some evidence indicating that air pollution may be a contributing factor to hypertension. Long-term exposure to pollutants like PM2.5, NO2, and CO has been linked to elevated blood pressure.
What role do endocrine-disrupting chemicals (EDCs) in water and soil play in hormonal imbalances?
EDCs occur in pesticides, plastics and industrial chemicals, and are known to disrupt the regulation of hormones. These chemicals can impair the action of insulin resulting in resistance to it and heighten the chances of diabetes. Metabolic disorders have been associated with chronic EDC exposure due to contaminated water and food.
How can chronic exposure to industrial pollutants increase the risk of thyroid disorders or other endocrine-related conditions?
Industrial contaminants such as polychlorinated biphenyls (PCBs) and heavy metals can interfere with thyroid hormone synthesis causing hypothyroidism or hyperthyroidism. These pollutants disrupt the endocrine system and influence metabolic activity, growth and energy balance.
How does indoor air pollution, such as from cooking fuels, impact glucose metabolism and insulin resistance?
Household fuels such as biomass, coal or kerosene generate soot and indoor air pollution that can penetrate deep in the lungs, damaging lung tissue and causing systemic inflammation. This inflammation disturbs glucose metabolism resulting in insulin resistance.
Which specific pollutants are more strongly associated with obesity and diabetes-related complications?
Pollutants like bisphenol A (BPA), found in plastics, and persistent organic pollutants (POPs), such as DDT, are strongly linked to obesity and diabetes.
Dr Ankita Tiwari