Air pollution could be a major trigger for diabetes in developing nations: Study

The correlation between air pollution, respiratory ailments and cancers are well-known and documented. However, a new study by Chennai-based MV Hospital for Diabetes and Professor M Viswanathan Diabetes Research Centre, a WHO collaborating centre for research, education and training in diabetes, has shed light on the link between diabetes and exposure to suspended particulate matter.

The study which has been published in the current issue of the Journal of Health and Pollution opens the forum for discussion on the link between suspended particulate matter (PM) and diabetes in low and middle-income countries.

The cross sectional study conducted in Chennai by the centre along with the Directorate of Public Health and Preventive Medicine showed that in the highly polluted areas of Manali, an industrial area in north Chennai, the prevalence of diabetes was higher – almost 78 per cent more- when compared to those living in Adyar.

The study assessed pollution data in the areas and studied the sample of 410 people in both areas, while analysing the PM 2.5 levels obtained from the Central Pollution Control Board, Tamil Nadu Pollution Control Board and National Air Quality Monitoring Station. Manali reported a PM2.5 annual average of 74.22μgm/m3 and Adyar, predominantly a residential area in south Chennai reported 27.22 μgm/m3 .

The study also established that there was not much difference in the family history of diabetes and associated risk factors among the respondents in both areas.

Talking to The Federal, Dr Vijay Viswanathan, head and chief diabetologist, MV Hospital for Diabetes, Royapuram, said that the there is a link between insulin resistance and particulate matter. He added, “As a result there is a destruction of beta cells and inflammation of blood vessels. Diabetes is also called an inflammatory disease.”

Worrying trend in public health in developing countries

Viswanathan says that while considering the body mass index and weight among others as risk factors for diabetes, developing countries like India and China, where pollution levels are high are a cause for worry for public health experts. He observes, “We need long-term studies to determine the impact PM has on diabetes. Further prospective studies on populations exposed to elevated pollution are needed to establish whether this association has a causative link.”

The increasing prevalence of diabetes globally is evident with the number of people with diabetes rising from 108 million in 1980 to 422 million in 2014, according to the World Health Organisation (WHO). The WHO also observes that diabetes prevalence has been rising more rapidly in middle and low income countries. Diabetes is a major cause of blindness, kidney failure, heart attacks, stroke and lower limb amputation. In 2016, an estimated 1.6 million deaths were directly caused by diabetes.

Strokes on the higher side

In 2016, a study published in Lancet Neurology attributed 30 per cent of global stroke cases to air pollution. The same study also observed that the burden of the disease is higher among developing countries like India, where traditional and non-traditional risk factors are both high. Dr U Meenakshisundaram, head of department, neurology, Apollo Hospitals, says that particulate matter and gases in the air are known to accelerate atherosclerosis (thickening of arteries), the base of heart disease and stroke. He also explained that the alarming increase prompted the World Federation of Neurology to take up pollution as the theme in 2018. “The presence of sulphur dioxide in alarming levels in Delhi is a cause of worry for health experts for the same reason,” he said.

The prevalence of stroke is 110 for a lakh population in rural areas and about 240 for a lakh population in the urban areas. Dr Meenakshisundaram, says that the two fold rise in prevalence is also indicative of higher stress and poor food habits.

Of late the younger age group (below 40 years) of stroke patients has been attributed to heart disease and diabetes that can result in embolism, triggering a stroke. “Therefore in India, we have a worrying scenario of both traditional and non-traditional risk factors like diabetes and exposure to high levels of pollution. Stroke is also one of the major causes of disability,” he added.