Finding it difficult to manage your blood glucose level and diabetes despite following a disciplined diet and lifestyle in the big city? The answer might just be blowing in the wind.
Air pollution — especially from vehicular emissions (nitrogen dioxide) and excess particulate matter (PM 2.5) — and its adverse effects are widely accepted as major health concern. The worst-affected are those already dealing with lifestyle diseases such as diabetes and cardiovascular complications.
Multiple studies across the globe have already established a direct link among air pollution, type 2 diabetes and fatalities due to comorbid conditions associated with diabetes, especially from cardiovascular complications. This is a grim scenario for a country such as India that already reports alarming stats for both diabetes on one hand and pollution on the other.
Experts have called out for more extensive research and policy-level intervention to ensure that air pollution does not become the Achilles heel in the country’s fight against diabetes.
“’I don’t think we have enough comparative studies or data to show that the gaseous pollutants are more likely to adversely affect diabetic and cardiovascular patients, and we obviously need more data on this. When the pollutants are gaseous, it is easy to mix in the blood and hence to cause vascular damage. Diabetes air pollution affects the blood vessels and hence anything that adversely affects the blood will obviously be worse,” Dr V Mohan, director, Madras Diabetes Research Foundation and chairman of Dr Mohan’s Diabetes Specialities Centre, Chennai, said in an email conversation when asked if gaseous pollutants were more likely to affect diabetic and cardiovascular patients than suspended particulate matter in the air. He also stressed that both gaseous pollutants and particulate matter were undesirable and should be avoided to ensure good health.
Researchers in various countries have already established that gaseous pollutants, mainly nitrogen dioxide (NO2), have a direct adverse impact on diabetes and the mortality of the affected people. Nitrogen content in the atmosphere was also found to interact with oxygen molecules, especially ozone (O3), and change into oxidizing agents that act as catalysts for oxidative stress. (Oxidative stress is a state of chemical imbalance caused when highly reactive gases and some toxic oxygen derivatives react with each other after leading to vascular complications in diabetics.)
This leads to systemic inflammation, which triggers a chain reaction that adversely affects insulin sensitivity. This, in turn, could eventually lead to high blood sugar levels and eventually could even cause cardiovascular and neurological complications in people already affected with diabetes depending on their age and other physical conditions.
“Prolonged exposure to some of the toxic pollutants could cause internal chemical imbalances in the body leading to hormonal abnormality, especially like endocrine disruptions that ultimately reflects on your overall diabetes control or management,” says Dr Tom C Babu, medical director, diabetologist and consultant endocrinologist, Silverline Hospital, Kochi, Kerala.
In 2019, a group of researchers carried out an extensive study in Canada and established the impact of rising air pollution (mainly from NO2 fumes) on diabetes along with a subsequent surge in mortality rates among diabetics and cardiovascular patients. They based their study – eventually published in the January 2020 edition of Environment International, a journal on public health and environmental sciences research and issues — on extensive cohort health data from the administrative records of 4.8 million adults without diabetes and 4,52,590 individuals with diabetes.
The data compiled between 2001 and 2015 as part of the cohort study – essentially, collection and subsequent data analysis from a particular group of people over a prolonged time interval. Air pollution and diabetes stats were also extensively collected from monitoring stations and satellite imagery of the residential areas of the test subjects for the same period.
These two sets of data were compiled, analysed and collated and it was found that from the initial group 7,90,461 were diagnosed with diabetes. Among those who were already diabetic, 26,653 died of diabetes and another 64,773 died from cardiovascular diseases.
It was found that an increase in NO2 levels in the air over a period in a particular area coincided with a rise in the number of incident diabetes cases in people who participated in the study from that region. This upward variation was also found in the mortality rate among diabetics and cardiovascular patients in that area.
Similar variations were also found in correspondence with levels of suspended particulate matter (PM2.5) and oxidizing agents formed out of chemical combinations of nitrogen and oxygen in the atmosphere. However, NO2 was found to be the most harmful out of all major air pollutants for diabetics and those suffering from its various co-morbid conditions.
“The strongest association was observed between diabetes mortality and exposure to NO2,” said the study. The hazard ratio recorded for diabetes mortality and N02 was 1.04. The ratio for those who reportedly developed diabetes from prolonged exposure to NO2 was 1.08.
In July 2022, the Lancet published an article in its Planetary Health journal, collating the estimated trends and driving factors of the global burden of type 2 diabetes due to PM 2.5 air pollution, analysing data from 1999 to 2019 on the basis of the Global Burden of Disease 2019 study. Based on its analysis, air pollution was rated as a major risk factor for type 2 diabetes and about one-fifth of the global burden of type 2 diabetes was attributed to air pollution with PM 2.5 fine particulate matter.
Similar studies conducted in China, London and Milan in recent years have also concluded that air pollution indeed was a major external risk factor various vascular conditions, mainly diabetes.
Great Indian pollution-diabetes challenge
In India, both diabetes and air pollution are a matter of concern.
According to the International Diabetes Federation (IDF), 537 million people are living with diabetes across the world and this number is expected to increase to 643 million by 2030 and 783 million by 2045. The IDF has attributed 6.7 million deaths globally in 2021 to diabetes and has also pointed out that it has a prevalence rate of 8.9% in India with at least 85,99,56,100 adults in the country diagnosed with diabetes.
Meanwhile, a recent report by the Centre for Research on Energy and Clean Air identified coal combustion (in power plants), factories and vehicles as the main source of air pollution.
The annual practice of stubble burning was also listed as a major cause of smog and particulate pollution in air over northern India during the winter. At least 16.7 lakh people died of various health complications due to air pollution in India in 2019, the report said.
“I think each city in India has a different problem when it comes to pollution,” Dr Mohan said. “In Delhi, for example, the biggest problem might be stubble burning, while it is vehicular emissions in most other cities. A tight control should be brought in over the auto industry to ensure safe emission levels. Old vehicles should be taken off the roads and the new ones should maintain strict European emission standards to reduce pollution.”
Need more data, awareness in India: experts
There are numerous global studies that have directly and indirectly equated air pollution — especially from vehicular emissions — as a major contributor to numerous conditions, including diabetes and dementia. Recently, air pollution got formally inducted into the list of risk factors for dementia too. In 2020, after it was proven that at least 40 per cent of dementia cases in senior citizens could either be delayed or prevented by ensuring better air quality and keeping pollution levels under strict control, the Lancet Commission formally included air pollution as one of the 12 modifiable risk factors for this condition (especially among senior citizens).
It had already been proven that dementia and diabetes are interlinked, especially in senior citizens. Individuals who have uncontrolled blood glucose levels and diabetes in their middle age have higher chances of developing dementia and other cognitive complications in their old age. Diabetes and its host of comorbid vascular conditions often adversely affect blood flow into the brain and result in neurological complications, cognitive impairments and even dementia in senior citizens.
But when it comes to diabetes management in India, there seems to be a general lack of awareness among diabetics and non-diabetics alike about external risk elements. Many medical experts also tend to often not educate their patients about the relevance of monitoring additional parameters such as air pollution to ensure better blood glucose management, especially among senior citizens. Indian experts have called out for more extensive data and region-specific research to get better understanding and clarity on the topic.