The relationship between pollution and diabetes is growing, but will it take an environmental tragedy to finally demonstrate a causal link between the two?
Earlier this month, a two-year study concluded that insulin-treated type 2 diabetes patients who lived next to heavy traffic had increased inflammation compared to lower traffic areas.
In March, German researchers found high levels of dust pollution could accelerate the development of type 1 diabetes in children. But is this all just co-incidence?
Popular idiom “There’s no smoke without fire” springs to mind, and the dust is definitely not clearing on the issue of whether pollution can cause diabetes.
The damage pollution can do is clear.
Air pollution is responsible for an estimated seven million deaths per year, according to the World Health Organisation (WHO), and is regarded as the largest environmental health risk.
Air pollution, in particular, is the most perilous form of pollution, and easily created by the burning fuel that keeps our cars running and food cooking, releasing chemical substances into the air every day.
When “environmental factors” are considered as a cause of diabetes, air pollution is not prominently considered in this bracket. This is despite an increasing number of studies assessing the relationship between the two and the main sources of nitrogen dioxide in most UK urban areas – where diabetes prevalence is increasing – being through road traffic and domestic heating.
In August 2014, the WHO ranked Pakista, Qatar, Afghanista, Bangladesh, Egypt, United Arab Emirates (UAE), India and Bahrain among the top 10 countries in the world for the worst air pollution.
The likelihood of developing type 2 diabetes is reportedly up to six times higher in South Asians – people from countries such as Bangladesh, India, and Pakistan
Generally, the increased risk has been attributed to poor economies and lifestyles, especially if dietary patterns among patients with diabetes have been unhealthy.
Could this link, however, actually be related to pollution?
Pakistani women are five times more likely to develop diabetes, Indian women have a two and a half times increased risk, while diabetes prevalence is four times more higher in Bangladeshi and Indian people.
The International Diabetes Federation released a report in 2014 of which countries had the highest prevalence of type 2 diabetes. Four countries in the top 20 happened to be Bahrain (#8), Qatar (#12), UAE (#13) and Egypt (#17).
While on the surface, these findings offer a link between diabetes and pollution, and nothing more, the rising tide of scientific investigations suggest plenty more studies could be imminent.
While on the surface, these findings offer a link between diabetes and pollution, and nothing more, the rising tide of scientific investigations suggest plenty more studies could be imminent.
An early investigation in 2006 saw EH Hartout et al conclude that children may be predisposed to the development of type 1 diabetes due to ozone and sulphate exposure in ambient air.
In 2014, a Swiss study found long-term exposure to nitrogen oxide was associated with diabetes, while a large-scale, national study in the United States in 2010 also observed a 20 per cent higher prevalence of diabetes in people living below acceptable air quality levels of the Environment Protection Agency.
Despite these findings, the disclaimers were not too far away.
American Diabetes Association Vice President of Medicine and Science Vivian Fonsecan, MD, told WebMD of the 2010 report: “This study is thought provoking, but it is certainly not definitive. It makes sense that exposure to air pollution might play a role in diabetes, but more research is needed to prove it.”
How much research is necessary?
Therein lies the concern. Without systemic evidence, disclaimers will continue to follow findings similar to these.
One thing that seems relatively clear, though, is that not a whole lot of research is exonerating pollution from being a risk factor of diabetes.
Given the accumulating evidence, it also seems unlikely that the link will be refuted. It may just be a matter of time before it is established, especially as the prevalence of diabetes continues to rise and pollution levels remain dangerously high.
With high air pollution also tied to high cancer rates, the dangers of pollution are becoming increasingly well-know, but when relating to diabetes, organisations such as the NHS and National Institutes of Health have not declared pollution as a potential risk factor.
With high air pollution also tied to high cancer rates, the dangers of pollution are becoming increasingly well-know, but when relating to diabetes, organisations such as the NHS and National Institutes of Health have not declared pollution as a potential risk factor.
The necessity to reduce pollution across the world is nothing new, but at least European Union limits for air pollution are being recognised as a genuine problem.
If legal action can be brought upon the UK Government, then the indication might just be that the severity of pollution is being taken seriously.
Hopefully, this level of acknowledgement will advance on to a much larger, medical scale – at least before the infrequent studies on whether pollution causes diabetes becomes a full-blown epidemic.
