Is pollution a risk factor for the onset of diabetes?


In 2016, the Clinical Epidemiology Center in St. Louis began a cohort study with the goal of quantifying the importance of pollution in the appearance of new cases of diabetes. The patients were army veterans, with no prior history of diabetes, who were followed for 8.5 years.

In this follow-up a degree of exposure to PM2-5 particles was assigned according to their place of residence, and a statistical study was designed to isolate this exposure from other factors that could act on the study. The results were clear regarding the existence of a direct relationship between pollution and the onset of diabetes, and when quantifying the relationship between exposure to air pollution and the onset of Type 2 diabetes.

Dr. Francisco Martínez Peñalver – Neolife Medical Team


Pollution is a known problem for human health, but until now only the repercussions it has on the respiratory system have been considered.

For over a decade medical experts in diabetes have been warning of the risk of a pandemic of this disease for the coming years. It’s estimated that in 2040 the number of diabetic patients will reach 642 million (1). Numerous efforts have been made in doctors’ surgeries to improve the prognosis and incidence of the disease in terms of increasing patients’ physical activity, dietary control, etc., and yet the numbers are still shocking as far as prevalence is concerned.

For some time now, the theory that healthy lifestyles are an important component in preventing the onset of diabetes has been gaining strength, but that there must also be other aspects that contribute to the onset and development of the disease.

pollution

We refer specifically to pollution, to particles in suspension of less than 2.5 micrometers (PM 2-5), which float in the air in polluted environments, usually as a secondary effect from the use of fossil fuels.

Pollution is a known problem for human health, but until now only the repercussions it has on the respiratory system have been considered. In October 2017 the journal Lancet began spelling out the effects that can occur, inventing the term “pollutome” to refer to the totality of damages associated with such pollution. One of those “targets” was, as we have already mentioned, the increase in the prevalence of diabetes in areas with a high exposure to air pollution, but the Lancet report provided little existing scientific evidence to explain the relationship between the risk factor and the disease; there being no bibliography on the subject that justified the alarm at that time.

In 2016, the Clinical Epidemiology Centerin St. Louis began a cohort study with the goal of quantifying the importance of pollution in the appearance of new cases of diabetes (2). The patients were army veterans, with no prior history of diabetes, who were followed for 8.5 years. A degree of exposure to PM2-5 particles was assigned according to their place of residence, and a statistical study was designed to isolate this exposure from other factors that could act on the study as confounding factors, such as obesity, hypertension, kidney failure, etc.

The results were clear regarding the existence of a direct relationship between pollution and the onset of diabetes, and when quantifying the relationship between exposure to air pollution and the onset of Type 2 diabetes. As we have said, the relationship exists and also occurs at pollution levels lower than those indicated as safe by the regulatory authorities.

Other studies already pointed in this direction, but this is the first one that quantifies that from 10 micrograms in microliter of exhaled air upwards the risk that pollution can contribute to the onset of diabetes increases. Of course, the diagnosis of diabetes is coupled with all the consequences regarding the increase in vascular risk presented by these patients (3 and 4), in addition to the direct vascular damage produced by suspended particles in exhaled air at the vascular endothelium level .

The study quantified that in areas of high exposure to environmental pollution, pollution contributed to the development of 3.2 million cases of diabetes in 2016, representing 14% of all cases diagnosed that year. As pollution rates continue to rise year after year, it’s logical to think that in future years this figure will be even higher.

To date, the very high incidence of diabetes in underdeveloped countries, especially the dramatic incidence of Type 2 child diabetes, was attributed to poor diet, with excess carbohydrates mainly, and the change of habits towards a totally sedentary lifestyle. While we’re not affirming that these factors are not behind the majority of cases, it’s nonetheless coincidental that these developing countries are precisely those where environmental pollution is less controlled.

In developed countries we should think about this study when we have a patient who lives in a big city and, despite having good lifestyle habits and not having an obvious genetic load, presents a diabetes that is also resistant to the treatments applied. Having said that, it should be pointed out that Spain is one of the countries where pollution exerts the least influence on the onset of diabetes.


BIBLIOGRAPHY

(1) International Diabetes Federation. IDF Diabetes Atlas Seventh Edition. Available online: http//www.diabetesatlas.org/resources/2017-atlas.html

(2) Bowe B et al. The 2016 global and national burden of diabetes mellitus attributable to PM2-5 air pollution. 2018 July;2:301-311(7):794-805.

(3) Chin MT et al. Basic mechanisms for adverse cardiovascular events associated with air pollution. Heart 2015; 101:253-256.

(4) Miller MR et al. Inhaled nanoparticles accumulate at sites of vascular disease. ACS Nano 2017; 11:4542-52.