Diabetes is a matter of global concern, and is one of the main causes of healthcare expenditures across the world. The condition occurs when the body is unable to produce insulin, or cannot efficiently use the insulin produced by the pancreas. This leads to hyperglycemia, or heightened blood sugar levels, which in the long term, can cause significant damage to the body’s organ systems, especially the kidneys and heart. The number of diabetic patients has increased four times since 1980, from 108 million then, to 422 million in 2014, and in 2016, 1.6 million people died due to complications from diabetes (WHO, 2018). According to Kaiser, Zhang and Van Der Pluijm (2018), the global prevalence of diabetes mellitus (DM) was 500 million cases in 2018, and this number is only going to increase in the next ten years.
While a number of factors, such as genetic predisposition, obesity and physical inactivity, have been forwarded as reasons for the occurrence of DM, there is a growing body of evidence that links exposure to air pollution as a major risk factor. Xu et al. (2011) used a mouse model, and found that a 10 month exposure to PM2.5 caused an impairment in glucose tolerance, as well as insulin resistance.
Epidemiological studies conducted on human subjects have found similar linkages between long term exposure to pollutants and diabetes prevalence (Bowe et al., 2018), however the results have been mixed and inconclusive. There is, therefore, a need for long term cohort-based studies that can provide a causal linkage between air pollution and DM prevalence.
P (Population) Adults with diabetes mellitus
I (Intervention) Exposure to PM2.5
C (Comparison/control) Adults without diabetes mellitus
O (Outcome) Increased prevalence of diabetes mellitus
T (Time) Long term (>5 years)
Does long term exposure to air pollution (PM2.5) lead to increased prevalence of Diabetes Mellitus?
Research ArticlePark, S. K., Adar, S. D., O’Neill, M. S., Auchincloss, A. H., Szpiro, A., Bertoni, A. G., … & Diez-Roux, A. V. (2015). Long-term exposure to air pollution and type 2 diabetes mellitus in a multiethnic cohort. American journal of epidemiology, 181(5), 327-336.
This study addressed the relation between long-term exposure to PM2.5, and the prevalence and incidence of DM. The methodology used provides more validity to the study; the authors conducted a 9 year long cohort-based study, with over 5,000 participants. The study began with baseline measurements of DM prevalence (between July 2000 and August 2002), with follow ups conducted after. Patient exclusions included those who were missing data on their diabetic status, on their exposure to pollutants, as well as sociodemographic variables, like alcohol consumption, smoking, education levels, family history of diabetes and BMI. The final number of participants in the DM prevalence analysis was 5,839 participants, a large enough number to ensure the results would be statistically significant. The Air Quality System utilized by the Environment Protection Agency was used by the authors to generate data on PM2.5 and nitrogen oxide. This was supplemented with pollution data taken from equipment within the community and houses of the participants. During the baseline period, the level of air pollutants was measured for 2 weeks. This measurement was then taken as a proxy pollution level for the remainder of the study period, to assess long term exposure to PM2.5 and nitrogen oxide.
Questionnaires were used to collect data on a large number of additional variables, so as to make the model more robust.Thus, even though the authors initially found no linkage between PM2.5 exposure and DM, this result changed when the co-variates were manipulated in the model. When adjusted for socioeconomic and demographic factors, the authors found significant association between DM prevalence and PM2.5 exposure. Interestingly, no associations were found between proximity to roadways, a major source of air pollution due to vehicular traffic, and DM prevalence.
Ultimately, the authors were able to support their initial hypothesis that prevalence of diabetes mellitus is affected by exposure to air pollutants. However, they were unable to prove that the latter impacted the incidence of DM in the study population. This could be because those who were vulnerable to developing DM had already exhibited the disease prior to the start of the study (all participants were over 45 years of age). This also meant that the people who were less vulnerable to DM, were also less influenced by air pollution. Additionally, the pollution levels during the study period may have been too low to actually show any discernible impact on the participants. This is particularly important, as pollution levels in US cities, and in Europe, have been decreasing with increasingly stringent vehicular laws. However, it is this point that makes the study results only generalizable to within these populations, but not to countries in Asia or South America, where both pollution levels and cases of DM are rising at an alarming rate.
The study made use of superior quality pollution data, apart from having a statistically significant study population and inclusion of a number of additional variables. This made the results robust. However, there was a flaw in its assessment of pollution levels, since the measurements were only conducted during the two weeks in the baseline period. Thus, to truly understand the connection between exposure to air pollution and diabetes mellitus, consistent pollution data, covering a range of pollutants, is a must. In addition, the study must be conducted in high pollution countries, like China or India, to get a better understanding of the causal impact of such pollution levels on the prevalence and incidence of diabetes mellitus on a global scale. This can help policy makers across the world anticipate and create targeted interventions,to reduce the healthcare burden of countries.Free essay samples and research paper examples available online are plagiarized. They cannot be used as your own paper, even a part of it. You can order a high-quality custom essay on your topic from expert writers:
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KAISER, A. B., ZHANG, N., & VAN DER PLUIJM, W. O. U. T. E. R. (2018). Global Prevalence of Type 2 Diabetes over the Next Ten Years (2018-2028).
World Health Organization (2018). Diabetes. Accessed from https://www.who.int/news-room/fact-sheets/detail/diabetes
Xu, X., Liu, C., Xu, Z., Tzan, K., Zhong, M., Wang, A., … & Sun, Q. (2011). Long-term exposure to ambient fine particulate pollution induces insulin resistance and mitochondrial alteration in adipose tissue. Toxicological Sciences, 124(1), 88-98.
Park, S. K., Adar, S. D., O’Neill, M. S., Auchincloss, A. H., Szpiro, A., Bertoni, A. G., … & Diez-Roux, A. V. (2015). Long-term exposure to air pollution and type 2 diabetes mellitus in a multiethnic cohort. American journal of epidemiology, 181(5), 327-336.
Bowe, B., Xie, Y., Li, T., Yan, Y., Xian, H., & Al-Aly, Z. (2018). The 2016 global and national burden of diabetes mellitus attributable to PM 2· 5 air pollution. The Lancet Planetary Health, 2(7), e301-e312.