How Air Pollution Plays a Role in Diabetes

Can exposure to particulate matter in air pollution increase an individual’s risk for type 2 diabetes? 

 Diabetes Mellitus (DM) is considered a primary cause of death throughout the world today, and its prevalence is increasing. The International Diabetes Federation (IDF) has predicted that the number of individuals with type 2 diabetes will continue to rise, as a result of factors like lack of exercise, weight gain, poor eating habits, and contact with particulate matter in the form of air pollution (AP). Particulate matter is a component of pollution, and is known to cause significant damage to the body and the environment. The number of individuals believed to be susceptible to AP has surpassed the World Health Organization’s prediction. The World Health Organization states that “80% of human beings are threatened directly by AP in the world” (Azizi et al., 2020). As the number of type 2 diabetes and AP related deaths increase, epidemiologists need to review the reasons for the increase. Previous studies done to display the relationship between AP and diabetes yield varying results. Some epidemiologists have proposed a relationship between AP and type 2 diabetes mellitus, while others perceived that little to no relationship between the two exists.  

This study depicts the prevalent relationship between the effects of exposure to particulate matter in air pollution and its connection to type 2 diabetes mellitus. Researchers conducted an exposure assessment to explore the relationship between AP and type 2 diabetes. The study population reflects individuals from Tehran, the capital city of Iran, older than 20. This population includes information from participants in the initial 20-year study, the Tehran Liquid and Glucose Study (TLGS). This study included the issuance of a survey, the Tehran cardiometabolic genetic study (TCGS), which evaluates the effects of leading a healthier lifestyle to lessen susceptibility to non-communicable diseases, such as type 2 diabetes. Within this particular study, 2428 participants, or participant cases, were enrolled and evaluated from the initial research. The Exposure Assessment included data from 21 Tehran Air Quality and Control Company (TAQCC) for three years to assess pollution distribution. Concentrations of Particulate Matter 10, PM10 were observed and recorded along with information from the geographic information system. “Inverse distance weighting (IDW) method was employed to measure the yearly concentration of air pollutants” (Azizi et al., 2020). This study also factored in age, gender, BMI, smoking status, education level, income status, and physical activity levels. Researchers also obtained genetic DNA for evaluation. Regarding the statistical analyses, STATA and the Genetic R package V.5 were implemented to “determine the Hardy-Weinberg equilibrium” (Azizi et al., 2020). Primary and secondary outcomes show missing values being considered for physical activity and education levels.  

The results of this study show several varying outcomes. The participants’ mean values in the study, ages and BMI, are equivalent to 45.4 years and 28.09. Forty-four percent of the cases of type 2 diabetes mellitus (172) were found to be amongst participants that were 50 to 69 years old. These participants also had higher blood pressure than non-diabetics. The analyst also found that over three years, levels of PM10 in Tehran have been increasing by 1.1 every year. Researchers found a strong association between high-risk individuals and significant exposure to levels of PM10. Therefore, participants who resided in Tehran areas where levels of PM10 are significant typically were predicted to be at high risk of developing type 2 diabetes mellitus. Researchers did not discover a strong association between PM10 and type 2 diabetes mellitus in any other regard. “BMI, SBP, and HDL (p < 0.05)” (Azizi, et al., 2020).   

This study further explores the relationship between PM10 and rs10830963 and their connection to, or influence on, type 2 diabetes mellitus. This study consisted of 392 individuals with diabetes and 2306 non-diabetic cases. The number of female participants surpassed the number of male participants. Results implicated that particulate matter (PM) and type 2 diabetes mellitus have a considerable amount of association with each other. Long-term exposure to PM10 results in an increased risk for type 2 diabetes mellitus and genetic makeup interference. This study is of interest due to diabetes mellitus’ role as a leading cause of death worldwide. Future studies should include longer termed studies to assess the consistent effects of additional variables, such as physical activity. Weaknesses of the study surround the need for more information in regards to PM10. Unfortunately, not much research on PM10 has been done before 2009, which poses a possible lack of factual and consistent data. Additional specific data in regards to physical activity and education showed limitations within this study. Essentially, further research would need to obtain more information on all parties of research studies as we advance. 

Practice Pearls:  

• Air pollution influences the susceptibility of exposure to particulate matter and type 2 diabetes mellitus and alters genetics. 
• There is a lack of research on particulate matter. 
• Further research should be conducted to find the relative risk of particulate matter among other risk factors in type 2 diabetes 

Jabbari, F., Bandpei, A., Role of Air Pollution and Incidence of Type 2 Diabetes: Tehran Cardiometabolic Genetic Study  

Shadrielle Robbins, Pharm D. Candidate 2020, South College School of Pharmacy