Can Pollution Cause Diabetes and Obesity?

Exposure to persistent organic pollutants: relationship with abnormal glucose metabolism and visceral adiposity. By Dirinck and colleagues. Diabetes Care 2014;37:1951–1958

What is the problem and what is known about it so far?

Type 2 diabetes and obesity are spreading at an alarming rate, and factors that may contribute to the spread are the subject of many recent studies. 

Why did the researchers do this particular study?

Researchers have long thought that certain environmental factors could contribute to the development of type 2 diabetes and obesity. Among these factors are man-made chemicals called persistent organic pollutants (POPs). Humans are exposed to POPs by eating contaminated food, mainly meat, fish, and dairy products.

Who was studied?

The researchers examined 151 adult obese subjects with or without known type 2 diabetes and compared them with 44 normal-weight volunteers. 

How was the study done?

Researchers examined the relationship between body levels of two POPs (PCBs and DDE, man-made, toxic chemicals that persist in the environment and in food) and detailed markers of glucose metabolism and body composition.

What did the researchers find?

They found higher levels of POPs in participants who were obese, particularly in those with high visceral (intra-abdominal) fat mass—the type of central adiposity that is strongly linked to heart disease and type 2 diabetes. Additionally, they detected a connection between high blood glucose levels and total body levels of POPs. This link was significant, even when taking into account known risk factors, such as body mass index, age, family history of diabetes, and physical activity level.

What were the limitations of the study?

The higher levels of POPs in obese participants could be the result of simply having more body fat available to absorb POPs. In addition, it is not known whether other factors, such as diet, birth of a child, or breast-feeding, could have affected the levels of POPs in participants. Also, there are other chemicals that have been linked to diabetes and obesity that were not studied in these participants.

What are the implications of the study?

POPs exist in our everyday environment, and they are contributing to the diabetes and obesity epidemic. Exposure to POPs should be considered a new risk factor for type 2 diabetes and obesity.

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