Written by Chrystal Moulton, Staff Writer. The study analyzed the effect of organic pollutants, industrial chemicals and pesticides on the development of type II diabetes. The participants that had diabetes had a significantly higher concentration of all chemicals compared to non-diabetics.

Diabetes is a well known chronic disease that affects about 25.8 million people over the age of 20 in the US. Much of our understanding of the disease is attributed to obesity. (1) However a group of researchers in Spain hypothesized that a more indiscriminate culprit may be one of the contributing factors of this disease.(2) Persistent organic pollutants (as the researchers named them) are fat soluble pollutants that are normally found in animal fats. These usually include common industrial chemicals and pesticides that persist in soil after exposure to the atmosphere. Of particular importance are p,p’-dichlorodiphenyltrichloroethane ( p,p’-DDE), hexachlorobenze (HCB), beta- hexachlorocyclohexane  (beta-HCH), and PCBs (polychlorinated biphenyls). All of these chemicals at one point were used as pesticides worldwide and has since been banned. Some of them however, are still being used in industry for manufacturing of materials or act as common by-products of manufacturing.

In the current study, researchers from Spain set out to determine if these environmental by-products are associated with the risk of developing diabetes. They recruited 386 from two hospitals in the Granada province of Spain. Qualified participants must have lived in the region about 10 years or more, must not have cancer, and were not undergoing hormone therapy. Adipose tissue  (body fat) and serum was extracted from each participant and assessed for levels of the aforementioned organic pollutants. Researchers took into account the age, sex, and body mass index (BMI) of each participant. Associations were calculated based on odds ratios.

Of the 386 volunteers, 34 (8.8%) were diagnosed with Type II diabetes. When researchers compared diabetics to non-diabetics, they found a significant association between all chemicals listed above: ( p,p’-DDE), (HCB), (beta-HCH), an or PCBs ) and the risk of diabetes. The participants with diabetes had significantly higher concentrations of all chemicals compared to non-diabetics. Furthermore, raw material data demonstrated that diabetes was significantly associated with all pollutants in both  serum and adipose tissue. However, when accounting for age, sex, BMI, and tissue origin, p,p’-DDE was the only pollutant that remained significantly associated with diabetes risk with odds ratio= 3.61 for p,p’-DDE level between 45.56-154.88ng/g of lipid and odds ratio= 4.44 for p,p’-DDE level greater than 154.88ng/g of lipid (p=0.07). Individuals with BMI less than 30kg/m2 showed consistent gradual increase in the risk of diabetes as p,p’-DDE levels increased. Individuals with BMI ≥30kg/m2 demonstrated high risk only when p,p’-DDE exposure was between 45.56-154.88 ng/g of lipid. Researchers believes this interaction may be due to a dilution effect of very high BMI levels on pollutant concentration, but more research is needed to clarify the exact relationship between high BMI and pollutant concentration. What was most interesting, when analyzing the risk of diabetes in association with BMI, the risk increases by 7% for each unit of BMI. However, when organic pollutants in adipose tissue are accounted for in the association, the significance between BMI and diabetes no longer exists.

Source: Arrebola, Juan P., et al. “Adipose tissue concentrations of persistent organic pollutants and prevalence of type 2 diabetes in adults from Southern Spain.” Environmental research 122 (2013): 31-37.

Copyright © 2012 Elsevier Inc. All rights reserved.

Posted March 6, 2013. 

References:

  1. National Diabetes Fact Sheet 2011. Available at: Center for Disease Control Website. Assessed February 27, 2013.
  2. Adipose tissue concentrations of persistent organic pollutants and prevalence of type 2 diabetes in adults from southern Spain. Arrebola JP, Pumarega J, Gasull M, et al. Environ. Res. (2013).