Exposure to arsenic increases the risk for developing type 2 diabetes, concludes a recent study. Arsenic levels in urine were seen to be significantly higher in diabetics than in individuals without the disease.
Inorganic arsenic finds its way into drinking water through natural mineral deposits in groundwater. Arsenic is a chemical element known to be toxic to humans, especially in high doses. It can facilitate mechanisms in the body that lead to organ failure, as well as increasing risk for developing bladder cancer. Many millions of people are exposed to arsenic contaminated drinking water, ranging from poor countries such as Bangladesh, to parts of the north-central United States (such as Wisconsin and Michigan). According to the study, “13 million individuals live in areas with a concentration of inorganic arsenic in the public water supply that exceeds 10 µg/L, which is the US Environmental Protection Agency’s standard for arsenic concentration in public water systems.” In smaller doses, arsenic can also be found in fish exposed to the natural mineral deposits, so eating these fish can possibly cause arsenic related problems as well.
Past studies have also shown a connection between high arsenic levels and high blood sugar and insulin levels in animals. Decreased insulin sensitivity was also observed in arsenic contaminated animals as well. These are characteristics of type 2 diabetes, and provided the initial motivation for the following human study, which aimed to see if the low to moderate arsenic levels found in drinking water were associated with type 2 diabetes.
The urine of 788 individuals above the age of 20 years were tested for arsenic content. These people had been part of a larger American study between 2003-2004 called the National Health and Nutrition Examination Survey (NHANES), which aimed to discover various general health and nutritional trends of people in the United states by studying a group representative of the total United States population.This study focused only on the association between arsenic levels and type 2 diabetes. Approximately 8% of the participants had previously been diagnosed with type 2 diabetes.
The researchers found that people withtype 2 diabetes averaged a 26% higher arsenic concentration in their urine.This amounted to an arsenic-urine content of approximately 10 µg/L for diabetics (as compared to an average of 7.1 µg/L for the entire study population). This conclusion was made following risk factor adjustments, such as body mass index (BMI), age, raceand seafood intake. It is also important to note that only inorganic arsenic was shown to be connected to type 2 diabetes, as organic arsenicals, such as dimethylarsinate, was shown to have no association. This was not a surprise to the researchers, who hypothesized that only inorganic arsenic would be seen to be connected to type 2 diabetes.
Given that inorganic arsenic deposits in drinking water are a very common occurrence, the demonstrated connection between low to moderate arsenic contents and type 2 diabetes is very significant. This study is not conclusive however, as the researchers did not have the means to show definitively whether arsenic intake helps cause diabetes, though it certainly helps support this field of thought. “These results support our hypothesis that exposure to inorganic arsenic, which in this population was most likely derived from drinking water, is associated with an increased risk of diabetes while exposure to organic arsenicals is not. Our findings extend previous studies conducted in populations exposed to high inorganic arsenic concentrations in drinking water to a population with low- or moderate-arsenic exposure, and suggest that inorganic arsenic may have a role in diabetes development,” conclude the researchers. Further studies should now be performed to further establish the connection, and campaigns of awareness mounted in order to notify people in arsenic contaminated areas of the potential risk for developing diabetes that comes with drinking the water.
Source: Defeat Diabetes Foundation: Navas-Acien, Ana. Sibergeld, Ellen. Pastor-Barriuso. Guallar, Eliseo. JAMA. “Arsenic Exposure and Prevalence of Type 2 Diabetes in US Adults.” August 2008.