August 2008

Diabetes-arsenic link

It's been known that high exposure to arsenic from drinking water contributes to development of diabetes. For years, this fact was overshadowed by the arsenic cancer risk, which prompted new lowered standard for allowable level of arsenic in drinking water in 2001. But the story of arsenic toxicity doesn't seem to be ending yet. Even at low concentrations, there may still be a significant diabetes-arsenic link, as indicated by a recent study.

The study by Navas-Acien et al. (published in JAMA, 08/20/2008)analyzed urine arsenic level in 788 adults, 7.7% of which had diabetes 2. AIt has found that the average arsenic level for the entire group was 7.1 micrograms/liter (or 7.1 parts per billion, ppb). After adjustments for diabetes risk factors, the group with diabetes had 26% higher average level than the rest of participants.

Breaking down the numbers, the average level of arsenic for the diabetes 2 group was 8.8 ppb, vs. 7ppb in the non-diabetic group. Comparison of the incidence rate near the high and low end of the range (80the vs. 20th percentile) gave the odds of developing diabetes 3.6 times higher near the high end. If we apply that figure, roughly, on the overall incidence rate of 7.7%, those with elevated arsenic level are in proximity of 25%, or one in four incidence of type 2 diabetes.

What is particularly worrisome, is how infinitesimally small amount of arsenic in your system can significantly increase your risk of developing diabetes. We are talking about

less than 2 parts per billion over the average urine concentration!

Just recall that up to 2001 the official limit to acceptable level of arsenic in drinking water was 50 ppb! And all three average levels in the study - for the entire group, diabetics and non-diabetics - are still bellow the current official limit of 10 ppb.

It doesn't make you feel better knowing that arsenic is also potent carcinogen. It is also significant contributing factor to developing cardiovascular disease. A meta study by this same researcher (American Journal of Epidemiology, 11/03/2005), aroused the possibility that arsenic significantly increases the risk of developing coronary disease, stroke and peripheral arterial disease.

Considering all this, the question is how safe is the current "safe" level of arsenic in drinking water - assuming it is effectively enforced, which is not a fair assumption. Obviously, one can't look at arsenic toxicity alone, but as a part of the cumulative effect of hundreds, if not thousands of other toxins and contaminants it contains. R