Researchers have discovered that a drop in blood potassium levels caused by diuretics commonly prescribed for high blood pressure could be the reason why people on those drugs are at risk for developing type 2 diabetes.

The drugs are intended to accelerate loss of fluids, but they also deplete important chemicals, including potassium.

Researchers examined data from nearly 4,000 nondiabetic subjects. Half of the subjects were treated with the diuretic chlorthalidone and half with a fake drug. For each 0.5 milliequivalent-per-liter decrease in serum potassium caused by the drug, there was a 45 percent increased risk of diabetes. None of the people in the group receiving the fake drug developed low potassium levels.