Researchers in Boston have pinpointed a primary trigger for the most common form of diabetes and have uncovered evidence that simple, inexpensive aspirin-like drugs could keep the disease that affects millions in check. The researchers, from Joslin Diabetes Center in Boston, discovered a genetic ''master switch" in the liver that is turned on when people become obese. Obesity has long been linked to diabetes, but the reason, until now, has been unknown. Joslin researchers found that once on, this switch produces low-level inflammation, which disrupts the body's ability to process insulin, causing type 2 diabetes.