Diabetes is a complicated disease that's confounded doctors for generations.

So it's a medical surprise that a common, inexpensive, anti-inflammatory medication similar to aspirin has potential to treat and even prevent type 2 diabetes.

Results from a clinical trial conducted by the Joslin Diabetes Center in Boston appear in the February issue of Diabetes Care.

Three followup trials will determine whether the generic drug salsalate lowers blood-glucose levels in people with type 2. It also will show whether it slows the progression of coronary artery disease and prevents development of type 2 in people at high risk for the disease.

Dr. Allison B. Goldfine, lead researcher in the study, said the findings are "exciting and promising" because they show that salsalate "may be useful in preventing diabetes."

She is head of clinical research at Joslin and assistant professor at Harvard Medical School.

Salsalate is a nonsteroidal, anti-inflammatory drug long used to treat arthritis. But Joslin research shows evidence that it lowers blood-sugar levels in people with type 2, who have problems producing and effectively using their own insulin.

Aspirin has a similar beneficial impact on diabetes, but would require an unsafe daily dose. So researchers sought a safe alternative from the same family of drugs. Tests show that salsalate is effective but doesn't cause stomach bleeding.

"It should be effective for most people, but perhaps not all," Dr. Goldfine said, noting the complexity of the disease. "It might be something new to add to our arsenal. The drug has been used for 40 years and has a good safety profile. "It is inexpensive, useful and effective," she said.

Researchers already have launched a three-month followup trial in type 2 diabetes, and if that succeeds, they will undertake a six-month trial next fall. Within two years it should be clear whether salsalate is a useful treatment and effective in preventing type 2, Dr. Goldfine said.

Lack of insulin, the hormone that allows blood-glucose to enter cells, causes blood sugar levels to rise to dangerous levels, leading to heart and kidney disease, blindness and amputations due to circulation problems, among other problems.

Dr. Goldfine said elevated levels of certain proteins and enzymes from inflammation occur in people prior to development of type 2. As such, inflammation plays a pathogenic role in making a person insensitive to his or her own insulin. But salsalate effectively reduces inflammation, explaining how it prevents type 2.

During Joslin's clinical trial, 20 obese young adults participated in a double-masked, placebo-controlled study. Salsalate substantially reduced blood-glucose levels and inflammation and showed promise of reducing their risk of developing type 2.

It was the first study to focus on metabolic changes that the drug causes in obese people.

"We're excited by both the potential, safety and efficacy [of salsalate]," Dr. Goldfine said. "Diabetes is occurring at an epidemic rate, and this could be useful for a lot of people."