Patients who get treatment within a day of having a minor stroke cut their risk of a second stroke by 80 percent, researchers reported.

Aspirin, blood thinners and other common therapies given within 24 hours may prevent almost 10,000 major attacks a year in the United Kingdom, scientists said Monday in the medical journal The Lancet. Sending patients to a specialized clinic also reduced the risk of a stroke, a separate study in The Lancet Neurology found.

A stroke occurs when the normal blood supply to part of the brain is cut off, damaging or killing cells. Symptoms depend on the area of the brain affected and can include weakness or numbness down one side of the body, dizziness and headache. About 15 million people a year suffer a stroke, according to the World Health Organization in Geneva.

"The key to successful lowering of the risk of early stroke lies in prompt assessment and early treatment by stroke specialists in a dedicated clinic," Naeem Dean and Ashfaq Shuaib, physicians in Edmonton, Canada, wrote in a comment in The Lancet.

About 600 patients were assessed by doctors and given prescriptions within a day, on average, in the study published in The Lancet. They were 80 percent less likely to have a second stroke within three months, compared with a group of 600 patients who were assessed within three days and got their first prescription within 20 days, the study found.

French researchers showed immediate treatment for minor strokes at a Paris clinic that specialized in assessing the condition reduced the risk of having another attack within three months by 80 percent, according to the study in The Lancet Neurology. Those admitted to the clinic were evaluated within four hours after being referred by their family doctors.