Researchers at Sir Charles Gairdner Hospital will involve more than 4,000 West Australians in a study by reassessing former patients in a bid to solve the mystery of sleep apnea’s link to poor health, reports Perth Now.

The lead investigator for the West Australian cardio Vascular Endpoints in Sleep apnoea (WAVES) study Professor Bhajan Singh said sleep specialists around the world had recently become “uncertain” about the real relationship between obstructive sleep apnoea and heart disease and stroke.