Mandisa’s cause of death has been revealed as complications of “class III obesity”. The ‘American Idol’ contestant – who was a star of the fifth series of the show before going on to win a Grammy – passed away on 18 April at her home in Nashville, and an autopsy report has now revealed how she died. It said the singer was found dead in her home by friends, and that she “was last known alive approximately three weeks” earlier. Class III obesity is defined a disease in which a sufferer has a “body mass index (BMI) of 40 or higher or a BMI of 35 or higher and is experiencing obesity-related healt…