Sign up for our free Health Check email to receive exclusive analysis on the week in health Get our free Health Check email Get our free Health Check email Email * SIGN UP I would like to be emailed about offers, events and updates from The Independent. Read our Privacy noticeAvoiding three key factors in middle age could lead to 13 more years free from dementia, experts suggest. A study by NYU Langone Health in the US examined these crucial risk factors among more than 12,000 people. People were assessed for high blood pressure, diabetes and smoking, and followed for an average of 26 years. Those who had none of the three risk factors lived without developing dementia nearly 13 years longer than those who had all three.