Up to 73% of dementia cases could be prevented by lifestyle changes, a new study of 344,000 people over 15 years suggests. Researchers behind the study, published in the journal Nature Human Behaviour, investigated 210 modifiable risk factors and found that personal measures such as increasing physical strength, more leisure and social activities, more time at the gym, less time watching TV or a computer screen, better dental health and drinking more water all contributed to a reduction in risk. Conversely, unemployment, low income, diabetes and high blood pressure were among factors raising risk. “We have probably under-estimated the power of prevention.” said Professor David Smith from the University of Oxford, one of the study authors. “Even this figure of up to 73% of cases preventable could be higher if a person’s omega-3 and B vitamin status, measured by a blood test for homocysteine that any GP can do, were taken into account.”