Healthy aging and education appear to be having an effect on reducing dementia rates.  A new study finds dementia rates among people 65 and older in England and Wales have plummeted by 25-percent over the past two decades.  Another recent study conducted in Denmark, found people in their 90’s given a standard test of mental ability in 2010 scored substantially better than people who reached their 90’s a decade earlier.  Both sets of research confirm something researchers on aging have long suspected but lacked good evidence to prove: dementia rates would fall and mental acuity improve as the population grew healthier and better educated.  Epidemiologists have found incidence of dementia is lower among those who control their blood pressure and cholesterol, and its lower among those who are better educated.  Both the British and Danish studies are published in The Lancet.