aug 16 2012151 ralph light has a garden for years he has been growing beans strawberries sweet corn wheat asparagus and tomatoes for his neighbors and family its a hard hobby at any age but for light who is 94 years old the work is an exceptional testament to his physical and mental health we raised what we ate for years says ralph we used to can hundreds of quarts of fruits and vegetables light who lives with his wife of 68 years is also an avid reader with a fondness for detective novels he reads two or three of them every week and the only question that seems to stump him is what the secret is to his spry nature ive kept active light says on wednesday a study published online in the journal neurology shows some evidence that protection from dementia clusters in families in other words those like light may have their genes to thank for their healthy minds indeed light seems to be cut from longlived stock i had four brothers almost all who lived in to their 90s light says none of them had dementia whats more enticing to the rest of us who may or may not be so genetically gifted is that learning more about the genes in lights family and other like it may be the key that will one day help protect the rest of us from dementia lead investigator jeremy m silverman a professor in the department of psychiatry at the mount sinai school of medicine and his colleagues examined 277 male veterans aged 75 and older who were free of dementia symptoms they conducted blood tests to measure levels of a substance called creactive protein in the mens blood since high levels of creactive protein tend to correspond to high levels of dementia in younger elderly patients some assume those elderly patients with high levels of creactive protein who do not develop dementia are somehow resistant to cognitive decline the researchers then interviewed 1329 of the test subjects relatives to assess their rates of dementia what they found was that the rates of dementia in the families of patients who exhibited resistance was lower than the rate seen in families of patients who did not show resistance to validate these findings further investigators repeated the study with an older group of 51 patients and surveyed 202 of their relatives this group returned the same results in both study populations patients with resistance to dementia were over 30 percent less likely to have relatives with dementia since creactive protein is not always linked to dementia the conclusions drawn should be met with a critical eye dementia is a very complicated disorder and the findings in a study like this need to be reproduced in other studies before they are going to be transformative says dr eric larson vice president for research at the group health research institute based in seattle still while the study does not