This article was published in Scientific American’s former blog network and reflects the views of the author, not necessarily those of Scientific American
As we age, all sorts of things may start to break down. Joints ache, or vision fails, and or maybe cognitive abilities falter. The leading known risk for getting Alzheimer's disease or other forms of dementia is simply getting older, followed, some studies suggest, by major illnesses, such as diabetes, heart disease, high blood pressure and stroke. But new research suggests that many of the littler aches, pains or minor disabilities that often pile on with age are linked to increased risk for Alzheimer's and dementia.
The new study compared data from 7,239 Canadian adults 65 or older who were dementia-free. After five and 10 years, those in the study were asked about cognitive clarity and asked to report on 19 different health and wellbeing factors (including hearing, foot problems and how well their dentures fit). After the full decade, of the 4,324 people who were still alive, 416 had Alzheimer's disease, 191 had another sort of dementia and 677 had other cognitive problems (1,023 were of uncertain cognitive ability). The findings were described online July 13 in Neurology.
Each individual health complaint increased the risk of having dementia by an average of about 3 percent. But as issues accumulated, one's risk for cognitive decline grew, too. A healthy older adult had about an 18 percent chance of having dementia after 10 years, whereas those who reported poor health on a dozen of the health and wellbeing measures had, on average, closer to a 40 percent chance.
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The findings suggest that Alzheimer's prevention be focused not just on drugs or major health issues, but that "keeping up your general health may help reduce the risk for dementia," Kenneth Rockwood, of the Division of Geriatric Medicine at Veterans Memorial Lane in Halifax, Canada and a co-author of the new study, said in a prepared statement.
The links held after adjusting for age and other known risk factors. But they will require verification from future studies. The data comes from broader health surveys that were not specifically assembled to measure these risk factors for dementia, and many of those who died during the course of the study likely had dementia. "Much uncertainty remains," cautioned the authors of an essay published in the same issue of Neurology, Jean Francois Dartigues and Catherine Ferat, both of Victor Segalen University Bordeaux in France. But, they note, the findings "suggest a new vision of preventive or curative treatments which, instead of targeting specific etiologic mechanisms, would instead aim at improving general health."
And even if a small fraction of cases could be prevented or limited in severity by improving overall health and lifestyle, it could make a big difference in the burden of Alzheimer's, which is expected to reach some 100 million people worldwide by 2050.
The 19 minor health issues analyzed for the study were overall health, eyesight, hearing, denture fit, arthritis/rheumatism, eye trouble, ear trouble, stomach trouble, kidney trouble, bladder control, bowel control, feet/ankle trouble, stuffy nose/sneezing, bone fractures, chest problems, cough, skin problems, dental problems, other problems. The most common complaint for all surviving individuals after 10 years was arthritis/rheumatism, which was only slightly higher among those with Alzheimer's or dementia. But two of the largest differences between those who were cognitively healthy and those with Alzheimer's after a decade was poor eyesight (3 percent and 9 percent, respectively) and poor hearing (3 percent and 6 percent, respectively).
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