Subtle problems with memory and thinking skills - known as mild cognitive impairment - often precede Alzheimer's disease, and a new study finds that men are at higher risk for these troubles than women.
Lead researcher Rosebud Roberts and her colleagues looked at 1 450 people from Olmsted County, Minn., who were between 70 and 89 years old and free of dementia in October 2004. Some three and a half years later, 296 had become mildly impaired.
New cases of mild cognitive impairment were consistently higher among men, except in the 85 to 89 age group. Overall, the risk was 40% higher for men.
Having a high school or less education was also linked to greater risk, and the study found that the combination of being male without college education brought an "unexpectedly high risk" of impairment that did not involve memory loss.
Currently married people were at lower risk of mild cognitive impairment than those widowed, divorced or single.
"One of every 16 persons in this age group develops this condition in a given year," said Roberts, a professor of epidemiology at the Mayo Clinic in Rochester, Minn. "As we have a large increase in baby boomers reaching the age of 65 and older, this is going to have a tremendous impact."
Bill Thies, chief medical and scientific officer for the Alzheimer's Association, commented on the study.
Timing risk factors
"It's an interesting observation that mild cognitive impairment is a little more common in men than in women," he said. "It's not clear what that means or even if it's universal. Certainly, it hadn't been reported before in much smaller studies. It may be that they found it because their study is big."
Roberts said the difference may be due to timing of risk factors for dementia. "Diseases such as obesity, diabetes and hypertension may occur at an earlier age in men than women," she said. In future studies, the risk factors should be studied separately for men and women, the study authors said.
According to the Alzheimer's Association, everyone who develops the age-related brain disorder experiences a stage of minimal impairment. "People with mild cognitive impairment experience a decline in memory, reasoning or visual perception that's measurable and noticeable to themselves or to others, but not severe enough to be diagnosed as Alzheimer's or another dementia," the association states.
However, not everyone who has mild cognitive impairment will go on to develop Alzheimer's.
For the study, participants met with nurses and physicians and took tests at 15-month intervals to measure memory, executive function, visual-spatial skills, dementia symptoms and neurological, psychological and mental status. At each interval, a panel of examiners made a fresh assessment of the participants' cognitive status.
The study findings are published in an online edition of the journal Neurology.
About 88% of study participants who developed mild cognitive impairment each year either continued with the condition or progressed to full-blown dementia. The others reverted to normal when tested later, but these were marginal cases, Roberts said.
Most of the participants were of European ancestry, and the researchers said the findings might be different for other ethnic groups.
Thies said he was surprised by the high percentage of people living in the community with cognitive impairment that caused them difficulties. "The issue is even broader than Alzheimer's disease, and the importance of finding medications for cognitive decline is even more important than we might have thought," he said.
Having the occasional "senior moment" - forgetting an acquaintance's name, for instance - does not mean you have mild cognitive impairment, Roberts explained.
It becomes more significant "if the individual notices this is happening more frequently, that it's affecting other aspects of their life," she said. "They're having more problems balancing their cheque book or remembering the names of people they know very well - their own nieces or grandchildren or whatever."
Recognising whether you're experiencing simple forgetfulness or a warning sign of impairment isn't always cut and dried, Thies said.
One day misplacing your car keys is a trivial, normal event, and the difference between that and the "first time it's a pathological event are absolutely indistinguishable," he said. "There is a moment where you can clearly have an overlap."
(HealthDay News, January 2012)
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