Slight cognitive problems like forgetting people's names or misplacing items plague more older men than women, according to a Minnesota study.
The findings are surprising because Alzheimer's disease, which is preceded by this type of mental decline, affects more women than men.
In the new study, published in the journal Neurology, 19% of men aged 70 to 89 years had so-called mild cognitive impairment, compared to only 14% of women.
According to the National Institutes of Health, "mild cognitive impairment" falls in between normal forgetfulness and dementia.
Mild cognitive impairment not always dementia
People with mild cognitive impairment have problems with thinking and memory, but they can still carry on everyday activities. They generally realise that they're forgetful. Although not everyone with mild cognitive impairment develops dementia, some people do, which makes it a risk factor for Alzheimer's disease.
Dr Ronald C. Petersen, who heads the Mayo Alzheimer's Disease Research Centre in Rochester, Minnesota and who led the new research, said up to 15% of people with mild cognitive impairment end up with full-blown dementia each year.
In the general population, that number is between 1% and 2%.
More than 2,000 randomly sampled elderly people from Olmsted County, Minnesota, participated in the study. The Minnesota researchers spent hours testing each participant specifically for mild cognitive impairment and dementia.
About a fourth of the seniors had cognitive problems beyond the signs of normal aging, including Alzheimer's. Not surprisingly, mild impairment became more common with older age.
But it also turned out that the more education people had under their belt, the less likely they were to have cognitive problems. Even after accounting for differences in education, age, and diseases like diabetes and hypertension, men had about 50% higher odds than women of having mild cognitive impairment.
"The gender differences were somewhat surprising to us because most people believe that women are at higher risk than men," said Petersen.
It is unclear how to explain the finding.
Lifestyle changes may help
The researchers speculate that perhaps men get memory problems earlier in life, but then decline more slowly than women. In other words, the reason more men have mild cognitive impairment might be that more women are skipping that stage and going directly to dementia.
While there aren't any drugs available to treat mild cognitive impairment, Petersen said lifestyle changes could have a positive effect. He recommended reading and going to the movies, as well as keeping up with friends and family, eating healthy foods and being physically active.
"There are more and more data coming out indicating that some of these lifestyle modifications may work," he noted. (Reuters Health, September 2010)