Men have a higher risk than women of developing memory problems and other mental impairments that are early signs of Alzheimer's disease, a new study suggests.
Researchers at the Mayo Clinic in Rochester, Minn., followed 1,450 people ages 70 to 89, and found that 296 patients developed mild cognitive impairment (MCI) over the course of the three-and-a-half year study.
People with mild cognitive impairment have memory, language, thinking and judgment problems that are noticeable to themselves and their families, but not serious enough to interfere with day-to-day life.
"We found that the incidence was higher in men than in women," said study co-author Rosebud Roberts, professor of epidemiology at the Mayo Clinic. Of the 722 men in the study, 161 developed MCI, whereas 135 of the 728 women did.
The findings counter earlier research that suggests women have a higher incidence of mild cognitive impairment.
Researchers re-evaluated study participants with a battery of tests designed to diagnose mild cognitive impairment every 15 months for a median of 3.4 years.
The research is published online today (Jan. 25) in the journal Neurology.
Marriage and education
In addition to gender differences, researchers also found that mild cognitive impairment was more common in people who were widowed, divorced or separated, or in those who were less educated, than those who were married or who had more education.Researchers did not detect a higher risk of MCI in people who had never married.
People who are widowed, divorced or separated are more likely to experience depression, loneliness and lack of social support than those who are married, Roberts said.
"We think that these may contribute to why previously married people have a higher risk of MCI," she said. "These factors have been associated with an increased risk of MCI and dementia in other studies."
The incidence of mild cognitive impairment in elderly persons ages 70 and older was "quite high," Roberts said. "One out of every 16 men and women in this age group will develop a new onset of MCI in a given year."
The study highlights the need for doctors to check for risk factors of mild cognitive impairment that are treatable, such as depression and sleep apnea, said Dawn McGuire, professor of neurology at the Neuroscience Institute of Morehouse School of Medicine. McGuire was not associated with the study.
"This means user-friendly detection tools," McGuire said. "And we need to have, as standard of care, an aggressive approach to MCI work up."
Roberts agreed, saying researchers need to assess whether those treatable conditions related to mild cognitive impairment differ between men and women. "It's important for us to understand whether risk factors for MCI — obesity, Type 2 diabetes, hypertension, depression, lack of exercise and a lack of intellectual stimulation — affect risk of MCI differently in men and women."
While the study was well-designed, it had some weaknesses, Roberts said. The researchers would have liked to have had a larger group of participants, she said. "[And] people who were sicker were more likely to refuse to participate."
The study authors also acknowledged that the population was mostly of European descent, which McGuire said is both a strength and a weakness.
Because the study had relatively homogenous group of participants — most were elderly whites of European descent who lived in the same region — many potentially confounding factors were reduced, she said. Therefore, results "such as the gender difference in MCI, a surprise finding, may otherwise have been masked."
However, the findings might not apply as well to other groups. "As the authors are the first to note, these findings may not be generalizable," McGuire said. "This is a fairly big limitation given the changing demographic. Within 30 years, whites of European descent will be the minority in our country; and, the population most at risk of MCI and dementia — those 65 and over — will have doubled."
Pass it on: Men may have a higher risk than women of mild cognitive impairment, a precursor to Alzheimer's disease.