Men are more likely than women to suffer problems with memory and thinking as they age, research has shown.
Rates of mild cognitive impairment (MCI) were found to be 1.5 times higher in men than in women.
MCI involves a level of mental decline beyond that which can be explained by normal ageing. It is often associated with Alzheimer's disease later in life.
Scientists conducting the study tested the memory and thinking skills of more than 2,000 people aged 70 to 89 in Minnesota, US.
They found almost 14% of participants had MCI, 10% were suffering from dementia, and 76% had normal mental faculties.
A total of 19% of men had MCI compared with 14% of women.
Lead researcher Dr Ronald Petersen, from the Mayo Clinic in Rochester, Minnesota, said: "This is the first study conducted among community-dwelling persons to find a higher prevalence of MCI in men.
"The finding that the frequency of MCI is greater in men was unexpected, since the frequency of Alzheimer's disease is actually greater in women. It warrants further study.
"If these results are confirmed in other studies, it may suggest that factors related to gender play a role in the disease. For example, men may experience cognitive decline earlier in life but more gradually, whereas women may transition from normal memory directly to dementia at a later age but more quickly."