Mild memory loss more common in men than women

By Sophie Ramsey

BMJ Group News

What do we know already?

Many people become more easily confused or forgetful as they get older. If these changes are more than would be expected with normal ageing, but don’t meet the criteria for dementia, doctors say a person has mild cognitive impairment. Although many people with mild cognitive impairment go on to develop Alzheimer’s disease or another type of dementia, some stay about the same and a few actually get better.

In the study, researchers explored how the risk of this condition varies for men and women, and how factors such as education and marital status might affect people’s risk. They also looked separately at two types of impairment: with and without memory loss.

What does the new study say?

The researchers recruited 1,450 people aged 70 to 89 who did not have memory or thinking problems at the start of the study, based on thorough examination and tests. The researchers then repeated these evaluations every 15 months to check whether they’d developed the condition.

After an average follow-up of around three years, 296 people had developed mild cognitive impairment. This equalled a rate of nearly 64 in 1,000 people developing these problems per year. Impairment involving memory loss was more than twice as likely as without memory problems.

Men were at more risk than women, with 72 in 1,000 men diagnosed with the condition per year, compared with 57 in 1,000 women. This was a surprising finding, as dementia is more common in women than in men and mild cognitive impairment often precedes dementia.

People with less education also had a higher risk. Among those with more than 12 years of schooling, 48 in 1,000 were diagnosed with mild cognitive impairment per year. This compared with nearly 80 in 1,000 for those with less education. People who were not married also had a raised risk.

As in previous studies, some people got better. The researchers estimated that around 12 in 100 people per year recovered.

How reliable is the research?

This was a fairly large study that used high-quality tests and evaluations to determine whether people had mild cognitive impairment. Also, the researchers doing the evaluations didn’t know how people had scored previously, so this couldn’t affect their assessment. These things should make these findings fairly reliable.

However, bear in mind that this US-based study mainly included people of European descent. So we can’t be certain that these findings apply to people of different backgrounds.

Where does the study come from?

This study raises several questions about how mild cognitive impairment develops and why certain people are more at risk. More research will need to explore these issues, and also sort out why men seem to have a higher risk than women, but a lower risk of dementia. An editorial published with the study suggests some possibilities, including that men may be more likely to die before mild cognitive impairment becomes dementia or - more optimistically - that they may be more likely to recover from mild cognitive impairment, or at least not have their symptoms get worse.

It’s important to see your GP if you, or someone close to you, has noticed a change in your memory or thinking. Your doctor may reassure you that your symptoms simply reflect normal ageing. But if there is a problem, you can explore possible causes and treatments.