Cognitive Impact From Dementia Risk Factors Greater in Women

Medscape

4 hours ago

TORONTO — A number of modifiable risk factors are more common in women than in men and have a greater impact on cognition, an early look at new research showed.
Six modifiable dementia risk factors were more prevalent in women, whereas only three were more common in men. Investigators also found that the impact on cognition from some of these factors was greater in women than in men, especially hearing loss and diabetes.
However, the impact of these and other risk factors varied by age.
Megan Fitzhugh, PhD
The results suggest personalized health and lifestyle interventions should consider both sex and age, study author Megan Fitzhugh, PhD, assistant professor, Department of Neurosciences, University of California San Diego, told Medscape Medical News.
'Clinicians should familiarize themselves with the 14 identified modifiable risk factors, and if their patients have these risk factors, consider their sex and age, and try to target the behavior changes accordingly to minimize the impact on cognition and dementia risk,' Fitzhugh said.
The findings were presented on July 28 at the Alzheimer's Association International Conference (AAIC) 2025.
At Greater Risk
It's well-known that women are at greater risk for dementia. The lifetime risk for Alzheimer's disease (AD) is 1 in 5 for women compared with 1 in 10 for men.
Sex-specific factors such as pregnancy and menopause may contribute to this imbalance. But while many researchers tackle this issue from a biological perspective, Fitzhugh focuses on the effects of modifiable risk factors.
She used the 2008 wave of the Health and Retirement study, an ongoing population-based study of a representative sample of American retirees and their spouses who complete questionnaire every 2 years (in 'waves').
After excluding anyone younger than 40 years and those without self-reported risk factor information, the study sample included 17,182 individuals.
Fitzhugh concentrated on items included in the Lancet Report on Dementia Prevention. As reported by Medscape Medical News , 45% of dementia risk factors are potentially modifiable.
Risk factors identified in the Lancet report include less education in early life (contributing 5% to risk); hearing loss (7%), elevated low density lipoprotein (LDL) cholesterol (7%), depression (3%), traumatic brain injury (3%), physical inactivity (2%), diabetes (2%), smoking (2%), hypertension (2%), obesity (1%), and excessive alcohol (1%) in midlife; and social isolation (5%), air pollution (3%), and vision loss (2%) in late life.
Looking at prevalence, investigators found that six of the 14 risk factors were more common in women, including physical inactivity, depression, smoking, poor sleep, less education and poor vision (for example, glaucoma or cataracts).
Only three risk factors were more common in men, including hearing loss, diabetes, and alcohol use.
There was no difference in prevalence between men and women in high BMI, hypertension, and social isolation.
Plotting Cognition
The Health and Retirement Study also gathers data on global cognition (immediate recall, delayed recall, numeracy, etc.) using a 27-item scale.
Fitzhugh separated mean cognitive scores for men and women and for three age groups (middle age: 40-59 years; middle to older age: 60-79 years; and oldest age: 80 years and over), then plotted risk factors in each group.
The graphs she created illustrate the differences in cognitive performance between having and not having a risk factor for each sex.
For example, the diabetes plot shows this risk factor has a much bigger impact on cognition in women.
'The line for men is relatively flat, so their cognition is really the same if they have diabetes or not, but for women, if they have diabetes, cognition is much lower compared to women who don't have diabetes', explained Fitzhugh.
In addition to diabetes, other risk factors that have a greater cognitive impact on women included poor sleep, BMI, hypertension, poor vision, less education, and hearing loss.
Along with high LDL, hearing loss is the largest modifiable risk factor, accounting for 7% of dementia risk, according to the Lancet Commission report. But even though more men have hearing loss across all ages, it appears to be more impactful on women in terms of cognition, said Fitzhugh.
'Maybe we should be targeting women with hearing loss in middle to older age, making sure they get hearing aids,' she said.
Elsewhere in her research, Fitzhugh found women with hearing loss have a greater risk for dementia than men with hearing loss. 'There's something about hearing loss in women that is particularly detrimental.'
The cognitive impact of risk factors also varies by age, investigators found.
Among women, the impact of hearing loss was greatest in middle to older age. Poor sleep only had a significant impact in middle age, which coincides with the menopause transition. And in the oldest age, less education was the only risk factor to have a significant impact on cognition.
In men, only smoking had a greater cognitive impact, but interestingly, only in the older age group.
'The way I think about age in this study is it's telling us when, potentially, we should be targeting these risk factors,' said Fitzhugh.
She recognizes this is 'just a snapshot' in time and said she'd like to 'map out' how risk factors impact cognition over time.
Commenting on the research, Liisa Galea, PhD, Treliving Family Chair in Women's Mental Health, Centre for Addiction and Mental Health, and professor of psychiatry, University of Toronto, Toronto, Ontario, Canada, said that more modifiable factors are associated with cognition in females than males is 'most surprising.'
'Clearly these factors are important for everyone, but we need more targeted messaging to women across the lifespan about the importance of these variables for their brain health,' Galea said.