WASHINGTON, DC—Women with mild cognitive impairment (MCI) decline faster on measures of cognition and function than men over a period of up to eight years, according to an analysis presented at the 2015 Alzheimer’s Association International Conference. Investigators analyzed longitudinal data for 398 patients with MCI from a national biomarker study. Their findings also were published online ahead of print July 21 in Alzheimer’s & Dementia: Translational Research & Clinical Interventions.
Men may have a greater risk of MCI, but more than two-thirds of Alzheimer’s disease patients are women. Although longer life expectancy and detection biases may contribute to the higher prevalence of Alzheimer’s disease in women, some findings have suggested that women at risk of Alzheimer’s disease progress to the disease at faster rates. A prior study by Holland et al found that women with MCI had a greater rate of cognitive change over a one-year period.
To examine if women with MCI progressed at faster rates over longer periods, Katherine Amy Lin, Wrenn Clinical Research Scholar in Alzheimer’s disease at Duke University Medical Center, and colleagues analyzed eight-year longitudinal data from the Alzheimer’s Disease Neuroimaging Initiative. The patients—257 men (mean age, 75) and 141 women (mean age, 73)—had Mini-Mental State Examination (MMSE) scores ranging from 24 to 30, subjective memory complaints, objective evidence of impaired memory, absence of significant confounding conditions, normal or near-normal daily activities, and absence of clinical dementia. Average follow-up duration was 4.1 years.
The researchers found that cognitive abilities as measured using the Alzheimer’s Disease Assessment Scale-cognitive subscale (ADAS-cog) declined 1.05 points per year for men, compared with 2.3 points per year for women.
In a mixed-effects model, after adjusting for age, education, baseline MMSE score, follow-up time, and APOE4 status, the effect of gender on ADAS-cog rate of change was highly significant, the researchers said. Women also progressed significantly faster on the Clinical Dementia Rating-Sum of Boxes.
Men and women APOE4 carriers declined faster than noncarriers. Rate of conversion from MCI to dementia was slightly higher among women, but this finding was not statistically significant. Follow-up time may not have been long enough to test rates of conversion to dementia, the researchers said.
“Overall, these data confirm and extend prior findings that women with MCI may have a greater vulnerability for cognitive and functional decline,” the researchers concluded.