Who Will Develop Alzheimer’s Disease?

According to a new Mayo Clinic Study of Aging, Mild Cognitive Impairment (MCI), which can be a transitional stage between age-related forgetfulness and the full-blown, irreversible dementia associated with Alzheimer’s disease (AD), is more common in men than in women. This is surprising, given that more women than men have dementia.

The Mayo study found that more than 6 percent of Americans age 70 to 89 develop MCI every year. Among 1,450 participants, the rate for men was 7.2 percent per year, while that of women was 5.7 percent.  Participants with only a high school education, versus those with higher education, were also more vulnerable, as were unmarried individuals.

MCI does not automatically develop into dementia. The actual risk is variable. The challenge for doctors has long been to discover a way to assess that risk in order to determine an appropriate course of management for each patient. Now, a team of physicians and scientists, from the University of California San Diego School of Medicine and elsewhere, have used a combination of broadly available medical tests to determine the likelihood of impending AD in patients with MCI. 

The researchers compared risk factors based on magnetic resonance imaging (MRI), cerebrospinal fluid (CSF), and neuropsychological testing. In combination, these biomarkers had a prediction rate that was almost perfect: none of the patients who tested negative on all three measures went on to develop AD in the three-year follow-up. By comparison, nearly nine of ten individuals who tested positive on all three measures were demented three years later.

“I’m extremely excited about these results,” said neurologist James Brewer, MD, PhD, an associate professor of radiology and neurosciences and part of the Alzheimer’s Disease Neuroimaging Initiative research team at UC San Diego. “The good news is that we can partially reassure those folks who are negative on these tests, at least regarding their next three years. We have never been able to do that before.”