Dementia risk in women: Researchers at the University of California, San Diego say a blood-based marker may help identify dementia risk in women decades before symptoms begin.
In a study published March 10 in JAMA Network Open, the team found that higher blood levels of phosphorylated tau 217, or p-tau217, were linked to a greater likelihood of developing mild cognitive impairment or dementia later in life. The association was seen in older women who had no cognitive problems when they entered the study, and the follow-up extended as long as 25 years.
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The findings came from 2,766 participants in the Women’s Health Initiative Memory Study, which enrolled women aged 65 to 79 in the late 1990s. Researchers analysed blood samples collected at the start of the study and later compared those results with long-term cognitive outcomes. Women with higher p-tau217 levels at baseline were more likely to develop dementia over time, with risk rising alongside the biomarker level.
The study also found that the strength of the association was not uniform across all groups. The link between higher p-tau217 and poorer cognitive outcomes was stronger among women older than 70 at baseline and among those carrying the APOE e4 variant, a well-known genetic risk factor for Alzheimer’s disease. Researchers also reported that p-tau217 appeared more predictive among women assigned to estrogen-plus-progestin hormone therapy than among those given placebo.
Differences were also observed between white and Black participants, although the researchers said combining p-tau217 with age improved dementia prediction in both groups.
The researchers said blood-based biomarkers such as p-tau217 are drawing attention because they are less invasive and potentially easier to use than brain imaging or spinal fluid testing. Even so, they cautioned that such tests are not currently recommended for routine clinical use in people who do not have symptoms of cognitive decline. More research is still needed to determine how the marker could be used in regular care and whether earlier identification would lead to better outcomes.
The authors said future work will examine how age, genetics, hormone therapy and other health factors may influence p-tau217 levels and long-term dementia risk across the lifespan.