Taipei: A research team at Taiwan's National Health Research Institutes (NHRI) has found that middle-aged and older Taiwanese carrying the APOE4 gene variant experienced faster cognitive decline over time, the first such finding for a Taiwanese population.

According to Focus Taiwan, the APOE4 gene variant, one of four APOE variants, has been associated with Alzheimer's disease since the early 1990s, and several studies have examined APOE4's prevalence in different populations. However, the NHRI study was the first to confirm that the APOE4 gene was associated with accelerated cognitive decline in a population of cognitively healthy middle-aged and older Taiwanese, NHRI researcher Chung Yu-chu stated at a press conference.

The study, published in JAMA Network Open on March 6, highlights the potential utility of early genetic risk awareness and supports consideration of targeted preventive strategies for APOE4 carriers. Although APOE4 carrier status is linked with an increased risk of Alzheimer's disease, the mechanism remains unclear.

NHRI researcher Lai Rai-hua explained that the APOE gene plays a role in regulating blood lipid levels and in metabolizing and clearing harmful proteins. The fourth variant may also be linked to severe chronic inflammation and stress hormones, potentially contributing to amyloid buildup, a factor in late-onset Alzheimer's disease.

To assess whether APOE4 is associated with faster cognitive decline in Taiwan, the team analyzed data from 4,392 adults aged 55 and older who had not been diagnosed with dementia. Of these participants, 33 carried two copies of APOE4, 723 carried one copy, and the rest were non-carriers. Using results from the Mini-Mental State Examination (MMSE), researchers tracked cognitive changes over approximately six years.

The findings indicated that adults carrying one or two copies of APOE4 experienced significantly faster cognitive decline than non-carriers, particularly after age 70. Those with two copies of APOE4 showed the fastest decline, suggesting a dose-dependent pattern in cognitive decline acceleration.

The study revealed that 17.3 percent of Taiwanese carry at least one copy of the gene variant, lower than the 20-30 percent of carriers in white populations. Although no therapy targeting the APOE4 gene variant has entered clinical trials, Lai expressed hope that the study could inform early detection programs and encouraged lifestyle changes to mitigate risk.

According to a 2023 survey conducted by the NHRI and the Ministry of Health and Welfare, dementia prevalence among people aged 65 and older in Taiwan was nearly 8 percent, indicating that about one in every 13 older adults had the condition.