Could a Simple Urine Test Detect Early-Stage Alzheimer’s Disease?

Researchers from China have discovered a potential new biomarker in urine that could lead to earlier diagnosis of Alzheimer’s disease.

Alzheimer’s disease (AD) is a common form of dementia that impacts around 5.8 million people in the United States. Individuals with AD experience progressive memory loss and cognitive decline that can severely impact daily functioning.

Although healthcare providers can prescribe medications that help slow the progression of AD, they are most effective when given in the earlier stages of the disease. Therefore, early detection is critical.

Currently, diagnosing AD involves cognitive assessments, medical testing to rule out other causes of memory decline, and brain scans — including magnetic resonance imaging (MRI), computed tomography (CT), or positron emission tomography (PET). Still, these may be inconclusive, leading to delayed diagnosis.

In addition, these tests can be expensive, invasive, or expose people to radiation, making them more challenging to use as routine AD screening tools.

Recently, a cross-sectional study published November 30th in Frontiers in Aging Neuroscience found that levels of urinary formic acid, a metabolic product of formaldehyde, were higher in people with Alzheimer’s — including those in the early stages of the disease.

These results suggest that urinary formic acid could be a potential biomarker for screening and diagnosis of early-stage ED.

Could a urine test detect Alzheimer’s?

The scientist’s previous research found a relationship between formaldehyde levels in urine and cognitive function, indicating that urinary formaldehyde may be a potential biomarker for early AD diagnosis.

Building on their earlier findings, the research team investigated the relationship between AD biomarkers in the blood and urinary formic acid — a by-product of formaldehyde. They recruited 574 participants from the Memory Clinic of Shanghai Sixth People’s Hospital in China to conduct the study.

The scientists divided the participants into five diagnostic groups. Among them:

  • 71 had normal cognitive function.
  • 101 had subjective cognitive decline (SCD).
  • 131 had cognitive impairment without mild cognitive impairment (CINM).
  • 158 had mild cognitive impairment (MCI).
  • 113 had a diagnosis of AD.

Then, the team administered standardized tests evaluating the participant’s memory, language, executive function, and visuospatial abilities. They also drew blood samples to determine AD-related blood biomarker measurements. In addition, they collected morning urine samples to measure formaldehyde and formic acid levels.

After analyzing the data, the scientists found that urinary formic acid levels were higher in all Alzheimer’s groups compared to those with healthy cognitive function. In addition, the data showed that as the disease progressed, urinary formic acid levels trended upward.

The team also compared urinary formic acid and formaldehyde levels with AD blood biomarkers. They found that combining all three potential biomarkers could enhance AD prediction accuracy for different stages of the disease. Moreover, urinary formic acid levels showed more prediction accuracy than formaldehyde.

The study authors suggest that formic acid urine testing could be a simple, convenient, and inexpensive way to screen people for AD in its early stages.

Limitations to the study

According to the study authors, the connections between formaldehyde, formic acid, and Alzheimer’s are still unclear. Also, the PET and CT scan data sample size was not adequate to draw definitive conclusions, especially in participants with normal cognitive function. Therefore, more long-term follow-up studies are needed.

However, in a press release, the study authors said, “urinary formic acid showed an excellent sensitivity for early Alzheimer’s screening.”

“The detection of urine biomarkers of Alzheimer’s is convenient and cost-effective, and it should be performed during routine physical examinations of the elderly,” they concluded.

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