Scientists discovered that a genetic test measuring tau protein in blood could help identify people at higher risk of developing Alzheimer’s disease or memory problems before symptoms appear. Researchers followed over 600 healthy older adults for about 3 years and found that those with genetic markers linked to higher tau levels were 29% more likely to develop memory issues. The findings were confirmed in a larger study of over 140,000 people. This genetic test could eventually help doctors spot who needs early treatment, though more research is needed before it becomes a standard screening tool.

The Quick Take

  • What they studied: Whether a genetic test that predicts high tau protein levels in blood can help identify people who will develop Alzheimer’s disease or memory problems in the future
  • Who participated: Two groups: 618 healthy older adults (average age 73) from Greece followed for about 3 years, and 142,637 people from the UK (average age 64) followed for about 13 years. All participants had normal memory at the start.
  • Key finding: People with genetic markers for higher tau levels had a 29% increased risk of developing memory problems or Alzheimer’s in the Greek study. This finding held up in the larger UK study, though the effect was smaller (5% increased risk per genetic unit).
  • What it means for you: This research suggests a simple blood test measuring genetic risk for tau could someday help doctors identify who might develop Alzheimer’s years before symptoms appear, allowing for earlier treatment. However, this is still research—it’s not yet ready for routine use in doctor’s offices.

The Research Details

Researchers used a ‘polygenic risk score’—basically a genetic report card that combines information from many genes linked to tau protein levels. They followed healthy older adults over several years to see who developed memory problems or Alzheimer’s disease. They used a statistical method called Cox regression to account for other factors that might affect risk, like age, sex, education level, and a well-known Alzheimer’s gene called APOE. The main study involved 618 Greek participants followed for about 3 years, and they confirmed their findings in a much larger group of 142,637 British participants followed for about 13 years.

The researchers specifically looked at whether the genetic risk score worked differently for men versus women, and for younger versus older people. This is important because Alzheimer’s affects men and women differently, and age is a major risk factor.

The study was ’longitudinal,’ meaning they followed the same people over time rather than just taking a snapshot. This approach is stronger for understanding what causes disease because it shows that the genetic risk came before the disease developed.

This research matters because current Alzheimer’s diagnosis usually happens after significant brain damage has already occurred. If doctors could identify high-risk people years in advance using a simple blood test, they might be able to start treatments earlier when they could be more effective. The genetic approach is also appealing because it’s based on unchangeable biology—your genes don’t change—so it could be a stable, reliable predictor.

This study has several strengths: it followed real people over years rather than just observing them once, it was confirmed in a second large population, and it was published in a respected medical journal (Neurology). However, the Greek study was relatively small with only 73 people developing memory problems, which means the results could have happened by chance. The effect was also stronger in women and younger people, but didn’t reach statistical significance in men and older people, suggesting the test may work better for some groups. The UK study had a much larger sample, which makes those findings more reliable.

What the Results Show

In the Greek study of 618 healthy older adults, 73 people developed either mild cognitive impairment (early memory problems) or Alzheimer’s disease over the 3-year follow-up period. For every standard increase in the genetic risk score for tau, the risk of developing these memory problems increased by 29%. This means if you had a higher genetic risk score, you were about 1.3 times more likely to develop memory problems compared to someone with a lower score.

The larger UK study confirmed this finding. Among 142,637 people without dementia at the start, 2,737 developed Alzheimer’s disease over about 13 years. Higher genetic risk scores were linked to increased Alzheimer’s risk, though the effect was smaller—about a 5% increased risk per unit increase in the score. The smaller effect in the UK study might be because Alzheimer’s develops slowly and the genetic test is just one of many risk factors.

Interestingly, the genetic test appeared to work better for predicting risk in women and younger people. Women with higher genetic risk scores had a 45% increased risk, and people under 65 with higher scores had an 87% increased risk. However, in men and older participants, the genetic test didn’t show a statistically significant effect, meaning the results could have been due to chance.

The study found that the relationship between genetic risk for tau and Alzheimer’s disease appears to depend on both sex and age. This is important because it suggests that a one-size-fits-all approach to genetic risk screening might not work—doctors may need to interpret the test differently depending on whether the person is male or female, and how old they are. The fact that the effect was stronger in younger people is particularly interesting because it suggests the genetic risk might be more predictive earlier in life, before other age-related factors become dominant.

Previous research has shown that tau protein in the brain is a hallmark of Alzheimer’s disease, and recent studies have found that tau can be measured in blood. This study builds on that work by showing that genetic factors affecting tau levels might help predict who will develop Alzheimer’s. It adds to growing evidence that blood biomarkers could eventually replace more invasive tests like spinal taps or brain imaging for identifying Alzheimer’s risk.

Several important limitations should be considered. First, the Greek study was relatively small—only 73 people developed memory problems, so the results could have occurred by chance. Second, the genetic test only explained part of Alzheimer’s risk; many other factors matter too, including lifestyle, education, and other genes. Third, the effect was stronger in women and younger people but not statistically significant in men and older people, suggesting the test may not work equally well for everyone. Fourth, this is still a research finding—the genetic test hasn’t been validated for clinical use yet. Finally, both studies involved mostly European ancestry populations, so results might differ in other ethnic groups.

The Bottom Line

Based on this research, a genetic test for tau risk is a promising research tool but is not yet ready for routine clinical use (low confidence for clinical application at this time). If such a test becomes available in the future, it might be most useful as one piece of information among many—combined with family history, lifestyle factors, and other medical tests—to identify people at higher risk who might benefit from early interventions or closer monitoring. Anyone concerned about Alzheimer’s risk should discuss their individual risk factors with their doctor rather than relying on a genetic test alone.

This research is most relevant to people with a family history of Alzheimer’s disease, those concerned about memory changes, and researchers developing new diagnostic tools. People aged 60-75 without memory problems might find this most applicable. However, this is not yet a test for the general public. Men and older adults (over 75) should note that the genetic test showed weaker effects in these groups, so it may be less predictive for them.

In the studies, memory problems or Alzheimer’s developed over 3-13 years in people with higher genetic risk scores. This means the genetic test identifies long-term risk, not immediate risk. If someone had a high genetic risk score today, they might not show symptoms for many years. This long timeline is actually helpful because it provides a window for potential early interventions, but it also means the test predicts probability, not certainty.

Want to Apply This Research?

  • If a genetic risk score becomes available, users could track their cognitive health by recording monthly scores on simple memory tests (like remembering a list of words or recalling recent events) and noting any changes in memory, word-finding, or concentration. This would create a baseline to compare against over time.
  • Users with higher genetic risk could use the app to build protective habits: tracking weekly exercise (aim for 150 minutes), monitoring sleep quality (aim for 7-9 hours), logging cognitive activities (puzzles, reading, learning), and recording social interactions. These lifestyle factors are known to reduce Alzheimer’s risk regardless of genetics.
  • Set up quarterly check-ins to review cognitive function trends, annual reviews of lifestyle factors that protect brain health, and alerts to discuss results with a doctor if memory concerns emerge. The app could also track family history updates and remind users about recommended health screenings as they age.

This research describes a genetic test that is currently used only in research settings and is not approved for routine clinical diagnosis or risk assessment. The findings suggest potential future applications but do not constitute medical advice. A genetic risk score is only one factor among many that influence Alzheimer’s disease risk; having a high score does not mean you will definitely develop the disease, and having a low score does not guarantee you won’t. If you have concerns about memory loss or Alzheimer’s risk, please consult with a qualified healthcare provider who can evaluate your individual situation, family history, and other risk factors. This information should not be used to make medical decisions without professional guidance.