Dementia: Shorter telomeres on white blood cells may increase risk

  • Researchers say they have linked shorter leukocyte telomeres on white blood cells to smaller brain volume and white matter.
  • They said this association translates into a higher risk of all forms of dementia, including Alzheimer’s disease, for people with shorter telomeres.
  • Other experts, however, say the study has limitations and more research is necessary.

The length of telomeres on white blood cells may help predict the risk of dementia, including Alzheimer’s disease and vascular dementia, according to a long-term study published in the online journal General Psychiatry.

The researchers used records from the UK Biobank, an extensive biomedical database that has in-depth genetic and health information for around 500,000 people.

In the biobank, there was information on leucocyte telomere length of 439,961 people between the ages of 37 and 73 who did not have dementia when they enrolled. Scientists determined the length by analyzing blood samples at enrollment.

The scientists for the biobank used an average monitoring period of around 12 years. During this time:

  • 5,820 participants developed dementia of some type.
  • Of those, 1,551 participants were diagnosed with Alzheimer’s disease.
  • Another 767 were diagnosed with vascular dementia.

A brain volume analysis based on brain imaging (MRI) was done on 38,470 participants.

What researchers found in dementia risk study

The researchers in the new study said they discovered a linear association between shorter leukocyte telomeres and smaller brain volume and white matter as well as brain structures such as the hippocampus (learning and memory), thalamus (sensory processing), and the nucleus accumbens (pleasure center).

“It’s an exciting time for dementia research and a very important part of this research lies in biomarkers for early detection, precision medication, monitoring disease progression, development of new medications, reducing misdiagnosis, further advancing research and reducing healthcare costs,” said Dr. Emer MacSweeney, the chief executive office and consultant neuroradiologist at Cognition Health who was not involved in the study.

“This is a really interesting study where leukocyte telomere length testing appears to be a potential biomarker for conditions, including Alzheimer’s and vascular disease, which cause dementia,” MacSweeney told Medical News Today.

After accounting for age and sex, the researchers reported that participants with the shortest leukocyte telomeres were 14% more likely to be diagnosed with dementia and 28% more likely to be diagnosed with Alzheimer’s than those with the longest leukocyte telomeres.

The risk of vascular dementia also increased but was not statistically significant, they said.

“Telomeres protect the ends of our DNA through ‘caps’ consisting of hundreds of thousands of repeats of the same DNA sequence (5′-TTAGGG-3′).,” said Keiland Cooper, PhD, a neuroscientist at the University of California Irvine who was not involved in the study.

“Because the lengths of these caps wear down with time, Leukocyte telomere length (LTL) has been proposed as one potential biomarker for biological aging and overall health. However, findings from studies are scattered without clear specific consensus,” Cooper explained to Medical News Today.

“To help shed light on whether telomere length is predictive of age-related diseases, such as cognitive impairment or dementia, the authors looked at a correlative study of telomere length and brain health, to which the authors found a relationship between shorter telomere length and brain volume,” Cooper added.

Experts note that this research was an observational study and therefore cannot establish cause.

“This study suggests a potential interesting association between LTL and different types of dementia/brain volume changes,” said Dr. Robert M Greenberg, a clinical professor of psychiatry (geriatrics) at the RWJ Rutgers Medical School as well as medical director for ECT, RWJ Barnabas Health who was not involved in the study.

“It may be a marker for modest to moderate increased risk for dementia in certain populations, but by no means is of current diagnostic utility, and the association has to be replicated by different labs and in different populations. I don’t see any major clinical utility at present. I also have no idea where such testing could be done, and it seems highly unlikely that any insurance would pay for it,” Greenberg told Medical News Today.

Limitations to the dementia study

There are several limitations noted in this study:

  • The telomere length was measured only once, so the scientists could not determine if changes over time might affect the risk of dementia.
  • The researchers obtained diagnoses from electronic health records that may not have had complete information.

“The effectiveness is still inconclusive,” Emer said. “While shorter telomeres are associated with various age-related conditions, including many causes of dementia, the study highlights that LTL alone may not reliably predict the individual’s risk of developing dementia. Its utility may depend on combining LTL with other clinical assessments and biomarkers for a more accurate prediction. Further research is needed to establish LTL testing’s role in dementia risk assessment and its practicality as a diagnostic tool, emphasizing the need for comprehensive evaluation methods.”

Despite the limitations, the researchers reported that leucocyte telomere length acted as an aging biomarker associated with the risk of dementia.

“Given the large variance in conclusive results. and the recency of these technologies, it is likely still too early for testing outside of the context of a research study,” Cooper said. “However, as these studies become more commonplace, what we learn will likely be valuable to our understanding of human health and treatment of disease.”

What to know about dementia

“Dementia is the loss of cognitive function – thinking, remembering, and reasoning – to such an extent that it interferes with a person’s daily life and activity,” according to the National Institute on Aging.

Worldwide, more than 55 million people have dementia, according to the World Health Organization. Risk factors for dementia include:

  • age (more common in those 65 or older)
  • high blood pressure (hypertension)
  • high blood sugar (diabetes)
  • smoking
  • drinking too much alcohol
  • physically inactivity
  • socially isolation
  • depression

Dementia can be caused by several diseases, with Alzheimer’s being the most common. No matter what the cause, some common symptoms are:

  • forgetting things or recent events
  • losing or misplacing things
  • getting lost when walking or driving
  • being confused, even in familiar places
  • losing track of time
  • difficulties solving problems or making decisions
  • problems following conversations or trouble finding words
  • difficulties performing familiar tasks
  • misjudging distances to objects visually
  • feeling anxious, sad, or angry about memory loss
  • personality changes
  • inappropriate behavior
  • withdrawal from work or social activities.

There is no cure for dementia, and there are only limited treatments. The life expectancy for a person with dementia depends on the type and the age of diagnosis.

  • For Alzheimer’s disease, the life expectancy is 8 to 10 years.
  • For vascular dementia, it is around 5 years, with an increase in the risk of stroke or heart attack.
  • For Lewy body dementia, the life expectancy is around 6 years, with an increase in the risk of falls and infection.
  • For frontotemporal dementia, the life expectancy is around 6 to 8 years

Caring for someone with dementia

“Treating patients with dementia requires the ability to recognize not only the medical needs, but the emotional, cognitive, and physical needs as well,” said Daniel Kevorkian, the vice president of clinical innovation and technology for Accent Care who was not involved in the study.

“It’s vitally important to develop person-centered care plans that affirm their human value, recognize their perspective and provide a supportive social environment. Care must be provided in a way that recognizes subtle changes in condition and anticipates need in order to prevent responsive behaviors,” he told Medical News Today.

People in the early stages of dementia may experience problems with forgetfulness and reasoning, according to

Some of the ways a caregiver can help include:

  • Help the person create “to do” lists for appointments and events
  • Plan events the person can enjoy at the same time every day
  • Use reminders for taking medication
  • Buy loose fitting comfortable clothes that are easy to put on and take off
  • Use a sturdy shower chair
  • Serve meals in a consistent and familiar place

“Familiarity, routine, and patience are key,” said Tracy Dent, the vice president of clinical operations for Accent Care who also was not involved in the study.

“For those with difficulty sitting for a meal, having healthy snacks they can consume on-the-go helps, ensuring safety for those who become confused at night is critical. Locks above their reach or security systems that alert when the door is open but do not startle or scare the patient are best practices,” she told Medical News Today.

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