Alzheimer’s Disease Has Been Linked to Decades-Old Medical Procedure

By: Alyssa Miller | Published: Jul 09, 2024

Researchers at University College London are examining medical procedures performed decades ago that seem to have triggered cases of Alzheimer’s disease.

In this new study, key cases of the brain disorder show a link between them and a growth hormone treatment.

What Is Alzheimer’s?

Alzheimer’s is a type of dementia that affects memory, thinking, and behavior. Those with a family history of Alzheimer’s are at higher risk as they age, or if they have certain medical conditions or unhealthy lifestyle behaviors.

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In the US, nearly 5.8 million people have Alzheimer’s disease and related dementias. According to the Centers for Disease Control and Prevention, individuals 65 years old or older account for the majority of these cases, but about 200,000 cases occur in people under 65.

Looking At a Cause for Alzheimer’s 

In a new study published in “Nature Medicine,” researchers focused on a procedure in which doctors administered a type of human growth hormone, c-hGH, extracted from deceased people’s pituitary glands.

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The study notes that this growth hormone treatment has led to a greater amount of amyloid-beta protein in the brain. An excess of this protein could cause Alzheimer’s.

The Connection Between the Decline

The study looked at eight people who received the treatment as children. Five of these patients developed symptoms of dementia and were diagnosed with Alzheimer’s.

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According to the study, the five patients who developed the brain disorder began to show signs of cognitive decline between the ages of 38 and 55.

The Cause In the Five Patients

“We have found that it is possible for amyloid-beta pathology to be transmitted and contribute to the development of Alzheimer’s disease,” the author of the study, Dr. Gargi Banerjee, who is also a researcher at the UCL Institue of Prion Diseases, said in a press release.

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“This transmission occurred following treatment with a now-obsolete form of growth hormone, and involved repeated treatments with contaminated material, often over several years.”

Similar to a Prion Disease 

The researchers wrote in their study that Alzheimer’s disease may be transmissible in certain circumstances, potentially spreading like “prion diseases.”

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While Alzheimer’s is not a prion disease, separate research suggests that the two proteins that are hallmarks of the disease—amyloid beta and tau—behave like prions.

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Nothing to Fear

However, the general public has nothing to fear. The researchers found that Alzheimer’s disease can be transmissible in certain circumstances after the transmission of amyloid beta protein from a cadaver’s growth hormone to a recipient was feasible.

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However, experts consider this type of transmission “rare,” and there is no suggestion that amyloid beta can be transmitted to people.

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Not Transmittable From Person to Person

While the procedure these patients underwent may have caused early-onset Alzheimer’s, the study emphasizes that the disease cannot be transmitted through person-to-person contact.

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“There is no suggestion whatsoever that Alzheimer’s disease can be transmitted between individuals during activities of daily life or routine medical care,” Professor John Collinge, lead author of the study and the director of the UCL Institute of Prion Disease, said.

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The Medical Treatment That Caused the Problem

The study found that all five adults had growth hormone deficiency as children, and received pituitary growth hormones prepared in a specific way from cadavers that promoted growth in children.

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They suspended the medical treatment in 1985 after finding it caused degenerative brain disorders leading to dementia and death.

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This Procedure Treated People Around the World

According to the study, before authorities suspended the practice in 1985, they treated about 18,480 people in the UK with a human growth hormone derived from a cadaver’s pituitary gland.

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At the time, doctors also used this treatment in other parts of the world, including the US. Repeated exposure over multiple years to the human growth hormone contaminated by both prions associated with Creutzfeldt–Jakob disease and amyloid beta seeds could transmit Alzheimer’s disease.

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A Rare Occurrence

“The patients we have described were given a specific and long-discontinued medical treatment that involved injecting patients with material now known to have been contaminated with disease-related proteins,” Collinge said.

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“I should emphasize these are very rare occurrences, and the majority of this relates to medical procedures that are no longer used,” Collinge said in a news briefing (via CNN Health).

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Treatment for Alzheimer’s

Treatment for Alzheimer’s can help people manage the mild to moderate symptoms of the cognitive disease. Doctors can prescribe US Food and Drug Administration-approved medications for those dealing with the disease, but they should carefully consider some drugs before use.

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Most people living with Alzheimer’s have caregivers who should monitor them closely for side effects from these medications.

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