No Evidence for Transmission of Alzheimer Pathology Through Blood Transfusions

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If transmission of neurodegenerative diseases such as dementia of any type, AD, or PD does occur, it is rare.
If transmission of neurodegenerative diseases such as dementia of any type, AD, or PD does occur, it is rare.

There is no evidence that neurodegenerative brain diseases such as dementia of any type, Alzheimer Disease (AD), or Parkinson Disease (PD) can be transmitted through blood transfusions, according to a retrospective cohort study published in Annals of Internal Medicine.

A team of investigators led by Dr Gustaf Edgren, of the Karolinska Institute in Stockholm, analyzed the data of more than 40 000 patients in a nationwide Swedish-Danish transfusion database who had received blood between 1968 and 2012 from donors who were later diagnosed with dementia, AD, or PD.

The data from this group of patients were then compared with data from a total of 1.4 million patients who never received blood from donors with a subsequent diagnosis of any of these neurodegenerative disorders.

The researchers reported that 2.9% of identified patients received a blood transfusion from a donor who was later diagnosed with one of the studied neurodegenerative diseases. The investigators did cite possible insufficient statistical power as a limitation, but show that there is no evidence of transmission of any of these diseases through blood.

They estimated the risk of dementia of any type, AD, or PD, and found that the association between exposure to blood from donors later diagnosed with these disorders and diagnosis for dementia (hazard ratio, 1.04, 95% CI, 0.99-1.09), AD (hazard ratio, 0.99, 95% CI, 0.85-1.15), or PD (hazard ratio, 0.94, 95% CI, 0.78-1.14) was not significant.

The patients who received blood from donors who were later diagnosed with any of these diseases were followed for up to 44 years, and the experimental group and controls were matched for sex, age, residence, blood group, number of transfusions, and time since first transfusion.

The researchers did not draw conclusions about amyotrophic lateral sclerosis (ALS), as only 7 patients were exposed to blood from donors diagnosed with this disease. They used data on chronic hepatitis prior to and after implementation of hepatitis virus screening as a control, as it is known that this disease can be transmitted through blood.

“If transmission [of neurodegenerative diseases such as dementia, AD, or PD] does occur, it is rare,” the investigators concluded.

Reference

Edgren G, Hjalgrim H, Rostgaard K, et al. Transmission of neurodegenerative disorders through blood transfusion: a cohort study. Ann Intern Med. 2016. doi: 10.7326/M15-2421. [Epub ahead of print]

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