A recent study published in the journal Nature Medicine has revealed that five patients in the United Kingdom have developed Alzheimer's disease as a result of contaminated injections they received as children several decades ago. This groundbreaking research has the potential to reshape our understanding of the causes of dementia and has raised concerns among patients who underwent similar therapy.

The five patients in the study received injections of human growth hormone from cadavers over a period of several years to treat very short stature. What scientists discovered was that the hormone extracted from the cadavers' pituitary glands was contaminated with amyloid-beta protein, which is associated with the formation of the brain plaques seen in Alzheimer's disease. The study authors admitted that they do not fully understand how exposure to these proteins can trigger the development of plaques and tangles in the brain, the key characteristics of Alzheimer's disease.

Typically, Alzheimer's cases are categorized into those caused by genetic mutations and those that develop sporadically in older individuals due to various risk factors such as smoking, obesity, and high blood pressure. However, the patients in this study did not fall into either of these groups. They experienced symptoms of dementia between the ages of 38 and 55 and did not possess any genetic mutations associated with early-onset dementia.

This study introduces a potential third pathway for the development of Alzheimer's disease: contaminated medical products. Doctors who specialize in treating hormone-related conditions were surprised by these findings, as the connection between Alzheimer's and a medical treatment was previously unknown. The revelation that a once-regarded safe therapy could cause harm has prompted concerns among medical professionals.

While the findings of this study were based on a small sample size, Christopher Weber, director of global science initiatives at the Alzheimer's Association, stated that the credibility of the research would be enhanced if other scientists can reproduce similar results in future studies.

It is important to note that Alzheimer's disease is not contagious and cannot be transmitted through contact, proximity, or caregiving. Nevertheless, previous studies have demonstrated the ability to induce abnormal amyloid buildup in animals by injecting them with amyloid-beta, and human Alzheimer's genes have been transferred to animals to initiate Alzheimer's-like processes in their brains.

The administration of cadaver-derived growth hormone occurred worldwide between 1959 and 1985, with approximately 27,000 children receiving such treatment, including around 7,700 patients in the United States. Synthetic growth hormone has been used for treating short stature in children since 1985, eliminating the risk associated with the cadaver-derived hormones.

Lead study author Dr. John Collinge, a neurologist and the director of the University College London Institute of Prion Diseases, emphasized that although other individuals who received cadaver-derived hormones could be at a higher risk of developing Alzheimer's, the overall transmission risk is believed to be very low, resulting in a rarity of cases.

Dr. Collinge advises patients to be aware of the potential risk for Alzheimer's and seek testing and treatment if necessary. Patients receiving treatment for short stature today are not considered at risk due to the use of synthetic growth hormone.

Dr. Paul Kaplowitz, a professor emeritus at Children's National Hospital, explained that U.S. manufacturers developed safer purification methods for cadaver-derived human growth hormone in 1977, significantly reducing the risk of contamination. He believes that if contamination were a substantial issue, numerous cases would have been reported by now.

The study initially focused on the risk of Creutzfeldt-Jakob disease (CJD), a rare and fatal condition caused by contaminated hormone samples. More than 250 growth hormone patients have been diagnosed with CJD globally, with 35 deaths in the U.S. alone. CJD is related to bovine spongiform encephalopathy, commonly known as mad cow disease. However, it remains uncertain whether the proteins responsible for Alzheimer's can be transmitted through blood transfusions or organ donations.

Dr. Collinge and his team's research has shed light on the potential link between contaminated injections received in childhood and the development of Alzheimer's disease. While further research is needed to confirm these findings, their work serves as a reminder of the importance of monitoring and assessing the safety of medical products throughout their administration.

As the prevalence of Alzheimer's disease continues to rise globally, understanding its causes and identifying potential risk factors becomes crucial in developing effective prevention and treatment strategies for this debilitating condition.