Those who received hospital treatment for the infection in early and middle age have the highest risk in later years
Numerous hospital visits due to infections in the first and middle years of life can increase the risk of later developing Alzheimer’s disease and Parkinson’s disease. This was revealed by a document from the Karolinska Institute in Sweden. However, the association between recurrent infection and Lou Gehrig’s disease, or amyotrophic lateral sclerosis (ALS), has not been established.
Previous animal studies have shown that infection plays a role in the development of some neurodegenerative diseases. However, the evidence in humans has been limited. In the new study, the team used data from people diagnosed with Alzheimer’s, Parkinson’s and Lou Gehrig in Sweden between 1970 and 2016, as well as data from five controls for each patient. All data was collected from the Swedish National Patient Registry.
Subjects analyzed in the study included 293,941 Alzheimer’s disease, 103,919 Parkinson’s disease, and 11,161 ALS.
Those who were hospitalized for infection five years prior to diagnosis had a 16% higher risk of developing Alzheimer’s. They also had a 4% higher risk of contracting Parkinson’s disease. Similar risks were observed at bacterial, viral and other infection sites, as well as at other infection sites.
The risk of the disease was higher in those with multiple infections treated in hospital before age 40. Their risk of Alzheimer’s disease more than doubled and their risk of Parkinson’s disease increased by more than 40%. No association with ALS was observed regardless of age at diagnosis.
Professor Ji Yangwei-sun of the institute said: “In particular, those who received hospital treatment for the infection in early and middle age were mainly associated with an increased risk of Alzheimer’s and Parkinson’s diagnosed before age 60.”
‘These findings suggest that infectious diseases may play a role in triggering or amplifying existing disease processes,’ the researchers said. “This could lead to the onset of clinical neurodegenerative diseases at a relatively early age.”
This study is an observational study and the study results do not demonstrate a formal causal relationship.
The study was published in PLOS Medicine. The original title was “Early and Middle Age Hospital Treated Infections and Risk of Alzheimer’s, Parkinson’s Disease, and Amyotrophic Lateral Sclerosis: A Nationwide Nested Case-Control Study in Sweden”.
