Those who received hospital treatment for infection in early and middle age have the highest risk in later years
Multiple hospital visits due to infection in the early and middle years of life may increase the risk of later Alzheimer’s and Parkinson’s disease. This was revealed in a paper by 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, 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’s disease in Sweden between 1970 and 2016, as well as data from five controls for each patient. All data were collected from the Swedish national patient registry.
The 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 before diagnosis had a 16 percent higher risk of developing Alzheimer’s. They also had a 4% higher risk of Parkinson’s disease. Similar risks were observed at bacterial, viral, and other sites of infection as well as at other sites of infection.
The disease risk was highest in those with multiple infections treated in the hospital before the age of 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 infection in early and middle age were mainly associated with an increased risk of Alzheimer’s disease and Parkinson’s disease diagnosed before the age of 60.”
“These findings suggest that infectious diseases may play a role in triggering or amplifying existing disease processes,” the researchers said. “This may lead to the onset of clinical neurodegenerative diseases at a relatively early age.” .
This study is an observational study, and the results of the study do not prove a formal causal relationship.
The study was published in PLOS Medicine. The original title was ‘Hospital-treated infections in early- and mid-life and risk of Alzheimer’s disease, Parkinson’s disease, and amyotrophic lateral sclerosis: A nationwide nested case-control study in Sweden’.