A study from Helsinki University Hospital, Finland suggests that excessive usage of certain antibiotics may increase one’s risk of developing Parkinson’s later on in life.

For the study, researchers took data from national registries to compare antibiotic exposure between 1998 and 2014 of 13,976 patients with Parkinson’s disease and 40,697 people without the condition. Matching the datasets for age, sex and place of residence, they measured patients’ antibiotic exposure over three time periods: 1-5, 5-10 and 10-15 years according to infromation on oral antibiotic purchase.

During their analysis, they considered exposure to be the number of courses purchased by each patient. Meanwhile, the “quality” of each exposure was investigated by categorizing each antibiotic by chemical structure, antimicrobial spectrum and mechanism of action.

Looking at the results, the researchers found that broad spectrum antibiotics, such as Amoxicillin, and those that act against anaerobic bacteria and fungi, were particularly associated with the development of Parkinson’s later on in life. They also found that their effects were usually not immediate, and had a delay of 10 to 15 years following exposure.

According to research team leader, neurologist Filip Scheperjans, “It was known that the bacterial composition of the intestine in Parkinson's patients is abnormal, but the cause is unclear. Our results suggest that some commonly used antibiotics, which are known to strongly influence the gut microbiota, could be a predisposing factor.”

Pathological changes in the gut indicative of Parkinson’s disease have been observed up to 20 years prior diagnosis. Meanwhile, other gut issues including constipation, irritable bowel syndrome and inflammatory bowel disease have also previously been associated with a higher risk of developing the disease. As exposure to antibiotics has been shown to change the gut microbiome, and has thus been shown to increase risk factors for other diseases such as Crohn’s disease, researchers are keen to investigate the link between gut health and Parkinson’s further.

Scheperjans said, “The discovery may also have implications for antibiotic prescribing practices in the future. In addition to the problem of antibiotic resistance, antimicrobial prescribing should also take into account their potentially long-lasting effects on the gut microbiome and the development of certain diseases.”

Sources: EurekAlert, Medical News Today and Wiley Online Library