Diseases of tooth-supporting tissues, such as severe gingivitis and periodontitis, appear to increase the risk of developing and rupturing a cerebral artery aneurysm, according to a recent doctoral study from Finland based on 13 years of follow-up data.1

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Joona Hallikainen

Around 2–3% of adults have a cerebral artery aneurysm, which, if ruptured, can cause a life-threatening subarachnoid haemorrhage. High blood pressure and smoking are known risk factors, but many patients have no identifiable risks, suggesting that not all contributing factors are yet understood. Previous studies have even detected DNA from oral bacteria in the walls of both ruptured and unruptured aneurysms, hinting at a possible role in disease progression.

In his doctoral research, dentist and oral and maxillofacial surgeon Joona Hallikainen (pictured) found that widespread gingivitis and severe periodontitis increased both the prevalence and rupture risk of aneurysms over a 13-year follow-up. Tooth decay, however, did not show such an association.

The study included patients with unruptured or ruptured cerebral aneurysms treated at the neurosurgery outpatient clinic of Kuopio University Hospital in central eastern Finland. The age- and gender-adjusted participant group from the Health 2000 survey in the Northern Savo region was used as a control group. The Health 2000 survey was a nationwide study carried out in Finland in 2000–2001 to assess the population's health, functional capacity, and welfare.

Dr Hallikainen's work also confirmed a link between oral bacteria and aneurysms. Blood samples from aneurysm patients contained antibodies against Porphyromonas gingivalis and Aggregatibacter actinomycetemcomitans, two bacteria typical of periodontal disease. The magnitude of this immune response correlated with aneurysm occurrence and rupture. Histological analysis of two aneurysm wall samples further suggested exposure to P. gingivalis.

According to the research, oral bacteria may contribute directly by infiltrating the aneurysm wall, or indirectly through systemic inflammation. Dr Hallikainen's findings highlight the importance of maintaining good oral health – especially gum health – for individuals with unruptured aneurysms. Future research will need to determine whether treating oral diseases could help prevent aneurysm formation or rupture.