Poor oral health linked to reduced risk for IBD
Researchers observed an inverse association between poor oral health and risk for developing inflammatory bowel disease in a Swedish population-based cohort study.
The hygiene hypothesis — which “suggests that absence of microbial exposure due to improved hygienic conditions causes an immunological imbalance that predisposes to autoimmune diseases,” — has often been proposed as an explanation for the rising incidence of IBD. However, “the relationship between oral health and IBD has been debated as earlier studies show contradictory results,” Jonas F. Ludvigsson, MD, PhD, from Karolinska Institutet and Örebro University Hospital in Sweden, Weiyao Yin, MD, from Karolinska Institutet and West China Second University Hospital, and colleagues wrote.
Jonas F. Ludvigsson
To further investigate this relationship, they performed a population-based cohort study of 20,162 people followed from 1973 through 2012 (mean follow-up, 28 years), who were examined for tooth loss, dental plaques and oral mucosal lesions at enrollment. They also used the Swedish National Patient and Cause of Death Registers to identify individuals who later developed ulcerative colitis (n = 67) or Crohn’s disease (n = 142), and used Cox proportional hazards regression to estimate hazard ratios for IBD.
“To our knowledge, this is the first prospective cohort study exploring the association between oral health and IBD,” they wrote.
The overall IBD incidence rate was 37.3 per 100,000 person-years.
The researchers found that poor oral health was associated with a reduced risk for developing IBD, especially among patients with severe oral problems. Patients missing five to six out of the six Ramfjord index teeth at baseline had an HR for IBD of 0.56 (95% CI, 0.32-0.98), and the protective effect increased with deterioration of oral hygiene as indicated by all levels of tooth loss.
They also found that having dental plaques covering more than 33% of tooth surface was associated with a lower risk for Crohn’s disease (HR = 0.32; 95% CI, 0.1-0.97), but not ulcerative colitis. Oral mucosal lesions appeared to be protective against IBD, but these associations were not statistically significant.
“Our data on a negative relationship between poor oral health and later IBD supports the ‘hygiene hypothesis,’” the researchers concluded. “We believe that excessive oral hygiene might generate dysbiosis in bacterial colonization, dysregulate the innate immune responses and promote the inflammatory process. Conversely, poor oral health might contribute to the induction of immune tolerance and suppression of overreactive inflammation, thereby reducing the risk of immune-mediated diseases such as IBD.”
While good oral hygiene should not be discouraged based on these findings, “over-protective” daily hygiene warrants attention, they added. – by Adam Leitenberger
Disclosures: The researchers report no relevant financial disclosures.