Pathological gum inflammation is associated with minor brain damage in elderly people

The study compared a cohort of patients with periodontal disease with others who had “healthy mouths”. The study found a significant relationship (after eliminating confounding factors, i.e. those factors known to be associated with brain damage) between periodontal disease and damage to the brain's white matter. These “spots” on the brain, which are nothing more than small scars caused by cardiovascular risk factors or simply age, may be related to brain ageing, stroke risk or dementia (specifically, vascular dementia).

This article joins the stream of articles published over the last decade and a half that attempt to link periodontal disease with multiple factors such as cardiovascular disease, stroke, vascular damage, dementia, and even brain atrophy. The results must be interpreted with caution, firstly because there was a long time between the dental check-up and the [brain] MRI scan, and secondly because it is an observational study that does not allow for a clear causality to be demonstrated.

The study is based on solid data and methods, and its main strength is the fairly high number of patients. However, as previously mentioned, it is an observational study with the limitations that this entails. The most significant limitation in this study is the long time between the dental analysis and the MRI scan.

It provides more information and evidence on several previous studies of a similar nature, i.e., those seeking a relationship between periodontal disease and various types of brain damage. The main novelty probably lies in the number of patients and the apparent follow-up time, although it is not a “real” follow-up but rather a cohort of patients. It does not, in itself, contribute anything radically new, as there are previous articles that already described this relationship between periodontal disease and vascular damage, albeit with fewer patients. Without going any further, there is a similar Japanese study from 2020, although with fewer patients.

Unfortunately, the relevance of this study is limited. The reality is that we have been studying and trying to report on the possible relationship between periodontal disease and various factors of brain damage for about a decade. It would be interesting to be able to refer patients who we believe to be at high risk of vascular disease or dementia for a complete oral assessment through the national health service.

The recommendations are clear, although this has been known for a long time: good oral health must be maintained, not only for dental health itself (which is something we all understand) but also for its possible future implications for factors such as vascular damage or even brain damage and atrophy. This is especially important in people with high vascular risk or high risk of dementia.

Is the study based on solid data and methods?

"This study is an analysis of data from the ARIC study combining dental and neurological variables. This study presents a rigorous and correct methodology for the hypothesis to be tested by the authors. In addition, it includes a 15-year follow-up of the participants. This makes the study design ideal for investigating whether, in this particular case, periodontitis may be a risk factor for white matter lesions.‘

How does it fit in with previous work? What new information does it provide?

’There are previous studies that associate tooth loss or edentulism with white matter lesions in the brain. However, this study provides new prospective (longitudinal) evidence on the effect of periodontitis on this type of lesion.‘

Are there any important limitations to consider?

’The definition used in the study for cases of periodontitis is not the one recommended by the American Academy of Periodontology and the European Federation of Periodontology. In the study, the prevalence of periodontitis is 70%, which seems a little high compared to other epidemiological studies and may overestimate the number of cases of periodontitis. Furthermore, the analysis does not include the different degrees of severity of periodontitis (mild, moderate and advanced), which would provide more information for the study. Based on previous studies, it is the more advanced forms that are associated with neurological diseases such as stroke or dementia. Regarding the analysis of other forms of small vessel brain disease, the authors did not find statistically significant results. The small sample size of patients with microbleeds (25%) or lacunar stroke (17%) may have influenced these results.