AsianScientist (May 23, 2016) – Multiple tooth loss and its related oral diseases could be linked to the development of vascular cognitive impairment (VCI) in stroke patients, reveals a study by researchers in Hong Kong. It was published in the Journal of Periodontal Research.
Tooth loss in adults worldwide, particularly in the elderly population, is primarily caused by severe periodontitis, a common peripheral infection and inflammation. Periodontitis leads to the destruction of tooth-supporting tissue and alveolar bone, and is also related to systemic inflammation. The latter is a well-documented risk factor, among others, for Alzheimer’s disease.
The present study, led by the Professor Jin Lijian from the University of Hong Kong, points out that multiple tooth loss does not only indicate poor oral health, but also could be a sign of Alzheimer’s disease or dementia.
Researchers examined and evaluated 161 acute ischemic stroke patients (mean age 63.8) for medical, oral and cognitive conditions. They found that the patients who had a higher amount of tooth loss of around eight teeth tended to get lower scores on the Montreal Cognitive Assessment, a test designed for clinicians to detect cognitive impairment.
The subjects with higher number of missing teeth also exhibited a significantly higher proportion of VCI than those with seven or less missing teeth.
The findings of the study showed that apart from stroke history, the number of teeth lost could be an independent risk factor of VCI in subjects with acute stroke. This association between tooth loss and VCI in the subjects remained statistically strong even after adjusting for cofounding factors such as gender, congenital heart defects, smoking status, drinking habits, and cholesterol and low-density lipoprotein levels.
Jin said the finding is consistent with some emerging studies around the world that showed a relationship between tooth loss and cognitive function. He added that there are some potential pathways that account for the association of multiple tooth loss with cognitive impairment in subjects with acute ischemic stroke.
“Currently, the well-documented risk factors for Alzheimer’s disease include cerebrovascular disease and its related vascular risk factors, and many of them are significantly associated with systemic inflammation that links to periodontitis and other oral diseases,” he said.
As periodontal disease and other oral diseases can increase the systemic level of inflammation, they may therefore contribute to the development of cognitive impairment, according to Jin.
Another possible factor underlying the connection between multiple tooth loss and cognitive decline was reduced mastication, due to edentulousness, or lack of teeth. Jin explained that edentulousness could have an impact on normal chewing function, which helps maintain the sensory input from the periodontal mechanoreceptors around the tooth roots, transmits spatial information of tooth loading to the brain and maintains neuronal activity.
Some evidence has suggested a possible connection between brain function and mastication. This was further supported by animal studies which connected reduced mastication due to tooth loss to impairment of spatial memory, weakening of learning ability and degeneration of hippocampal neurons in the brain.
While the findings may point to the fact that tooth loss and its related oral diseases could be a risk factor contributing to cognitive impairment, Jin called for greater focus on prevention of oral diseases. There are also the possible health benefits of providing holistic oral care and regular supportive periodontal care to ageing populations.
The article can be found at: Zhu et al. (2015) Multiple Tooth Loss is Associated with Vascular Cognitive Impairment in Subjects with Acute Ischemic Stroke.
Source: University of Hong Kong; Photo: Shutterstock.
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