Missing teeth linked to dementia risk, but the reason remains elusive

The loss of teeth has been linked to an increased risk of developing dementia and cognitive impairment later in life, but the reasons aren't quite known at this time. According to the study, which comes from New York University, the more teeth a person loses over their life, the greater their chances of suffering from cognitive impairment or developing dementia.

Many risk factors for dementia exist, quite a number of which are related to lifestyle. The association between tooth loss and this risk may be another to add to the list, though the researchers note there could be multiple reasons that explain the link between the two. The research is a meta-analysis of 14 existing studies on cognitive impairment and tooth loss.

More than 34,000 adults were covered by these studies, of which there were more than 4,600 cases of "diminished cognitive function," according to the researchers. After controlling for other potentially influential risk factors, the analysis linked tooth loss with 1.48 times greater risk of cognitive impairment and a slightly lower 1.28 times higher risk of dementia.

There was an interesting exception, however, which is that adults who had missing teeth but who had also received dentures weren't at any sort of significant risk of cognitive impairment. Likewise, the analysis found that the risk increased with the more teeth someone was missing — this is noted as a "dose-response relationship" between the two.

What could explain the association between tooth loss and cognitive decline risk? There could be multiple explanations, with the researchers pointing out that gum disease is a major cause of tooth loss and has also been linked to cognitive decline. As well, tooth loss points toward disadvantages in one's life that could have contributed to other risk factors for dementia.

Beyond that, tooth loss can make it harder to chew and this, the researchers suggest, may cause some brain changes or simply result in nutritional deficiencies that increase the risk of cognitive decline.