Press Release

Dental is the new mental: retaining natural teeth reduces depression symptoms

The impact of oral health on well-being has often been neglected. One of the main reasons for such neglect could be the previous absence of evidence for links between oral health and other relevant health outcomes. In a new publication in Epidemiology and Psychiatric Sciences, a team of researchers from Japan, the Netherlands, Germany, and the UK investigated that losing more natural teeth causally increased depression symptoms. 

Oral diseases are among the most prevalent diseases worldwide. However, oral health has often been neglected in the past. This study substantiates that good oral health is essential to general health and well-being. This is the first study to demonstrate the causal effect of oral health on a key component of human well-being, that is, mental health. The findings emphasize the substantial relevance and value of oral health for individuals and society as a whole.

Natural experiment study 
An experiment is a scientific tool investigating cause-effect relationships, whereby fixing conditions other than the factor of interest in laboratory settings or randomly allocating medical treatment in clinical studies. However, it is ethically not possible to randomly assign tooth loss in the population and follow them to see whether their mental health is reduced. The researchers utilized a quasi-random variation in tooth loss due to differential childhood exposure to drinking water fluoride in the US as a natural experiment. 

Tooth loss causes depressive symptoms 
The researchers analyzed the data of 169,061 adults from the Behavioral Risk Factor Surveillance System. Being exposed to fluoridated water in childhood prevented losing teeth, and retaining more natural teeth reduced depressive symptoms. Losing ten or more teeth had an impact comparable to adults with major depressive disorder not receiving antidepressant drugs. 

Journal Article

JOURNALEpidemiology and Psychiatric Sciences

TITLE:Causal effect of tooth loss on depression: evidence from a population-wide natural experiment in the USA 



Correspondence to

Yusuke Matsuyama,Assistant Professor

Department of Global Health Promotion,
Graduate School of Medical and Dental Sciences,
Tokyo Medical and Dental University(TMDU)

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