Adult tooth loss linked to increased risk of diabetes, according to new 45 and Up research

Significant tooth loss in older adults is linked to developing diabetes, although it’s not yet clear why, according to new research using data from the 45 and Up Study.

Researchers from the University of Sydney found that older adults with fewer than 20 of their own teeth – one-third of participants in the Study – increased their later risk of diabetes by up to 20%. The researchers also found that participants who had diabetes along with significant tooth loss had up to 24% greater risk of developing heart or limb complications, and up to 19% greater risk of developing kidney or eye complications. More than half the participants with diabetes had fewer than 20 of their own teeth.

The findings, published in two papers in Diabetes Research and Clinical Practice, are important because such a large proportion of Australians are affected, says co-lead author Dr Alice Gibson. “The increased risk of diabetes and diabetic complications is moderate, but on a population level it really adds up,” says Dr Gibson. “Especially when you consider the impact that diabetic complications have on individuals, their families and society and the healthcare system in general.”

Data from more than 200,000 participants in the 45 and Up Study were used to investigate the link between tooth loss and diabetes. The researchers looked at tooth loss as reported by participants in the first survey of the 45 and Up Study, as well as linked data on participants’ medical and pharmaceutical claims and hospitalisations up until 2019.

Tooth loss is viewed as a general indicator of oral health, often caused by untreated gum disease.  The use of self-reported data on tooth loss for this kind of research is not common, says Dr Gibson. “Most of the previous studies looking at oral health and the risk of diabetes or diabetes complications have used a costly measure of oral health which require a dentist to perform an oral exam,” she says. “That’s what made the 45 and Up Study so helpful for this research – it’s one of the few data sets to collect self-reported oral health information.”

The findings will help health professionals caring for people at risk of or with diabetes but have the potential for greater impact, Dr Gibson says. “We hope our research informs guidelines on screening for diabetes and on oral health as part of routine diabetes care. We also want this work to advocate for better access to dental healthcare.”

Why the link between oral health and diabetes? 

This research doesn’t show a direct causal link between oral health and diabetes but there are popular theories on the connection, says Dr Shalinie King, co-author of both papers and Senior Lecturer at the University of Sydney Dental School.

“It’s thought that gum disease which is essentially an inflammatory condition of the oral tissues triggered by the build-up of bacteria could cause general inflammation in the body, increasing the risk of diabetes,” Dr King says. Oral bacteria could also enter the blood stream and lodge in organs like the pancreas or liver, leading to inflammation and an increased risk of diabetes.

Having diabetes also increases the risk of developing gum disease – the relationship goes both ways, adds Dr King. “Anyone diagnosed with diabetes should be made aware that they need to monitor the health of their gums more closely in order to prevent the loss of teeth,” she says.

Hopefully more research can be done to understand oral health outcomes in people with chronic disease, Dr King says. “Diabetes, heart disease, kidney disease and cognitive decline have all been linked to inflammation,” she says.

“We also need research to look at how we can better integrate basic oral health care into broader chronic disease management. The Australian health system treats oral health separate to general health but the two are connected and we need to look at ways to better integrate the two.”