Poor glycaemic control results in tooth loss in middle age, study finds

ŌTSU, Japan: In the largest study of its kind, researchers in Japan have analysed glycaemic control and natural tooth retention to investigate the association between the two. They have uncovered evidence that people with higher haemoglobin A1c (HbA1c) levels and elevated fasting plasma glucose (FPG) levels, indices of poor glycaemic control, have poorer tooth retention.

Speaking to Dental Tribune International, Dr Katsutaro Morino, one of the researchers and an assistant professor in the Division of Diabetology, Endocrinology, Nephrology and Neurology at Shiga University of Medical Science, said: “There have already been many reports on the relationship between diabetes and periodontal disease and the risk of tooth loss. We wanted to identify who are suitable subjects for an intervention. We thought it would be important to analyse data obtained from the real world with relatively large numbers to clarify the impact of fasting glucose and HbA1c levels on tooth loss among multiple age groups.”

For their large-scale study, the researchers employed the medical records and information from health insurance claims of 233,567 patients between 2015 and 2016. They split the patients, who were between 20 and 70 years old, into five ten-year age groups and then assigned them to five groups based on their HbA1c levels and three groups according to their FPG levels. The researchers then compared the number of natural teeth between the groups.

They found that, compared with patients with normal FPG levels, people with impaired fasting glucose levels were already at risk of fewer teeth between 40 and 69 years of age. Regarding the results, Dr Morino and his division colleague Prof. Hiroshi Maegawa highlighted that at-risk patients who smoked negatively impacted their likelihood of tooth retention. Additionally, they advised that those diagnosed with diabetes or prediabetes should improve their glycaemic control and undergo regular dental check-ups and that patients with high blood glucose levels should look to preventive oral care to protect against tooth loss. In another study using the same data, the high HbA1c group, which corresponded to HbA1c ≥ 7%, showed a lower retention rate regarding many tooth types, especially molars.

Commenting on how dentists can best implement the findings into their clinical practice, Dr Morino noted: “Since this is a cross-sectional study, caution must be exercised in interpreting causality. However, I believe that the importance of smoking cessation has been reaffirmed, as lifestyle improvement and oral care with awareness of blood glucose control are necessary from a young age to prevent tooth loss. I am convinced that collaboration between dentistry and internal medicine will lead to the prevention of mutual diseases and improvement of quality of life.”

The study, titled “Glycemic control and number of natural teeth: Analysis of cross-sectional Japanese employment-based dental insurance claims and medical check-up data”, was published on 28 August 2021 in Diabetology International, ahead of inclusion in an issue.