Grit Your Teeth for a Lesser-Known Complication of Diabetes

Marlene Busko 

May 11, 2022

Type 2 diabetes was associated with a 20% increased risk of tooth loss after adjusting for multiple other risk factors in a meta-analysis of 22 recent observational studies from around the world.

The risk of tooth loss with type 2 diabetes (versus no diabetes) ranged from 15% higher in cross-sectional studies to 29% higher in cohort studies to five times higher in case-control studies.

"For diabetes, there are various known complications that are considered in [patient] treatment and management, including neuropathy, nephropathy, cardiovascular [disease] and hypertension, and kidney disease," senior author Abdolhalim Rajabi, PhD, told Medscape Medical News in an email.

"However, a chronic complication of this disease, which may be less noticeable and less tangible, is missing teeth, which can also exacerbate other complications” in patients with diabetes," Rajabi, a biostatistician at Golestan University of Medical Sciences, Gorgan, Iran, continued.

The meta-analysis showed that "physicians should pay attention to [dental health] in the management and control of diabetic patients," he summarized.

The analysis by Amir Reza Ahmadian, DDS, dean of the Faculty of Dentistry, Golestan University of Medical Sciences, and colleagues was recently published in BMC Endocrine Disorders.

"Our study is the first comprehensive meta-analysis about the association between [type 2 diabetes] and tooth loss," Ahmadian and colleagues write. It summarizes articles in dentistry and medicine about "an important question," the relationship between type 2 diabetes and tooth loss.  

Nevertheless, "large-scale prospective studies are needed to validate the current results in the future," they conclude.

Oral Complications of Diabetes

Diabetes increases the risk of oral disease directly by a gingival inflammatory response and indirectly by decreased saliva production due to antidiabetic medications.

Oral complications arising from this include dry mouth, tooth decay, and periodontal disease (gum disease). The latter ranges from gingivitis (gum inflammation) to severe periodontal disease (periodontitis) that can lead to tooth loss, the authors explain.

About a third of people with diabetes have severe periodontal disease, and the American Diabetes Association estimates that one in five cases of tooth loss in adults is related to diabetes.

Tooth loss has decreased over the past decades but is still a major health problem and is associated with poorer quality of life as well as risk of cardiovascular disease, hypertension, stroke, and cancer.

Previous studies and meta-analyses of the relationship between type 2 diabetes and tooth loss have reported inconsistent findings, and they did not include several more recent studies.

Therefore, Ahmadian and colleagues performed a meta-analysis of 13 cross-sectional, six cohort, and three case-control studies that investigated the link between type 2 diabetes and tooth loss published from 2007 to 2021.

Eleven studies were from North and South America: Brazil (2), Columbia (1), Mexico (2), and the United States (6). Seven studies were from Europe: Belgium (1), Finland (2), France (1), Germany (2), and Portugal (1). Four studies were from the Middle East and Asia: Saudi Arabia (1), South Korea (1), Thailand (1), and Yemen (1).

Diabetes was diagnosed based on glucose or A1c levels in half the studies and based on self-report in the other studies. Most studies investigated any tooth loss (16 studies) and the rest only considered loss of five or more teeth.

The meta-analysis included 677,532 patients, ranging from 60 to 379,021 patients per study. Most studies (77%) were judged to be of moderate or high quality.

The studies adjusted for confounders including age, sex, place of residence, education, lifestyle factors (smoking, alcohol consumption, physical activity), use of medications and vitamin supplements, and health insurance.

Overall, after adjusting for confounders, participants with type 2 diabetes had a significantly 20% greater risk of tooth loss than participants without diabetes (adjusted odds ratio [OR], 1.20; P < 0.001).

The association persisted in the different study types. The risk of tooth loss was highest in the case-control studies (OR, 5.10), but was also significantly higher in the cohort (OR, 1.29) and cross-sectional studies (OR, 1.15).

The association "was also present in other subgroups, including...method of diagnosing type 2 diabetes, continent, study quality, and number of tooth loss," the researchers write.

"This event seems to be in line with what has been reported in other epidemiologic studies, as several cases have supported the link between diabetes, periodontal disease, and tooth decay," which "are two common reasons for the endpoint of the tooth loss parameter," they note.

The researchers did not find any publication bias. However, most of the studies were cross-sectional, so they cannot determine a causal relationship between diabetes and tooth loss.

The authors have reported no relevant financial disclosures.

BMC Endocr Disord.  Published online April 13, 2022. Article

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