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Brush Your Teeth for Decreased Risk of New-Onset Diabetes 

Mar 24, 2020
Editor: Steve Freed, R.PH., CDE

Author: Mit Suthar, PharmD. Candidate, LECOM School of Pharmacy 

Could decreasing systemic inflammation as a result of better oral hygiene lead to a decreased occurrence of new-onset diabetes?  

There are already many suggested preventative strategies for new-onset diabetes, including implementing a healthier lifestyle, maintaining proper weight and waist circumference, increasing regular exercise/physical activity, better dietary choices, and identifying risk factors. However, an argument can be made that the methods for prevention are still very lacking.  


A cross-sectional population-based sample demonstrated a positive correlation between inflammation and diabetes. Since periodontal disease is a microbially triggered chronic inflammatory disease, it follows that the release of inflammatory mediators as a result of poor oral hygiene can influence the occurrence of new-onset diabetes. Studies examining the relationship between oral health and incident diabetes are deficient and therefore, this study is a useful investigation. 

The primary aim of the study was to illustrate the relationship between periodontal disease and new-onset diabetes, with the secondary goal being to identify links between other oral hygiene indicators and new-onset diabetes in a dataset of a nationwide population-based cohort. 

The study analyzed data that was collected between 2003 and 2006. The dataset contained information on 188,013 subjects who had no missing data for demographics, past medical history, oral hygiene indicators, or laboratory findings from the National Health Insurance System-Health Screening Cohort (NHIS-HEALS) in Korea. The NHIS is supported by the Korean government and is the sole insurance provider which covers around 97% of the Korean population. 

The existence of periodontal disease was defined by a modified version of ICD-10 codes. Claims of treatment for acute periodontitis (K052), chronic periodontitis (K053), and periodontosis (K054) if made more than twice by a dentist or if the medical record indicated that a patient received treatment by a dentist for these treatments, were used as indicators for periodontal disease. 

Data about oral hygiene behaviors were self-reported and included the number of tooth brushings (0-1 time, two times, ≥3 times per day), a dental visit for any reason, and professional dental cleaning. Dental visits and professional dental cleanings were dichotomized as never or as at least once a year. Dentists established the number of missing teeth during an oral health examination. The number of missing teeth was defined as 0, 1–7, 8–14, and ≥15 irrespective of the cause, such as whether the missing teeth were due to periodontal disease or some other explanation. The most recent results from an oral health status examination were used if more than two dental visits occurred between 2003 and 2006.

The criteria for identification of incidence of new-onset diabetes was: “at least one claim per year for both visiting an outpatient clinic and admission accompanied by prescription records for any hypoglycemic agents. Alternatively, at least one fasting plasma glucose ≥7 mmol/l result from NHISHEALS led to a diagnosis of new-onset diabetes.” 

The included subjects had a mean age of 53.3 years old, 57.9% were men, 34.6% had hypertension, 16.9% had dyslipidemia, and 20.5% were current smokers.  Importantly though, 17.5% had periodontal disease: “44.0% of subjects visited a dental clinic for any reason, and 1.1% were missing 15 or more teeth. Moreover, 42.6% of the subjects brushed their teeth ≥3 times per day. Approximately 25.9% of the subjects had visited a dental clinic for professional dental cleaning at least once per year.” After a median follow-up of 10 years, 31,545 patients developed diabetes. This represented a 10-year event rate of 16.1% (95% CI 15.9%,16.3%) for new-onset diabetes. 

After adjusting for demographics, regular exercise, alcohol consumption, smoking status, vascular risk factors, history of malignancy and laboratory findings, multivariate analyses still found that the presence of periodontal disease (HR 1.09, 95% CI 1.07, 1.12, p < 0.001) and several missing teeth (≥15 teeth) was positively associated with the occurrence of new-onset diabetes (HR 1.21, 95% CI 1.09, 1.33, p < 0.001, p for trend <0.001). As hypothesized, frequent tooth brushing (greater than or equal to three times daily) was negatively associated with the incidence of diabetes (HR 0.92, 95% CI 0.89, 0.95, p < 0.001, p for trend <0.001).  

The results show that the frequency of tooth brushing indeed decreases the risk of new-onset diabetes and that the presence of periodontal disease and an increased number of missing teeth can increase the risk of new-onset diabetes. An earlier case-control study from Japan found that a lower frequency of tooth brushing was associated with a  higher odds ratio (OR 1.61) of diabetes. This data is encouraging because it shows just how easily subjects can decrease their risk for diabetes by brushing their teeth more frequently, along with the other myriad benefits of better oral hygiene in general! 

Practice Pearls: 

  • Inflammatory reactions due to periodontal disease and poor oral hygiene may be associated with an increase in the occurrence of new-onset diabetes 
  • The presence of periodontal disease and the more missing teeth you have, the higher risk you have for new-onset diabetes 
  • Frequent tooth brushing is associated with decreased risk of new-onset diabetes; therefore improved oral hygiene is recommended 

Change, Yoonkyung, et al. “Improved Oral Hygiene Is Associated with Decreased Risk of New-Onset Diabetes: a Nationwide Population-Based Cohort Study.” Link Springer, Diabetologia, 2 Mar. 2020, link.springer.com/article/10.1007%2Fs00125-020-05112-9. 


Mit Suthar, PharmD. Candidate, LECOM School of Pharmacy 


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