In a first-of-its-kind study, researchers analyzed the impact of obesity on the number and position of residual teeth by age groups in a study published in PLOS One. An increase in body mass index (BMI) was tied to tooth loss.
Researchers used an online database that combined data from health insurance claims and health check-ups to gather data on 234,000 participants ranging in age from 20 to 74. They examined whether smoking status increases the impact of obesity on residual teeth and whether obesity predicts the risk of tooth loss independently of other risk factors, including diabetes and smoking status.
An increase in BMI was associated with a decrease in the number of residual teeth from a younger age, according to the study's findings. Additionally, obesity was associated with the loss of residual molars in people over the age of 30. Smoking status also had an impact on tooth loss.
"The number of residual teeth decreased with increasing BMI in subjects over the age of 40," the study authors wrote, led by Mayu Hayashi from the research and development department at Sunstar Inc. in Osaka, Japan. "This finding is consistent with previous studies demonstrating that a high BMI and energy intake are associated with a reduced number of residual teeth in women ages 37-60, and that BMI and obesity are associated [with] tooth loss in individuals younger than 60 years old, regardless of age or sex" (PLOS One, September 14, 2022).
Previous studies have also shown that high BMI is associated with the progression of periodontal disease. Further, increased sugar intake is positively associated with both weight gain and the decayed, missing, and filled teeth (DMFT) index, an epidemiological index that describes the history of dental caries.
The studies suggest that "the progression of periodontal disease and dental caries could reduce the number of residual teeth in the populations with disease and dental caries could reduce the number of residual teeth in the populations with obesity," wrote the study authors.
The present study found that a high BMI is associated with a greater number of residual teeth in participants ages 20 to 40. Tooth extraction due to orthodontic treatment is common in people between the ages of 10 and 40 worldwide, and people with obesity often have poorer oral hygiene habits.
"Thus, young subjects with obesity may have fewer tooth extractions as a result of orthodontic treatments due to poorer awareness of dental maintenance," the study authors wrote. "Therefore, the low prevalence of tooth extraction as a result of orthodontic treatment in subjects with obesity in their 30s and 40s may explain the association between BMI and the number of residual teeth we observed in this population."
Further, the percentage of participants with residual teeth decreased with age, specifically in participants over the age of 30. In obese subjects, significant tooth loss is more commonly found in the maxillary area than in the mandibular area.
"As people with obesity have a higher risk of developing progressive periodontal disease, occlusal trauma may have significantly impacted the molars," explained the study's authors.
The present study also confirmed that smoking status increases the risk of tooth loss in obese individuals. A recent study found that individuals who quit smoking did not have an increased risk of tooth loss compared with individuals with no history of smoking.
"This suggests that smoking cessation is important for preventing tooth loss in people with obesity," wrote the study authors.