The triglyceride-glucose (TyG) index, an indicator of insulin resistance, may be linked to higher odds of moderate to severe periodontitis, particularly in individuals with obesity, hypertension, and dyslipidemia, according to research published in the Journal of Periodontal Research.
Systolic blood pressure (SBP) levels partially explained the association, suggesting a potential connection between cardiometabolic issues and periodontal health and highlighting the complex interplay of systemic factors in periodontitis, the authors wrote.
"The TyG index was associated with increased odds of moderate/severe periodontitis, especially in individuals with obesity, hypertension, and dyslipidemia," wrote the authors, led by Ashish C. Kalhan of the National Dental Centre Research Institute in Singapore (J Periodontal Res, August 9, 2024).
The study analyzed data from nearly 6,000 U.S. adults ages 30 to 64 who underwent periodontal exams from 2011-2014 and were categorized as having moderate, severe, or mild to no periodontitis. The study examined the TyG index as the exposure, with systolic (SBP) and diastolic (DBP) blood pressure evaluated as mediators using the parametric G formula.
Analyses were adjusted for age, sex, ethnicity, poverty-to-income ratio, and smoking using inverse probability treatment weighting. Obesity (body mass index [BMI] ≥30 kg/m²), self-reported hypertension, and dyslipidemia (based on National Cholesterol Education Program-Adult Treatment Panel-III thresholds) were tested as effect modifiers, they wrote.
The TyG index was associated with increased odds of moderate/severe periodontitis (odds ratio [OR], 1.17; 95% confidence interval [CI], 1-1.36). Stratified analysis showed a stronger association in individuals with cardiometabolic conditions such as obesity (OR, 1.31; 95% CI, 1.06-1.60) compared to nonobese individuals (OR, = 1.06, 95% CI, 0.79-1.41), those with hypertension (OR, 1.22; 95% CI, 1.01-1.47) versus those without hypertension (OR, 1.09; 95% CI, 0.85-1.40), and individuals with dyslipidemia (OR, 1.18; 95% CI, 1.01-1.37) versus those without dyslipidemia (OR, 0.83; 95% CI, 0.42-1.64).
Furthermore, half of the total effect of the TyG index on moderate to severe periodontitis was mediated by SBP, with significant natural indirect (β = .08; 95% CI, 0.04-0.12) and direct effects (β = .08; 95% CI, 0.01-0.14). The controlled direct effect at SBP = 121 mm Hg was β = .11 (95% CI, 0.04-0.19), according to the results.
However, the study had limitations. Given the cross-sectional design of the study, a cause-and-effect relationship should be interpreted cautiously, as reverse causation cannot be entirely ruled out, the authors wrote.
"Mediation analysis showed the association to be partially explained by systolic blood pressure, highlighting a potential mechanistic link between cardiometabolic dysregulation and periodontal health and emphasizing the multifaceted interplay of systemic factors in the occurrence of periodontitis,” Kalhan and colleagues concluded.
