Association between weight-adjusted waist index and severe periodontitis using NHANES 2009-2014

Abstract

The Weight-adjusted Waist Index (WWI) is a novel anthropometric indicator for assessing obesity. Given the well-established association between obesity and periodontitis, this cross-sectional clinical study aimed to investigate the relationship between WWI and severe periodontitis while evaluating its potential as a simple predictive marker for periodontitis. The study analyzed periodontal examination data and WWI measurements from participants in the 2009-2014 National Health and Nutrition Examination Survey (NHANES), employing weighted logistic regression, smoothed curve fitting, and subgroup analyses. Among the 10,307 eligible participants, results demonstrated a significant positive correlation between WWI and the prevalence of stage III/IV periodontitis. After comprehensive adjustment for all confounding factors, each 1-unit increase in WWI was associated with a 1.19-fold higher risk of stage III/IV periodontitis (OR = 1.19, 95% CI 1.06-1.32, P = 0.007977). Subgroup analysis revealed that this association showed statistically significant variation only in the hypertension subgroup, indicating that the WWI-severe periodontitis relationship is particularly applicable to non-hypertensive individuals. These findings confirm that WWI can serve as a novel obesity-based predictive indicator for severe periodontitis.

Keywords: Cross-sectional study; NHANES; Obesity; Periodontitis; Weight-adjusted waist index.

Fig. 1

Flowchart of the sample selection from NHANES 2009–2014. A total of 30,468 participants were enrolled at first. After excluding participants missing the complete data about periodontitis examination (n = 19,784) and WWI (n = 377), 10,307 eligible participants were included in our final analysis.

Fig. 2

Smooth curve fitting for WWI and stage III/IV periodontitis. A nonlinear relationship between WWI and stage III/IV periodontitis was detected by the generalized additive model.The solid and dashed line denoted the estimated values and their corresponding 95% confidence interval, respectively. The adjusted factors involved gender, age, race, education level, marital status, PIR, alcohol consumption, smoking status, sleep disorder, physical activity, mental health (depression), hypertension, diabetes, frequency of using dental floss/devices, and BMI.

Fig. 3

Subgroup analysis for the association between WWI and stage III/IV periodontitis. The effect of WWI on severe periodontitis was consistent across subgroups of gender, BMI, diabetes, mental health, alcohol consumption, smoking status, sleep disorder, frequency of using dental floss/devices and physical activity status. An inconsistent interaction was demonstrated only in the hypertension subgroup (P for interaction = 0.0003).