Central adiposity indices and inflammatory markers mediate the association between life's crucial 9 and periodontitis in US adults

Abstract

Background: Periodontitis, a chronic inflammatory disease, is closely linked to cardiovascular health. While Life's Essential 8 (LE8) evaluates cardiovascular metrics, recent recommendations suggest incorporating psychological health (PHQ-9) to form Life's Crucial 9 (LC9). However, evidence regarding the utility of LC9 in periodontal disease remains limited.

Methods: We analyzed data from 7,674 adults in the 2009-2014 NHANES cycles. LC9 scores were calculated by integrating LE8 and PHQ-9 metrics, then categorized into quartiles. The association between LC9 and periodontitis was examined using weighted logistic regression, restricted cubic spline (RCS), subgroup and WQS analyses. Mediation analysis assessed the roles of central adiposity (ABSI, WWI) and systemic inflammation (SII, SIRI).

Results: Higher LC9 scores were associated with lower periodontitis prevalence (29.4% in highest vs. 52.1% in lowest quartile; P < 0.001), with a 15.5% risk reduction per 10-unit increase (OR = 0.845; 95% CI: 0.795-0.897). WQS analysis identified nicotine exposure, sleep health, blood glucose, blood pressure, and depressive symptoms as key contributors. Mediation analysis showed partial effects through WWI (21.617%), ABSI (10.869%), SIRI (7.120%), and SII (5.351%). LC9 did not significantly outperform LE8 in prediction.

Conclusions: Higher LC9 score is linked to reduced periodontitis prevalence and severity, with central adiposity and systemic inflammation partially mediating this relationship. These findings emphasize comprehensive cardiovascular health management may help reduce periodontal disease risk.

Keywords: Abdominal fat; Cardiovascular health; Central adiposity; NHANES; Oral health; Periodontitis; Systemic inflammation response.

Fig. 1

Flow chart of the sample selection

Fig. 2

Age-adjusted prevalence of periodontitis in different levels of Life’s Crucial 9 score

Fig. 3

Dose–response relationships between Life’s Crucial 9 and periodontitis. (A) Unadjusted; (B) Adjusted for age, gender, race/ethnicity, PIR, marital status, education level, alcohol consumption, health insurance and dental floss/device. ORs (solid lines) and 95% confidence levels (dotted lines). Abbreviations: OR, odds ratio; CI, confidence interval; LC9, Life’s Crucial 9

Fig. 4

Subgroup analysis for the associations between per Life’s Crucial 9 10-score increase and periodontitis. The multivariable model is adjusted for age, gender, race/ethnicity, PIR, marital status, education level, alcohol consumption, health insurance and dental floss/device except the corresponding stratification variable. Abbreviations: OR, odds ratio; CI, confidence interval; PIR, poverty-to-income ratio

Fig. 5

WQS analysis of LC9 metrics and Periodontitis. Models were adjusted for age, gender, race/ethnicity, PIR, marital status, education level, alcohol consumption, health insurance and dental floss/device. Abbreviations: WQS, Weighted Quantile Sum, PHQ-9, Patient Health Questionnaire-9; HEI, Healthy Eating Index; LC9, Life’s Crucial 9; PIR, poverty-to-income ratio

Fig. 6

ROC curve for predictive ability of LC9 compared to LE8 for periodontitis

Fig. 7

Estimated proportion of the association between LC9 and periodontitis mediated by ABSI (A), WWI (B), SII (C) and SIRI (D). Models were adjusted for age, gender, race/ethnicity, PIR, marital status, education level, alcohol consumption, health insurance and dental floss/device. Abbreviations: CI, confidence interval; LC9, Life’s Crucial 9; ABSI, a body shape index; WWI, weight-adjusted-waist index; SII, Systemic Immune-Inflammation Index; SIRI, System Inflammation Response Index; ACME, average causal mediation effect; ADE, average direct effect