Salivary Inflammatory Biomarkers in Males With Nephrolithiasis Correlate With Periodontal Status: A Case-Control Study.

BACKGROUND

Systemic inflammation links periodontal disease (PD) and nephrolithiasis. Proinflammatory cytokines like IL-6, IL-8, TNF-α, IL-1β, and MMP-8 are implicated in both conditions. This study investigates salivary levels of these biomarkers in young adult males with kidney stones and their association with periodontal status (CPITN) and body mass index (BMI).

METHODS

This case-control study enrolled 109 males (25-35 years): 52 with kidney stones and 57 healthy controls. Unstimulated whole saliva was analyzed for IL-6, IL-8, TNF-α, IL-1β, and MMP-8 via ELISA. Periodontal health was assessed using the community periodontal index of treatment needs (CPITN). Serum C-reactive protein (CRP) and BMI were also measured.

RESULTS

The kidney stone group had significantly higher salivary IL-6 (3.95 [2.0-5.2] pg/mL vs. 2.7 [1.5-4.0] pg/mL; adj. p = 0.042) and TNF-α (11.99 [8.5-13.8] pg/mL vs. 9.5 [7.0-11.6] pg/mL; adj. p = 0.021) than controls. Differences in IL-1β (adj. p = 0.051) and MMP-8 (adj. p = 0.058) showed a consistent trend toward elevation but did not retain statistical significance after FDR correction. No significant difference was observed in salivary IL-8 levels (adj. p = 0.120). Patients also showed elevated CRP (p = 0.010) and worse CPITN scores (p = 0.002). In the kidney stone group, salivary IL-6, TNF-α, and MMP-8 positively correlated with CPITN scores (p < 0.01), whereas TNF-α also correlated with BMI (p = 0.048).

CONCLUSION

Elevated salivary inflammatory biomarkers (IL-6 and TNF-α) are significantly associated with kidney stones and periodontal status (CPITN) in young males, whereas IL-1β and MMP-8 showed a trend toward elevation. Salivary analysis may be a noninvasive tool for assessing systemic inflammation and identifying at-risk individuals.