Association of salivary lactate dehydrogenase level with systemic inflammation in a Japanese population

Background and Objective Salivary lactate dehydrogenase (LDH) was reported to be a useful parameter for the screening of periodontal disease. We performed a cross‐sectional study to verify the usefulness of salivaryLDHas a biomarker of periodontitis and to investigate the association of severity of periodontitis with systemic inflammation by measuring salivaryLDHand serum high sensitive C‐reactive protein (hs‐CRP) levels in a community‐based middle‐aged and elderly population in Japan. Material and Methods We recruited 644 men and 1171 women, aged 30‐79 years, who participated in the Toon Health Study during 2011–15. Periodontal condition was assessed by full‐mouth examination including mean value of probing depth, percentage ofprobing depthof ≥4 mm and ≥6 mm, and bleeding on probing. Saliva and blood serum samples were collected for measurement of salivaryLDHlevel and hs‐CRP, respectively. A linear trend across quartiles of salivaryLDHwas calculated using linear regression. Interaction of salivaryLDHand overweight status (body mass index of ≥25 kg/m2) was tested using the cross‐product term of log‐transformed continuous salivaryLDHand overweight status. Results Analysis of covariance adjusted for potential confounders revealed strong associations between salivaryLDHlevel and the indicators of periodontal condition (P < .01) in both men and women. Sex‐ and age‐adjusted mean values of hs‐CRPaccording to salivaryLDHquartiles were 0.40, 0.45, 0.45 and 0.50 mg/L (Pfor trend <.01). Although the association was attenuated after further adjustment for body mass index, hypertension, diabetes mellitus, dyslipidemia, alcohol intake, smoking status and physical activity. When stratified by overweight status, the association remained significant in overweight individuals (P = .03). The multivariable adjusted odds ratio of hs‐CRPlevel of ≥1 mg/L for the highest vs lowest quartile of salivaryLDHwas 1.93 (95%CI, 1.01‐3.69) in overweight individuals, but not significant in non‐overweight individuals. Conclusion SalivaryLDHappears to be a promising biomarker for the mass screening of periodontitis in local community health settings. High salivaryLDHlevels, particularly in overweight individuals might contribute to prevention of cardiovascular disease, through measuring systemic inflammatory burdens as well as traditional cardiovascular risk factors.