A comparative evaluation of serum and salivary levels of apelin in chronic periodontitis associated with obesity and type 2 diabetes mellitus.

Periodontitis is an inflammatory destructive condition influenced by obesity and type 2 diabetes mellitus (T2DM). Apelin, a bioactive peptide, is linked to periodontitis, obesity, and T2DM. This study aimed to investigate apelin levels in individuals with periodontitis who are affected by obesity and T2DM. This cross-sectional observational study included 84 participants categorized into 3 main groups of 24 patients based on their periodontal status, body mass index (BMI), and glycated hemoglobin (HbA_1c) levels. Group 1 comprised systemically healthy participants, group 2 comprised individuals with obesity (BMI of 30.0 to 39.0 kg/m2), and group 3 comprised individuals with both obesity and T2DM (HbA_1c of 6.5% to 8.5%). Each group was subcategorized based on the presence or absence of chronic periodontitis (CP), resulting in 6 subgroups with 14 participants each. The clinical parameters assessed included the Sulcus Bleeding Index (SBI), probing depth (PD), clinical attachment loss (CAL), BMI, and HbA_1c level. Apelin levels in serum and saliva were quantified using enzyme-linked immunosorbent assay. Data were analyzed using 1-way analysis of variance and independent samples t test. Pearson correlation coefficients were calculated to assess relationships between different parameters. Within groups, individuals with CP had lower serum and salivary levels of apelin than those without CP, and the differences were statistically significant except in the case of salivary levels in patients with obesity (P < 0.05). Individuals with obesity, as well as those with both T2DM and obesity, had elevated levels of serum apelin compared with systemically healthy individuals. A significant negative correlation was observed between serum apelin and periodontal parameters (SBI, PD, and CAL) in specific subgroups. Apelin could be a valuable biomarker for evaluating periodontal disease affected by obesity and T2DM. However, further longitudinal research with a larger patient sample is needed. Trial registration: Clinical Trials Registry - India No. CTRI/2019/02/017522.