Serum biomarker levels in smokers and non-smokers following periodontal therapy. A prospective cohort study

To compare presence and levels of serum cytokines in smokers and non-smokers with periodontitis following periodontal therapy. Thirty heavy smokers and 30 non-smokers with stage III or IV periodontitis were included in this prospective cohort study. Clinical data and blood serum were collected at baseline (T0), after step I-III (T1), and after 12 months step IV periodontal therapy (T2). Cytokine IL-1β, IL-6, IL-8, TNF-α, IL-10, and IP-10 levels were measured using multiplex kit Bio-Plex Human Pro™ Assay. Linear regression models with cluster robust variance estimates to adjust for repeated observations were used to test intra- and intergroup levels for each marker, IL-6 and IL-8 defined as primary outcomes. Clinical outcomes improved in both groups following therapy (p < 0.05). IL-6 levels increased with 75.0