Saliva Cotinine Levels and Periodontal Disease in Puerto Rican Adolescents

Objectives: To evaluate salivary cotinine levels of Puerto Rican adolescents and determine their association with periodontal disease and cytokine levels.
Methods: A convenience sample of 186 Puerto Rican adolescents aged 13 to 17 years from 5 high schools (middle class private, middle class public, and lower-class public) from the San Juan Metropolitan area was evaluated. Two calibrated dentists conducted oral evaluations; saliva samples were analyzed for cotinine and cytokine levels. Height and weight were measured; relative weight was classified according to age-and sex-specific body mass index percentiles. Periodontal disease was defined as having ≥2 sites with pocket depth ≥ 4mm and/or ≥20% of sites with bleeding on probing. We used Fisher’s exact or Kruskal-Wallis tests, as appropriate, and logistic regression models for cytokine levels (using medians as cut-off), according to cotinine levels (≥1.0 ng/ml vs. <1.0), adjusting for age and sex.
Results: Mean age of participants was 15.7 (±1.3) years; most were female (61.1%) and healthy-weight (41.4%). Periodontal disease prevalence was 34.1%. Mean salivary cotinine level was 0.4 (±0.7) ng/ml; 86.7% had low (<1.0 ng/ml) cotinine levels. Adolescents in middle- and lower-class public schools were more likely to have low cotinine levels, compared to those in middle-class private schools (89% vs. 93% vs. 40%, respectively; p<0.001). Cotinine levels were associated with IL-1b, IL-6, MMP8, MMP9, and TNF-alpha (p≤0.05), but not with sex, periodontal disease, or relative weight. In multivariate analysis, participants with high cotinine levels had three- to four-fold higher odds of having high IL-1b, IL-6, MMP8, and MMP9 levels; cotinine was inversely associated with TNF-alpha (OR: 0.36, 95% CI: 0.13-0.98).
Conclusions: Although salivary cotinine levels were not related to presence of periodontal disease and most of the adolescents had low exposure to tobacco smoke, cotinine levels were related to salivary cytokines, suggesting presence of inflammatory process in this group.