ORIGINAL ARTICLE Serum cotinine, vitamin D exposure levels and dental caries experience in U.S. adolescents Aderonke A. Akinkugbe 1,2 | Oswaldo Moreno 2,3 | Tegwyn H. Brickhouse 1,2 1 Oral Health Services Research Core, Philips Institute for Oral Health Research, School of Dentistry, Virginia Commonwealth University, Richmond, Virginia 2 Oral Health in Childhood and Adolescence Core of the Institute for inquiry, Innovation and Inclusion, Virginia Commonwealth University, Richmond, Virginia 3 Department of Psychology, School of Humanities and Sciences, Virginia Commonwealth University, Richmond, Virginia Correspondence Aderonke A. Akinkugbe, Oral Health Services Research Core, Philips Institute for Oral Health Research, Virginia Commonwealth University, Richmond, VA. Email: aaakinkugbe@vcu.edu Abstract Introduction: Epidemiologic studies of risk and protective factors for poor oral health have mostly been among children and adults, seldom focusing on adoles- cents. The aims of this study were to examine whether serum cotinine, a marker of tobacco exposure, and serum vitamin D are independently associated with dental caries experience among adolescents. Methods: Cross‐sectional data from 2579 adolescent participants in the 2005‐2008 National Health and Nutritional Examination Survey were analysed. The exposures, cotinine and vitamin D, were measured in serum while dental caries experience was determined by screening examination, and a case defined as having ≥1 decayed or filled teeth. Survey‐adjusted logistic regression estimated prevalence odds ratios (POR) and 95% confidence intervals (CI) between the respective exposures and out- come. Results: The overall median (IQR) serum cotinine level was 0.15 ng/mL (0.04, 1.80) while the mean (SE) serum vitamin D concentration was 68.2 nmol/L (1.36). In con- trast to participants with serum cotinine ≤3 ng/L, those with levels >3 ng/L had covariate‐adjusted estimate of 1.69 (1.16, 2.47) for caries experience. Each addi- tional mean (ng/L) serum cotinine level was associated with an 8% (95% CI = 1.01, 1.16) greater adjusted prevalence odds of having caries experience. In contrast to participants with vitamin D ≥ 50 nmol/L, those with levels of30‐ < 50 nmol/L and <30 nmol/L had non‐statistically significant adjusted estimates of 1.02 (0.72, 1.44) and 1.23 (0.70, 2.16) respectively for caries experience. Conclusions: Serum cotinine is associated with dental caries experience among ado- lescents and while deficient (<30 nmol/L) levels of vitamin D appear to be associ- ated with greater prevalence odds of caries experience, this association is inconclusive. KEYWORDS adolescents, dental caries, epidemiology, public health, serum cotinine, vitamin D 1 | INTRODUCTION Dental caries is a complex chronic disease 1 of multifactorial aetiol- ogy, affecting individuals of all ages. It is associated with poor oral health‐related quality of life, school absenteeism among children, compromised masticatory function, pain and suffering. 2 Although recent reports from the National Center for Health Statistics suggest declining dental caries prevalence, about a quarter of U.S. children ages 2‐5 years, and 3 out of 5 adolescents are affected. 3 Given the complex chronic nature of dental caries, its aetiology is multifactorial, Received: 16 May 2018 | Revised: 13 November 2018 | Accepted: 17 November 2018 DOI: 10.1111/cdoe.12442 Community Dent Oral Epidemiol. 2019;47:185–192. wileyonlinelibrary.com/journal/cdoe © 2018 John Wiley & Sons A/S. Published by John Wiley & Sons Ltd | 185