title: Association between vitamin D deficiency and periodontal status in current smokers.
abstract: OBJECTIVE
  The aim of this study was to examine whether vitamin D level is associated with periodontitis using a representative sample of Korean adults.
  
  
  METHODS
  A total of 6011 subjects who participated in the fourth Korea National Health and Nutrition Examination Survey (KNHANES) were examined. Vitamin D deficiency was defined as 25-hydroxyvitamin D serum concentrations to be under or equal to 20 ng/ml. We assessed periodontal conditions by Community Periodontal Index (CPI) and defined higher CPI as ≥code 3. Multivariate logistic regression analyses were performed adjusting for sociodemographics, oral and general health behaviors, and systemic health status. All analyses considered a complex sampling design, and a subgroup analysis was performed to determine estimates stratified according to the effect modifier.
  
  
  RESULTS
  There was no association between vitamin D deficiency and higher CPI after adjusting for the covariates in the total sample. According to the strata of smoking, the significant association was found in only current smokers after adjusting for the covariates including pack-years (odds ratio: 1.53, 95% confidence interval: 1.07-2.18).
  
  
  CONCLUSIONS
  A significant association between vitamin D deficiency and periodontal status was found in only current smokers. Smoking could modify the effect of vitamin D on periodontitis.
authors.affiliation: Department of Preventive and Public Health Dentistry, School of Dentistry, Seoul National University, Seoul, Korea.|Dental Research Institute, School of Dentistry, Seoul National University, Seoul, Korea.
authors.forename: Hyo-Jin
authors.initials: HJ
authors.lastname: Lee
authors.affiliation: Korean Minjok Leadership Academy, Gangwon-do, Korea.
authors.forename: Dong-Il
authors.initials: DI
authors.lastname: Je
authors.affiliation: Korean Minjok Leadership Academy, Gangwon-do, Korea.
authors.forename: Seong-Jae
authors.initials: SJ
authors.lastname: Won
authors.affiliation: Department of Preventive and Public Health Dentistry, School of Dentistry, Seoul National University, Seoul, Korea.|Dental Research Institute, School of Dentistry, Seoul National University, Seoul, Korea.
authors.forename: Dai-Il
authors.initials: DI
authors.lastname: Paik
authors.affiliation: Department of Preventive and Public Health Dentistry, School of Dentistry, Seoul National University, Seoul, Korea.|Dental Research Institute, School of Dentistry, Seoul National University, Seoul, Korea.
authors.forename: Kwang-Hak
authors.initials: KH
authors.lastname: Bae
mesh_terms: D000328:Adult; D003753:Dental Health Surveys; D005260:Female; D006304:Health Status; D006801:Humans; D008297:Male; D008875:Middle Aged; D009910:Oral Hygiene; D010512:Periodontal Index; D010518:Periodontitis / Q000453:epidemiology / Q000209:etiology*; D056910:Republic of Korea / Q000453:epidemiology; D012907:Smoking / Q000009:adverse effects* / Q000453:epidemiology; D014808:Vitamin D Deficiency / Q000150:complications* / Q000453:epidemiology
keywords: epidemiology; nutrition; periodontitis; smoking; vitamin D