title: Are sickle cell anaemia and sickle cell trait predictive factors for periodontal disease? A cohort study.
abstract: OBJECTIVE
  Periodontal diseases are associated with bacterial challenge and the host immune response, and are also modulated by genetic factors. There is evidence that sickle cell anaemia (SCA) does not represent a risk factor for periodontal diseases. However, it is still unclear whether the heterozygous condition [sickle cell trait (SCT)] is associated with periodontal diseases. SCT is a genetic condition that can cause vaso-occlusive events, which may be associated with a propensity to bacterial infections. The aim of this study was to investigate the association of SCA and SCT with periodontal diseases by evaluating clinical and radiographic characteristics.
  
  
  METHODS
  The sample (n = 369) was selected and divided into two groups: exposed groups [HbSS (SCA genotype) and HbAS (SCT genotype) = 246] and a nonexposed group (HbAA = 123). HbAA consisted of individuals without SCA and SCT. The clinical parameters evaluated were plaque index, gingival index, calculus index, clinical probing depth, clinical attachment level, gingival recession, tooth mobility and furcation involvement. The percentage of alveolar bone loss was measured using a Schei ruler. Binomial and Poisson regressions were used to estimate correlations of interest (α = 0.05).
  
  
  RESULTS
  None of the periodontal parameters was associated with SCA. SCT was associated with gingivitis (p = 0.041) and periodontitis (p = 0.002). Individuals with SCT had a lower plaque index (p = 0.044) but a higher calculus index (p = 0.003) and greater alveolar bone loss (p = 0.010) compared with subjects in the HbAA group.
  
  
  CONCLUSIONS
  SCT can act as a predictor for establishment of periodontal diseases. There was no correlation between SCA and periodontal diseases.
authors.affiliation: Postgraduate Dentistry Program, Federal University of Maranhão, São Luıs, Maranhão, Brazil.
authors.forename: H L C C
authors.initials: HL
authors.lastname: de Carvalho
authors.affiliation: Department of Public Health, Federal University of Maranhão, São Luıs, Maranhão, Brazil.
authors.forename: E B A F
authors.initials: EB
authors.lastname: Thomaz
authors.affiliation: Postgraduate Dentistry Program, Federal University of Maranhão, São Luıs, Maranhão, Brazil.
authors.forename: C M C
authors.initials: CM
authors.lastname: Alves
authors.affiliation: Postgraduate Dentistry Program, Federal University of Maranhão, São Luıs, Maranhão, Brazil.
authors.forename: S F C
authors.initials: SF
authors.lastname: Souza
mesh_terms: D000293:Adolescent; D000328:Adult; D016301:Alveolar Bone Loss / Q000150:complications; D000755:Anemia, Sickle Cell / Q000150:complications* / Q000235:genetics / Q000276:immunology*; D001938:Brazil; D002648:Child; D002675:Child, Preschool; D015331:Cohort Studies; D003728:Dental Calculus; D003774:Dental Plaque Index; D005260:Female; D005838:Genotype; D005889:Gingival Recession / Q000150:complications; D005891:Gingivitis / Q000150:complications; D006441:Hemoglobin A / Q000032:analysis; D006451:Hemoglobin, Sickle / Q000032:analysis; D006801:Humans; D008297:Male; D008875:Middle Aged; D017622:Periodontal Attachment Loss / Q000150:complications; D010510:Periodontal Diseases / Q000150:complications* / Q000276:immunology*; D010512:Periodontal Index; D010514:Periodontal Pocket / Q000150:complications; D010518:Periodontitis / Q000150:complications / Q000276:immunology; D012307:Risk Factors; D012805:Sickle Cell Trait / Q000150:complications* / Q000235:genetics / Q000276:immunology*; D014086:Tooth Mobility / Q000150:complications
chemical_list: D006451:Hemoglobin, Sickle; C028672:hemoglobin AA; C028671:hemoglobin AS; D006441:Hemoglobin A
keywords: dental radiography; epidemiology; gingivitis; periodontal diseases; periodontitis; sickle cell anaemia; sickle cell trait