title: Background factors of molar-incisor hypomineralization in a group of Finnish children.
abstract: OBJECTIVE
  Molar-Incisor Hypomineralization (MIH) is a common developmental enamel defect characterized by demarcated opacities in permanent molars and incisors. Its etiology still remains unclear. The aim of this retrospective cohort study was to assess if the socioeconomic environment of the child is associated with MIH.
  
  
  METHODS
  The study was located in two rural towns and three urban cities in Finland. A total of 818 children, between 7-13 years old, were examined for MIH using the evaluation criteria in line with those of the European Academy of Paediatric Dentistry, but excluding opacities smaller than 2 mm in diameter. The mothers filled in a questionnaire which included questions related to the family's way of living (e.g. area of residency, farming, day care attendance) and socioeconomic status (family income, number of mother's school years, level of maternal education).
  
  
  RESULTS
  The prevalence of MIH in the study population was 17.1%. Family income, urban residency and day care attendance were associated with MIH in the univariate analysis. In the multivariate analysis using binary logistic regression, only urban residency during a child's first 2 years of life remained associated with MIH. The prevalence of MIH in urban areas was 21.3% and in rural areas 11.5% (OR = 2.18, CI = 1.35-3.53, p = 0.001).
  
  
  CONCLUSIONS
  The prevalence of MIH was related to urban residency and could not be explained by any other factor included in the study.
authors.affiliation: Department of Pediatric and Preventive Dentistry, Institute of Dentistry, University of Helsinki , Helsinki , Finland.
authors.forename: Emma
authors.initials: E
authors.lastname: Wuollet
authors.forename: Sakari
authors.initials: S
authors.lastname: Laisi
authors.forename: Eija
authors.initials: E
authors.lastname: Salmela
authors.forename: Anneli
authors.initials: A
authors.lastname: Ess
authors.forename: Satu
authors.initials: S
authors.lastname: Alaluusua
mesh_terms: D000293:Adolescent; D000383:Agriculture / Q000706:statistics & numerical data; D001942:Breast Feeding / Q000706:statistics & numerical data; D002648:Child; D002654:Child Care / Q000706:statistics & numerical data; D015331:Cohort Studies; D003744:Dental Enamel Hypoplasia / Q000453:epidemiology*; D004522:Educational Status; D005260:Female; D005387:Finland / Q000453:epidemiology; D006801:Humans; D007182:Income; D008297:Male; D009035:Mothers / Q000193:education; D015995:Prevalence; D012111:Residence Characteristics; D012189:Retrospective Studies; D012423:Rural Health / Q000706:statistics & numerical data; D012907:Smoking / Q000453:epidemiology; D012923:Social Class; D012959:Socioeconomic Factors; D014504:Urban Health / Q000706:statistics & numerical data
keywords: aetiology; developmental enamel defects; hypomineralization; socioeconomic status; urban living