title: Environmental tobacco and wood smoke increase the risk of Legg-Calvé-Perthes disease.
abstract: BACKGROUND
  The etiology of Legg-Calvé-Perthes disease (LCPD) remains unknown. A few studies have suggested passive smoke inhalation may be a risk factor, although the association is not confirmed and a causal relationship has not been established.
  
  
  OBJECTIVE
  We therefore undertook this study to confirm an association between environmental tobacco smoke, firewood smoke, and socioeconomic status and the risk of LCPD.
  
  
  METHODS
  We prospectively recruited 128 children with LCPD and 384 children attending the hospital for other orthopaedic complaints. The control subjects were frequency-matched with the cases by age and gender. Conditional logistic regression was used to assess the association between the exposures and risk of LCPD.
  
  
  RESULTS
  The main risk factors for LCPD were indoor use of a wood stove (adjusted odds ratio [OR], 2.56) and having a family member who smoked indoors (adjusted OR, 2.07). Children from the middle socioeconomic group appeared to be at a greater risk of developing LCPD (adjusted OR, 3.60).
  
  
  CONCLUSIONS
  This study provides further evidence that environmental tobacco smoke is associated with an increased risk of LCPD. Exposure to wood smoke also appears to be a risk factor. However, it remains unclear why there are profound differences in the incidence of the disease between regions when the prevalence of smoking is comparable and why bilateral involvement and familial disease are infrequent.
authors.affiliation: Department of Community Medicine, Kasturba Medical College, Manipal, Karnataka State, India.
authors.forename: Anjali Benjamin
authors.initials: AB
authors.lastname: Daniel
authors.forename: Hitesh
authors.initials: H
authors.lastname: Shah
authors.forename: Asha
authors.initials: A
authors.lastname: Kamath
authors.forename: Vasudev
authors.initials: V
authors.lastname: Guddettu
authors.forename: Benjamin
authors.initials: B
authors.lastname: Joseph
mesh_terms: D000293:Adolescent; D016022:Case-Control Studies; D002648:Child; D002675:Child, Preschool; D004781:Environmental Exposure; D005260:Female; D006801:Humans; D007194:India; D007873:Legg-Calve-Perthes Disease / Q000209:etiology*; D016015:Logistic Models; D008297:Male; D015999:Multivariate Analysis; D016017:Odds Ratio; D011446:Prospective Studies; D012111:Residence Characteristics; D018570:Risk Assessment; D012307:Risk Factors; D012906:Smoke / Q000009:adverse effects*; D012959:Socioeconomic Factors; D014028:Tobacco Smoke Pollution / Q000009:adverse effects*; D014934:Wood / Q000009:adverse effects*
chemical_list: D012906:Smoke; D014028:Tobacco Smoke Pollution
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