title: Non-nutritive sucking habits after three years of age: a case-control study.
abstract: BACKGROUND
  Non-nutritive sucking habits can result in negative consequences on the development of orofacial structures and occlusion.
  
  
  OBJECTIVE
  Assess factors associated with non-nutritive sucking habits in children after 3 years old.
  
  
  METHODS
  A case-control study was carried out in two stages. In the first stage, a cross-sectional study was conducted with 638 children aged 3-6 years. In the second stage, a case-control study (1:2) was conducted. The case group included all children who presented some non-nutritive sucking habits in the first stage of the study (n = 110). The control group (n = 220) was made up of children who had never presented non-nutritive sucking habits, matched to the case group for gender and age. The data were collected during the national poliomyelitis vaccination campaign, through a questionnaire applied to parents/guardians with questions related to the presence of sucking habits, sociodemographic aspects, birth aspects, and early life of the child. Statistical analysis involved descriptive analysis, chi-square test, Mann-Whitney test, and conditional logistic regression.
  
  
  RESULTS
  Reduction in maternal education was a protective factor for the development of non-nutritive sucking habits (education ≤8 years OR = 0.38, CI 95%: 0.16, 0.89, P = 0.025). Prematurity (OR = 3.30, CI 95%: 1.13, 9.69, P = 0.030) and a longer period using a baby bottle (OR = 1.03, CI 95%: 1.01, 1.05, P = 0.006) remained associated with a greater possibility of the occurrence of sucking habits, regardless of monthly family income.
  
  
  CONCLUSIONS
  Non-nutritive sucking habits were associated with maternal education, premature birth, and greater time of bottle feeding in children after 3 years old.
authors.affiliation: Department of Pediatric Dentistry and Orthodontics, School of Dentistry, Federal University of the Jequitinhonha and Mucuri Valleys, Diamantina, Brazil.
authors.forename: Izabella Barbosa
authors.initials: IB
authors.lastname: Fernandes
authors.forename: Túlio Silva
authors.initials: TS
authors.lastname: Pereira
authors.forename: Monize Ferreira Figueiredo
authors.initials: MF
authors.lastname: de Carvalho
authors.forename: Joana
authors.initials: J
authors.lastname: Ramos-Jorge
authors.forename: Leandro Silva
authors.initials: LS
authors.lastname: Marques
authors.forename: Maria   Letícia
authors.initials: M
authors.lastname: Ramos-Jorge
mesh_terms: D016022:Case-Control Studies; D002648:Child; D002675:Child, Preschool; D005260:Female; D006184:Habits; D006801:Humans; D008297:Male; D012307:Risk Factors; D013391:Sucking Behavior; D011795:Surveys and Questionnaires