title: Are intrauterine growth restriction and preterm birth associated with dental caries?
abstract: OBJECTIVE
  To assess the association between two intrauterine growth restriction (IUGR) surrogates - IUGR [small for gestational age birth (SGA) and fetal growth restriction (FGR)] and preterm birth with dental caries.
  
  
  METHODS
  Data from the Third National Health and Nutritional Examination Survey (1988-1994) were used, including 2- to 5.9-year-old singletons (n = 3189). Dental caries was defined as presence of any teeth with dental caries (treated or untreated) and also as presence of at least two teeth with dental caries. Exposure variables were preterm birth (<37 gestational weeks), FGR, and SGA. Covariates included were poverty, race/ethnicity, age, sex, sucrose intake, environmental tobacco smoking, dental visits, education of head of household, breastfeeding, and use of baby bottle. Separate statistical analyses were conducted for IUGR and for preterm birth through the estimation of prevalence ratio (PR), taking complex sampling design into consideration and adjusting for confounders. Sensitivity analysis was conducted including and excluding 2-year-old children and also with the two definitions of dental caries.
  
  
  RESULTS
  In general, the inclusion of 2-year-old children and the case definition of presence of any teeth with dental caries biased the results toward the null, but with no major changes in the results. In bivariate analysis, SGA and FGR birth were both negatively but not significantly associated with dental caries while a significant positive association was found for preterm birth. Sensitivity analysis showed that the PR for preterm in bivariate analysis varied from 1.65 (95% CI 1.14-2.40) to 1.84 (95% CI 1.19-2.83). After adjusting for confounders, the PR for preterm birth varied from 1.38 (95% CI 1.00-1.89) to 1.64 (95% CI 1.22-2.20). After adjustment, the PR for SGA varied from 0.79 (95% CI 0.56-101) to 0.66 (95% CI 0.33-0.96). For children from 3 to 5.9 years old, the adjusted PR for FGR using the category 'none' as reference were mild (PR 1.10; 95% CI 0.76-1.58), moderate (PR 0.66; 95% CI 0.26-167), and severe (PR 0.59; 95% CI 0.36-0.99). These values for FGR were very similar for the other models using other classifications of case definition or inclusion of 2-year-old children.
  
  
  CONCLUSIONS
  Preterm birth was found to be positively associated with dental caries while there is an indication that SGA and FGR are negatively associated with dental caries. Although the negative association is counterintuitive, it is possible that increased antibiotic use and delayed tooth eruption may explain the negative association between IUGR and dental caries.
authors.affiliation: University of São Paulo at Ribeirão Preto, School of Dentistry, Ribeirão Preto, Brazil. mdsaraiv@umich.edu
authors.forename: Maria C D
authors.initials: MC
authors.lastname: Saraiva
authors.forename: Heliosa
authors.initials: H
authors.lastname: Bettiol
authors.forename: Marco A
authors.initials: MA
authors.lastname: Barbieri
authors.forename: Antonio A
authors.initials: AA
authors.lastname: Silva
mesh_terms: D000367:Age Factors; D001903:Bottle Feeding / Q000706:statistics & numerical data; D001942:Breast Feeding / Q000706:statistics & numerical data; D002675:Child, Preschool; D003430:Cross-Sectional Studies; D003729:Dental Care / Q000706:statistics & numerical data; D003731:Dental Caries / Q000453:epidemiology*; D019422:Dietary Sucrose / Q000008:administration & dosage; D004522:Educational Status; D005006:Ethnicity / Q000706:statistics & numerical data; D005260:Female; D005317:Fetal Growth Retardation / Q000453:epidemiology*; D006801:Humans; D007231:Infant, Newborn; D007236:Infant, Small for Gestational Age; D008297:Male; D010290:Parents / Q000193:education; D011203:Poverty / Q000706:statistics & numerical data; D011247:Pregnancy; D047928:Premature Birth / Q000453:epidemiology*; D015995:Prevalence; D044469:Racial Groups / Q000706:statistics & numerical data; D012737:Sex Factors; D014028:Tobacco Smoke Pollution / Q000706:statistics & numerical data; D014481:United States / Q000453:epidemiology