Table 4

Prevalence ratio (PR) of malocclusion requiring orthodontic treatment by maternal education level

CrudeModel 1Model 2Model 3
PR (95% CI)PR (95% CI)PR (95% CI)PR (95% CI)
Age of mother0.99 (0.96 to 1.02)0.99 (0.96 to 1.02)0.99 (0.96 to 1.01)
Education level of mother
 High1.46 (0.96 to 2.20)1.59 (1.04 to 2.44)*1.59 (0.98 to 2.56)1.72 (1.06 to 2.82)*
 Intermediate1.13 (0.75 to 1.73)1.22 (0.79 to 1.88)1.19 (0.76 to 1.85)1.3 (0.80 to 1.97)
 Lowreferencereferencereferencereference
Number of children in the family1.02 (0.88 to 1.19)1.03 (0.88 to 1.20)
Dwelling
 Apartment complex1.00 (0.64 to 1.57)1.03 (0.65 to 1.61)
 Detached house1.04 (0.70 to 1.54)1.07 (0.72 to 1.59)
 Traditional ‘ger’referencereference
Drinking habit of mother during pregnancy
 (+)0.92 (0.40 to 2.08)0.84 (0.37 to 1.94)
 (−)referencereference
Smoking habit of mother
 (+)1.39 (0.64 to 2.98)1.51 (0.70 to 3.32)
 (−)referencereference
X-ray exposure during pregnancy
 (+)0.90 (0.60 to 1.32)0.85 (0.57 to 1.27)
 (−)referencereference
Sex of participant
 Malereferencereferencereference
 Female0.83 (0.63 to 1.10)0.87 (0.65 to 1.16)0.85 (0.65 to 1.16)
Age1.08 (0.96 to 1.20)1.07 (0.95 to 1.20)1.07 (0.95 to 1.20)
Birth weight
 <2500 g0.46 (0.15 to 1.46)0.31 (0.08 to 1.28)
 ≥2500 greferencereference
Type of feeding during early childhood
 Breast feeding onlyreferencereference
 Mixed feeding0.92 (0.64 to 1.32)0.88 (0.61 to 1.27)
 Bottle feeding only1.03 (0.54 to 1.97)0.98 (0.51 to 1.89)
Use of a pacifier during childhood
 (+)1.14 (0.76 to 1.70)1.15 (0.77 to 1.73)
 (−)referencereference
Finger-sucking habit during childhood
 (+)1.21 (0.69 to 2.11)1.24 (0.71 to 2.17)
 (−)referencereference
Frequency of tooth brushing
 More than once a day0.82 (0.50 to 1.36)0.80 (0.48 to 1.32)
 Once a day1.02 (0.63 to 1.63)0.98 (0.60 to 1.58)
 Not every dayreferencereference
Regular breakfast
 (+)1.01 (0.75 to 1.37)1.01 (0.74 to 1.37)
 (−)referencereference
Level of dental caries (sum of decayed, filled teeth of both mixed and permanent dentition)1.02 (0.98 to 1.06)1.02 (0.98 to 1.07)
  • Model 1 adjusted for maternal age, education level and lifestyle (drinking and smoking habits and X-ray exposure) during pregnancy, participant's sex and age.

  • Model 2 adjusted for maternal age and education level, participant's sex and age, birth weight, environmental conditions (number of children in the family and type of dwelling), type of feeding and pacifier use, finger-sucking habit during childhood, frequency of tooth brushing, level of dental caries and regular breakfast consumption.

  • Model 3 adjusted for maternal age, education level and lifestyle (drinking and smoking habits and X-ray exposure) during pregnancy, participant's sex and age, birth weight, environmental conditions (number of children in the family and type of dwelling), type of feeding and pacifier use, finger-sucking habit during childhood, frequency of tooth brushing, level of dental caries and regular breakfast consumption.

  • *p<0.05.