Skip to main content

Table 1 Comparison of Non-Participants and Participants

From: Longitudinal associations of age and prenatal lead exposure on cortisol secretion of 12–24 month-old infants from Mexico City

  Non-participants 12 month-old infants 18–24 month-old infants
  n = 355 n = 255 n = 150
Mother
 Age at delivery (years) 26.7 ± 5.5 27.1 ± 5.6 27.5 ± 5.1
 Education (total years) 11.8 ± 2.8 11.9 ± 2.8 11.6 ± 2.8
 Pre-pregnancy BMI (kg/m2) 24.9 ± 4.1 25.8 ± 4.4* 24.7 ± 3.9
 2nd trimester blood lead (μg/dL)a 3.6 ± 2.5 3.5 ± 2.5 3.9 ± 2.8
 3rd trimester blood lead (μg/dL)b 3.8 ± 2.7 3.7 ± 2.9 4.2 ± 3.4
 Tibia lead (μg/g)c 4.7 ± 5.4 5.6 ± 5.8 4.9 ± 5.0
Infant
 Sex (male) n (%) 182 (51) 129 (51) 90 (60)
 Ever breastfed n (%)d 303 (85) 224 (88) 139 (93)
 Gestational Age, weeks 38.3 ± 1.9 38.3 ± 1.5 38.5 ± 1.6
 Birth Weight, kg 3.0 ± 0.5 3.1 ± 0.4 3.2 ± 0.4*
  1. For all analyses the imputed values for missing blood and tibia lead were used
  2. anon-participant n = 354, 18–24 month-old infants n = 149
  3. bnon-participant n = 301, 12 month-old infants n = 229, 18–24 month-old infants n = 139
  4. cnon-participant n = 270, 12 month-old infants n = 199, 18–24 month-old infants n = 117
  5. dnon-participant n = 329, 12 month-old infants n=, 18–24 month-old infants n = 145
  6. *Unless noted p > 0.05 for all comparison tests of covariates between non-participants and each age group