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Table 1 Characteristics of the study population at 24 months of age, overall and stratified by zinc status

From: Differential association of lead on length by zinc status in two-year old Mexican children

  Overall (N = 291) Zinc Replete (N = 241) Zinc Deficient (N = 50)  
Mean ± SD (or N (%)) p-value*
Sex (male) 150 (51.5 %) 123 (51 %) 27 (54 %) 0.7
Birthweight (kg) 3.1 ± 0.4 3.1 ± 0.4 3.1 ± 0.4 0.6
Birthlength (cm) 50.1 ± 1.9 50.1 ± 1.9 50 ± 1.5 0.4
Gestational Age (weeks) 39.0 ± 1.1 39.0 ± 1.1 39 ± 0.9 0.7
Age at anthropometry (months) 24.5 ± 0.2 24.5 ± 0.2 24.5 ± 0.3 0.8
Weight (kg) 11.9 ± 1.5 11.9 ± 1.5 11.6 ± 1.2 0.1
Length (cm) 86.3 ± 2.9 86.4 ± 2.9 86.1 ± 2.8 0.5
Length-for-Age Z score −0.02 ± 0.9 −0.01 ± 0.9 −0.1 ± 0.9 0.5
Stunting (<2 SD LAZ) 7 (2.4 %) 6 (2.5 %) 1 (2.0 %) 0.6
Serum Zinc (μmol/L) 12.2 ± 2.5 12.9 ± 2.2 9.0 ± 0.9 <0.01
Blood Lead (μmol/L)a 0.17 (0.12–0.26) 0.17 (0.12–0.27) 0.15 (0.12–0.23) 0.2
Blood Lead >0.24 μmol/L 85 (29 %) 74 (31 %) 11 (22 %) 0.1
Blood Lead >0.48 μmol/L 14 (5 %) 13 (5 %) 1 (2 %) 0.3
Energy Intake (Kcal/d) 1656.3 ± 426.2 1672.0 ± 432.6 1590.0 ± 390.3 0.2
Breastfeeding (months) 8.6 ± 6.2 8.9 ± 6.3 7.9 ± 5.6 0.3
Maternal Height (cm) 155.0 ± 5.7 155.0 ± 5.6 154.7 ± 6.0 0.8
Maternal Education (years) 11.0 ± 2.9 11.0 ± 2.8 11.5 ± 3.3 0.3
  1. *p-values for the comparison of the zinc replete and zinc deficient groups (T-tests were used for continuous and normally-distributed variables, Wilcoxon rank sum test for continuous and skewed variables, and two-sided Fisher’s Exact test for categorical variables)
  2. aMedian (interquartile range) and Wilcoxon test