Table 5

Associations between early infant factors and infant length-for-age z scores at 6 months of age (univariable and multivariable regression)

Univariable regressionMultivariable regression*
Early infant factorsCoefficient (95% CI)p ValueCoefficient (95% CI)p Value
Neonatal factors
 Birth weight (per 100 g)0.09 (0.07 to 0.10)<0.0010.10 (0.09 to 0.12)<0.001
 Gestational age at delivery (weeks)0.11 (0.08 to 0.14)<0.0010.04 (0.01 to 0.07)0.02
 Male sex−0.19 (−0.31 to −0.08)0.001−0.31 (−0.43 to −0.20)<0.001
Six-week anthropometric measurements†
 Infant length (cm)0.09 (0.08 to 0.11)<0.0010.09 (0.08 to 0.11)<0.001
 Infant weight (kg)0.90 (0.77 to 1.03)<0.001
 Infant head circumference0.07 (0.04 to 0.10)<0.001
Infant health status 6 weeks of age†
 Respiratory illness−0.22 (−0.40 to −0.04)0.02−0.20 (−0.38 to −0.02)0.02
 Fever−0.35 (−0.89 to 0.18)0.20
 Diarrhoea0.03 (−0.25 to 0.30)0.85
 Hospitalisation−0.40 (−0.62 to −0.18)<0.001−0.25 (−0.47 to −0.03)0.03
Infant health status 6 months of age
 Respiratory illness−0.10 (−0.21 to 0.02)0.10
 Fever−0.22 (−0.35 to −0.09)0.001
 Diarrhoea−0.05 (−0.17 to 0.07)0.39
 Hospitalisation−0.28 (−0.42 to −0.14)<0.001−0.22 (−0.41 to −0.04)0.02
Child care practices
 Exclusive breast feeding at 6 weeks of age0.03 (−0.09 to 0.15)0.60
 Exclusive breast feeding at 6 months of age−0.08 (−0.23 to 0.06)0.26
 Timing of introduction of complementary food (weeks) 0.01 (−0.009 to 0.03)0.07
 Use of formula at 6 weeks of age−0.03 (−0.15 to 0.09)0.62
 Use of formula at 6 months of age−0.11 (−0.30 to 0.08)0.27
 Use of dietary supplements for child in the first 6 months0.29 (0.11 to 0.47)0.0010.25 (0.07 to 0.43)0.01
 Micronutrient status at 6 months of age
 Haemoglobin (per 10 g/dL)0.10 (−0.40 to 0.60)0.75
 Ferritin (log2 μg/L)‡−0.08 (−0.15 to −0.01)0.02−0.19 (−0.25 to −0.12)<0.001
  • *Model adjusted for maternal age, gravidity, gestational age at enrolment and trial intervention.

  • †Variables at the 6 -week time point have been included in separate multivariable regression models as they are on the causal pathway between birth weight and length-for-age z scores at 6 months of age.

  • ‡log2 transformed—regression coefficient represents mean change in infant length-for-age z score associated with a twofold change in ferritin.