The relationships between optimal infant feeding practices and child development and attained height at age 2 years and 6-7 years

Limited evidence exists on the long-term effects of early feeding practices on child growth and development. We examined the relationships between infant feeding practices and child height and development at ages 2 and 6-7 years. We studied 885 mother-child dyads from a randomized controlled trial of preconception supplementation in Vietnam. Early initiation of breastfeeding (EIBF), exclusive breastfeeding (EBF), breastfeeding (BF) duration and minimum dietary diversity (MDD) were assessed using World Health Organization (WHO) guidelines. Child development was assessed by the Bayley Scales of Infant Development-III at 2 years and the Wechsler Intelligence Scale for Children® - IV at 6-7 years. Child height-for-age z-score (HAZ) was calculated from child height and age. Multivariable regression and structural equation models were used in analyses that controlled for confounding. EIBF and EBF at 6 months occurred in 52% and 62% of children, respectively. Mean breastfeeding duration was 18 months and 83% achieved MDD at 1 year. EIBF was associated with motor (β = 0.13, 95% confidence interval [CI]: 0.00, 0.28) and cognitive development at 2 years (β = 0.12, 95% CI: -0.01, 0.26), which in turn were positively associated with cognitive development at 6-7 years. EBF was directly associated with development at 6-7 years (β = 0.21, 95% CI:0.08, 0.34) whereas motor and cognitive development at 2 years explained 41%-75% of the relationship between EIBF and development at 6-7 years. HAZ at 2 years also mediated 70% of the association between MDD at 1 year and HAZ at 6-7 years. BF duration was not associated with child development and HAZ. Early infant feeding practices, especially EIBF and EBF, have important long-term implications for optimizing child linear growth and cognition as they begin school.

Maternal Preconception Body Size and Early Childhood Growth during Prenatal and Postnatal Periods Are Positively Associated with Child-Attained Body Size at Age 6-7 Years: Results from a Follow-up of the PRECONCEPT Trial

BACKGROUND

Growth faltering is associated with adverse consequences during childhood and later life. However, questions remain on the relative importance of preconception maternal nutritional status (PMNS) and child growth during the first 1000 d of life.

OBJECTIVES

We examined associations between PMNS, gestational weight gain (GWG), and child growth during the first 1000 d with attained body size at age 6-7 y.

METHODS

We used data from a follow-up of a double-blinded randomized controlled trial of preconception micronutrient supplementation in Vietnam (n = 5011 women). The outcomes included offspring height-for-age z score (HAZ), BMI-for-age z score (BMIZ), and prevalence of stunting and overweight/obese at age 6-7 y (n = 1579). We used multivariable linear and Poisson regression models to evaluate the relative contributions of PMNS (height and BMI), GWG, and conditional growth in 4 periods: fetal, 0-6 mo, 6-12 mo, and 12-24 mo.

RESULTS

PMNS was positively associated with child-attained size at 6-7 y. For each 1-SD higher maternal height and BMI, offspring had 0.28-SD and 0.13-SD higher HAZ at 6-7 y, respectively. Higher maternal BMI and GWG were associated with larger child BMIZ (β: 0.29 and 0.10, respectively). Faster linear growth, especially from 6 to 24 mo, had the strongest association with child HAZ at 6-7 y (β: 0.39-0.42), whereas conditional weight measures in all periods were similarly associated with HAZ (β: 0.10-0.15). For BMIZ at 6-7 y, the magnitude of association was larger and increased with child age for conditional weight gain (β: 0.21-0.41) but smaller for conditional length gain. Faster growth in the first 2 y was associated with reduced risk of stunting and thinness but increased risk of overweight/obese at 6-7 y.

CONCLUSIONS

Interventions aimed at improving child growth while minimizing the risk of overweight during the school age years should target both women of reproductive age prior to conception through delivery and their offspring during the first 1000 d. The trial was registered at clinicaltrials.gov as NCT01665378.

Plasma and Nail Zinc Concentrations, But Not Hair Zinc, Respond Positively to Two Different Forms of Preventive Zinc Supplementation in Young Laotian Children: a Randomized Controlled Trial

Plasma zinc concentrations (PZC) have been shown to significantly increase during zinc supplementation. This study investigated the effects of daily preventive zinc supplementation on hair and nail zinc concentrations compared with a control group. In a randomized controlled trial, 6- to 23-month-old children (n = 3407) in Lao PDR were randomly assigned to one of four groups and followed for ~ 36 weeks: daily preventive zinc dispersible tablet (7 mg/d; PZ), daily micronutrient powder (10 mg zinc/d; MNP), therapeutic zinc supplements for diarrhea treatment (20 mg/d for 10 days; TZ), or daily placebo powder (Control). Plasma, hair, and nail zinc concentrations were assessed in a sub-sample of participants (n = 457) at baseline and endline. At baseline, 75% of children had low PZC (< 65 μg/dL). At endline, geometric mean (95% CI) PZC were greater in the PZ and MNP groups compared with the TZ and control groups (P < 0.01), but hair zinc concentrations did not differ among groups (P = 0.99). Nail zinc concentrations were marginally higher in the PZ (115.8 (111.6, 119.9) μg/g) and the MNP (117.8 (113.3, 122.3) μg/g) groups than in the TZ group (110.4 (106.0, 114.8) μg/g; P = 0.055) at endline. This study does not support the use of hair zinc as a biomarker of zinc exposure in young children. However, it provides some evidence that zinc concentrations in nails may respond to supplemental zinc interventions and supports the need for collecting additional data on this emerging biomarker.