Antenatal supplementation with folic acid + iron + zinc improves linear growth and reduces peripheral adiposity in school-age children in rural Nepal

Abstract

Background: We previously reported that a randomized controlled trial of antenatal micronutrient supplements in rural Nepal decreased the risk of low birth weight by approximately 15%.

Objective: The objective was to examine the effects of micronutrient supplementation on growth and body composition in children of supplemented mothers through school age.

Design: Mothers received 1 of 5 micronutrient supplements daily: folic acid, folic acid + iron, folic acid + iron + zinc, multiple micronutrients, or a control. All of the supplements contained vitamin A. Children born during this trial were revisited at age 6-8 y to measure height, weight, midupper arm circumference, waist circumference, and triceps and subscapular skinfold thicknesses. Arm fat and muscle area were estimated by using standard formulas, and height-for-age, weight-for-age, and body mass index-for-age z scores were calculated by using the World Health Organization growth standard.

Results: Of the 3771 surviving children, 3324 were revisited and consented to anthropometric measurements. Maternal supplementation with folic acid + iron + zinc resulted in an increase in mean height (0.64 cm; 95% CI: 0.04, 1.25) and a reduction in mean triceps skinfold thickness (-0.25 mm; 95% CI: -0.44, -0.06), subscapular skinfold thickness (-0.20 mm; 95% CI: -0.33, -0.06), and arm fat area (-0.18 cm(2); -0.34, -0.01). No significant differences were found between groups in mean weight or body mass index-for-age z scores, waist circumference, or arm muscle area. Other micronutrient combinations including a multiple micronutrient formulation failed to show a growth benefit.

Conclusion: Antenatal supplementation with zinc may benefit child growth, particularly in areas where a deficiency of this nutrient is common.

FIGURE 1

Enrollment and losses to follow-up of children through 6–8 y of age by maternal supplement group. The initial sample size included live born children. All children of mothers who participated in the initial trial and who survived to 6 mo of age were eligible for follow-up. Losses to follow-up include children who moved out of the study area, were not at home despite repeated household visits, or refused to participate. The follow-up rate is based on the percentage of living children who were met by at least one team.

FIGURE 2

Differences (95% CIs) in triceps skinfold (TSF) thickness, subscapular skinfold (SSF) thickness, and arm fat area (AFA) among children aged 6–8 y in each maternal supplementation group compared with the control group. Values were adjusted for the design effect and child age at follow-up by using a generalized estimation equation linear regression model. *Significantly different from control, P < 0.05.