Early Life Thiamine Study

Overview

Thiamine (vitamin B1) is an important nutrient needed for energy metabolism, brain development, and overall health. However, low thiamine intake is a concern in countries where white rice is the main staple since it contains little thiamine. If pregnant or breastfeeding women do not eat enough thiamine, their babies may also become deficient. Severe thiamine deficiency can cause beriberi, which can be life-threatening. Milder deficiency during early life may affect brain development. Healthy pregnant women should eat 1.4 mg thiamine daily. In a previous study in rural Cambodia, study investigators found that giving breastfeeding mothers a higher dose of thiamine (10mg per day) improved their infants' brain development at six months of age. However, supplementation began two weeks after birth. Since much of an infant's brain development occurs in utero, starting mother's supplementation earlier - in pregnancy - may provide greater benefits. Study investigators are now conducting a study with pregnant women in Cambodia. Participants will receive either the usual amount of thiamine found in multiple micronutrient supplements or a higher dose, beginning in pregnancy and continuing until their child is 18 months old. The primary outcome is cognition at 18 months, to see whether higher thiamine intake during pregnancy and early childhood leads to measurable improvements in early brain development.

Please see attached study protocol for full details. Background: Thiamine (vitamin B1) is an essential micronutrient crucial for normal physiological functioning and healthy child development. Thiamine requirements increase with carbohydrate-rich diets (e.g. white rice) and during periods of high metabolism (e.g. perinatal women, infancy). The limited data available show that the prevalence of thiamine deficiency is high in women of childbearing age and their infants in several low- and middle-income settings, notably in South and Southeast Asia, where white rice is the dietary staple, but also in several African countries. Thiamine-deficient pregnant and lactating women produce breastmilk low in thiamine, putting their breastfed infants at risk of deficiency, and potentially fatal beriberi. In addition, recent evidence suggests that sub-clinical thiamine deficiency may be conferred prenatally, placing millions of infants at risk of neurocognitive deficits, undercutting life-long well-being and productivity. Preliminary Data: In coordination with the Cambodian Ministry of Health, study investigators undertook a four-parallel-arm, randomized, controlled trial (NCT03616288) in rural Cambodia to estimate the dose of maternal thiamine required postpartum to optimize breastmilk thiamine concentrations; secondary exploratory outcomes included neurocognitive assessments. Mothers were randomized to consume 0, 1.2, 2.4, or 10 mg daily thiamine from 2 weeks through 6 months postnatal. While milk thiamine concentrations were significantly higher in all thiamine groups compared to placebo, critically, at 6 months postnatal, only infants in the 10 mg/d group showed robust neurocognitive benefits. Additionally, infants whose mothers had higher milk thiamine concentrations at our pre-supplementation baseline (2 weeks postpartum) showed significantly improved neurocognitive outcomes at 6 months postnatal, suggesting that infants' prenatal access to adequate thiamine may have critical benefits for neurocognitive development. Research Gap: The prior trial indicated that 10 mg/d maternal thiamine supplementation, higher than current recommendations, was needed to support infant neurocognitive development in several domains. However, supplementation started at 2 weeks postpartum. Given how much foundational neurodevelopment occurs from conception through infancy, earlier and longer thiamine supplementation -- starting in pregnancy and maintained through 18 months postnatal -- is likely to further support neurocognitive development. Design: This will be a two parallel-arm, double-blind randomized controlled trial to compare the standard dose of thiamine in multiple micronutrient supplements throughout the perinatal and early childhood periods to a higher thiamine dose. Our primary outcome is infant neurocognitive development (Mullen Scales of Early Learning Early Learning Composite, MSEL-ELC) at 18 months postnatal. Secondary neurocognitive outcomes include the MSEL sub-scales, Global Scales of Early Development (GSED), and Visual Paired-Comparison Task (VPC), at 18 months postnatal. Sample Size: To detect a mean difference in 3 points in MSEL scores with 90% power (d=0.16, two-tailed α=0.05), and accounting for 20% losses, this study will require N=1,972 participants, 986 per group, to detect the main effect on the primary outcome, MSEL-ELC, at 18 months postnatal. Statistical Analysis for Primary Outcome: Scores on MSEL-ELC at 18 months will be compared between groups using a linear-regression model, with adjustment for health center, gestational age at enrolment, and birth anthropometry, and using generalized estimating equations with an independence working-correlation structure to account for multiple births. The effect of treatment will be described as a mean difference with a 95% CI. In all analyses, missing outcome data will be addressed using multiple imputation, performed separately by randomized group using chained equations. Outcomes will be analyzed on an intention-to-treat basis.