Stunting, Poor Iron Status and Parasite Infection Are Significant Risk Factors for Lower Cognitive Performance in Cambodian School-Aged Children

BACKGROUND Nutrition is one of many factors affecting the cognitive development of children. In Cambodia, 55% of children <5 y were anemic and 40% stunted in 2010. Currently, no data exists on the nutritional status of Cambodian school-aged children, or on how malnutrition potentially affects their cognitive development. OBJECTIVE To assess the anthropometric and micronutrient status (iron, vitamin A, zinc, iodine) of Cambodian schoolchildren and their associations with cognitive performance. METHODS School children aged 6-16 y (n = 2443) from 20 primary schools in Cambodia were recruited. Anthropometry, hemoglobin, serum ferritin, transferrin receptors, retinol-binding protein and zinc concentrations, inflammation status, urinary iodine concentration and parasite infection were measured. Socio-economic data were collected in a sub-group of children (n = 616). Cognitive performance was assessed using Raven's Colored Progressive Matrices (RCPM) and block design and picture completion, two standardized tests from the Wechsler Intelligence Scale for Children (WISC-III). RESULTS The prevalence of anemia, iron, zinc, iodine and vitamin A deficiency were 15.7%; 51.2%, 92.8%, 17.3% and 0.7% respectively. The prevalence of stunting was 40.0%, including 10.9% of severe stunting. Stunted children scored significantly lower than non-stunted children on all tests. In RCPM test, boys with iron-deficiency anemia had lower scores than boys with normal iron status (-1.46, p<0.05). In picture completion test, children with normal iron status tended to score higher than iron-deficient children with anemia (-0.81; p = 0.067) or without anemia (-0.49; p = 0.064). Parasite infection was associated with an increase in risk of scoring below the median value in block design test (OR = 1.62; p<0.05), and with lower scores in other tests, for girls only (both p<0.05). CONCLUSION Poor cognitive performance of Cambodian school-children was multifactorial and significantly associated with long-term (stunting) and current nutritional status indicators (iron status), as well as parasite infection. A life-cycle approach with programs to improve nutrition in early life and at school-age could contribute to optimal cognitive performance.