Prenatal Micronutrient Supplementation and Intellectual and Motor Function in Early School-aged Children in Nepal
“Prenatal Micronutrient Supplementation and Intellectual and Motor functions in Early School-aged Children in Nepal”
(JAMA, December 22/29, 2010—Vol 304, No. 24)
Dissemination of the study
What is the rationale behind this study?
The rationale behind the study was to evaluate the effects of zinc and iron supplementation on the development of intellectual and motor skills in children, whose mothers were supplemented with such micronutrients during the gestational period. Micronutrients are essential for the growth and development of an individual. Micronutrients are so called because they are required in trace amounts in the daily diet. However, they perform important roles in the synthesis of haemoglobin and repair of tissues.
Very few studies have examined the effects of Iron and Zinc supplementation during the gestational period to mothers, on the future development of cognitive skills in their children. Data from primates suggested that a decreased supply of such micronutrients resulted in 20% cognitive deficits. 2) What were the objectives of this research?
The objectives of this research were to assess the intellectual and motor skills in children, whose mothers were supplemented with the essential micronutrients Iron and Zinc, during the gestational period. Pregnancy is a condition which demands resource utilization between a mother and their child. Micronutrient deficiency can occur in children as a result of mother’s equal requirement for those during such periods. 3) Describe the methodology for this study.a) Subjects (including criteria for inclusion/exclusion)
The subjects who were selected in this cohort follow-up study included 676 children, in the age group of 7 to 9 years achieved during June 2007 to April 2009, whose mother’s received Iron and Zinc supplementation during gestational period during the period of 1999 to 2001.
b) Study Design
The study was a cohort follow-up study. The study was community-based, double-blind and randomized control trial. Since, the study was blinded and randomized, chances of bias were reduced in the study, which could have influenced the results. The control arm was supplemented with placebo, while the experimental arm had micronutrients supplemented to their mothers, during pregnancy. c) Enrolment Interview and Assessment
Children of only such mothers were assessed, who received iron/folic acid, or iron/folic acid/zinc or multiple micronutrients containing these and other 11 micronutrients during their gestational period. All of them received vitamin A supplementation too during such period. Children of such mothers were also assessed who did not receive these micronutrients during pregnancy (only vitamin A was supplemented), and these children formed the control, group.
The assessments included intellectual function in children as measured by Universal Nonverbal intelligence Test, tests of motor function execution like Stroop test, backward digit span tests and other motor tests were also evaluated. The motor function was assessed by Movement assessment Battery for Children (MABC) and finger tapping test. Other evaluations were routine anthropometric measurements and haemoglobin estimations. d) Psychological Testing
Psychological testing was done through Universal Nonverbal intelligence Test, which is an assessment of non-verbal execution of the body towards certain commands. The children demonstrated such behaviours through non-verbal gestures and this criterion was fixed as an indicator of cognitive function. e) Anthropometric and Biochemical Assessment
The anthropometric measurements that were made were height, weight and mid-upper arm circumference. Biochemical tests included estimation of haemoglobin level by using a fingerstick coupled with B-Haemoglobin analyzer. f) Environment
The measurements were done in community settings and the environmental influences on child outcomes were indexed with Middle childhood home observation for the measurement of environment (HOME) Inventory and Raven coloured progressive matrices were administered to the mothers during site visit. g) Data Analysis
The sample size was pre-fixed with numbers needed to treat was clearly outlined. The means of various variables were considered for the study. The statistical tests that were implemented were Mantova for analyzing the differences on mean from various groups. The chosen level of significance was considered as 0.05 for the two-tailed tests of significance. This indicates that when the probability value of such statistical tests was less than 0.05, it indicated that there was the statistically significant difference between the means of two or more groups. However, if the p value was more than 0.05, it indicated that here was no statistically significant difference between the experimental and control groups. The p-value considered was the Bonferroni-adjusted p value. Age-adjusted Weight and Height data were also assessed along with the Body mass Index scores. Reproducibility of data was estimated from 95% Confidential Interval scores. 4) Summarize the results from this research also explaining the tables.
There was significant difference in outcomes in the iron/folic acid treated versus control group, but not for other groups supplemented with different combination of micronutrients..The mean UNIT score
(Measurement of intelligence) of Iron/ folic acid group was significantly higher than the control group (51.7 versus 48.2, p=0.04). For the tests of execution also, there was a significant difference in outcomes in the iron/folic acid treated versus control group with respect to the Stroop test and backward digit span tests. The finger tapping tests were significantly higher in the iron acid/folic acid group compared to controls while the MABC scores were significantly lower in iron/ folic acid group versus controls.
5) What were the main conclusions of this study?
From the study it may be concluded that intellectual functioning like working memory, motor control, and motor functioning in children are positively correlated to supplementation of iron and Folic acid in their mothers during the period of pregnancy. Hence, in areas where Iron deficiency is prevalent, mothers at the gestational phase should be supplemented with Iron/folic acid combinations.