Effect of Iodine Deficiency on Academic Performance of School Children in Dawro Zone, Southwest Ethiopia: A Prospective Cohort Study

Abstract

Background:

The most visible effect of iodine deficiency (ID) is goiter, but the worst and much greater public health problem is its impact on the developing brain. Despite relatively increased attention to the consequences of ID on physical health, there are only a few studies on the influence of ID on schooling in Ethiopia. The main objective of this study was to determine the effect of chronic ID on academic performance of school children in southwest Ethiopia.

Methods:

This study was conducted on 652 schoolchildren selected from six primary schools in southwest Ethiopia. Using prospective cohort study design, 362 iodine-deficient and 290 iodine-sufficient children were followed for the difference in academic grade scores for a period of 18 months.

Results:

Average grade score of children for both groups was 72.5%. Among iodine-deficient children, about two-thirds (65.8%) performed below the mean grade score (χ² (df), 46.86 (1), p<0.001). Both school absenteeism and dropout from school were significantly higher for iodine-deficient children. For example, for a single day's absence from a class, the average grade score declined by 1.1 points (β=−1.10, 95% CI, −1.52, −0.70).

Conclusion:

Despite the efforts made by the Ethiopian government on universal salt iodization and other iodine deficiency disorder prevention programs for the last decade, many south Ethiopian children were unable to utilize their full academic potential due to chronic iodine deficiency.

Trial Registration:

PACTR201809544276357 (www.pactr.org), Registered September 14, 2018.

Keywords:

• academic performance
• grade scores
• iodine deficiency
• school absenteeism
• southwest Ethiopia

Abbreviations

BAZ, BMI for age Z score; BMI, body mass index; HAZ, height for age Z score; IRB, Institutional Review Board; IQ, Intelligence Quotient; ICC, intracluster correlation coefficient; ID, iodine deficiency; IDD, iodine deficiency disorder; IGN, Iodine Global Network; PCA, Principal Component Analysis; PI, principal investigator; SRS, simple random sampling; SNNPR, South Nation Nationalities and People’s Region; UIC, urinary iodine concentration; VIF, Variance Inflation Factor; WAZ, weight for age Z score; WHO, World Health Organization.

Data Sharing Statement

All data used and/or analyzed during the current study are available from the corresponding author on reasonable request.

Ethical Considerations

Ethical clearance and approval was obtained from Jimma University, College of Public Health and Medical Sciences ethical clearance review committee (IRB). An official letter of co-operation (Ref. No-RPGC/4052/08) was written by the University to Dawro zone administrative and health offices. The zonal offices in turn wrote official letters to their respective district offices and school directors. A written consent was obtained from the parents of each pupil through the school director and parent committee for disclosure of school performance (grade scores) of the student. Moreover, all the study participants/guardians were informed about the purpose and confidentiality of the information along with their right to refuse. The study was also registered on pan African clinical trials registration with a registration number of PACTR201809544276357 on September 14, 2018.

Acknowledgments

The authors would like to thank the study subjects, data collectors and supervisors; without their willingness and participation this study could not have been achieved. Our special thanks go to Jimma University, Wolkite University and Dawro zone administration and health departments for their continuous support and encouragement.

Author contributions

Both authors contributed to data analysis, drafting or revising the article, have agreed on the journal to which the article will be submitted, gave final approval of the version to be published, and agree to be accountable for all aspects of the work.

Funding

This research was funded by Jimma University (Ref. No- RPGC/4052/2008). The funder had no role in the design, data collection, analysis, and interpretation of this study.

Disclosure

The authors report no conflicts of interest in this work.