Estimation of Mean Intelligence Quotient with Wechsler Scale in Iran: Systematic Review and Meta-Analysis

Abstract

The low intelligence quotient (IQ) level is one of the most common and important medical, social, and familial problems in all countries. The current study aimed to estimate mean IQ with the Wechsler scale in Iran by performing a systematic review and meta-analysis. In the current meta-analysis, all articles related to IQ conducted in Iran using the Wechsler scale were deeply searched by reviewing citation databases including Science Direct, PubMed, Scopus, Web of Science, Springer, SID, Magiran, Iranmedex, Medlib, and Google Scholar motor search and using valid keywords without time limits. Due to heterogeneity between studies, a random effects model was used to combine the results of studies. To investigate the heterogeneity of the studies, the I2 index was used. All statistical analyses were performed using STATA software version 11.1. The number of participants in the 51 studies was 5352. The mean total IQ score in Iran was estimated 97.12 (95% confidence interval [CI]: 88.71–105.52), the practical intelligence was 92.84 (95% CI: 79.14–106.55), and the verbal intelligence was 94.50 (95% CI: 83.90–105.10). The total IQ score in the northern, southern, central, eastern, and western regions of Iran was 97.08, 108.90, 92.31, 101.76, and 96.45, respectively. The mean IQ score in Iran in subjects under 20 years of age is 97.73 and in subjects over 20 years of age is 105.61. There is also no significant relationship between the mean total IQ in Iran and two parameters of the year of research and number of research samples. For prevention of decrease IQ and given that proper nutrition and breastfeeding directly contribute to increase IQ, nutrition should be provided free of charge in poorer areas during pregnancy until baby born. Moreover, the media should provide adequate education for breastfeeding and nutrition, because IQ affects people's academic, occupational, personal, and social performance, and also prevents elite immigration with suitable planning and provides conditions for elites to return to the country.