Investigating the Characteristics of Intelligence Quotient in Individuals with Intellectual Disability in Rafsanjan, 2019

Background: Comprehensive and reliable information about intellectual disability (ID) and its association with environmental and demographic variables is scarce. Objectives: This study aimed to investigate the characteristics of intelligence quotient (IQ) in children with ID. Methods: In this descriptive cross-sectional study, all children with ID under the care of the welfare organization and special needs schools of the city of Rafsanjan were included in the study by census sampling (n = 207). After obtaining informed consent, parents completed a checklist including participants’ age, gender, birth month, birth season, and birth order, and also parents’ age and education level. Data were analyzed by one-way ANOVA and chi-square tests. Results: Out of 207 children, 107 (51.7%) were male, 100 (48.3%) were female, 36.2% were first-born, 14.5% were born in May, and 5.3% were born in March (the most-the least). The relationship of IQ to birth season and month was not significant (P > 0.05). Among the children, 39.6% were offspring of consanguineous marriages, but no significant relationship was observed between their IQ and consanguineous marriages (P > 0.05). The level of ID was correlated with parents’ age (P < 0.05). A significant relationship was also found between IQ and the number of offspring (P = 0.004). All cases of severe ID were seen in girls and a significant relationship was detected between IQ and gender (P = 0.0001). Conclusions: Individuals with ID have an IQ below 70. ID in children was correlated with the parents’ old age and low education level, but not with their birth season. However, given the higher prevalence of infectious diseases especially viral infections in cold months, it is only sensible to educate couples about how to protect the health of mother and fetus during these periods.