Intellectual disability (ID) is characterized by
significant limitations in both intellectual functioning
and adaptive behavior that begin before the age of 18
years.[1] Prevalence of ID has been reported around
1-3% population in the world and of these mild,
moderate, severe, and profound ID affects about
85%, 10%, 4%, and 2% of the population, respectively.
[1-4] According to Harris[5] and Maulik et al.[2] studies,
the highest prevalence is in low income countries
(16.41/1000 population), whereas for middle- and
high-income countries is around 15.94 and 9.21/1000
population, respectively. Furthermore, the prevalence
of ID is more among child/adolescent population
(18.30/1000) in comparison with an adult population
(4.94/1000).
In this study, data were extracted from the Statistical
Center of Iran.[6] According to census results in 2011,
the prevalence of ID is around 13/1000 population
in Iran. In Figure 1, the prevalence of ID is showed
according to age and gender. In general, the prevalence
of ID among men (5.3/1000) is more than women
(3.5/1000), and it has the highest rate for adolescents
and young people.