Intellectual disability, which begins before adulthood, has a lasting effect on development, causes impairment of social functioning and has a high opportunity cost for the caregiver (Ambikile and Outwater, 2012). Most often, children and adults with ID have inadequate rights and privileges with little regard for their psychological needs (Hazarika et al., 2017). As children cannot outgrow ID, we must contain its severity through early interventions (Singh and Anekar, 2018) can reduce economic strain due to developemntal disabilities (Sapiets et al., 2021).
In India, evidence on gender differential in ID is limited, given the narrow body of literature on its prevalence in the first place. Lakhan and Ekúndayò (2017) make persuasive comments on the lack of ID prevalence estimates and conclude that India requires identifying, mapping and understanding of determinants of ID. A localised study by Lakhan and Sharma (2010) found a higher prevalence of ID among men, and this gender differential increased with the severity of ID. Sagar et al. (2020) in a comprehensive attempt to outline the prevalence of mental illness across states of India, identify a prevalence of 11.8% among males and 9.7% among females. They also show a growing gender differential with increase in age.
Female children in India face negative health consequences due to a preference for male offspring, gender inequalities and the socio-cultural dominance of patriarchy (Pillai and Ortiz-Rodriguez, 2015). This gender disadvantage in health implicates the importance of understanding ID prevalence across gender. However, existing studies (Lakhan et al., 2010; Sagar et al., 2020; Russell et al., 2022) do not provide such evidence across socio-economic characteristics which are fundamental determinants of gender discrimination and hence its disparity. Motivated by the lack of such contextual understanding of gender variation in ID, we provide nationally representative estimates of ID prevalence for males and females based on the National Sample Survey Organisation (NSS-76) on disability. These estimates are calculated as the marginal probability of ID prevalence with controls for education, age, gender, income and place of residence. Any variation by child gender signifies a reporting differential within the population. We then trace such reporting differential according to the age category separately for rural-urban areas, education the income of the head of household, and the developmental status of the geographic states.
Our study has three major findings. First, the prevalence of ID and its gender differential follows an inverted U pattern with age, i.e. increases from childhood to middle-age and reduces thereafter. Second, the prevalence of ID is higher among males with a difference of 58 points and a male to female ratio of 1.5. Third, the shape of the age gradient in male-female difference of ID prevalence has different slopes by education, income, place of residence and SDI of states.
We estimated that in India, the prevalence of ID per 100,000 people is 179 for males and 120 for females. This gender difference and its age pattern are steeper in urban areas and states with middle SDI. Further, it reduces with education and income of the household head. The higher prevalence of ID among males is well established in the literature (McKenzie et al., 2016; Lai et al., 2012). The only evidence for India that is temporally comparable to our findings is provided by the Global Burden of Disease (GBD) study (Sagar et al., 2020) that reported a declining prevalence of ID among males and females in India, with little but growing gender differential with time. McKenzie et al. (2016), in their systematic review, show that males are consistently over-represented in ID studies across time and geographies. Biological reasons such as lower expression of ‘fragile X syndrome’ and higher male susceptibility are responsible for the sex differential (Lubs et al., 2012). However, the role of socio-economic factors that influence the identification and reporting of ID cannot be undermined. Boys, who may have more behavioural problems and are more likely to receive medical attention, have higher chances of identification and reporting (Yeargin-Allsop et al., 1992; Murphy et al., 1998). Similar to ASD, underdiagnoses and underreporting among females may also be warranted as the primary reasons for gender differential in ID prevalence (Fombonne, 2003; Devlin, 2018). Stigma and ignorance among family members impediment social recognition of disability rights, causing under-reporting (Ganesh et al., 2008). Such underreporting may be higher for females owing to gender inequalities and socio-cultural factors (Boyle et al., 2011).
Increased diagnosis among females may explain the declining ratio (McKenzie et al., 2016). However, if purposeful underreporting is prevalent for females, then the fear of marriageability for girls in the reproductive age group is a plausible explanation for higher gender differential at ages 15–29 years. By education, the gender differential in ID prevalence is higher among those with primary education or less for all age groups. For ages below 5 years, gender differential in ID prevalence declines by 90% (from 44 to 4 per 100,000) between lowest and highest educational groups. Also, the age gradient for gender differential is highest for those with primary education or less. Such estimates highlight the role of education for ID reporting.
The main observations of the study, i.e., increasing prevalence of ID and gender differential with age, large gender differential by education and peaking of gender differential
at 15–29 years of age, hints under-identification and underreporting of ID among females and younger ages as a common plausible explanation. The families of young children/
adolescents may be unaware of the intellectual state of their children or maybe unwilling to report it due to stigma. The sharp increase in ID prevalence and wide gender differential among those with low education supports premise. Either way, we realize the lacuna of the public health system in recognizing intellectual disability as a concern and spearheading its awareness and mapping among the population.
While lack of data limits such assessment in India, one can gauge its severity from the evidence in developed nations. Inability to recognise the symptoms by physicians and
lack of specialist training (Doherty et al., 2020) is a common reason for underreporting of ID (Mishra et al., 2021). In this context, systematic steps must be taken to sensitize
the issue of gender in disability. Gender budgeting for disability interventions tackling the social stigma of ID among females by workforce engagement could be attempted. Further, we may need social movements involving civil rights organizations international agencies to de-stigmatize intellectual disability, whose most prominent victims are women of marriageable age. Such approaches are well discussed in Girimaji & Kommu (2016) and Girimaji and Srinath (2010).
Such considerations are relevant given the focus of Government of India on early identification and cure of developmental disorders among children through the Rashtriya Bal Swashtya Karyakram (GOI, 2013). The scheme aims to reduce out of pocket expenditure (OOPE), especially among the marginalised that face higher burden of developmental disabilities such as ID. It aims to achieve this through health screening and early intervention services. The focus group is all children aged 0–6 years in rural areas and urban slums along with children enrolled in government school up to age 18. Cognitive, language, learning delays and behavioural disorders, all of which border ID symptoms are targeted for early interventions. The early identification and intervention are mobilised through ASHA workers, Aanganwadi centres and mobile health teams. The mobile health team comprises of four members- one male and one female AYUSH doctors, one Auxiliary nurse midwife and one pharmacist. Special screening tools have also been developed for screening of children 0–6 and 6–18 y of age, in pictorial format for quick and easy identification. RBSK has achieved substantial screening of 12.2 crore children, of which nearly 6 lakh children were identified for developmental disorder (GOI, 2013). However, our findings suggest many missed opportunities to identify girls with intellectual disability. Therefore, RBSK needs to adopt a more gender centric approach to improve its outcome further.
As the intellectually disabled become more integrated into the society through medical and social interventions, new questions will emerge, such as their changing life span, their morbidity profiles (chronic and acute), prevalence of other mental comorbidities such as depression, educational and workforce rehabilitations. In this context it is pertinent to expand the social research on ID in India on issues such as social epidemiology of ID, community involvement, social acceptability and taboo, gender and age-related problems of intellectually disabled, family reinforcement interventions and so on. However, at first, it is essential to map the landscape of ID in India, geographically as well as on the basis of socio-economic status. Such exercises should be undertaken multiple times to trace the temporal changes.
While this paper serves an important purpose of highlighting gender differential and underreporting, its limitation lies in its capacity to assess intellectual disability. There was no formal test conducted on household members to determine intellectual disability. Even though enumerators were trained to determine intellectual disability by a set of survey questions, they had to rely on the household respondent to report if a member had an intellectual disability or not. However, this limitation does not affect the critical point of the paper, which is to assess households’ reportage of the intellectually disabled.
Mudit Kapoor is Associate Professor at Indian Statistical Institute, Delhi. Mayanka Ambade is Visiting Faculty at SVKM University, Mumbai. Shamika Ravi is Senior Fellow at Brookings India. S. V. Subramanian is of Harvard University.
This is an edited excerpt from the authors’ paper Age- and Gender-Specific Prevalence of Intellectually Disabled, first published in the Journal of Autism and Developmental Disorders. Read the full paper here.