Russell PSS, Nagaraj S, Vengadavaradan A, Russell S, Mammen PM, Shankar SR, Viswanathan SA, Earnest R, Chikkala SM, Rebekah G. Prevalence of intellectual disability in India: A meta-analysis. World J Clin Pediatr 2022; 11(2): 206-214 [PMID: 35433303 DOI: 10.5409/wjcp.v11.i2.206]
Corresponding Author of This Article
Paul Swamidhas Sudhakar Russell, DNB, MBBS, MD, Full Professor, Child and Adolescent Psychiatry Unit, Christian Medical College, Bagayam, Vellore 632 002, Tamil Nadu, India. russell@cmcvellore.ac.in
Research Domain of This Article
Psychiatry
Article-Type of This Article
Meta-Analysis
Open-Access Policy of This Article
This article is an open-access article which was selected by an in-house editor and fully peer-reviewed by external reviewers. It is distributed in accordance with the Creative Commons Attribution Non Commercial (CC BY-NC 4.0) license, which permits others to distribute, remix, adapt, build upon this work non-commercially, and license their derivative works on different terms, provided the original work is properly cited and the use is non-commercial. See: http://creativecommons.org/licenses/by-nc/4.0/
Paul Swamidhas Sudhakar Russell, Sahana Nagaraj, Ashvini Vengadavaradan, Sushila Russell, Priya Mary Mammen, Satya Raj Shankar, Shonima Aynipully Viswanathan, Swetha Madhuri Chikkala, Child and Adolescent Psychiatry Unit, Christian Medical College, Vellore 632 002, Tamil Nadu, India
Richa Earnest, Department of Psychiatry, Christian Medical College, Vellore 632 002, Tamil Nadu, India
Grace Rebekah, Department of Biostatistic, Christian Medical College, Vellore 632 002, Tamil Nadu, India
Author contributions: Russell PSS conceived and designed the study; Chikkala SM and Earnest R performed the literature search and collected data; Russell S and Shankar SR extracted data; Nagaraj S and Vengadavaradan A appraised the quality of studies; Mammen PM resolved the conflicts in data extraction and quality appraisal; Russell PSS, Viswanathan SA and Rebekah G carried out the statistical analyses; and all authors contributed to the writing and approval of the final manuscript.
Conflict-of-interest statement: The authors declare that they have no conflict of interest.
PRISMA 2009 Checklist statement: The authors have read the PRISMA 2009 Checklist, and the manuscript was prepared and revised according to the PRISMA 2009 Checklist.
Open-Access: This article is an open-access article that was selected by an in-house editor and fully peer-reviewed by external reviewers. It is distributed in accordance with the Creative Commons Attribution NonCommercial (CC BY-NC 4.0) license, which permits others to distribute, remix, adapt, build upon this work non-commercially, and license their derivative works on different terms, provided the original work is properly cited and the use is non-commercial. See: https://creativecommons.org/Licenses/by-nc/4.0/
Corresponding author: Paul Swamidhas Sudhakar Russell, DNB, MBBS, MD, Full Professor, Child and Adolescent Psychiatry Unit, Christian Medical College, Bagayam, Vellore 632 002, Tamil Nadu, India. russell@cmcvellore.ac.in
Received: March 21, 2021 Peer-review started: March 21, 2021 First decision: May 6, 2021 Revised: May 18, 2021 Accepted: February 11, 2022 Article in press: February 11, 2022 Published online: March 9, 2022 Processing time: 352 Days and 20.4 Hours
Abstract
BACKGROUND
Burden due to intellectual disability (ID) is only third to the depressive disorders and anxiety disorders in India. This national burden significantly contributes to the global burden of ID and hence one has to think globally and act locally to reduce this burden. At its best the collective prevalence of ID is in the form of narrative reviews. There is an urgent need to document the summary prevalence of ID to enhance further policymaking, national programs and resource allocation.
AIM
To establish the summary prevalence of ID during the past 60 years in India.
METHODS
Two researchers independently and electronically searched PubMed, Scopus, and the Cochrane library from January 1961 to December 2020 using appropriate search terms. Two other investigators extracted the study design, setting, participant characteristics, and measures used to identify ID. Two other researchers appraised the quality of the studies using the Joanna Briggs Institute critical appraisal format for Prevalence Studies. Funnel plot and Egger’s regression test were used to ascertain the publication and small study effect on the prevalence. To evaluate the summary prevalence of ID, we used the random effects model with arcsine square-root transformation. Heterogeneity of I2 ≥ 50% was considered substantial and we determined the heterogeneity with meta-regression. The analyses were performed using STATA (version 16).
RESULTS
Nineteen studies were included in the meta-analysis. There was publication bias; the trim-and-fill method was used to further ascertain bias. Concerns with control of confounders and the reliable measure of outcome were noted in the critical appraisal. The summary prevalence of ID was 2% [(95%CI: 2%, 3%); I2 = 98%] and the adjusted summary prevalence was 1.4%. Meta-regression demonstrated that age of the participants was statistically significantly related to the prevalence; other factors did not influence the prevalence or heterogeneity.
CONCLUSION
The summary prevalence of ID in India was established to be 2% taking into consideration the individual prevalence studies over the last six decades. This knowledge should improve the existing disability and mental health policies, national programs and service delivery to reduce the national and global burden associated with ID.
Core Tip: Intellectual disability (ID) is prevalent in India and earlier epidemiological studies on mental disorders have documented the lifetime prevalence of ID. However, the documented prevalence of ID in the country shows a wide range. The burden posed by ID is only third to the depressive disorders and anxiety disorders among mental disorders. The burden of ID in India significantly contributes to the global burden of ID; to decrease this we need to think globally and act locally in an evidence-based manner. To date, the prevalence of ID in India has been shown in narrative reviews. This suggests that the summary prevalence of ID in India has to be ascertained to help improve the existing disability and mental health policies, national programs and service delivery. This meta-analysis established that the summary lifetime prevalence of ID in India is 2%.
