Printer Friendly

Intellectual disability among special children and its associated factors: A case control study, Lahore Pakistan.

Byline: Naureen Omar and Farkhanda Kokab

Keywords: Intellectual disability, Factors, Advanced maternal age, Consanguinity, Asphyxia, Trauma.

Introduction

Intellectual disability (ID) is defined as a significant limitation in intellectual functioning and adaptive behaviour covering many everyday social and practical skills, originating before the age of 18 years.1 Intellectual functioning refers to general mental capacity, learning, reasoning, problem-solving measured by an intelligence quotient (IQ) score. A score of around 70-75 indicates a limitation in intellectual functioning that may include children of Down's syndrome, autism, mental retardation etc.1 ID, a stigmatising condition of mental origin, not only affects the sufferer but has major implications on the family, society and country as a whole.2 Global prevalence of ID is 1.04%3 and is predicted to increase by 15% till 2020.4 In Pakistan, estimated ID prevalence is 17% with an 8% contribution of mental retardation.5 Severe mental retardation is quoted to be 1.9%, mild 6.5%, and is affected by various socioeconomic statuses and geographical distributions.6

ID faces the dilemma that among the cases so diagnosed, causes can be identified only in 25%.7 These can be attributed to autosomal recessive chromosomal disorders.8 Genetic, acquired, socio-demographic and cultural factors are also highly associated with ID.9 Consanguinity is associated predominantly with undiagnosed cases.10 Prenatal, perinatal causes in mothers and perinates like low birth weight (LBW), asphyxia, delayed cry, anoxia, trauma and kernicterus at the time of birth and postnatal causes in infants have a considerable share as well.10 Early initiation, exclusivity and duration of breastfeeding have an impeccable impact on the IQ scores and academic performance of children.11

The most authentic and standardised method to measure intelligence globally and for research is Wechsler intelligence scale for children (WISC) aged 6-16 years.12 It is unique as it focuses on conduction of multiple numbers of tests measuring the quality via performance rather than quantity of intelligence.12 Scoring criteria is based on performance and verbal questions. Highest range is 130 and above; gifted, 120-129; high intelligence, 110-119; normal intelligence, 90-109; average intelligence 70-89. Anything 70 and below indicates borderline intelligence or ID.13 Public health can play a vital role in reducing the impact of ID by applying levels of prevention, essentially tertiary prevention, by advocating development of special centres and rehabilitation to improve both physical and mental functioning of the disabled.14

Most studies have been conducted in the Western world, and there is a need to determine the association of geographic, demographic and cultural factors in countries like Pakistan as these factors are modifiable and can be targeted in prevention programmes to reduce the burden of this disability. Role of perinatal factors needs to be highlighted. Scarcity of data, especially in our part of the world, needs to be addressed so as to promote evidence-based practices. The current study was planned to determine the association of maternal, paternal and social factors with ID in Pakistani special children.

Subjects and Methods

The case-control study was conducted at four schools in Lahore, Pakistan, from September 2014 to September 2015. The sample size was calculated while keeping significance level at 95%, prevalence at 50% (due to unavailability of data), power of the study at 80% and considering p75%) constituted the controls.16 Cases were taken from the Rising Sun Institute and the National Special Education Centre, Lahore. The total number of students at both institutes was 900.

A list of students suffering from mental retardation, diagnosed with the help of WISC-IV, autism, diagnosed with the help of Diagnostic and Statistical Manual of Mental Disorders (DSM) IV,17 and Down's syndrome, diagnosed with the help of distinctive facial and physical features, and having an IQ score of 70 or less determined with the help of WISC-IV was prepared, and cases were raised from within this pool A list of all the public schools of Lahore was prepared and they were visited. A second list of schools giving permission to interview the parents was prepared. By simple random sampling technique, Latif Academy High School and Naveed Foundation were selected. Students securing good grades (>75%) from classes 1-10 were identified, 15 students from each class fulfilling the inclusion criteria were selected to raise the control group.

Data was collected by the investigator through personal interviewing of the parents using a pretested structured questionnaire, which was tested before initiating the data-collection on 10 cases and controls and no changes were needed to be incorporated in the questionnaire. About 25-30 minutes were spent in filling up the questionnaires. Matching for age and gender was taken in consideration during the data-collection stage. Records of the institutes visited were also rechecked to reduce the element of recall bias. SPSS 17 was used to analyse the data. Frequencies and percentages for categorical variables were calculated. P<0.05 was considered statistically significant. Logistic regression was applied. Ethical clearance was taken from institutional review board (Fatima Memorial College of Medicine And Dentistry, Lahore, Pakistan). Permission from the respective institutions and consents from the parents of the subjects were taken.

Table-1: Social factors associated with intellectual disability.

Variables###Cases (n=149)###Controls (n=149)###p value

###n###%###n###%

Economic Status of parents

Low###42###28###32###22

Middle###78###52###116###78###<0.001

High###29###19###1###1

Educational Status of Mother

Illiterate###23###15###13###9

Primary - Matriculation###77###52###128###86###<0.001

Graduate and above###49###33###8###6

Educational Status of Father

Illiterate###17###11###5###3

Primary - Matriculation###68###46###109###73###0.001

Graduate and above###64###43###35###24

Consanguinity

Yes###109###73###60###40###0.001

No###40###27###89###60

Relationship to Spouse

(first cousin)

Yes###77###52###37###25###0.001

No###72###48###112###75

Table-2: Paternal genetic factors associated with intellectual disability.

Variables###Cases (n=149)###Controls (n=149)###Odd's Ratio###95% CI###p value

###n###%###n###%

Congenital Malformations

Yes###3###2###1###0.7###3.0###0.31

No###146###98###148###99###0.313-29.57

Mental Retardation

Yes###23###16###1###0.7###27.0###<0.001

No###126###85###148###99###3.598-202.88

Down's Syndrome

Yes###4###3###0###0###2.0###0.04

No###145###97###149###100###1.806-2.277

Table-3: Perinatal factors associated with intellectual disability.

Variables###Cases###Controls###Odd's Ratio###95%CI###p value

###n###%###n###%

Trauma to the participant at the time of birth

Yes###4###3###0###0###2.03###1.806-2.27###0.04

No###145###97###149###100

Asphyxia to the participant at the time of birth

Yes###48###32###6###4###11.33###4.67-27.48

No###101###68###143###96###<0.001

Delayed cry at the time of participant

Yes###55###37###3###2###28.48###8.67-93.65###<0.001

No###94###63###146###98

Use of Oxygen at the time of birth of participant

Yes###27###18.2###5###3###6.37###2.38-17.05###<0.001

No###122###81.8###144###97

Breast feeding (participant)

Yes###115###77.2###134###90###0.38###o.196-0.73###0.003

No###34###22.8###15###10

Table-4: Regression Analysis: Data was matched for age and gender.

Variables Name###Unadjusted###Adjusted###p value

###OR###Confidence Interval###OR###Confidence Interval

Asphyxia###11.33###4.67 -- 27.48###0.63###0.11 -- 3.34###0.58

Breastfeeding###0.38###0.20 --0.73###0.40###0.17 -- 0.94###0.03

Consanguinity###4.04###2.48 -- 6.59###4.30###6.69 -- 8.07###<0.001

Delayed Cry###28.48###8.67 -- 93.65###47.31###6.69 -- 334.59###<0.001

Economic status###0.07###0.038 -- 0.116###1.39###0.70 -- 2.75###0.34

Maternal Educational status###1.91###0.93 -- 3.39###0.82###0.57 -- 1.20###0.31

Paternal Educational status###3.71###1.33 -- 10.33###1.46###1.03 -- 2.08###0.03

Paternal history of mental retardation###27.0###3.6 -- 202.9###16.06###1.89 -- 136.33###0.01

Maternal history of mental retardation###2.1###1.83 -- 2.33###539517.0###0.00 --1.0###0.97

Use of oxygen###6.37###2.38 -- 17.05###3.03###0.76 -- 12.09###0.12

Trauma to baby###2.0###1.81 -- 2.27###124527.11###0.00 -- 10###0.98

Results

Of the 298 participants, there were 149(50%) each in the cases and control groups. There were 83(56%) boys and 66(44%) girls overall. Among the cases, 109(73%) had consanguinity compared to 89(60%) in the controls. Educational levels varied in mothers and fathers of both the cases and the controls (Table-1). Majority of the mothers in both groups - 136(91%) cases and 143(95%) in controls - were housewives. Among the cases, 33(22%) fathers were unskilled, while 34(23%) were skilled labourers and professionals. Among the controls, 102(68.8%) fathers belonged to either of these categories. Age of the mother at the time of marriage ranged 14-24 years in 136(92%) cases and 141(95%) controls. Mothers age at the time of the birth of the participant ranged 18-30 years in 117(79%) cases and 121(81%) controls. Besides, 129(87%) cases and 138(93%) controls were born to fathers aged 20-39 years (p=0.08). Overall, 55(37%) mothers in the sample had a parity of more than five.

Participants in the order of firstborn were more; 52(34.8%) cases and 48(32.3%) controls compared to second in 48(32%) cases and 42(28%) controls, and third-born 26(18%) and 30(20%) respectively. Further, 113(76%) cases and 123(83%) controls were delivered in institutions. Normal vaginal delivery was the most common mode of delivery in 94(63%) cases and 110(74%) controls, but caesarean section (CS) was more in cases 52(35%) than controls 32(21%), (p=0.02) Paternal genetic factors were also noted (Table-2). Perinatal factors were significantly associated with ID. At the time of birth, trauma (odds ratio [OR] 2.03, 95% confidence interval [CI] 1.806-2.27, p=0.04), asphyxia (OR 11.33, 95%CI 4.67-27.48, p=0.001), delayed cry (OR 28.48, 95% CI 8.67-93.65, p=0.001), use of oxygen (OR 6.37, 95% CI 2.38-17.05, p=0.001) exhibited significant associations.

The impact breastfeeding was significant (OR 0.38, 95% CI 0.196-0.73, p=0.003), but the duration of breastfeeding had no significant impact (OR 0.53, 95% CI 0.35-0.79, p=0.270) (Table-3). Logistic regression was applied and after adjusting, only history of consanguinity, delayed cry at the time of birth, and paternal history of mental retardation were found to have significant association with ID, while breastfeeding showed a protective effect in relation to ID (Table-4).

Discussion

Pakistan has been reported as one of the developing countries with the highest possible rate of intellectual disabilities in children.18 Scarcity of research leads to difficulty in identifying the cause. As observed in India, 35% cases having no definitive cause were attributed to environmental, familial and psychosocial factors.19 This current research was designed to be a case-control study, targeting maternal, paternal and social factors so as to add up to the causal pathway of ID. In our sample, male predominance was observed in ID cases which is concurrent with an earlier study.20 In the current study, more than half of the mothers of controls were matriculate (high school). It was supported by a review that indicated that mild ID was dependent on the level of maternal education, availability, accessibility of education and healthcare facilities.20 The current study emphasises on the role of female education and awareness of mothers in aiding prevention of this disability.

Mostly fathers of controls were educated with varying levels of degrees compared to fathers of cases which is consistent with an Indian study in which father's level of education was higher compared to mothers in ID children.21 A relationship between ID and paternal education has been highlighted even after adjustment in the current study which needs further exploration with the help of longitudinal studies. In majority of cases, mothers were housewives, while one-third fathers belonged to unskilled, skilled labour and professional class. A study observed that one-third of mothers were housewives compared to more than half the fathers belonging to unskilled, skilled labour and professional class.21 Mothers of most of the cases and controls belonged to the 14-24 years age group at the time of marriage while one-fourth were categorised within the range of 31-50 years at the time of birth of the participant.

Concurrent with the results of a study, mothers of more than half of the cases had the age above 30 years,22 thus leading to the conclusion that although early marriage has no significant relationship, advanced maternal age can be considered an influencing factor in the development of ID. This study exhibited a significant association between father's age with development of ID. Majority cases were born to fathers in the 40-55 years age group. These results corroborate with results of a study conducted in Andhra Pradesh, India, which reported 1.8-fold rise in relative risk in fathers in the 30-34 years age group. Another study highlighted a dose-response relationship between advancing paternal age and ID.23 Disparities in social status were observed, as more than half the cases belonged to middle class and one-third to lower class respectively. This is supported by a systematic review of 19 studies conducted in 50 low and middle income countries.23

In another study, severe ID (IQ<50) was more profound in illiterate mothers, rural areas and low socioeconomic status.24 Consanguinity (cousin marriage) is influenced by religion, ethnicity, culture and geography exhibiting high trends in Pakistan.24 The current study results depicted more than two-third cases giving history of consanguinity between their parents, establishing a highly significant association, as supported by an Indian study where consanguinity was established as one of the major causes in one-third cases.22 This study highlighted more than 70% cases with history of first cousin marriages. The same was observed in Iran where 77% cases had a history of consanguinity, 50% of these were first cousin marriages.25 This is an important finding as it not only bridges the gap between socio demographic factors, but also emphasises the need for awareness among the masses via public health interventions.

A very low percentage of cases indicated a genetic origin, and after adjustment only paternal history of mental retardation was associated significantly, emphasising the novelty of this study in aiming to highlight the association of maternal, paternal and social factors with ID. It is noteworthy that this study highlights significant associations between perinatal factors and ID. More than half the cases had experienced trauma, one-third asphyxia and a quarter were resuscitated with oxygen at the time of birth. Supporting evidence comes from a study conducted in the United Kingdom in which an association was observed between resuscitation at the time of birth and lower IQ levels. Besides, need for resuscitation was associated with poor maternal education, LBW babies of primigravida delivered by caesarean section.26 Another study identified that resuscitation with assisted ventilation increased risk of ID.27

Delayed cry at the time of birth is significantly associated with ID, especially in developing countries. In an Indian study, one-third cases had a history of delayed cry at the time of birth.11 Similar results were observed in this study with more than one-third cases having a history of delayed cry. This study is one of its kind having been conducted in Pakistan, as it throws light on perinatal factors globally recognised as responsible for ID, to be understood and identified in our settings. The role of breastfeeding has been stressed upon by the current study. Majority of the controls had a history of having been breastfed, which is consistent with the findings of a Scottish study in which breastfeeding was observed in majority controls being discharged, concluding that ID may be linked to babies not being breastfed and discharged from special baby care unit.28

It should be noted that no effect of duration of breastfeeding was observed which is contrary to the results of a study which concluded, that after adjusting a dose-response relationship it was observed, between IQ and nine months of breastfeeding.29 Multivariate logistic regression concluded that after adjusting for asphyxia at the time of birth, economic status of parents, maternal and paternal educational status, maternal history of mental retardation, use of oxygen and trauma to the baby, only history of consanguinity, delayed cry at the time of birth, paternal history of mental retardation had a significant association with ID among special children. Breastfeeding had a protective effect in relation to ID. In Pakistan, limited literature is available on ID. The current case-control study highlights the cause-effect relationship between the factors under study and ID, thus opening up avenues for longitudinal studies to be conducted.

As the study was self-funded, a few limitations were encountered. The ratio of cases-to-controls should have been 1:2. Ideally, the IQ test of cases should have been conducted by the researchers, but only the results of the tests conducted at the institutions was taken for analysis. Similarly, for the controls, IQ test should have been conducted but students with good academic score were selected. Prospective study with a larger sample would is recommended.

Conclusion

In order to address the neglected avenue of mental health in Pakistan, the results of the current study are a help to understand that not only genetic but parental, social, environmental and familial causes contribute to ID, especially perinatal and paternal factors. These factors presumably can be prevented by conduction of premarital counselling, genetic screening sessions as well as health education and awareness regarding breastfeeding and provision of antenatal and perinatal care which is a challenging task.

Acknowledgments: The researcher would like to acknowledge the contributions of Miss Salma Rashid, Late Dr Tawab, Dr Anjum Razzaq, Mr Tipu Sultan and above all Late Prof Amanullah Khan.

Disclaimer: The study is part of an M-Phil thesis and was presented at an international Public Health conference in 2016.

Conflict of Interest: None.

Source of Funding: None.

References

1. American Association of Intellectual and Developmental. [Cited May 16, 2018]. Available from http://aaidd.org/intellectual-disability/definition#.WvvLK4iFPak

2. Park K. Preventive medicine in obstetrics, paediatrics and geriatrics. Textbook of preventive and social medicine. 20th ed. Jabalpur: Banarsidas Bhanot. 2009; pp 774.

3. World Health Organization.WHO methods and data sources for global burden of disease estimates 2000-2011. [Cited 23 Jan 2015]. Available from URL: http://cdrwww.who.int/healthinfo/statistics/GlobalDALYmethods_2000_2011.pd

4. World Health Organization. The World Health Report 2001: Mental health: new understanding, new hope. [Online] 2001 [Cited 15 Dec 2014]. Available from URL: http://www.who.int/whr/2001/en/

5. Jawaid A. Paediatric mental health in Pakistan: a neglected avenue. J Pak Med Assoc 2007; 57: 50-1.

6. World Health Organization. Dept. of Mental Health, Substance Abuse. Mental health atlas 2005. [Online] 2005 [Cited 8 Jan 2015]. Available from URL: http://www.who.int/mental_health/evidence/mhatlas05/en

7. Kliegman RM, Behrman RE, Jenson HB, Stanton BM. Nelson Textbook of Pediatrics. Elsevier Health Sciences.Incomplete reference

8. Banavandi MS, Kahrizi K, Behjati F, Mohseni M, Darvish H, Bahman I, et al. Investigation of Genetic Causes of Intellectual Disability in Kerman Province, South East of Iran. IRCMJ 2012; 14: 79.

9. Shah PS, Shukla SD, Patel AA, Patel SS. Profile of patients with intellectual disability visiting a tertiary care center in western India. Int J Res Med Sci. 2014; 2: 429-33.

10. Iqbal Z, Van Bokhoven H. Identifying genes responsible for intellectual disability in consanguineous families. Human heredity 2014; 77: 150-60.

11. Kramer MS, Aboud F, Mironova E, Vanilovich I, Platt RW, Matush L, et al. Breastfeeding and child cognitive development: new evidence from a large randomized trial. Arch Gen Psychiatry 2008; 65: 578-84.

12. Wechsler D. Wechsler intelligence scale for children-Fourth Edition (WISC-IV). San Antonio, TX: The Psychological Corporation. [Online] 2003 [Cited 2014 Dec 18]. DOI 10.1177/0734282906288389

13. What's a good score on the Wechsler Individual achievement test. [Cited 2016 June 7]. Available from URL: https://wechslertest.com/about-wechsler-intelligence-test/whats-good-score-wechsler-individual-achievement-test

14. Maxcy and Rosenau, Textbook of Public Health and Preventive medicine. LA. Iowa City, 1998.

15. Lwanga, S, Lemeshow, S. WHO sample size determination in health studies: a practical manual. [Online] [Cited 12 May 2018]. Available from URL: http://apps.who.int/iris/handle/10665/40062

16. Kaya F, Juntune J, Stough L. Intelligence and its relationship to achievement. https://www.researchgate.net/publication/281764945_Intelligence_and_Its_Relationship_to_Achievement.[ cited 6 March 2017]. Available from URL: http://dx.doi.org/10.17051/io.2015.25436

17. Autism.DSM-IV Diagnostic Classifications. [Online] [Cited 24 Sep 2018].Available from URL: https://www.autism-society.org/dsm-iv-diagnostic-classifications/#autism

18. Mirza I, Tareen A, Davidson LL, Rahman A. Community management of intellectual disabilities in Pakistan: a mixed methods study. JIDR. 2009; 53: 559-70.

19. Aggarwal S, Bogula VR, Mandal K, Kumar R, Phadke SR. Aetiologic spectrum of mental retardation and developmental delay in India. IJMR. 2012; 136: 436.

20. Kaufman L, Ayub M, Vincent JB. The genetic basis of non-syndromic intellectual disability: a review. J Neurodev Disord. 2010; 2: 182.

21. Sahay A, Prakash J, Khaique A, Kumar P, Meenakshi SP, Ravichandran K, et al. Parents of intellectually disabled children: a study of their needs and expectations. IJHSSI. 2013; 2: 1-8.

22. Krishnasubha S, Lakshmikalpana V, Ramesh M, Sudhakar G. A case-control study on risk factors of mental retardation from an urban area of North Coastal Andhra Pradesh. J Life Sci 2010; 2: 93-8.

23. Simkiss DE, Blackburn CM, Mukoro FO, Read JM, Spencer NJ. Childhood disability and socio-economic circumstances in low and middle income countries: systematic review. BMC Pediatrics 2011; 11: 1.

24. Hamamy H. Consanguineous marriages. J Community Genet. 2012; 3: 185-92.

25. Jazayeri R, Saberi SH, Soleymanzadeh M. Etiological characteristics of people with intellectual disability in Iran. Neurosciences (Riyadh). 2010; 15: 258-61.

26. Odd DE, Lewis G, Whitelaw A, Gunnell D. Resuscitation at birth and cognition at 8 years of age: a cohort study. Lancet 2009; 373(9675): 1615-22

27. Langridge AT, Glasson EJ, Nassar N, Jacoby P, Pennell C, Hagan R, et al. Maternal conditions and perinatal characteristics associated with autism spectrum disorder and intellectual disability. PLoS One 2013; 8: e50963.

28. Sussmann JE, McIntosh AM, Lawrie SM, Johnstone EC. Obstetric complications and mild to moderate intellectual disability. Br J Psychiatry. 2009; 194: 224-8.

29. Mortensen EL, Michaelsen KF, Sanders SA, Reinisch JM. The association between duration of breastfeeding and adult intelligence. JAMA 2002; 287.
COPYRIGHT 2019 Knowledge Bylanes
No portion of this article can be reproduced without the express written permission from the copyright holder.
Copyright 2019 Gale, Cengage Learning. All rights reserved.

Article Details
Printer friendly Cite/link Email Feedback
Publication:Journal of Pakistan Medical Association
Article Type:Report
Geographic Code:9PAKI
Date:May 31, 2019
Words:4102
Previous Article:Assessment of the changes in the oral health related quality of life 24 hours following insertion of fixed orthodontic appliance components - An...
Next Article:Determination of epidemiology and antimicrobial susceptibility of extended spectrum beta lactamase producing uropathogens.
Topics:

Terms of use | Privacy policy | Copyright © 2021 Farlex, Inc. | Feedback | For webmasters