The Estimated Prevalence of Autism in School-Aged Children Living in Rural Nepal Using a Population-Based Screening Tool

Prevalence of autism spectrum disorder among children in Southeast Asia from 2002 to 2022: An updated systematic review and meta-analysis

Background and Aims

Autism spectrum disorder (ASD) is a neurodevelopmental condition that impacts the brain, characterized by challenges in social communication and interaction, often accompanied by repetitive behaviors or focused interests. This study sheds light on the prevalence of ASD within the Southeast Asian region.

Methods

The study protocol was registered in PROSPERO (Registration No: CRD42023413915). Appropriate search terms and Boolean operators were employed to explore electronic databases for relevant articles. Data thus extracted were prepared in Excel and analyzed in Comprehensive Meta-Analysis Software. The effect measure utilized in the study was represented by the proportion, and the choice between a fixed or random-effect model depended on the observed heterogeneity. Visual feedback was provided through the use of forest plots and funnel plots.

Results

A total of 14 studies were included in the qualitative and quantitative synthesis after screening the imported studies. The prevalence of ASD was six per 1000 population (proportion: 0.006; CI: 0.002-0.017; I 2: 99.263%). Among the ASD cases, 64.4% (proportion: 0.644; CI: 0.590-0.693; I 2: 9.937%) were males and 35.6% (proportion: 0.356; CI: 0.307-0.410; I 2: 9.937%) were females.

Conclusion

The prevalence of ASD in Southeast Asia was estimated to be six cases per 1000 individuals, with a higher prevalence among males. This study contributes to our understanding of ASD prevalence in the region, although it is essential to note certain limitations in estimating prevalence.

The global prevalence of autism spectrum disorder: a comprehensive systematic review and meta-analysis

Background

Autism spectrum disorder (ASD) is one of the serious developmental disorders that is usually diagnosed below the age of three years. Although the severity of the disease’s symptoms varies from patient to patient, the ability to communicate with others is affected in all forms of ASD. This study aimed to determine the prevalence of ASD in high-risk groups by continent.

Methods

The present study was conducted by systematic review and meta-analysis from 2008 to July 2021. Databases such as Science Direct, PubMed, Scopus, SID, Magiran, Web of Science (WoS), and Google Scholar from 2008 to July 2021 were searched to find related studies. Data were analysed using Comprehensive Meta-Analysis software (Version 2).

Results

A total of 74 studies with 30,212,757 participants were included in this study. The prevalence of ASD in the world was 0.6% (95% confidence interval: 0.4–1%). Subgroup analyses indicated that the prevalence of ASD in Asia, America, Europe, Africa and Australia was 0.4% (95% CI: 0.1–1), 1% (95% CI: 0.8–1.1), 0.5% (95% CI: 0.2–1), 1% (95% CI: 0.3–3.1), 1.7% (95% CI: 0.5–6.1) respectively.

Conclusion

ASD imposes a heavy health burden on communities around the world. Early detection of ASD can reduce the incidence of developmental disorders and improve patients’ communication skills. Therefore, health policymakers need to be aware of the prevalence and increasing trend of ASD to implement appropriate planning and interventions to reduce its consequences.

Global prevalence of autism: A systematic review update

Prevalence estimates of autism are essential for informing public policy, raising awareness, and developing research priorities. Using a systematic review, we synthesized estimates of the prevalence of autism worldwide. We examined factors accounting for variability in estimates and critically reviewed evidence relevant for hypotheses about biological or social determinants (viz., biological sex, sociodemographic status, ethnicity/race, and nativity) potentially modifying prevalence estimates of autism. We performed the search in November 2021 within Medline for studies estimating autism prevalence, published since our last systematic review in 2012. Data were extracted by two independent researchers. Since 2012, 99 estimates from 71 studies were published indicating a global autism prevalence that ranges within and across regions, with a median prevalence of 100/10,000 (range: 1.09/10,000 to 436.0/10,000). The median male‐to‐female ratio was 4.2. The median percentage of autism cases with co‐occurring intellectual disability was 33.0%. Estimates varied, likely reflecting complex and dynamic interactions between patterns of community awareness, service capacity, help seeking, and sociodemographic factors. A limitation of this review is that synthesizing methodological features precludes a quality appraisal of studies. Our findings reveal an increase in measured autism prevalence globally, reflecting the combined effects of multiple factors including the increase in community awareness and public health response globally, progress in case identification and definition, and an increase in community capacity. Hypotheses linking factors that increase the likelihood of developing autism with variations in prevalence will require research with large, representative samples and comparable autism diagnostic criteria and case‐finding methods in diverse world regions over time.

The role of bullying victimization in the pathway between autistic traits and psychotic experiences in adolescence: Data from the Tokyo Teen Cohort study

Autistic traits are associated with psychotic experiences in adolescence; however, the mechanisms underlying this relationship are not well understood. Prior research indicates that bullying victimization increases the risk of psychotic experiences in general adolescent populations, and autistic youth are at higher risk of being bullied than their non-autistic peers. Using longitudinal data from general population adolescents aged 10-14 in the Tokyo Teen Cohort study, we tested the hypothesis that bullying is responsible for the association between autistic traits and psychotic experiences in adolescence. We identified an indirect effect (estimate = 0.033 [95% CIs: 0.014-0.057], p < 0.001) between autistic traits and psychotic experiences via bullying victimization, even after controlling for known confounders. Prevention of bullying victimization may be one avenue for reducing risk of psychosis among adolescents with high levels of autistic traits.

Implementing and evaluating Social Attention and Communication Surveillance (SACS) to prospectively identify autism in very young children in Nepal

BACKGROUND

Although Autism Spectrum Disorder (ASD) can be identified as early as 12 months and diagnosed by 24 months, the mean age of diagnosis of ASD in Nepal is ∼58 months, with children missing the opportunity for early intervention.

AIMS

This study implemented and evaluated a Nepali version of the Social Attention and Communication Surveillance (SACS-N) tool, to identify children between 11-30 months who are at "high likelihood" of ASD in a local community in Nepal.

METHODS

Sixty Female Community Health Volunteers (FCHVs) were trained to monitor and identify the early signs of ASD using SACS-N.

RESULTS

Overall, 1926 children were monitored with the SACS-N, with 11 children (0.57 %) referred for further assessments at 11-15 months (n = 4), 16-21 months (n = 4), and 22-30 months (n = 3). Of these children, 10 children had a developmental disorder, including ASD and Global Developmental Delay; no information was available on one child who migrated. Hence, the positive predictive value (PPV) of SACS-N for all developmental disorders was 100 %. Of seven children attending a gold standard diagnostic/ developmental assessment, three had ASD (43 % PPV for ASD). The estimated prevalence of ASD ranged between 0.16 % to 0.26 %.

CONCLUSION

Community-based developmental monitoring of ASD and other developmental delays by FCHVs is a feasible, cost-effective and sustainable approach to promoting early identification of ASD in Nepal. Further training and awareness of autism is needed for more accurate and increased referral rates using the SACS-N, including regular supervision of FCHVs.

Changes in Knowledge on the Signs of Autism in Young Children (11-30 Months) among Female Community Health Volunteers in Nepal

Nepalese Female Community Health Volunteers' (FCHVs) knowledge on social attention and communication development and the early signs of autism was evaluated before, immediately after, and 12-months following training on typical and atypical social-communicative development in infants/toddlers, early signs of autism, and monitoring of key "markers" of autism using Social Attention and Communication Surveillance. FCHVs (N = 60) significantly improved their knowledge about autism and reported increased perceived confidence in monitoring and referring young children at high likelihood of autism following training, which was sustained one year later. FCHVs also reported a positive impact of training on their work. These findings indicate the effectiveness of training in improving FCHVs' knowledge and perceived confidence to monitor and refer young children at high likelihood of autism.

The effectiveness and adverse effects of D-cycloserine compared with placebo on social and communication skills in individuals with autism spectrum disorder

BACKGROUND

Symptoms of autism spectrum disorder (ASD) have been associated, in part, with the dysfunction of N-methyl-D-aspartate (NMDA) glutamate receptors at excitatory synapses and glutamate abnormalities. Medications related to glutamatergic neurotransmission, such as D-cycloserine - which is a partial agonist of the NMDA glutamate receptor - are potential treatment options for the core features of ASD. However, the potential effect of D-cycloserine on the social and communication skills deficits of individuals with ASD has not been thoroughly explored and no systematic reviews of the evidence have been conducted.

OBJECTIVES

To assess the efficacy and adverse effects of D-cycloserine compared with placebo for social and communication skills in individuals with ASD.

SEARCH METHODS

In November 2020, we searched CENTRAL, MEDLINE, Embase, six other databases and two trials registers. We also searched the reference lists of relevant publications and contacted the authors of the included study, Minshawi 2016, to identify any additional studies. In addition, we contacted pharmaceutical companies, searched manufacturers' websites and sources of reports of adverse events.  SELECTION CRITERIA: All randomised controlled trials (RCTs) of any duration and dose of D-cycloserine, with or without adjunct treatment, compared to placebo in individuals with ASD.

DATA COLLECTION AND ANALYSIS

Two review authors independently selected studies for inclusion, extracted relevant data, assessed the risk of bias, graded the certainty of the evidence using the GRADE approach, and analysed and evaluated the data. We provide a narrative report of the findings as only one study is included in this review.

MAIN RESULTS

We included a single RCT (Minshawi 2016) funded by the United States Department of Defense. It was conducted at two sites in the USA: Indiana University School of Medicine and Cincinnati Children's Hospital Medical Centre. In the included study, 67 children with ASD aged between 5 and 11 years were randomised to receive either 10 weeks (10 doses) of (50 mg) D-cycloserine plus social skills training, or placebo plus social skills training. Randomisation was carried out 1:1 between D-cycloserine and placebo arms, and outcome measures were recorded at one-week post-treatment. The 'risk of bias' assessment for the included study was low for five domains and unclear for two domains. The study (67 participants) reported low certainty evidence of little to no difference between the two groups for all outcomes measured at one week post-treatment: social interaction impairment (mean difference (MD) 3.61 (assessed with the Social Responsiveness Scale), 95% confidence interval (CI) -5.60 to 12.82); social communication impairment (MD -1.08 (measured using the inappropriate speech subscale of the Aberrant Behavior Checklist (ABC)), 95% CI -2.34 to 0.18); restricted, repetitive, stereotyped patterns of behaviour (MD 0.12 (measured by the ABC stereotypy subscale), 95% CI -1.71 to 1.95); serious adverse events (risk ratio (RR) 1.11, 95% CI 0.94 to 1.31); non-core symptoms of ASD (RR 0.97 (measured by the Clinical Global Impression-Improvement scale), 95% CI 0.49 to 1.93); and tolerability of D-cycloserine (RR 0.32 (assessed by the number of dropouts), 95% CI 0.01 to 7.68).  AUTHORS' CONCLUSIONS: We are unable to conclude with certainty whether D-cycloserine is effective for individuals with ASD. This review included low certainty data from only one study with methodological issues and imprecision. The added value of this review compared to the included study is we assessed the risk of bias and evaluated the certainty of evidence using the GRADE approach. Moreover, if we find new trials in future updates of this review, we could potentially pool the data, which may either strengthen or decrease the evidence for our findings.

Epidemiology of Autism Spectrum Disorders: A Review of Worldwide Prevalence Estimates Since 2014

The prevalence of Autism Spectrum Disorder (ASD) has increased dramatically in recent decades, supporting the claim of an autism epidemic. Systematic monitoring of ASD allows estimating prevalence and identifying potential sources of variation over time and geographical areas. At present, ASD prevalence estimates are available worldwide, coming either from surveillance systems using existing health and educational databases or from population studies specifically performed. In the present article, we present a review of the ASD prevalence estimates published since 2014. Data confirm a high variability in prevalence across the world, likely due to methodological differences in case detection, and the consistent increase of prevalence estimates within each geographical area.

Prevalence of autism spectrum disorder in Asia: A systematic review and meta-analysis

There has been an increased prevalence of the diagnosis of Autism Spectrum Disorder (ASD) globally during the last decade. An updated and overall estimate of ASD prevalence in Asia would assist health professionals to develop relevant public health strategies. We performed a systematic review by searching English databases (Medline, Embase, Web of Science, and Cochran Library) from inception date to August 6, 2018. Subgroup, sensitivity, and meta-regression analyses were performed to address heterogeneity. Publication bias was evaluated using Egger's test. A total of 2,195,497 subjects in Asia from 12 eligible studies were included in this meta-analysis. The pooled estimate of ASD prevalence among the included subjects was 0.36% (95% CI: 0.16-0.79%). The pooled ASD prevalence in males (0.45%, 95% CI: 0.19-1.04%) was higher than that in females (0.18%, 95% CI: 0.079-0.49%). ASD prevalence in East Asia, South Asia, and West Asia was 0.51% (95% CI: 0.06-4.22%), 0.31% (95% CI: 0.14-0.65%), and 0.35% (95% CI: 0.07-1.80%) respectively. The prevalence of ASD is increasing in Asia. Universal and standardized diagnostic processes for ASD should be adopted for the prevention and control programs of ASD in future.

[Abnormal brain structure in preschool and school-aged children with autism spectrum disorder]

OBJECTIVE

To investigate the prevalence and type of abnormal brain structure in preschool and school-aged children with autism spectrum disorder (ASD).

METHODS

A total of 74 252 preschool and school-aged children aged 3-12 years in Shanghai were enrolled as subjects. A questionnaire survey was performed to collect basic information, and their parents and teachers completed the Social Communication Questionnaire (SCQ) based on the children's conditions. ASD was diagnosed by specialist physicians according to the DSM-5 criteria. Brain magnetic resonance imaging (MRI) was performed according to their parents' desires.

RESULTS

The overall prevalence rate of ASD was 2.59‰ (192/74 252) in the preschool and school-aged children. Brain MRI data were collected from 73 children with ASD and 185 healthy children. Among the 73 children with ASD, 40 (55%) had abnormal brain structure, and the most common types were unilateral or bilateral ventriculomegaly in 32 children (80%) and unilateral or bilateral deep frontotemporal sulci in 12 children (30%). Children with ASD showed lower white matter signal in bilateral ventricular and unilateral or bilateral deep frontotemporal sulci, compared to their normal peers (P<0.05).

CONCLUSIONS

There is a high prevalence rate of abnormal brain structure in preschool and school-aged children with ASD, with major types of unilateral or bilateral ventriculomegaly and unilateral or bilateral deep frontotemporal sulci. It is speculated that abnormal brain structure might be associated with the pathogenesis of ASD, and further studies are needed to clarify the association between abnormal brain structure and symptoms in children with ASD.

Child and adolescent mental health problems in Nepal: a scoping review

Introduction

Globally, 10–20% of children and adolescents suffer from mental disorders, with half of all them starting by the age of 14 and three-quarters before the age of 25. In Nepal, 40% of the population is younger than 18 years of age, and as such there is a large proportion of the population that is at risk of developing a mental disorder. There has been a recent recognition of child and adolescent mental health problems in Nepal, although prior to this it had remained almost invisible on the health agenda. In response to growing concern, there is a need to conduct a review on children and adolescent mental health problems in Nepal.

Objective

To review the existing studies on child and adolescent mental health problems in Nepal.

Methodology

A scoping review approach was used to identify studies on child and adolescent mental problems in Nepal. A search of Medline and PubMed databases for articles published from the database inception to August 2018 was conducted.

Results

Ten papers were identified, and they all together included 7876 participants. Two studies reported on Post traumatic Stress Symptoms (PTSS) and described a prevalence of 10.7% to 51% of earthquake-affected children and adolescents in the Kathmandu district of Nepal. Another study reported that 53.2% of former child soldiers met the cut-off score for PTSS. Two school surveys found that the prevalence of emotional and behavioural problems in school children ranged between 12.9 and 17.03%, whereas a study on emotional and behavioural disorders in homeless children reported a prevalence of 28.6%. The prevalence of Autism Spectrum Disorder (ASD) was estimated to be as high as three in every 1000 persons in Nepal by one study. The clinical prevalence of anxiety disorders was reported ranging from 18.8% to 24.4% while that of Attention Deficit Hyperactivity Disorder (ADHD) was 10–11.7% in various clinical samples of children and adolescents.

Conclusion

Only a few studies on the prevalence of child and adolescent mental health in Nepal have been conducted. Clearly, there is a need for better study design and larger studies to understand more fully the prevalence of child and adolescent mental health disorders in Nepal, in order to adequately plan public health services accordingly.

Electronic supplementary material

The online version of this article (10.1186/s13033-019-0310-y) contains supplementary material, which is available to authorized users.