Children's Intellectual Functioning Research Articles

The identification of exceptional skills in school-age autistic children: Prevalence, misconceptions and the alignment of informant perspectives.

Although autism is commonly described in terms of deficits, many autistic individuals have been found to demonstrate exceptional skills. The shift to a strengths-based approach in the field of autism necessitates increased understanding of these skills. This study examined (1) rates of exceptional skills in autistic school-age children as reported by parents and teachers, (2) associations between exceptional skills, autism severity and intellectual disability and (3) correlations between parent and teacher reports of exceptional skills. Parents and teachers of 76 children attending autism-specific schools in Australia completed online questionnaires. Thereafter, 35 parents and teachers who identified their child as having one or more exceptional skills were interviewed by a clinical psychologist. Forty parents (53%) and 16 (21%) teachers reported that their child had at least one exceptional skill (agreement between the parent and teacher reports was low; κ = .03, p = .74). In comparison, clinical psychologist assessments identified 22 children (29%) as having at least one such skill. No statistically significant relationships were identified between exceptional skills, autism severity and intellectual disability. While different exceptional skills were identified, regardless of children's intellectual functioning or autism severity, parents and teachers varied substantially in their evaluations of these skills. Furthermore, the identified prevalence rates of exceptional skills did not always align with the rates identified in previous studies. The study findings highlight the need for definitional consensus on different types of exceptional skills, and the importance of multiple criteria/multi-instrument approaches in the identification of exceptional skills in autistic children.

Child Linear Growth During and After the First 1000 Days Is Positively Associated with Intellectual Functioning and Mental Health in School-Age Children in Vietnam

BackgroundMillions of children fail to meet their developmental potential and experience mental health concerns globally. Evidence is mixed on whether growth beyond the first 1000 d of life influences intellectual functioning and mental health in school-age children. ObjectivesWe examined associations of childhood growth before and after the first 1000 d of life with child intellectual functioning and mental health at age 6–7 y. MethodsWe used data from a follow-up of a randomized controlled trial of preconception supplementation (PRECONCEPT study) in Vietnam. A total of 5011 women participated in the study and 1579 children were born during 2012–2014. At age 6–7 y, child intellectual functioning was assessed using the Wechsler Intelligence Scale for Children, and mental health concerns were measured using the Strengths and Difficulties Questionnaire. Multivariable linear models were used to examine the independent association of child size at age 2 y [height-for-age z-score (HAZ) and body-mass-index z-score (BMIZ)] and conditional measures of linear and ponderal growth between the ages of 2 and 7 y. ResultsHAZ at 2 y was positively associated with the Full-Scale Intelligence Quotient (β = 1.4; 95% CI: 0.5, 2.2 points) and its subdomains, namely Perceptual Reasoning Index, Working Memory Index, and Processing Speed Index (β = 1.0–1.4 points). Higher HAZ at 2 y was associated with lower overall mental health concerns (β = −0.24; 95% CI: −0.47, −0.01) and peer problems (β = −0.08; 95% CI: −0.17, −0.01). Faster height gain between 2 and 7 y was associated with higher total intellectual functioning (β = 0.9; 95% CI: 0.02, 1.8) and fewer emotional issues (β = −0.09; 95% CI: −0.18, −0.01). BMIZ at 2 y was not associated with intellectual functioning but was marginally associated with higher conduct and peer problems. Conditional weight gain between 2 and 7 y was not associated with child intellectual functioning or mental health in young school-age children. ConclusionsChild linear growth both during and beyond the first 1000 d is positively associated with intellectual functioning and mental health during the early school-age years.

MOTOR AND INTELLECTUAL DEVELOPMENT IN CHILDREN: A REVIEW

The aim of this narrative review article is to present the effects of physical activity on the motor and cognitive development of children. Early childhood is one of the most critical periods in a child's physical and intellectual development. As much as seventy percent of the brain's connections develop during the pre-school years, these connections form the basis and framework for the child's later abilities and characteristics. A physically stimulating and varied environment undoubtedly has a significant impact on the mental functions of children. The brain is designed to learn and solve problems, initially simple, later complex. The earliest challenges that the brain needs to solve are related to movement. Children solve these problems spontaneously, intuitively, and in an unstructured manner. Later, with more organized movements, children acquire various motor skills, abilities, and sensory experiences, thereby gaining a new understanding of themselves and their surroundings. These insights and experiences will equip the child for the challenges and problems they will face later in life. Children enter into social interactions and group dynamics through movement and acquire a sense of autonomy and independence. A stimulating and varied motor environment undoubtedly has a significant impact on children's intellectual function and, thus, on the development of their potential abilities.

Differential Item Functioning Based on Autism Features, IQ, and Age on the Screen for Child Anxiety Related Disorders (SCARED) Among Youth on the Autism Spectrum.

Anxiety commonly occurs among youth on the autism spectrum, yet measurement of anxiety in this population is complicated by a number of factors, including potentially overlapping symptomatology, the child's intellectual functioning, and changes in anxiety across development. Moreover, few studies have examined the psychometric properties of anxiety measures in this population, and no study to date has tested whether there are systematic differences in the measurement of anxiety, or differential item functioning (DIF), across the high degree of heterogeneity and the developmental course of autism. To test this possibility, data were combined across multiple studies using the National Database for Autism Research, an NIH-funded data repository. Parent-report on the Screen for Child Anxiety Related Disorders (SCARED) and Social Communication Questionnaire (SCQ) were used as measures of anxiety and autism features, respectively. A confirmatory factor analysis indicated good fit of the literature standard five-factor structure. Moderated nonlinear factor analysis (MNLFA) revealed multiple items with intercept and loading DIF based on level of autism features, IQ, and age, especially for items related to social behavior. Therefore, although the measure's factor structure is consistent with that found in the general population, the SCARED may not capture differences in anxiety equivalently for all children on the spectrum and across their development. Clinicians and researchers need to be especially vigilant in measuring anxiety symptoms in children with autism by removing items flagged for DIF from the SCARED and/or by using multiple measures and informants. LAY ABSTRACT: Autistic youth often experience clinical levels of anxiety. Many tools used to measure anxiety were developed for the general population, but not for use with autistic youth. This study found that the Screen for Child Anxiety Related Disorders (SCARED) measures the same five dimensions of anxiety as in the general population. Parents, however, may respond differently to questions on the SCARED based on their child's autism features, intellectual functioning, and age, which impacts our ability to accurately measure anxiety among autistic youth.

Efficacy of Social Story Intervention in Training Toothbrushing Skills Among Special-Care Children With and Without Autism.

Toothbrushing is a routine practice for oral hygiene maintenance. It is also a challenging task for young children with special care needs. In this study, social stories were employed to teach toothbrushing skills for preschool children with special needs. Those children were recruited from the Special Child Care Centers, including 87 children with autism and 94 children without autism. A validated toothbrushing social story was used to demonstrate the toothbrushing procedure for all the recruited children. Parents were encouraged to show the stories to their children before or during their daily toothbrushing. Children's toothbrushing performance, oral hygiene status, and gingival health status were assessed at baseline and 6 months. Toothbrushing performance, oral hygiene, and gingival status of the recruited children were significantly improved after using social stories. Moreover, children with autism showed better oral hygiene status (P = 0.01) and better gingival status (P < 0.001) than their peers without autism. However, there were no significant differences in the toothbrushing performance among children with and without autism. The regression models indicated that the improvement of children's toothbrushing performance and oral health status were associated with children's intellectual functioning and parents' attitudes toward the usefulness of social story intervention. The principal findings suggested that social story intervention could be used to improve toothbrushing skills among children with or without autism, while it was more efficient in improving the oral hygiene status among children with autism. Autism Res 2020, 13: 666-674. © 2019 International Society for Autism Research, Wiley Periodicals, Inc. LAY SUMMARY: Toothbrushing is considered as a basic self-care practice that should be advocated in early childhood. We used social stories to train toothbrushing skills among preschoolers with special care needs. The toothbrushing skills of the recruited children were significantly improved after 6-months intervention, and children with autism showed better oral hygiene status than their peers without autism. These findings suggested that social story-based health promotion could be implemented among children with special needs.

Examining the Impact of Respondent-Level Factors on Scores on the Supports Intensity Scale - Children's Version.

This secondary analysis examined the impact of respondent-level factors on scores on the Supports Intensity Scale-Children's Version (SIS-C) for children and youth with intellectual disability to determine if there were any significant differences in the SIS-C scores by different respondent pairs when considering children's age, intellectual functioning level, and adaptive behavior level. Results indicated whenever a pair of respondents included a teacher or a paraprofessional, the support needs scores were lower than when the pair included a family member. Moreover, there was a significant interaction effect across respondent pairing, child age, and child intellectual functioning levels as well as across respondent pairing, child age, and child adaptive behavior levels. Implications for administration and use of the SIS-C are provided.

Adaptation of a mental development assessment tool for the evaluation of the long-term effect of a successful nutrition intervention in Ghana.

This study adapted a cognitive assessment tool to be used in evaluating nutrition interventions in developing countries and assessed its reliability and validity in Ghana. The tool was used to evaluate the long-term effect of the Enhancing Child Nutrition through Animal Source Food Management (ENAM) project. The former ENAM participants' children were contacted (now 13 to 15years old). The items in the Wechsler Abbreviated Scale of Intelligence-II were adapted, pretested, refined, and pretested again. Cross-sectional data collection was conducted with former ENAM participants (60 interventions and 51 comparison families) in one of ENAM's three sites (the Guinea Savanna zone). Data on participants' socio-economic status and food insecurity were collected, along with their children's intellectual functioning, dietary intake, school attainment, anthropometry, and symptoms of depression. Alpha coefficient of the verbal subscale improved between the first and second pretest (from .34 to .80). After controlling for age, the intelligence scores of the children were associated with their grade (r=.35, p=.001) and academic performance (r=.26 to .33, p<.05). The verbal scale was associated with their anthropometry (r=.24 to .27, p<.05). The intervention children still recorded a better dietary diversity score than controls (6.8 vs 5.8, p=.0001); however, significance was lost after adjusting for confounders. There were no significant group differences in growth or intellectual functioning. The adapted Wechsler Abbreviated Scale of Intelligence-II tool performed well in evaluating adolescent intellectual functioning in rural Ghana, and there were no long-term effects of ENAM intervention on child growth and development.

Oral health and associated factors among preschool children with special healthcare needs.

To investigate the oral health status and associated factors among preschool children with special healthcare needs. This was designed as a cross-sectional study. Dental examination was provided to 383 children at Special Child Care Centres. Covariates of interest included children's age, developmental profile, oral health-related behaviours and family social-economic status. The association between children's dental caries experiences, dental plaque deposition and gingival health status were analysed by negative binomial regression, multiple factor ANOVA and binary logistic regression when appropriate. The proportion of children with caries, gingival inflammation and plaque were 30.3%, 89.6% and 95.0%, respectively. Final regression models indicated that (a) tooth decay was associated with dental visit experiences, night bottle-feeding habit, fluoridated toothpaste and monthly income; (b) plaque deposition was associated with intellectual functioning, practical skills, night bottle-feeding habit, use of toothpaste, initiation of toothbrushing habit, toothbrushing duration and additional cleaning habit; (c) gingival status was associated with children's intellectual functioning and toothbrushing frequency. Poor oral hygiene status existed among preschool children with special healthcare needs. Children's oral health status was associated with their developmental profile, oral health-related behaviours and social-economic status.

The Associations between Adiposity, Cognitive Function, and Achievement in Children.

The aim of this study was to evaluate the relation of adiposity, particularly visceral adipose tissue (VAT), on achievement and cognitive function among children. Children with obesity (ages 8-9 yr old, N = 55, 35 females) completed cognitive and academic tests. Normal weight children (N = 55, 35 females) were matched to this group on demographic characteristics and aerobic fitness. Covariate analyses included age, Brief Intellectual Ability, socioeconomic status, and fat-free V˙O2 (V˙O2 peak adjusted for lean mass; mL·kg lean·min). Adiposity (i.e., whole body percent fat, subcutaneous abdominal adipose tissue, and VAT) was assessed using dual-energy x-ray absorptiometry. The results of this study revealed that, relative to their normal weight counterparts, children with obesity had significantly lower performance on tests of reading and math. Analyses revealed that among children with obesity, %Fat and subcutaneous abdominal adipose tissue were not related to cognitive abilities. However, higher VAT was associated with poorer intellectual abilities (Ps ≤ 0.04) and cognitive performance (i.e., thinking ability and cognitive efficiency, Ps ≤ 0.04). However, among normal weight children, VAT was positively associated with intellectual abilities and cognitive efficiency. In conclusion, the results suggest that VAT was selectively and negatively related with cognition among children with obesity. Along with the dangerous metabolic nature of VAT, its detrimental relationship with obese children's intellectual and cognitive functioning is concerning.

Processing Speed Mediates the Longitudinal Association between ADHD Symptoms and Preadolescent Peer Problems.

We investigated the relation between dimensional aspects of inattention and hyperactivity-impulsivity in childhood and peer problems 4 years later, as well as the potential mediating effects of intellectual function. The sample included 127 children (32 with attention-deficit/hyperactivity disorder). Symptoms of inattention and hyperactivity-impulsivity were assessed via parent and teacher reports on Swanson Nolan and Pelham-IV questionnaire. Peer problems were assessed by parent reports on the Strengths and Difficulties Questionnaire, and children's intellectual functioning by the third edition of the Wechsler Intelligence Scale for Children. Linear regressions showed a significant effect of inattention on future peer problems, partially mediated by slow processing speed. These effects remained significant when ADHD status was covaried. Findings highlight the importance of processing speed in explaining the predictive relation between childhood inattention and later peer problems. Inattention and processing speed in early childhood are potentially malleable factors influencing adolescent social functioning.

Parent Rated Symptoms of Inattention in Childhood Predict High School Academic Achievement Across Two Culturally and Diagnostically Diverse Samples.

Objective: To investigate parent reports of childhood symptoms of inattention as a predictor of adolescent academic achievement, taking into account the impact of the child’s intellectual functioning, in two diagnostically and culturally diverse samples.Method: Samples: (a) an all-female sample in the U.S. predominated by youth with ADHD (Berkeley Girls with ADHD Longitudinal Study [BGALS], N = 202), and (b) a mixed-sex sample recruited from a Norwegian population-based sample (the Bergen Child Study [BCS], N = 93). Inattention and intellectual function were assessed via the same measures in the two samples; academic achievement scores during and beyond high school and demographic covariates were country-specific.Results: Childhood inattention predicted subsequent academic achievement in both samples, with a somewhat stronger effect in the BGALS sample, which included a large subgroup of children with ADHD. Intellectual function was another strong predictor, but the effect of early inattention remained statistically significant in both samples when intellectual function was covaried.Conclusion: The effect of early indicators of inattention on future academic success was robust across the two samples. These results support the use of remediation procedures broadly applied. Future longitudinal multicenter studies with pre-planned common inclusion criteria should be performed to increase our understanding of the importance of inattention in primary school children for concurrent and prospective functioning.

FATHER-CHILD INTERACTIONS AT 3 MONTHS AND 24 MONTHS: CONTRIBUTIONS TO CHILDREN'S COGNITIVE DEVELOPMENT AT 24 MONTHS.

ABSTRACTThe quality of father–child interactions has become a focus of increasing research in the field of child development. We examined the potential contribution of father–child interactions at both 3 months and 24 months to children's cognitive development at 24 months. Observational measures of father–child interactions at 3 and 24 months were used to assess the quality of fathers’ parenting (n = 192). At 24 months, the Mental Developmental Index (MDI) of the Bayley Scales of Infant Development, Second Edition (N. Bayley, 1993) measured cognitive functioning. The association between interactions and cognitive development was examined using multiple linear regression analyses, adjusting for paternal age, education and depression, infant age, and maternal sensitivity. Children whose fathers displayed more withdrawn and depressive behaviors in father–infant interactions at 3 months scored lower on the MDI at 24 months. At 24 months, children whose fathers were more engaged and sensitive as well as those whose fathers were less controlling in their interactions scored higher on the MDI. These findings were independent of the effects of maternal sensitivity. Results indicate that father–child interactions, even from a very young age (i.e., 3 months) may influence children's cognitive development. They highlight the potential significance of interventions to promote positive parenting by fathers and policies that encourage fathers to spend more time with their young children.

Early Childhood Diarrhea Predicts Cognitive Delays in Later Childhood Independently of Malnutrition.

Understanding the complex relationship between early childhood infectious diseases, nutritional status, poverty, and cognitive development is significantly hindered by the lack of studies that adequately address confounding between these variables. This study assesses the independent contributions of early childhood diarrhea (ECD) and malnutrition on cognitive impairment in later childhood. A cohort of 131 children from a shantytown community in northeast Brazil was monitored from birth to 24 months for diarrhea and anthropometric status. Cognitive assessments including Test of Nonverbal Intelligence (TONI), coding tasks (WISC-III), and verbal fluency (NEPSY) were completed when children were an average of 8.4 years of age (range = 5.6-12.7 years). Multivariate analysis of variance models were used to assess the individual as well as combined effects of ECD and stunting on later childhood cognitive performance. ECD, height for age (HAZ) at 24 months, and weight for age (WAZ) at 24 months were significant univariate predictors of the studies three cognitive outcomes: TONI, coding, and verbal performance (P < 0.05). Multivariate models showed that ECD remained a significant predictor, after adjusting for the effect of 24 months HAZ and WAZ, for both TONI (HAZ, P = 0.029 and WAZ, P = 0.006) and coding (HAZ, P = 0.025 and WAZ, P = 0.036) scores. WAZ and HAZ were also significant predictors after adjusting for ECD. ECD remained a significant predictor of coding (WISC III) after number of household income was considered (P = 0.006). This study provides evidence that ECD and stunting may have independent effects on children's intellectual function well into later childhood.

Effort Testing in Children: Can Cognitive and Symptom Validity Measures Differentiate Malingered Performances?

Recent efforts have contributed to significant advances in the detection of malingered performances in adults during cognitive assessment. However, children's ability to purposefully underperform has received relatively little attention. The purpose of the present investigation was to examine children's performances on common intellectual measures, as well as two symptom validity measures: the Test of Memory Malingering and the Dot-Counting Test. This was accomplished through the administration of measures to children ages 6 to 12 years old in randomly assigned full-effort (control) and poor-effort (treatment) conditions. Prior to randomization, children's general intellectual functioning (i.e., IQ) was estimated via administration of the Kaufman Brief Intellectual Battery-Second Edition (KBIT-2). Multivariate analyses revealed that the conditions significantly differed on some but not all administered measures. Specifically, children's estimated IQ in the treatment condition significantly differed from the full-effort IQ initially obtained from the same children on the KBIT-2, as well as from the IQs obtained in the full-effort control condition. These findings suggest that children are fully capable of willfully underperforming during cognitive testing; however, consistent with prior investigations, some measures evidence greater sensitivity than others in evaluating effort.

Parental social support, coping strategies, resilience factors, stress, anxiety and depression levels in parents of children with MPS III (Sanfilippo syndrome) or children with intellectual disabilities (ID)

Mucopolysaccharidosis type III (MPS III, Sanfilippo syndrome) is a lysosomal storage disorder, caused by a deficiency in one of four enzymes involved in the catabolism of the glycosaminoglycan heparan sulphate. It is a degenerative disorder, with a progressive decline in children's intellectual and physical functioning. There is currently no cure for the disorder. To date there is a paucity of research on how this disorder impacts parents psychological functioning. Specifically, research in the area has failed to employ adequate control groups to assess if the impact of this disorder on parents psychological functioning differs from parenting a child with intellectual disability (ID). The current study examined child behaviour and parental psychological functioning in 23 parents of children with MPS III and 23 parents of children with ID. Parents completed postal questionnaires about their child's behaviour and abilities and their own psychological functioning. Parents of children with MPS III reported fewer behavioural difficulties as their child aged, more severe level of intellectual disability, and similar levels of perceived social support, coping techniques, stress, anxiety and depression levels as parents of children with ID. Both groups of parents scored above the clinical cut off for anxiety and depression. Parents of children with MPS III rated themselves as significantly less future-orientated and goal directed than parents of children with ID. Services should develop support packages for parents of children with MPS III that incorporate an understanding of the unique stressors and current-difficulty approach of this population. Future research should examine gender differences between parental psychological functioning, using mixed qualitative and quantitative approaches, and utilise matched developmental level and typically developing control groups.

Arsenic and manganese exposure and children's intellectual function

Recently, epidemiologic studies of developmental neurotoxicology have been challenged to increase focus on co-exposure to multiple toxicants. Earlier reports, including our own work in Bangladesh, have demonstrated independent associations between neurobehavioral function and exposure to both arsenic (As) and manganese (Mn) in school-aged children. Our earlier studies, however, were not designed to examine possible interactive effects of exposure to both As and Mn. To allow investigation of possible synergistic impact of simultaneous exposures, we recruited a new sample of 299 8–11 year old children, stratified by design on As (above and below 10μg/L) and Mn (above and below 500μg/L) concentrations of household wells. When adjusted only for each other, both As and Mn in whole blood (BAs; BMn) were significantly negatively related to most WISC-IV subscale scores. With further adjustment for socio-demographic features and ferritin, BMn remained significantly associated with reduced Perceptual Reasoning and Working Memory scores; associations for BAs, and for other subscales, were expectably negative, significantly for Verbal Comprehension. Urinary As (per gram creatinine) was significantly negatively associated with Verbal Comprehension scores, even with adjustment for BMn and other contributors. Mn by As interactions were not significant in adjusted or unadjusted models (all p's>0.25). Findings are consistent with other reports documenting adverse impact of both As and Mn exposure on child developmental outcomes, although associations appear muted at these relatively low exposure levels.

Direct and Indirect Effects of Parenting on the Academic Functioning of Young Homeless Children

Research Findings: Effects of parenting quality on the academic functioning of young homeless children were examined using data from 58 children ages 4 to 7 and their parents during their stay at an emergency homeless shelter. Parenting quality, child executive function, child intellectual functioning, and risk status were assessed in the shelter, and teacher reports of academic functioning were obtained when the children began kindergarten or 1st grade. As hypothesized, parenting quality was associated with children's academic success, and this effect was mediated by executive function skills in the child. Parenting quality also had a moderating effect on risk, consistent with a protective role of high-quality parenting among children with higher risk levels. Concomitantly, children with higher risk and lower parenting quality appeared to be more vulnerable to academic problems. Practice or Policy: In homeless families, parenting may play an especially important role in academic success through multiple pathways, including the development of executive function skills in their children. Policies and practices to support parents and foster the executive function skills of young children in homeless families may be important strategies to promote child academic success. Implications for intervention efforts with homeless parents and children are discussed.

The conundrum of unmeasured confounding: Comment on: “Can some of the detrimental neurodevelopmental effects attributed to lead be due to pesticides? by Brian Gulson”

The problem described by Dr. Brian Gulson – confounding by unmeasured exposures to pesticides – is only the most recent in a series of potential confounders cited to explain the observed effect of lead on children's intellectual abilities or behavioral problems. Despite the persistent problem of unmeasured confounders, there are several lines of evidence implicating lead as a toxicant at blood lead levels < 10 μg/dL. First, in striking contrast with pesticides, there is considerable evidence from numerous studies linking low-level lead exposure with cognitive deficits and behavioral problems, even after controlling for a variety of potential confounders. Second, the consistency of evidence from diverse cohorts and distinct, if not always directly measured potential confounders — enhances our confidence that the lead effect observed at blood lead levels < 10 μg/dL is not attributable to unmeasured confounders. Third, in our reanalysis of the Rochester Lead Study, the inclusion of parent-reported mouthing behaviors and breastfeeding status did not attenuate the effect of lead exposure on children's intellectual function. Finally, although we can never entirely dismiss unmeasured confounding in observational studies, we can rely on experimental studies of lead-exposed animals to confirm that lead is a toxicant. Thus, while we must remain vigilant for unmeasured or poorly measured confounders, it is crucial to balance the endless search for confounders with the evidence of toxicity and the need to take action to protect public health. The alternative, to perpetually permit children to be exposed to lead and other emerging toxicants, is both absurd and unacceptable.

Comment on Fiorello et al. “Interpreting Intelligence Test Results for Children with Disabilities: Is Global Intelligence Relevant?”

In this volume, Fiorello et al. purport to explore the structure of children's intellectual functioning in three different clinical groups. The authors performed a regression commonality analysis i...

Arsenic and Fluoride Exposure in Drinking Water: Children’s IQ and Growth in Shanyin County, Shanxi Province, China

BackgroundRecently, in a cross-sectional study of 201 children in Araihazar, Bangladesh, exposure to arsenic (As) in drinking water has been shown to lower the scores on tests that measure children’s intellectual function before and after adjustment for sociodemographic features.ObjectivesWe investigated the effects of As and fluoride exposure on children’s intelligence and growth.MethodsWe report the results of a study of 720 children between 8 and 12 years of age in rural villages in Shanyin county, Shanxi province, China. The children were exposed to As at concentrations of 142 ± 106 μg/L (medium-As group) and 190 ± 183 μg/L (high-As group) in drinking water compared with the control group that was exposed to low concentrations of As (2 ± 3 μg/L) and low concentrations of fluoride (0.5 ± 0.2 mg/L). A study group of children exposed to high concentrations of fluoride (8.3 ± 1.9 mg/L) but low concentrations of As (3 ± 3 μg/L) was also included because of the common occurrence of elevated concentrations of fluoride in groundwater in our study area. A standardized IQ (intelligence quotient) test was modified for children in rural China and was based on the classic Raven’s test used to determine the effects of these exposures on children’s intelligence. A standardized measurement procedure for weight, height, chest circumference, and lung capacity was used to determine the effects of these exposures on children’s growth.ResultsThe mean IQ scores decreased from 105 ± 15 for the control group, to 101 ± 16 for the medium-As group (p < 0.05), and to 95 ± 17 for the high-As group (p < 0.01). The mean IQ score for the high-fluoride group was 101 ± 16 and significantly different from that of the control group (p < 0.05). Children in the control group were taller than those in the high-fluoride group (p < 0.05); weighed more than the those in the high-As group (p < 0.05); and had higher lung capacity than those in the medium-As group (p < 0.05).ConclusionsChildren’s intelligence and growth can be affected by high concentrations of As or fluoride. The IQ scores of the children in the high-As group were the lowest among the four groups we investigated. It is more significant that high concentrations of As affect children’s intelligence. It indicates that arsenic exposure can affect children’s intelligence and growth.