Intellectual and psychological performance in males born small for gestational age

WISC-V motor-free cognitive profile and predictive factors in adolescents with cerebral palsy

BACKGROUND

The most commonly used intelligence tests - the Wechsler Scales - do not provide standardised procedures for assessing children with motor impairment, and as a result, may underestimate the intelligence quotient (IQ) of young people with CP.

AIMS

To characterise a motor-free cognitive profile of adolescents with CP using the Wechsler Intelligence Scale for Children - Fifth edition (WISC-V) and explore the influence of clinical factors on cognitive abilities.

METHODS AND PROCEDURE

The WISC-V was used to assess cognitive abilities in 70 adolescents (M = 14 years 6 months, SD = 10 months). Sixty-six adolescents (Gross Motor Function Classification System (GMFCS) Level I, n = 26 ; II, n = 23; III, n = 15; IV, n = 1; V, n = 1) obtained either a Motor-free IQ or index score using the motor-free method.

OUTCOMES AND RESULTS

MFIQ and index scores fell below the normative data and rates of borderline and impaired cognitive abilities were significantly higher in the CP group. Scores showed an uneven cognitive profile with a relative strength in verbal abilities. Severity of motor impairment and small for gestational age (SGA) were associated with lower IQ scores. A history of seizures was related to lower verbal abilities.

CONCLUSIONS AND IMPLICATIONS

Cognitive abilities of adolescents with CP are significantly below expectation compared to normative data. Severity of motor impairment, SGA, and seizures need to be recognised by health professionals as risk factors for cognitive impairment. A substantial proportion of adolescents showed borderline cognitive abilities, constituting a group with CP which are relatively neglected in the literature.

Effects of rapid growth on fasting insulin and insulin resistance: a system review and meta-analysis

Infants with congenital deficiency have high risk of glucose metabolism disorder, and often experience rapid growth in early childhood. However, the role of rapid growth on glucose metabolism is controversial. We conducted a systematic review and meta-analysis to examine the association of rapid growth with fasting insulin and homeostasis model assessment of insulin resistance (HOMA-IR). We searched EMBASE and Medline for English articles, and CNKI and WANFANG database for Chinese articles. Studies measuring the associations between rapid growth and insulin or HOMA-IR were included. Relevant information was extracted independently by two reviewers. Random effects model was adopted for combined and stratified analyses. At last, twenty-two relevant studies for insulin and 20 for HOMA-IR were identified. Rapid growth was associated with high insulin (weighted mean differences [WMD] 5.544, 95% confidence interval [CI] [1.436, 9.653], P = 0.008) and high HOMA-IR (WMD 0.194, 95% CI [0.098, 0.290], P < 0.001). This elevated association was statistically significant in rapid growth subjects that were >6 years old, full-term, and from developed countries. However, rapid growth among low birth weight subjects did not lead to high insulin and HOMA-IR, but decreased HOMA-IR among preterm children (WMD -0.305, 95% CI [-0.607, -0.004], P = 0.047). Follow-up age was positively correlated with HOMA-IR (r = 0.095, P < 0.001). This meta-analysis suggested that rapid growth would result in high insulin and HOMA-IR, especially for full-term infants. However, rapid growth is relatively harmless for subjects who are <6 years old, low birth weight or SGA, and is even protective for preterm subjects.

A gradient relationship between low birth weight and IQ: A meta-analysis

Multiple studies have reported that individuals with low birth weights (LBW, <2500 g) have a lower intelligence quotient (IQ) than those with normal birth weights (NBW, ≥2500 g). Based on 57 eligible individual studies including 12,137 participants, we performed a meta-analysis to estimate the association between low birth weight and individuals' IQ scores (IQs). The pooled weight mean difference (WMD) in IQs between NBW and LBW individuals was 10 (95% CI 9.26-11.68). The WMD was stable regardless of age. No publication bias was detected. The mean IQs of the extremely low birth weight (ELBW, <1000 g), very low birth weight (VLBW, 1000-1499 g), moderately low birth weight (MLBW, 1500-2499 g) and NBW individuals were 91, 94, 99 and 104, respectively. Additionally, the WMD in IQs with NBW were 14, 10 and 7 for ELBW, VLBW, and MLBW individuals, respectively. Two studies permitted estimates of the influence of social determinants of health to the discrepancy in IQs, which was 13%. Since IQ is inherited and influenced by environmental factors, parental IQs and other factors contribute to residual confounding of the results. As the conclusion was based on population studies, it may not be applicable to a single individual.

Intrauterine growth and neuropsychological performance in very low birth weight preschoolers

In this study we examined the association between intrauterine growth, indexed either as a categorical variable or continuous dimension, and neuropsychological outcome, in a very low birth weight (VLBW) sample of 143 preschoolers. When the commonly used split at the 10th percentile rank was applied to classify intrauterine growth restriction (IUGR), we found that the growth restricted group (n = 25) exhibited significantly poorer performance in the global motor domain, but not on any other neuropsychological measure. In contrast, when adequacy of intrauterine growth was indexed by standardized birth weight, a continuous dimension, this early risk factor explained a unique portion of the variance in global cognitive abilities and visuospatial skills, as well as in global, fine, and gross motor skills. These findings are consistent with recent magnetic resonance imaging data disclosing global neurodevelopmental changes in the brains of preterm infants with IUGR. When cases classified with IUGR (<10th percentile) were excluded, the relationship between adequacy of intrauterine growth and global cognitive abilities remained significant despite range restriction. Hence, an association between appropriateness of intrauterine growth and global intellectual outcome may be observed even within the population of VLBW preschoolers with adequate standardized birth weight.

Postnatal growth of preterm born children ≤ 750g at birth

BACKGROUND

Extremely low birth weight (ELBW) infants are at risk of impaired postnatal growth. Impaired postnatal growth has been reported to be associated with delayed cognitive and motor development.

AIMS

To describe postnatal growth patterns of appropriate and small for gestational age (AGA and SGA) ELBW children in relation to their cognitive and motor outcome at age 5.5.

STUDY DESIGN

Retrospective cohort study.

SUBJECTS

One hundred one children with a BW ≤ 750g, born between 1996 and 2005 in the University Hospital Utrecht, The Netherlands.

OUTCOME MEASURES

Height (Ht), weight (Wt), occipital-frontal circumference (OFC) at birth, 15 months and 2 years corrected age and 3.5 and 5.5 years. Cognitive and motor outcome at 5.5 years of age, classified as normal (Z-score ≥-1), mildly delayed (-2≤Z-score <-1) or severely delayed (Z-score <-2). AGA (Ht, Wt or OFC at birth ≥-2 SDS) infants were compared with SGA (Ht, Wt or OFC at birth <-2 SDS) infants.

RESULTS

Between birth and 5.5 years catch-up growth in Ht, weight for height (Wt/Ht), Wt and OFC was seen in 72.2%, 55.2%, 28.6% and 68.9% respectively of the SGA infants. For AGA infants we found substantial catch-down growth in Ht (15.4%) and Wt (33.8%). Cognitive and motor outcome was normal in 76.2% and 41.6% of the 101 children. A significantly higher percentage of normal cognitive outcome was found in AGA infants with Wt growth remaining at ≥-2 SDS compared to AGA infants with catch-down growth (83% vs 63%). Next, SGA infants who caught-up in OFC had a higher prevalence of normal cognitive outcome compared to SGA infants who did not catch-up in OFC. Furthermore, a higher percentage of severely delayed motor outcome was found in SGA infants without catch-up growth in Wt compared to SGA infants who caught-up in Wt (61.5% vs 32.2%).

CONCLUSIONS

Catch-up growth in Ht, Wt/Ht and OFC occurred in the majority of the SGA infants with a BW ≤ 750 g, but was less common in Wt. AGA children who remained their Wt at ≥-2 SDS have a better cognitive and motor developmental outcome at 5.5 years of age. Catch-up growth in OFC was associated with a better cognitive outcome at 5.5 years of age.

Prenatal smoking exposure and offspring stress coping in late adolescence: no causal link

BACKGROUND

In utero exposure to tobacco smoking has been suggested to cause persistent alterations in cognitive functioning. We examined if mothers' smoking during pregnancy (SDP) is associated with long-term impairment in offspring stress coping and the causal mechanism behind a possible link.

METHODS

We used a large cohort (n = 187,106) of young males in Sweden (mean age = 18.2 years), who underwent a semi-structured psychological assessment in 1997-2006, including an evaluation of stress coping ability, as part of the compulsory military conscript examination. We compared differentially exposed siblings within nuclear families and cousins in extended families and used multilevel structural equation models to disentangle genetic from environmental contributions to the association between SDP and stress coping.

RESULTS

SDP and offspring stress coping was moderately strongly associated when comparing unrelated individuals [regression coefficient (b) = -0.38 on a nine-point scale; 95% confidence interval (CI) -0.40 to -0.36, P < 0.0001]. In contrast, it disappeared when siblings were compared (b = 0.11; 95% CI -0.01 to 0.23, P = 0.071). This familial confounding was entirely due to genetic influences.

CONCLUSIONS

SDP is an established risk factor for pregnancy- and birth-related complications. However, we found no long-term effect of SDP on offspring stress coping. Rather, the observed association was due to familial confounding of genetic origin; women prone to SDP also transmit genes to their children that are associated with poorer coping with stress.

Associations of birth size, gestational age, and adult size with intellectual performance: evidence from a cohort of Norwegian men

The influences of prenatal and postnatal growth on intellectual performance are unclear. We examined the associations of birth size and gestational age with intellectual performance and explored whether these associations were influenced by adult body size and social factors. In this nationwide cohort study, the records of 317,761 male infants registered in the Medical Birth Registry of Norway (1967-1979) were linked to the Norwegian Conscript Service (1984-1999). The variation in intelligence test score at age 18 due to birth weight and birth length was evaluated using absolute and standardized (z scores) values. Mean intelligence score increased by gestational age, birth weight, and birth length. However, a decline in intellectual performance was observed for gestational age >41 wk and birth weight >4500 g. There was a strong interaction on intellectual performance between birth size and gestational age (p < 0.0005). Adjusting for adult size strongly attenuated the association of birth size with intellectual performance. The overall R of intellectual performance explained by birth size was <1%; however, adding adult body size and social factors to the model increased R to 12%. In conclusion, the association of birth size with intellectual performance was weak, but still present after adjustment for adult body size and social factors.

Long-term psychosocial consequences of hormone treatment for short stature

AIM

To examine psychosocial functioning of young adults with idiopathic short stature or short stature born small for gestational age after growth hormone (GH) and gonadotropin-releasing hormone agonist (GnRHa) treatment in early adolescence or no intervention.

METHODS

Thirty young adults (18 treated, 12 untreated; age 17-23 years; on average 5.5 years after the end of treatment) completed questionnaires regarding perceived competence and psychological distress. They and their parents were interviewed on social circumstances, height-related psychosocial stressors and parental worries about prospects in society.

RESULTS

Height gain was on average 2.3 cm more for the treated than for the untreated group. On none of the psychosocial variables differences were found between treated and untreated participants. Compared to Dutch population norms, psychological and social functioning was normal.

CONCLUSION

GH/GnRHa treatment, with arrest of pubertal development and lower than expected effects on final height, is not observed to lead to long-term negative or positive effects. Both treated and untreated participants go well through the psychosocial transition period of young adulthood. This suggests that, in the long term and independent of hormone treatment, adequate psychosocial adjustment is expected in case of short stature.

Growing up with idiopathic short stature: psychosocial development and hormone treatment; a critical review

To facilitate decisions on interventions in medically referred children with idiopathic short stature, the research on psychosocial functioning of these children, possible risk and protective factors influencing adaptation, and effects of hormone treatment were reviewed. Parents ranked the behaviour of their children on average between normal and below normal. The magnitude of these deviations varied from small to large. Little is known about the children's self-perceived psychosocial functioning. Some risk factors were found: being teased, being juvenilised, being a boy, having a younger but taller sibling, low intelligence, and low socioeconomic status. There have been few studies on the impact of protective factors including temperament, coping strategies, and social support. On average, hormone treatment did not improve psychosocial functioning. The research shows the advantages and disadvantages of hormone treatment that must be considered when choosing a suitable intervention. It is suggested that psychosocial adjustment can be improved by focusing on factors other than height alone.

Motives for choosing growth-enhancing hormone treatment in adolescents with idiopathic short stature: a questionnaire and structured interview study

BACKGROUND

Growth-enhancing hormone treatment is considered a possible intervention in short but otherwise healthy adolescents. Although height gain is an obvious measure for evaluating hormone treatment, this may not be the ultimate goal for the person, but rather a means to reach other goals such as the amelioration of current height-related psychosocial problems or the enhancement of future prospects in life and society. The aim of our study was to clarify the motives of adolescents and their parents when choosing to participate in a growth-enhancing trial combining growth hormone and puberty-delaying hormone treatment.

METHODS

Participants were early pubertal adolescents (25 girls, 13 boys) aged from 11 to 13 years (mean age 11.5 years) with a height standard deviation score (SDS) ranging from -1.03 to -3.43. All had been classified as idiopathic short stature or persistent short stature born small for the gestational age (intrauterine growth retardation) on the basis of a height SDS below -2, or had a height SDS between -1 and -2 and a predicted adult height SDS below -2. The adolescents and their parents completed questionnaires and a structured interview on the presence of height-related stressors, parental worries about their child's behavior and future prospects, problems in psychosocial functioning, and treatment expectations. Questionnaire scores were compared to norms of the general Dutch population.

RESULTS

The adolescents reported normal psychosocial functioning and highly positive expectations of the treatment in terms of height gain, whereas the parents reported that their children encountered some behavioral problems (being anxious/depressed, and social and attention problems) and height-related stressors (being teased and juvenilized). About 40% of the parents were worried about their children's future prospects for finding a spouse or job. The motives of the adolescents and their parents exhibited rather different profiles. The most prevalent parental worries related to the current or future functioning of their children, while a few cases were characterized by no observed motives or by psychosocial problems only reported by the adolescents themselves.

CONCLUSION

The motives for participating in a growth-enhancing hormone trial are more obvious in the parents than in the adolescents themselves. Two out of three parents report worries about the future opportunities or observe modest current psychosocial problems in their children. The adolescents want to gain height, but the motivation underlying this remains unclear. Few of the adolescents experience psychosocial problems. Our analyses revealed differences among individuals in terms of motives, which implies that in an evaluation of hormone treatment, the importance of divergent outcome variables will also differ among individuals. Effectiveness evaluations of hormone treatment to increase height and the consequential fulfillment of other goals must be awaited.

Nutrition for preterm infants after hospital discharge

Preterm infants accrue significant nutrient deficits during hospitalization, and at the time of discharge most VLBW preterm infants have moderate to severe growth failure. Infants with significant morbidities and infants with ELBW have more severe growth failure since they regain birth weight at a later age, and they gain weight more slowly. Catch-up growth accelerates after hospital discharge. The rates of catch-up growth vary according to many factors including birth weight, gestational age, parental size, adequacy of intrauterine growth, neurologic impairment, clinical course, and nutrition. Most catch-up growth occurs within the first 2 to 3 years of life; however, compensatory catch-up growth may continue into adolescence and adulthood. Despite evidence of ongoing catch-up growth, the mean growth measurements of children and adults who were born preterm and with VLBW are lower than their term-born peers. Accelerated rates of catch-up growth are associated with better neurodevelopmental outcomes. Inadequate head circumference growth, in particular, may have long-term prognostic significance for later neurodevelopment in preterm infants. Nutrient-enriched formulas that provide 22 kcal/oz are often prescribed for VLBW preterm infants after hospital discharge. Several studies have reported that preterm infants fed the enriched versus standard term infant formulas have greater rates of catch-up growth during the first year of life, including greater increases in head circumference. The nutrient-enriched formulas appear to be of particular benefit for male infants. There is less information regarding the nutrient needs of breast-fed infants after hospital discharge. However, several studies have demonstrated that preterm infants fed unfortified human milk after discharge have growth rates and bone mass that are lower than formula-fed infants during infancy. The use of fortified human milk, or alternate feedings with a nutrient-enriched formula may be useful for breast-fed infants who have delays in catch-up growth. Additional studies are needed to determine whether enriched feedings might be of particular benefit for preterm infants who are at greater risk for postnatal growth failure, including infants born SGA, or with extremely low birth weights, intrauterine growth restriction, or chronic conditions such as bronchopulmonary dysplasia. The potential effect of nutritional programming on long-term outcomes of preterm infants also requires further investigation.