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Avon Longitudinal Study (avon + longitudinal_study)
Selected AbstractsMaternal employment and the initiation of breastfeedingACTA PAEDIATRICA, Issue 4 2001S Noble This study examines whether planning to be employed postpartum has an effect on initiation of breastfeeding. Data were collected from questionnaires completed by mothers who were subjects in the prospective, population-based, Avon Longitudinal Study of Pregnancy and Childhood. The mothers of 10 530 full-term singleton infants gave information during pregnancy on their postpartum employment plans and their initial infant feeding methods. Information was also given by 7642 of these mothers on the timing of their postpartum employment plans. Adjusted logistic regression was performed to identify associations between (a) "any" plans to work postpartum and the initiation of breastfeeding, and (b) the timing of the commencement of work postpartum, and the initiation of breastfeeding. A total of 8316 (79%) of the women initiated breastfeeding. The decision to breastfeed was not associated with "any" plans to work postpartum. However, women who planned to commence work prior to 6 wk postpartum were significantly less likely to initiate breastfeeding compared with those not intending to work postpartum. Older, more highly educated women, women who had or were planning to attend childbirth classes, women who were breastfed as infants, women who did not smoke and women who were giving birth to their first child were significantly more likely to initiate breastfeeding. Conclusion: Planning to return to employment prior to 6 wk postpartum reduces the likelihood of initiating breastfeeding. As increasing numbers of mothers are returning to work shortly after the birth of their child, this finding could have implications for maintaining the current level of breastfeeding. [source] Prevalence and characteristics of autistic spectrum disorders in the ALSPAC cohortDEVELOPMENTAL MEDICINE & CHILD NEUROLOGY, Issue 9 2008Emma Williams MSc PhD The aim of this study was to determine the prevalence of autistic spectrum disorder (ASD) within a large representative population sample: the Avon Longitudinal Study of Parents and Children (ALSPAC). Cases of ASD were identified from the clinical notes of children in the ALSPAC with a suspected developmental disorder and from the Pupil Level Annual Schools Census (PLASC) for England in 2003. Seventy-one cases of ASD diagnosed after a multidisciplinary assessment were identified from health records. There were an additional 15 cases from PLASC data in which ASD was mentioned as a principal difficulty, thus giving a total of 86 children diagnosed by the age of 11 years. Prevalence of ASD per 10 000 population at 11 years was 51.1 for those with a multi-professional diagnosis, and 61.9 if cases from education were included, made up of 21.6 for childhood autism, 10.8 for atypical autism, 16.6 for Asperger syndrome, and 13.0 for unspecified ASD. The male:female ratio was 6.8:1. Median age at diagnosis ranged from 45 months in childhood autism to 116 months in Asperger syndrome. A comorbid developmental disorder was recorded in 33.8% of cases, including learning disability, in 14.7%, epilepsy in 10.3%, and mixed developmental disorder in 4.4%. We conclude that the prevalence of ASD diagnosed at 11 years in a UK representative population-based sample is at least 51.1/10 000. [source] Bone Fragility Contributes to the Risk of Fracture in Children, Even After Moderate and Severe Trauma,,JOURNAL OF BONE AND MINERAL RESEARCH, Issue 2 2008Emma M Clark Abstract We prospectively examined whether the relationship between skeletal fragility and fracture risk in children 9.9 ± 0.3 (SD) yr is affected by trauma level. Bone size relative to body size and humeral vBMD showed similar inverse relationships with fracture risk, irrespective of whether fractures followed slight or moderate/severe trauma. Introduction: Fracture risk in childhood is related to underlying skeletal fragility. However, whether this relationship is confined to low-trauma fractures or whether skeletal fragility also contributes to the risk of fracture caused by higher levels of trauma is currently unknown. Materials and Methods: Total body DXA scan results obtained at 9.9 yr of age were linked to reported fractures over the following 2 yr in children from the Avon Longitudinal Study of Parents and Children. DXA scan results that were subsequently derived included total body less head (TBLH) bone size relative to body size (calculated from TBLH area adjusted for height and weight) and humeral volumetric BMD (vBMD; derived from subregional analysis at this site). Trauma level was assigned using the Landin classification based on a questionnaire asking about precipitating causes. Results: Of the 6204 children with available data, 549 (8.9%) reported at least one fracture over the follow-up period, and trauma level was assigned in 280 as follows: slight trauma, 56.1%; moderate trauma, 41.0%; severe trauma, 2.9%. Compared with children without fractures, after adjustment for age, sex, socioeconomic status, and ethnicity, children with fractures from both slight and moderate/severe trauma had a reduced bone size relative to body size (1133 cm2 in nonfractured children versus 1112 cm2 for slight trauma fractures, p < 0.001; 1112 cm2 for moderate/severe trauma fractures, p = 0.001) and reduced humeral vBMD (0.494 g/cm3 in nonfractured children versus 0.484 g/cm3 for slight trauma fractures, p = 0.036; and 0.482g/cm3 for moderate/severe trauma fractures, p = 0.016). Conclusions: Skeletal fragility contributes to fracture risk in children, not only in fractures caused by slight trauma but also in those that result from moderate or severe trauma. [source] Habitual Levels of Physical Activity Influence Bone Mass in 11-Year-Old Children From the United Kingdom: Findings From a Large Population-Based Cohort,JOURNAL OF BONE AND MINERAL RESEARCH, Issue 1 2007Jon H Tobias MD Abstract We examined the influence of habitual levels of physical activity on bone mass in childhood by studying the relationship between accelerometer recordings and DXA parameters in 4457 11-year-old children. Physical activity was positively related to both BMD and bone size in fully adjusted models. However, further exploration revealed that this effect on bone size was modified by fat mass. Introduction: Exercise interventions have been reported to increase bone mass in children, but it is unclear whether levels of habitual physical activity also influence skeletal development. Materials and Methods: We used multivariable linear regression to analyze associations between amount of moderate and vigorous physical activity (MVPA), derived from accelerometer recordings for a minimum of 3 days, and parameters obtained from total body DXA scans in 4457 11-year-old boys and girls from the Avon Longitudinal Study of Parents and Children. The influence of different activity intensities was also studied by stratification based on lower and higher accelerometer cut-points for moderate (3600 counts/minute) and vigorous (6200 counts/minute) activity, respectively. Results: MVPA was positively associated with lower limb BMD and BMC adjusted for bone area (aBMC; p < 0.001, adjusted for age, sex, socio-economic factors, and height, with or without additional adjustment for lean and fat mass). MVPA was inversely related to lower limb bone area after adjusting for height and lean mass (p = 0.01), whereas a positive association was observed when fat mass was also adjusted for (p < 0.001). Lower limb BMC was positively related to MVPA after adjusting for height and lean and fat mass (p < 0.001), whereas little relationship was observed after adjusting for height and lean mass alone (p = 0.1). On multivariable regression analysis using the fully adjusted model, moderate activity exerted a stronger influence on lower limb BMC compared with light activity (light activity: 2.9 [1.2,4.7, p = 0.001]; moderate activity: 13.1 [10.6,15.5, p < 0.001]; regression coefficients with 95% confidence intervals and p values). Conclusions: Habitual levels of physical activity in 11-year-old children are related to bone size and BMD, with moderate activity exerting the strongest influence. The effect on bone size (as reflected by DXA-based measures of bone area) was modified by adjustment for fat mass, such that decreased fat mass, which is associated with higher levels of physical activity, acts to reduce bone size and thereby counteract the tendency for physical activity to increase bone mass. [source] Concurrent and prospective associations between facial affect recognition accuracy and childhood antisocial behaviorAGGRESSIVE BEHAVIOR, Issue 5 2010Erica Bowen Abstract This study examined the concurrent and prospective associations between children's ability to accurately recognize facial affect at age 8.5 and antisocial behavior at age 8.5 and 10.5 years in a sub sample of the Avon Longitudinal Study of Parents and Children cohort (5,396 children; 2,644, 49% males). All observed effects were small. It was found that at age 8.5 years, in contrast to nonantisocial children; antisocial children were less accurate at decoding happy and sad expressions when presented at low intensity. In addition, concurrent antisocial behavior was associated with misidentifying expressions of fear as expressions of sadness. In longitudinal analyses, children who misidentified fear as anger exhibited a decreased risk of antisocial behavior 2 years later. The study suggests that concurrent rather than future antisocial behavior is associated with facial affect recognition accuracy. Aggr. Behav. 36:305,314, 2010. © 2010 Wiley-Liss, Inc. [source] Types of drinks consumed by infants at 4 and 8 months of age: sociodemographic variationsJOURNAL OF HUMAN NUTRITION & DIETETICS, Issue 2 2000K. North Aim To investigate the variations in sociodemographic characteristics of mothers in relation to the types of milk and supplementary drinks consumed by their infants at 4 and 8 months of age. Study design The carers of a randomly chosen population sample of over 1000 infants from the Avon Longitudinal Study of Pregnancy and Childhood (ALSPAC) were asked to record all foods and drinks consumed by the child in a 24-h period at both 4 and 8 months of age. Self-completion postal questionnaires were used to ascertain sociodemographic characteristics of the mothers and their infants. Methods Significant differences in the types of milks and supplementary drinks consumed within sociodemographic groups were identified. Infants were also grouped according to the types of milks they were receiving at each age and further differences in sociodemographic characteristics were investigated. Results Highly significant differences existed among various sociodemographic characteristics with regard to the types of drinks used at both ages. Maternal educational level was the most influential of the sociodemographic variables in explaining the differences in consumption of all types of drinks given at 4 months, in particular for breast milk use. Maternal age was also significantly associated with breast feeding. The use of fruit drinks was significantly associated with the presence of older siblings in the family and the use of herbal drinks with the duration of breast feeding. At 8 months of age maternal educational level was again the most highly associated of the sociodemographic variables, being significantly associated with the use of most of the drinks. The presence of older siblings also had a significant independent effect as did duration of breast feeding. The feeding of cows' (or animal) milk as a main drink at 8 months, contrary to recommendation, was most likely in the group of mothers with vocational education, those in council accommodation, those with two or more children and those with difficulty affording food. Conclusion We have identified certain characteristics of mothers who were more likely than others not to follow current recommendations on infant feeding. The educational level of mothers appears to be of major significance in the choices made about the types of drinks given to infants. It may be possible to target information about infant feeding to certain groups of mothers thus improving weaning patterns. [source] Patterns of breastfeeding in a UK longitudinal cohort studyMATERNAL & CHILD NUTRITION, Issue 1 2007David Pontin Abstract Although exclusive breastfeeding for the first 6 months of infant life is recommended in the UK, there is little information on the extent of exclusive breastfeeding. This study has taken the 1996 and 2003 World Health Organization (WHO) definitions of breastfeeding and investigated breastfeeding rates in the first 6 months of life in infants born to mothers enrolled in a longitudinal, representative, population-based cohort study , the Avon Longitudinal Study of Parents and Children (ALSPAC). Information about breastfeeding and introduction of solids was available for 11 490 infants at 6 months of age (81% of live births). Exclusive breastfeeding declined steadily from 54.8% in the first month to 31% in the third, and fell to 9.6% in the fourth month mainly due to the introduction of solids to the infants. In the first 2 months, complementary feeding (breastmilk and solid/semi-solid foods with any liquid including non-human milk) was used in combination, and declined from 22% in the first month to 16.8% in the second due to a switch to exclusive commercial infant formula feeding. Replacement feeding (exclusive commercial infant formula or combined with any liquid or solid/semi-solid food but excluding breastmilk) increased steadily from 21.9% in the first month to 67.1% by the seventh. This obscured the change from exclusive commercial infant formula feeding only to commercial infant formula feeding plus solids/semi-solids, a change which started in the third month and was complete by the fifth. Using categories in the 1996 and 2003 WHO definitions, such as complementary feeding and replacement feeding, presented difficulties for an analysis of the extent of breastfeeding in this population. [source] Artificial neural networks as statistical tools in epidemiological studies: analysis of risk factors for early infant wheezePAEDIATRIC & PERINATAL EPIDEMIOLOGY, Issue 6 2004Andrea Sherriff Summary Artificial neural networks (ANNs) are being used increasingly for the prediction of clinical outcomes and classification of disease phenotypes. A lack of understanding of the statistical principles underlying ANNs has led to widespread misuse of these tools in the biomedical arena. In this paper, the authors compare the performance of ANNs with that of conventional linear logistic regression models in an epidemiological study of infant wheeze. Data on the putative risk factors for infant wheeze have been obtained from a sample of 7318 infants taking part in the Avon Longitudinal Study of Parents and Children (ALSPAC). The data were analysed using logistic regression models and ANNs, and performance based on misclassification rates of a validation data set were compared. Misclassification rates in the training data set decreased as the complexity of the ANN increased: h = 0: 17.9%; h = 2: 16.2%; h = 5: 14.9%, and h = 10: 9.2%. However, the more complex models did not generalise well to new data sets drawn from the same population: validation data set misclassification rates: h = 0: 17.9%; h = 2: 19.6%; h = 5: 20.2% and h = 10: 22.9%. There is no evidence from this study that ANNs outperform conventional methods of analysing epidemiological data. Increasing the complexity of the models serves only to overfit the model to the data. It is important that a validation or test data set is used to assess the performance of highly complex ANNs to avoid overfitting. [source] ALSPAC,The Avon Longitudinal Study of Parents and ChildrenPAEDIATRIC & PERINATAL EPIDEMIOLOGY, Issue 1 2001Golding ALSPAC (The Avon Longitudinal Study of Parents and Children, formerly the Avon Longitudinal Study of Pregnancy and Childhood) was specifically designed to determine ways in which the individual's genotype combines with environmental pressures to influence health and development. To date, there are comprehensive data on approximately 10 000 children and their parents, from early pregnancy until the children are aged between 8 and 9. The study aims to continue to collect detailed data on the children as they go through puberty noting, in particular, changes in anthropometry, attitudes and behaviour, fitness and other cardiovascular risk factors, bone mineralisation, allergic symptoms and mental health. The study started early during pregnancy and collected very detailed data from the mother and her partner before the child was born. This not only provided accurate data on concurrent features, especially medication, symptoms, diet and lifestyle, attitudes and behaviour, social and environmental features, but was unbiased by parental knowledge of any problems that the child might develop. From the time of the child's birth many different aspects of the child's environment have been monitored and a wide range of phenotypic data collected. By virtue of being based in one geographic area, linkage to medical and educational records is relatively simple, and hands-on assessments of children and parents using local facilities has the advantage of high quality control. The comprehensiveness of the ALSPAC approach with a total population sample unselected by disease status, and the availability of parental genotypes, provides an adequate sample for statistical analysis and for avoiding spurious results. The study has an open policy in regard to collaboration within strict confidentiality rules. [source] Identification of children with the same level of impairment as children on the autistic spectrum, and analysis of their service useTHE JOURNAL OF CHILD PSYCHOLOGY AND PSYCHIATRY AND ALLIED DISCIPLINES, Issue 6 2010Ginny Russell Background:, Data from epidemiology have consistently highlighted a disparity between the true prevalence of childhood psychiatric disorders and their recognition as defined by receiving a clinical diagnosis. Few studies have looked specifically at the level of unidentified autistic spectrum disorder (ASD) in the population. Method:, Logistic regression was used to determine the behavioural traits associated with receiving a diagnosis of ASD using data from the Avon Longitudinal Study of Parents and Children (ALSPAC). A composite score was derived to measure levels of autistic traits; undiagnosed children with scores matching those diagnosed with ASD were identified. Levels of educational provision beyond that provided by standard schooling were examined. Results:, Fifty-five percent of children with autistic traits at the same levels as those who had an autism diagnosis had not been identified as needing extra support from education or specialised health services. Of those who were identified as having special needs, 37.5% had been formally diagnosed with an ASD. For children with impairment at the same level as that associated with Asperger's syndrome, 57% had no special provision at school, and were not accessing specialised health services. Twenty-six percent of those who did have special provision at school had an ASD diagnosis. Conclusions:, The results suggest that there may be a substantial proportion of children on the autistic spectrum who are never identified by services. [source] An Investigation of FRAXA Intermediate Allele Phenotype in A Longitudinal SampleANNALS OF HUMAN GENETICS, Issue 2 2006S. Ennis Abstract The FRAXA trinucleotide repeat at Xq27.3 gives rise to fragile X syndrome when fully expanded, and both premature ovarian failure (POF) and fragile X tremor and ataxia syndrome (FXTAS) when in the premutation range. Reports of phenotypic effects extending into the intermediate repeat range are inconsistent but some studies suggest that these smaller expansions predispose to special educational needs (SEN). This study utilises the Avon Longitudinal Study of Parents and Children (ALSPAC) cohort to investigate cognitive and behavioural variables that might be associated with FRAXA intermediate alleles. The current study failed to find any strong evidence of association of FRAXA intermediate alleles with SEN, behavioural problems or cognitive difficulties. However, our findings illustrate some of the difficulties encountered in identifying individuals with SEN. The power to identify specific components of cognitive and behavioural difficulties was reduced due to elective drop-out, which is characteristic of longitudinal studies. Our findings demonstrate the non-random loss of participants from this cohort and highlight problems that may arise when such data are used in genetic association studies. [source] The natural history of daytime urinary incontinence in children: a large British cohortACTA PAEDIATRICA, Issue 7 2010LV Swithinbank Abstract Aim:, Few studies have looked at the prevalence of daytime incontinence in a longitudinal cohort of children. This study set out to determine the prevalence of daytime incontinence and relationships between daytime incontinence and bedwetting, faecal incontinence and urgency in a large cohort of British children. Methods:, Parents of children taking part in the Avon Longitudinal Study of Parents and Children (ALSPAC) were asked questions concerning the child's daytime wetting, bedwetting and faecal incontinence at different time points, 4.5, 5.5, 6.5, 7.5 and 9.5 years. The difference between the sexes for these different conditions was compared. Results and limitations:, Data were available for 10 819 of the 13 973 children who entered the study. The prevalence of any daytime incontinence declined from 15.5% at 4.5 years to 4.9% at 9.5 years, and was mainly described as infrequent. Daytime incontinence was more common in girls than boys and frequent (DSM-IV) incontinence was more commonly related to urgency, bedwetting and faecal incontinence than infrequent incontinence. Conclusions:, Daytime incontinence is relatively common among children of primary school age and frequent incontinence more commonly coexists with other conditions, such as bedwetting and urgency. This study suggests the need for treatment to focus on children with frequent incontinence. [source] Developmental outcomes in early compared with delayed surgery for glue ear up to age 7 years: a randomised controlled trialCLINICAL OTOLARYNGOLOGY, Issue 1 2009A.J. Hall Objectives:, To investigate whether early versus delayed surgery for children severely affected by otitis media with effusion (OME) results in improved performance on developmental tests up to age 7 years. Design:, Follow-up of a randomised controlled trial. Setting:, University of Bristol. Participants:, One hundred and eighty-two children (mean age 35 months) with persistent OME, hearing loss and speech, language or behaviour problems who were originally eligible and randomised to either early surgery or delayed surgery after a period of watchful waiting were followed-up as part of the Avon Longitudinal Study of Parents and Children (ALSPAC) at age 4½ and 7,8 years. Main outcome measures:, Measures included behaviour, language, educational attainment tests, hearing, reading, cognition and coordination. Results:, Of the original randomised trial, 88 of 92 of the early surgery and 74 of 90 of the watchful waiting group were still participating in ALSPAC. Analysis was by intention to treat. At age 4 ½ years there were significant differences in teacher assessment of language (adj OR 3.45, 95% CI: 1.42,8.39) and writing (adj OR 3.74, 95% CI: 1.51,9.27), in favour of early surgery. At age 7,8 years, there was a significant difference on teacher report of emotional problems (adj OR 4.11, 95% CI: 1.15,14.64) in favour of early surgery. There were no other significant differences. Conclusions:, Early surgery for the child severely affected by OME may be associated with subtle benefits at age 4½ years. This may continue to 7,8 years but the small study size makes it difficult to distinguish these effects from chance. A larger study is recommended. [source] Is there a relationship between Birthweight and subsequent growth on the development of Dental Caries at 5 years of age?COMMUNITY DENTISTRY AND ORAL EPIDEMIOLOGY, Issue 5 2010A cohort study Kay EJ, Northstone K, Ness A, Duncan K, Crean SJ. Is there a relationship between Birthweight and subsequent growth on the development of Dental Caries at 5 years of age? A cohort study. Community Dent Oral Epidemiol 2010; 38: 408,414. © 2010 John Wiley & Sons A/S Abstract,,, Objectives:, To examine the associations between childhood growth and the presence of dental caries at age 5. Methods:, Data from the Avon Longitudinal Study of Parents and Children (ALSPAC) a population-based, prospective cohort study were used. We enrolled 14 541 pregnancies, and a 10% sample of these were dentally examined and measured at 61 months of age. Birthweight was obtained from medical records, and birth length and birthweight were assessed by trained ALSPAC measurers. A number of social and lifestyle factors were treated as potential confounding factors. Results:, Of 985, children, 242 (24.6%) had caries at 61 months of age. After adjustment, increased weight at birth was associated with a small increased risk of caries at 61 months (OR: 1.08 (95% CI: 1.03, 1.13) per 100 g increase, P = 0.002). A similar association was noted with respect to increased length at birth. Current weight and height did not appear to be associated with caries risk. Children who had caries at 61 months had slower increases in weight and height between birth and 61 months than those without decay at 61 months. Conclusions:, The weak associations we have demonstrated between weight and length at birth and risk of caries at age 61 months cannot be considered causal, however, the relationship between the two variables warrants further investigation. [source] | |||||||||||||