1,721,182 research outputs found
Family type and depression in pregnancy: Factors mediating risk in a community sample
No full textThe rate of severe depression among women in single-parent and biological families and in a variety of stepfamilies was examined in a large community sample of 13,088 pregnant women in the United Kingdom. Compared with women in biological families and published population rates, women in single-parent families and step-families reported significantly elevated rates of depression. Family-type differences in several risk factors were examined, including cohabiting (vs. married) status, relationship history, and socioeconomic and psychosocial risks, such as crowding, social support, and stressful life events. Family-type differences in depression were mediated partly by differences in social support, stressful life events, and crowding, but a main effect of family type in predicting depression remained after statistically controlling for these risks
Understanding socio-economic inequalities in childhood respiratory health
Get PDFAsthma is the most common chronic disease of childhood. Recent evidence has shown a socio-economic gradient in its distribution. This paper examines whether a number of factors argued to have led to a rise in the incidence of asthma might also explain the social gradient. Several of these have been the object of policy intervention, though not necessarily with the aim of lowering childhood respiratory conditions. Using a large cohort study (the Avon Longitudinal Study of Parents and Children) we find significant inequalities in three respiratory conditions in middle childhood. We investigate eight potential mediating factors: exposure to other children in infancy, child's diet, poor housing conditions, maternal smoking, parental history of asthma, poor child health at birth, maternal age at child's birth and local deprivation. We find that each of these alone typically explains a relatively modest part of each respiratory inequality, with child's diet, local deprivation and maternal smoking generally the most important. But taken together, the mediating factors account for a substantial part of the respiratory inequalities. So the socio-economic gradient appears to operate through a number of inter-correlated pathways, some of which may be amenable to policy intervention.Asthma, wheeze, socio-economic inequalities, mediating
On the central role of Somers' D
Get PDFSomers' D and Kendall's tau-a are parameters behind rank or nonparametric statistics, interpreted as differences between proportions. Given two bivariate data pairs (X1, Y1) and (X2, Y2), Kendall’s tau-a parameter tau-XY is the difference between the probability that the two X–Y pairs are concordant and the probability that the two X–Y pairs are discordant, and Somers' D parameter DYX is the difference between the corresponding conditional probabilities, given that the X-values are ordered. The somersd package computes confidence intervals for both parameters. The Stata 9 version of somersd uses Mata to increase computing speed and greatly extends the definition of Somers' D, allowing the X and/or Y variables to be left- or right-censored and allowing multiple versions of Somers' D for multiple sampling schemes for the X–Y pairs. In particular, we may define stratified versions of Somers' D, in which we compare only X–Y pairs from the same stratum. The strata may be defined by grouping a Rubin–Rosenbaum propensity score, based on the values of multiple confounders for an association between exposure variable X and an outcome variable Y . Therefore, rank statistics can have not only confidence intervals but also confounder-adjusted confidence intervals. Usually, we either estimate DYX as a measure of the effect of X on Y , or we estimate DXY as a measure of the performance of X as a predictor of Y, compared with other predictors. Alternative rank-based measures of the effect of X on Y include the Hodges–Lehmann median difference and the Theil–Sen median slope, both of which are defined in terms of Somers' D.
Factors associated with different hygiene practices in the homes of 15 month old infants
No full textBackground: Improved hygiene in Westernised regions of the world may be partly responsible for the increased prevalence of diseases of the immune system, such as asthma and atopy. There is a paucity of data on cleanliness norms in young children in the UK and there has been no attempt to identify factors that influence the adoption of particular hygiene practices in the home.<p></p>
Aims: To examine levels of hygiene in a contemporary cohort of children and identify social and lifestyle factors influencing hygiene practices in the home.
Methods: The sample under study are participants in the Avon Longitudinal Study of Parents and Children (ALSPAC). Parental self completion questionnaires provided data on hygiene levels in children at 15 months of age, and a hygiene score was derived from these responses. Multivariable logistic regression models investigated associations between high hygiene scores (top quintile) and a number of perinatal, maternal, social, and environmental factors.
Results: Maternal smoking during pregnancy, low maternal educational achievement, and living in local authority housing were factors independently associated with high hygiene scores, as was increased use of chemical household products. High hygiene scores were inversely related to living in damp housing and attendance at day care. There were no gender or ethnic differences in hygiene score.
Conclusion: Important data on cleanliness norms for infants have been presented. The adoption of hygiene practices is influenced to some degree by social, lifestyle, and environmental factors—with higher hygiene scores occurring in more socially disadvantaged groups. Increased use of chemical household products in the more socially disadvantaged groups within ALSPAC has emerged as an important confounder in any study of hygiene and ill health.<p></p>
Hygiene levels in a contemporary population cohort are associated with wheezing and atopic eczema in preschool infants
No full textBackground: The hygiene hypothesis states that insufficient exposure to certain infectious agents during childhood increases the risk of developing asthma and atopic diseases. Improvements in hygiene levels may be partly responsible for this decline in exposure.<p></p>
Aims: To assess whether hygiene levels in infancy are associated with wheeze and/or atopic eczema, independent of a number of possible confounding factors.<p></p>
Methods: Data were gathered from the Avon Longitudinal Study of Parents and Children (ALSPAC). Parental self completion questionnaires provided symptom data on infant wheeze and atopic eczema at 0–6 months and 30–42 months, respectively. A simple hygiene score was derived using questionnaire responses at 15 months, which ranged from least hygienic to most hygienic. Multivariable logistic regression models analysed the effect of hygiene scores on health outcomes, while adjusting for a number of important confounding variables.<p></p>
Results: Increasing hygiene scores were independently associated with wheezing (OR = 1.04; 95% CI: 1.00 to 1.08) and atopic eczema (OR = 1.04; 95% CI: 1.01 to 1.07) between 30 and 42 months, but not in the first six months. The odds ratio was higher for atopic eczema if the rash was reported to have become sore and oozy (OR = 1.09; 95% CI: 1.02 to 1.16).<p></p>
Conclusions: High levels of hygiene at 15 months of age were independently associated with wheeze and atopic eczema reported between 30 and 42 months, and there was an increased risk for children with more severe eczema during this period. The importance of hygiene in public health should not be dismissed; however, the creation of a sterile environment through excessive cleanliness may potentially be harmful to the immune system.<p></p>
Child abuse registration, fetal growth, and preterm birth: a population based study
Get PDFObjectives: To study the relation of intra-uterine growth and gestational age with child protection registration in a 20 year whole population birth cohort.
Setting: West Sussex area of England.
Study design: Retrospective whole population birth cohort.
Outcomes: Child protection registration; individual categories of registration—sexual abuse, physical abuse, emotional abuse, and neglect.
Population and participants: 119 771 infants born in West Sussex between January 1983 and December 2001 with complete data including birth weight, gestational age, maternal age, and postcode.
Results: In all categories of registration a linear trend was noted such that the lower the birth weight z score the higher the likelihood of child protection registration. Similar trends were noted for gestational age. All these trends were robust to adjustment for maternal age and socioeconomic status.
Conclusions: The results of this study suggest that lower levels of fetal growth and shorter gestational duration are associated with increased likelihood of child protection registration in all categories including sexual abuse independent of maternal age or socioeconomic status. This study does not permit comment on whether poor fetal growth or preterm birth predispose to child abuse and neglect or the association arises because they share a common pathway
Does Father Absence Influence Children's Gender Development? Findings From a General Population Study of Preschool Children
No full textObjective. This study aimed to investigate whether preschool children in father-absent families are less gender-typed than their counterparts from father- present homes. Design. Samples of 283 single-mother families, including a subsample of 136 families where the child had no contact with the father, and 6,420 nuclear families were obtained from a longitudinal population study of 14,000 mothers and their children. Gender-role behavior was assessed when the child was 42 months old using the Pre-School Activities Inventory, a reliable and valid instrument designed to discriminate within as well as between the sexes. Results. No difference in parent-reported gender-role behavior was found between father-present and father-absent families for either boys or girls. Conclusions. The findings suggest that the gender-role behavior of preschool children develops typically despite the absence of a live-in father figure
The prevalence of food allergy in children up to the age of seven in ALSPAC: a population-based cohort study
No full textMultiple-test procedures and smile plots
Get PDFmultproc carries out multiple-test procedures, taking as input a list of p-values and an uncorrected critical p-value, and calculating a corrected overall critical p-value for rejection of null hypotheses. These procedures define a confidence region for a set-valued parameter, namely the set of null hypotheses that are true. They aim to control either the family-wise error rate (FWER) or the false discovery rate (FDR) at a level no greater than the uncorrected critical p-value. smileplot calls multproc and then creates a smile plot, with data points corresponding to estimated parameters, the p-values (on a reverse log scale) on the y-axis, and the parameter estimates (or another variable) on the x-axis. There are y-axis reference lines at the uncorrected and corrected overall critical p-values. The reference line for the corrected overall critical p-value, known as the parapet line, is an informal “upper confidence limit” for the set of null hypotheses that are true and defines a boundary between data mining and data dredging. A smile plot summarizes a set of multiple analyses just as a Cochrane forest plot summarizes a meta-analysis
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