Fiona Stanley

Association between breast feeding and asthma in 6 year old children: findings of a prospective birth cohort study

Abstract Objectives: To investigate the association between the duration of exclusive breast feeding and the development of asthma related outcomes in children at age 6 years. Design: Prospective cohort study. Setting: Western Australia. Subjects: 2187 children ascertained through antenatal clinics at the major tertiary obstetric hospital in Perth and followed to age 6 years. Main outcome measures: Unconditional logistic regression to model the association between duration of exclusive breast feeding and outcomes related to asthma or atopy at 6 years of age, allowing for several important confounders: sex, gestational age, smoking in the household, and early childcare. Results: After adjustment for confounders, the introduction of milk other than breast milk before 4 months of age was a significant risk factor for all asthma and atopy related outcomes in children aged 6 years: asthma diagnosed by a doctor (odds ratio 1.25, 95% confidence interval 1.02 to 1.52); wheeze three or more times since 1 year of age (1.41, 1.14 to 1.76); wheeze in the past year (1.31, 1.05 to 1.64); sleep disturbance due to wheeze within the past year (1.42, 1.07 to 1.89); age when doctor diagnosed asthma (hazard ratio 1.22, 1.03 to 1.43); age at first wheeze (1.36, 1.17 to 1.59); and positive skin prick test reaction to at least one common aeroallergen (1.30, 1.04 to 1.61). Conclusion: A significant reduction in the risk of childhood asthma at age 6 years occurs if exclusive breast feeding is continued for at least the 4 months after birth. These findings are important for our understanding of the cause of childhood asthma and suggest that public health interventions to optimise breast feeding may help to reduce the community burden of childhood asthma and its associated traits. Key messages Asthma is the leading cause of admission to hospital in Australian children and its prevalence is increasing Whether breast feeding protects against asthma or atopy, or both, is controversial Asthma is a complex disease, and the relative risks between breast feeding and asthma or atopy are unlikely to be large; this suggests the need for investigation in a large prospective birth cohort with timely assessment of atopic outcomes and all relevant exposures Exclusive breast feeding for at least 4 months is associated with a significant reduction in the risk of asthma and atopy at age 6 years and with a significant delay in the age at onset of wheezing and asthma being diagnosed by a doctor Public health interventions to promote an increased duration of exclusive breast feeding may help to reduce the morbidity and prevalence of childhood asthma and atop

A decade of data linkage in Western Australia: strategic design, applications and benefits of the WA data linkage system

OBJECTIVES The report describes the strategic design, steps to full implementation and outcomes achieved by the Western Australian Data Linkage System (WADLS), instigated in 1995 to link up to 40 years of data from over 30 collections for an historical population of 3.7 million. Staged development has seen its expansion, initially from a linkage key to local health data sets, to encompass links to national and local health and welfare data sets, genealogical links and spatial references for mapping applications. APPLICATIONS The WADLS has supported over 400 studies with over 250 journal publications and 35 graduate research degrees. Applications have occurred in health services utilisation and outcomes, aetiologic research, disease surveillance and needs analysis, and in methodologic research. BENEFITS Longitudinal studies have become cheaper and more complete; deletion of duplicate records and correction of data artifacts have enhanced the quality of information assets; data linkage has conserved patient privacy; community machinery necessary for organised responses to health and social problems has been exercised; and the commercial return on research infrastructure investment has exceeded 1000%. Most importantly, there have been unbiased contributions to medical knowledge and identifiable advances in population health arising from the research.

What constitutes cerebral palsy

Cerebral palsy (CP) is a term of convenience applied to a group of motor disorders of central origin defined by clinical description. It is not a diagnosis in that its application infers nothing about pathology, aetiology, or prognosis. It is an umbrella term covering a wide range of cerebral disorders which result in childhood motor impairment. The precise inclusion criteria vary with the objectives for using the term. For meaningful comparison of rates of CP, as performed by and between CP registers, it is important that the rates should be generated using the same criteria. As generally understood there must be motor impairment, and this impairment must stem from a malfunction of the brain (rather than spinal cord or muscles). Furthermore, the brain malfunction must be non‐progressive and it must be manifest early in life. For the purposes of comparisons of rates across time even when the condition meets all the above criteria, it must not historically have been excluded from the category of CP. This paper addresses the problem of standardizing the inclusion criteria for selecting people included on CP registers with particular reference to this last criterion.

Maternal cigarette smoking during pregnancy, low birth weight and subsequent blood pressure in early childhood

Given the widely acknowledged inverse relationship between birth weight and blood pressure, a raised blood pressure in the offspring of smoking mothers as compared to those whose mothers did not smoke, would be anticipated by virtue of the reduction in birth weight associated with smoking during pregnancy. The objective of the present study was to test the hypothesis that maternal cigarette smoking during pregnancy has an effect on blood pressure in childhood independent of its effect on birth weight. Data was obtained from a prospective cohort study of 1708 pregnant women and their singleton offspring, delivered live at term, in Perth, Western Australia, commenced at 16 weeks gestation with serial blood pressure measurements through early childhood. Statistically significant associations were found between maternal smoking during pregnancy and systolic blood pressure at age six, between birth weight and systolic blood pressure at ages three and six, and between maternal smoking during pregnancy and birth weight. The relationship between birth weight and blood pressure in early childhood differed significantly on the basis of maternal cigarette smoking or not during pregnancy. This differential relationship persisted after adjustment for the childs current weight and socio-economic status. We concluded that intra-uterine exposure to maternal cigarette smoking increased childrens blood pressure at age one through to age six. This was not wholly attributable to an effect on birth weight or confounding of the association between birth weight and subsequent blood pressure by the childs current weight or socio-economic factors. Furthermore, maternal smoking during pregnancy does not account for the acknowledged elevation in blood pressure associated with low birth weight. The present study is an exploration of a possible causal pathway underlying the birth weight/blood pressure association rather than simply a confirmation of such an association which has been detailed in many other papers.

Predictors of neonatal encephalopathy in full term infants

Abstract Objective: Preliminary investigation of the contribution of adverse antepartum and intrapartum factors to neonatal encephalopathy in singleton neonates born full term. Design: Matched case-control study based on incidence density sampling of controls. Setting: Two major teaching hospitals (one paediatric and one obstetric) and three peripheral maternity hospitals in Perth, Western Australia (population 1.2 million). Subjects: 89 cases, all the full term singleton neonates born during an eight month period in 1992 who fulfilled one or more of six criteria during the first week of life (seizures, abnormal conscious state, persistent hypertonia or hypotonia, and feeding or respiratory difficulties of central origin). One full term control infant without neonatal encephalopathy was matched to each case by sex, hospital of delivery, time of day and day of the week of birth, and maternal health insurance status. Main outcome measures: Odds ratio estimates of relative risk of neonatal encephalopathy associated with antepartum and intrapartum factors. Results: Estimated incidence of moderate or severe encephalopathy in first week of life was 3.75 per 1000 full term live births. Thirteen cases and no controls had evidence suggestive of important intrapartum hypoxia, and in only five of these cases was the neurological condition at birth attributed to events during the intrapartum period. Univariate conditional logistic regression analysis identified significant differences between cases and controls for maternal vaginal bleeding in pregnancy, maternal thyroxine treatment, congenital abnormalities, induction of labour, interval from membrane rupture to delivery, maternal pyrexia in labour, augmentation of labour, abnormal intrapartum cardiotocograms, and meconium in labour. Family history of convulsions also approached significance. Conclusions: Our preliminary results suggest that intrapartum hypoxia, according to currently used criteria, was not the cause of neonatal encephalopathy in most cases in this population. Our findings suggest that many aetiologies of neonatal encephalopathy originate in the antepartum period.

Predictors of body mass index and associations with cardiovascular risk factors in Australian children: a prospective cohort study

OBJECTIVE:To examine predictors of body mass index (BMI) at the age of 8 y in a prospective study of Australian children.DESIGN:Longitudinal survey of a cohort of Australian children followed from the 16th week of gestation to 8 y.SUBJECTS:In total, 741 boys and 689 girls who attended the survey as 8 y olds.MEASUREMENTS:Weight and height, blood pressure measured by automated oscillometry, fasting blood lipids and glucose. Questionnaire assessment of activity and diet.RESULTS:Proportions of overweight including obesity in boys and girls were, respectively, 22 and 25% at 1 y, 14 and 14% at 3 y, 13 and 18% at 5 y and 15 and 20% at 8 y. At the age of 1, 3, 6 and 8 y, children with overweight including obesity showed significantly more adverse cardiovascular risk factors. Blood pressure (BP) was significantly higher by 2/3 mmHg (systolic/diastolic) at 1 y, 3/2 mmHg at 3 y, 4/2 mmHg at 5 y and 6/2 mmHg at 8 y; HDL was significantly lower (P=0.002) by 8% and triglycerides were significantly higher by 27% (P<0.001). In multivariate regression, BMI at the age of 8 y was significantly predicted positively by birth weight, mothers BMI and hours spent in watching television at the time of the survey of 6 y olds. Mothers being ex-smokers or non smokers and children being ‘slightly active’ and ‘active’ negatively predicted BMI in 8 y olds. In a subset of 298 children with information about fathers, paternal BMI was an additional independent predictor. Maternal or paternal overweight including obesity each independently increased risk of overweight including obesity at the age of 8 y three-fold. A food factor with consumption of cereals and breads as the major components derived from a Food Frequency Questionnaire in a subset of 340 children was also an independent negative predictor of BMI in multivariate models.CONCLUSION:The increasing rate of overweight including obesity, particularly in girls, is associated with an increase in cardiovascular risk factors very early in life. Improvement of health-related behaviours within the family and a focus on promotion of activity in children should be priorities in achieving weight control.

The association between dietary patterns and mental health in early adolescence

OBJECTIVE To investigate the associations between dietary patterns and mental health in early adolescence. METHOD The Western Australian Pregnancy Cohort (Raine) Study is a prospective study of 2900 pregnancies recruited from 1989-1992. At 14 years of age (2003-2006; n=1324), the Child Behaviour Checklist (CBCL) was used to assess behaviour (characterising mental health status), with higher scores representing poorer behaviour. Two dietary patterns (Western and Healthy) were identified using factor analysis and food group intakes estimated by a 212-item food frequency questionnaire. Relationships between dietary patterns, food group intakes and behaviour were examined using general linear modelling following adjustment for potential confounding factors at age 14: total energy intake, body mass index, physical activity, screen use, family structure, income and functioning, gender and maternal education at pregnancy. RESULTS Higher total (b=2.20, 95% CI=1.06, 3.35), internalizing (withdrawn/depressed) (b=1.25, 95% CI=0.15, 2.35) and externalizing (delinquent/aggressive) (b=2.60, 95% CI=1.51, 3.68) CBCL scores were significantly associated with the Western dietary pattern, with increased intakes of takeaway foods, confectionary and red meat. Improved behavioural scores were significantly associated with higher intakes of leafy green vegetables and fresh fruit (components of the Healthy pattern). CONCLUSION These findings implicate a Western dietary pattern in poorer behavioural outcomes for adolescents. Better behavioural outcomes were associated with a higher intake of fresh fruit and leafy green vegetables.

Pre- and postnatal influences on preschool mental health: a large-scale cohort study.

BACKGROUND Methodological challenges such as confounding have made the study of the early determinants of mental health morbidity problematic. This study aims to address these challenges in investigating antenatal, perinatal and postnatal risk factors for the development of mental health problems in pre-school children in a cohort of Western Australian children. METHODS The Raine Study is a prospective cohort study of 2,868 live born children involving 2,979 pregnant women recruited at 18 weeks gestation. Children were followed up at age two and five years. The Child Behaviour Checklist (CBCL) was used to measure child mental health with clinical cut-points, including internalising (withdrawn/depressed) and externalising (aggressive/destructive) behaviours (n = 1707). RESULTS Multinomial logistic regression analysis showed that the significant risk factors for behaviour problems at age two were the maternal experience of multiple stress events in pregnancy (OR = 1.20, 95% CI = 1.06, 1.37), smoking during pregnancy (OR = 1.30, 95% CI = 1.06, 1.59) and maternal ethnicity (OR = 3.34, 95% CI = 1.61, 6.96). At age five the experience of multiple stress events (OR = 1.17, 95% CI = 1.08, 1.27), cigarette smoking (OR = 1.19, 95% CI = 1.03, 1.37), male gender (OR = 1.43, 95% CI = 1.02, 2.00), breastfeeding for a shorter time (OR = .97, 95% CI = .94, .99) and multiple baby blues symptoms (OR = 1.08, 95% CI = 1.02, 1.14) were significant predictors of mental health problems. CONCLUSIONS Early childhood mental health is significantly affected by prenatal events in addition to the childs later environment. Interventions targeting adverse prenatal, perinatal and postnatal influences can be expected to improve mental health outcomes for children in the early years.

Low–moderate prenatal alcohol exposure and risk to child behavioural development: a prospective cohort study

Please cite this paper as: Robinson M, Oddy W, McLean N, Jacoby P, Pennell CE, de Klerk N, Zubrick S, Stanley F, Newnham J. Low–moderate prenatal alcohol exposure and risk to child behavioural development: a prospective cohort study. BJOG 2010;117:1139–1152.

The relation of breastfeeding and body mass index to asthma and atopy in children: A prospective cohort study to age 6 years

OBJECTIVES We investigated the relationship between breastfeeding, asthma and atopy, and child body mass index (BMI). METHODS From a prospective birth cohort (n = 2860) in Perth, Western Australia, 2195 children were followed up to age 6 years. Asthma was defined as doctor-diagnosed asthma and wheeze in the last year, and atopy was determined by skin prick test of 1596 children. Breastfeeding, BMI, asthma, and atopy were regressed allowing for confounders and the propensity score for overweight. RESULTS Using fractional polynomials, we found no association between breastfeeding and overweight. Less exclusive breastfeeding was associated with increased asthma and atopy, and BMI increased with asthma. CONCLUSIONS Less exclusive breastfeeding leads to increases in child asthma and atopy and a higher BMI is a risk factor for asthma.