Infection is the major component of the disease burden in aboriginal and non-aboriginal Australian children: a population-based study

Australian and New Zealand Indigenous mothers' report respect for smoking bans in homes

BACKGROUND

There is limited data about the reasons behind residential rules to reduce environmental tobacco smoke (ETS) exposure or the establishment or enforcement of such rules in Indigenous populations.

AIM

We aimed to gain an understanding of smokefree rules around Australian and New Zealand (NZ) Indigenous infants.

METHOD

This was a qualitative study nested within a randomised controlled trial that aimed to test the efficacy of a family-centred tobacco control programme about environmental tobacco smoke (ETS) to improve the respiratory health of Indigenous infants in Australia and New Zealand. Qualitative semi-structured interviews were conducted with 26 Indigenous mothers of infants in Australia (n=7) and NZ (n=19). We asked about the presence of smokefree rules, who set the rules, how the rules were set and enforced, and presence of smokefree rules in participants' wider social circle. Interviews were audiotaped, transcribed, and inductively analysed to identify key themes.

FINDINGS

Sixty-nine percent of mothers had partners, 77% smoked and all reported some presence of smokefree rules for house and car. Three main themes were identified: strategies to minimise exposure to ETS, establishing smokefree rules in homes and cars, and, adherence and enforcement of smokefree rules. Several strategies were identified to limit children's exposure to ETS, including rules to limit exposure to third-hand smoke. Mothers extended their smokefree rules to apply to other people's houses or cars, and reported that their family and social circles also had smokefree rules. The main reason for having smokefree rules was for the health of their children. Rules were most commonly set by the mother, often jointly with their partner. Few mothers reported challenges or problems with other people adhering to the smokefree rules.

CONCLUSION

Women tried very hard to, and believed that they were effective in, protecting their children from the harmful effects of ETS exposure. In this context, health professionals need to emphasise smoking cessation in parents, so that children are maximally protected from ETS exposure.

Effect of a family-centered, secondhand smoke intervention to reduce respiratory illness in indigenous infants in Australia and New Zealand: a randomized controlled trial

INTRODUCTION

Secondhand smoke (SHS) is a significant cause of acute respiratory illness (ARI) and 5 times more common in indigenous children. A single-blind randomized trial was undertaken to determine the efficacy of a family centered SHS intervention to reduce ARI in indigenous infants in Australia and New Zealand.

METHODS

Indigenous mothers/infants from homes with ≥ 1 smoker were randomized to a SHS intervention involving 3 home visits in the first 3 months of the infants' lives (plus usual care) or usual care. The primary outcome was number of ARI-related visits to a health provider in the first year of life. Secondary outcomes, assessed at 4 and 12 months of age, included ARI hospitalization rates and mothers' report of infants' SHS exposure (validated by urinary cotinine/creatinine ratios [CCRs]), smoking restrictions, and smoking cessation.

RESULTS

Two hundred and ninety-three mother/infant dyads were randomized and followed up. Three quarters of mothers smoked during pregnancy and two thirds were smoking at baseline (as were their partners), with no change for more than 12 months. Reported infant exposure to SHS was low (≥ 95% had smoke-free homes/cars). Infant CCRs were higher if one or both parents were smokers and if mothers breast fed their infants. There was no effect of the intervention on ARI events [471 intervention vs. 438 usual care (reference); incidence rate ratio = 1.10, 95% confidence intervals (CI) = 0.88-1.37, p = .40].

CONCLUSIONS

Despite reporting smoke-free homes/cars, mothers and their partners continue to smoke in the first year of infants' lives, exposing them to SHS. Emphasis needs to be placed on supporting parents to stop smoking preconception, during pregnancy, and postnatal.

Lived experience of acute gastrointestinal illness in Rigolet, Nunatsiavut: "just suffer through it"

Enteric illness associated with foodborne and waterborne disease is thought to be common in some Canadian Indigenous communities. This study aimed to understand the lived experience of acute gastrointestinal illness (AGI), including symptoms and severity, perceived causes, and healthcare seeking behaviors of AGI in the small Inuit community of Rigolet, Canada. A concurrent mixed quantitative and qualitative methods design was used. Two cross-sectional retrospective surveys provided quantitative data to examine self-reported AGI symptoms and the distribution of potential risk factors in the community. Qualitative data from in-depth interviews with one-third of AGI cases were analyzed using a constant-comparative method to describe symptoms and severity, identify perceived risk factors, and explore health seeking behavior of AGI in Rigolet. Of the survey respondents reporting AGI, most reported symptoms of diarrhea without vomiting, followed by diarrhea with vomiting, and vomiting without diarrhea. The most common secondary symptoms included stomach cramps and abdominal pain, nausea, and extreme tiredness. Community members identified potential risk factors for AGI that reflect the epidemiology triad (host, agent, and environmental factors), including hygiene, retail food, tap water, boil water advisories, and personal stress. Risk aversion and healthcare seeking behaviors reflected the core constructs of the Health Belief Model (perceived susceptibility, severity, and benefits and barriers to action). Understanding community experience, perspectives, and beliefs related to AGI is useful for public health practitioners and health care providers. This information is important especially considering the relatively high estimated burden of AGI and the relatively low healthcare seeking behaviors in some Indigenous communities compared to national estimates. Moreover, the mixed-methods approach used to understand the burden of AGI could be extended to other health research in Indigenous contexts.

Modelling the seasonal epidemics of respiratory syncytial virus in young children

BACKGROUND

Respiratory syncytial virus (RSV) is a major cause of paediatric morbidity. Mathematical models can be used to characterise annual RSV seasonal epidemics and are a valuable tool to assess the impact of future vaccines.

OBJECTIVES

Construct a mathematical model of seasonal epidemics of RSV and by fitting to a population-level RSV dataset, obtain a better understanding of RSV transmission dynamics.

METHODS

We obtained an extensive dataset of weekly RSV testing data in children aged less than 2 years, 2000-2005, for a birth cohort of 245,249 children through linkage of laboratory and birth record datasets. We constructed a seasonally forced compartmental age-structured Susceptible-Exposed-Infectious-Recovered-Susceptible (SEIRS) mathematical model to fit to the seasonal curves of positive RSV detections using the Nelder-Mead method.

RESULTS

From 15,830 specimens, 3,394 were positive for RSV. RSV detections exhibited a distinct biennial seasonal pattern with alternating sized peaks in winter months. Our SEIRS model accurately mimicked the observed data with alternating sized peaks using disease parameter values that remained constant across the 6 years of data. Variations in the duration of immunity and recovery periods were explored. The best fit to the data minimising the residual sum of errors was a model using estimates based on previous models in the literature for the infectious period and a slightly lower estimate for the immunity period.

CONCLUSIONS

Our age-structured model based on routinely collected population laboratory data accurately captures the observed seasonal epidemic curves. The compartmental SEIRS model, based on several assumptions, now provides a validated base model. Ranges for the disease parameters in the model that could replicate the patterns in the data were identified. Areas for future model developments include fitting climatic variables to the seasonal parameter, allowing parameters to vary according to age and implementing a newborn vaccination program to predict the effect on RSV incidence.

The epidemiology and clinical features of Kawasaki disease in Australia

OBJECTIVES

The current Australian epidemiology of Kawasaki disease (KD) is poorly defined. Previous enhanced surveillance (1993-1995) estimated an incidence of 3.7/100,000 <5 years.

METHODS

We identified all patients hospitalized in Western Australia (current population ∼2.4 million) 1979 through 2009 with a discharge diagnosis of KD. We reviewed demographic, clinical, laboratory, and echocardiographic data from individual patient files and derived age-specific population estimates. KD diagnosis was made using standard criteria.

RESULTS

There were 353 KD cases, with incomplete KD in 34 (9.6%). Male to female ratio was 1.7:1 and median age was 3.8 years (interquartile range 12-60 months). Fifty (18.1%) patients were Asian. Mean annual incidence increased from 2.82 per 100,000 children aged <5 years (95% confidence interval, 1.93-3.99) in 1980 to 1989, to 7.96 (6.48-9.67) in 1990 to 1999, to 9.34 (7.72-11.20) in 2000 to 2009. The highest incidence was 15.7 in 2005. A total of 293 children (83%) received intravenous immunoglobulin and 331 (95.4%) aspirin. Of 282 children who completed echocardiographic studies, 47 (16.7%) had coronary artery (CA) ectasia/dilatation and 19 (6.8%) had CA aneurysms; male gender was significantly associated with CA abnormalities.

CONCLUSIONS

KD epidemiology in Western Australia mirrors that of other industrialized, predominantly European-Caucasian populations. The rising incidence likely reflects both improved ascertainment and a real increase in disease burden. The current Australian incidence is threefold higher than previously reported and similar to the United Kingdom. The CA outcomes, which include the pre-intravenous immunoglobulin era, are comparable to those reported elsewhere.

Morbidity due to acute lower respiratory infection in children with birth defects: a total population-based linked data study

BACKGROUND

Acute lower respiratory infections (ALRIs) are leading causes of hospitalisation in children. Birth defects occur in 5% of live births in Western Australia (WA). The association between birth defects and ALRI hospitalisation is unknown.

METHODS

We conducted a retrospective cohort study of 245,249 singleton births in WA (1996-2005). Population-based hospitalisation data were linked to the WA Register of Developmental Anomalies to investigate ALRI hospitalisations in children with and without birth defects. We used negative binomial regression to estimate associations between birth defects and number of ALRI hospitalisations before age 2 years, adjusting for known risk factors.

RESULTS

Overall, 9% of non-Aboriginal children and 37% of Aboriginal children with birth defects had at least one ALRI admission before age 2 years. Aboriginal children (IRR 2.3, 95% CI: 1.9-2.8) and non-Aboriginal children (IRR 2.0, 95% CI: 1.8-2.2) with birth defects had higher rates of hospitalisation for an ALRI than children with no birth defects. Rates of ALRI hospitalisation varied by type of defect but were increased for all major birth defects categories, the highest rate being for children with Down syndrome (IRR 8.0, 95% CI: 5.6-11.5). The rate of ALRI hospitalisation was 3 times greater in children with multiple birth defects than in those with isolated defects.

CONCLUSIONS

Children with birth defects experience higher rates of hospitalisation for ALRIs before age 2 years than children with no birth defects. Optimal vaccination coverage and immunoprophylaxis for specific categories of birth defects would assist in reducing hospitalisation rates for ALRI.

Diverging trends in gastroenteritis hospitalizations during 2 decades in western Australian Aboriginal and non-Aboriginal children

BACKGROUND

Gastroenteritis is a major cause of pediatric morbidity. We describe temporal, spatial and seasonal trends in age-specific gastroenteritis hospitalizations among Aboriginal and non-Aboriginal Australian children during 2 decades, providing a baseline to evaluate the impact of a rotavirus vaccine program begun in 2007.

METHODS

We conducted a population-based, data linkage study of Aboriginal and non-Aboriginal births in Western Australia, 1983 to 2006, and analyzed gastroenteritis-coded hospitalizations before age 15 years in the cohort of 596,465 births. Hospitalization rates in Aboriginal and non-Aboriginal children and between geographical regions were compared between 1983 to 1994 and 1995 to 2006.

RESULTS

Gastroenteritis rates were highest in children 6-11 months of age (Aboriginal: 259.3/1000/annum; non-Aboriginal: 22.7/1000/annum). Rates declined in Aboriginal children between 1983 to 1994 and 1995 to 2006, particularly in those 12-17 months of age (309/1000 to 179/1000). Rates in non-Aboriginal children<5 years increased 10-40%. The disparity for gastroenteritis rates between Aboriginal and non-Aboriginal children<5 years declined from being 15.4 times higher to 7.6 times higher in those aged 12-17 months and from 8.4 to 4.4 in those aged 2-4 years. Rates were highest in rural and remote regions, and diverging temporal trends were seen in different geographical regions. Seasonality varied between Aboriginal and non-Aboriginal children and climatic zones.

CONCLUSIONS

This is the largest study of gastroenteritis hospitalization trends in children. We found diverging trends of gastroenteritis hospitalization rates in Aboriginal and non-Aboriginal children. Although rates have declined in Aboriginal children, disparity between Aboriginal and non-Aboriginal children continues. Our findings highlight the need to consider age, ethnicity, seasonality and climate when evaluating rotavirus vaccine programs.

Clinic attendances during the first 12 months of life for Aboriginal children in five remote communities of northern Australia

BACKGROUND

The vast majority (>75%) of Aboriginal people in the Northern Territory (NT) live in remote or very remote locations. Children in these communities have high attendance rates at local Primary Health Care (PHC) centres but there is a paucity of studies documenting the reason and frequency of attendance. Such data can be used to help guide public health policy and practice.

METHODS AND FINDINGS

Clinic presentations during the first year of life were reviewed for 320 children born from 1 January 2001-31 December 2006. Data collected included reason for infectious presentation, antibiotic prescription and referral to hospital. The median number of presentations per child in the first year of life was 21 (IQR 15-29) with multiple reasons for presentation. The most prominent infectious presentations per child during the first year of life were upper respiratory tract infections (median 6, IQR 3-10); diarrhoea (median 3, IQR 1-5); ear disease (median 3, IQR 1-5); lower respiratory tract infection (median 3, IQR 2-5); scabies (median 3, IQR 1-5); and skin sores (median 3, IQR 2-5).

CONCLUSIONS

Infectious diseases of childhood are strongly linked with poverty, poor living conditions and overcrowding. The data reported in our study were collected through manual review, however many remote communities now have established electronic health record systems, use the Key Performance Indicator System and are engaged in CQI (continuous quality improvement) processes. Building on these recent initiatives, there is an opportunity to incorporate routine monitoring of a range of infectious conditions (we suggest diarrhoea, LRTI, scabies and skin sores) using both the age at first presentation and the median number of presentations per child during the first year of life as potential indicators of progress in addressing health inequities in remote communities.

Prevalence of and risk factors for human rhinovirus infection in healthy aboriginal and non-aboriginal Western Australian children

BACKGROUND

Human rhinovirus (HRV) species C (HRV-C) have been associated with frequent and severe acute lower respiratory infections and asthma in hospitalized children. The prevalence of HRV-C among healthy children and whether this varies with ethnicity is unknown.

OBJECTIVE

To describe the prevalence of HRV species and their associations with demographic, environmental and socioeconomic factors in healthy Aboriginal and non-Aboriginal children.

METHODS

Respiratory viruses and bacteria were identified in 1006 nasopharyngeal aspirates collected from a cohort of 79 Aboriginal and 88 non-Aboriginal Western Australian children before 2 years of age. HRV-positive nasopharyngeal aspirates were typed for HRV species and genotypes. Longitudinal growth models incorporating generalized estimating equations were used to investigate associations between HRV species and potential risk factors.

RESULTS

Of the 159 typed specimens, we identified 83 (52.2%) human rhinovirus species A (HRV-A), 26 (16.4%), human rhinovirus species B and 50 (31.4%) HRV-C. HRV-C was associated with upper respiratory symptoms in Aboriginal (odds ratio, 3.77; 95% confidence interval:1.05-13.55) and non-Aboriginal children (odds ratio, 5.85; 95% confidence interval: 2.33-14.66). HRV-A and HRV-C were associated with carriage of respiratory bacteria. In Aboriginal children, HRV-A was more common in the summer and in those whose mothers were employed prior to delivery. In non-Aboriginal children, day-care attendance and exclusive breast-feeding at age 6-8 weeks were associated with detection of HRV-A, and gestational smoking with detection of HRV-C.

CONCLUSIONS

Factors associated with the presence of HRV differ between Aboriginal and non-Aboriginal children. In contrast to HRV-A, HRV-C is associated with upper respiratory symptoms suggesting that HRV-C is likely to be implicated in respiratory illness.

Use of data linkage to investigate the aetiology of acute lower respiratory infection hospitalisations in children

AIM

To document the aetiology of acute lower respiratory infection (ALRI) hospitalisations in Western Australian children by linking population-based laboratory data with hospital morbidity data.

METHODS

Data from all ALRI hospitalisations and laboratory records related to respiratory pathogens between 2000 and 2005 were extracted and linked through a population-based record linkage system. The proportion of specimens that were positive for each respiratory viral or bacterial pathogen was documented.

RESULTS

Eight thousand nine hundred and eighty (45.2%) ALRI hospitalisations were linked to a laboratory record. Admissions to a private hospital and admissions from non-metropolitan areas were less likely to have a linked laboratory record. In 57.9% of linked hospitalisations, a respiratory virus and/or a bacterial pathogen was identified. Frequently identified viral pathogens included respiratory syncytial virus (RSV; n= 3226; 39.5% of those tested), influenza viruses (n= 664; 8.5%), parainfluenza virus type 3 (n= 348; 4.6%), picornaviruses (n= 292; 22.3%) and adenoviruses (n= 211; 2.7%). RSV was identified in 63.7% of bronchiolitis admissions in those aged under 6 months and 33.1% of pneumonia admissions in those aged under 12 months. Influenza viruses were identified in 81.6% of influenza-coded admissions. When a test was requested, Bordetella pertussis was identified in 21.2% of ALRI hospitalisations (n= 354), including 86.8% of whooping cough-coded admissions.

CONCLUSIONS

This is the first report of population-based data linkage between statewide laboratory data and hospitalisation records and demonstrates proof of principle. RSV continues to be an important pathogen in ALRI. As pathogens were identified across all diagnoses, relying on hospital diagnosis coding alone may not accurately estimate the burden of different categories of ALRI.

Observational Research in Childhood Infectious Diseases (ORChID): a dynamic birth cohort study

INTRODUCTION

Even in developed economies infectious diseases remain the most common cause of illness in early childhood. Our current understanding of the epidemiology of these infections is limited by reliance on data from decades ago performed using low-sensitivity laboratory methods, and recent studies reporting severe, hospital-managed disease.

METHODS AND ANALYSIS

The Observational Research in Childhood Infectious Diseases (ORChID) study is an ongoing study enrolling a dynamic birth cohort to document the community-based epidemiology of viral respiratory and gastrointestinal infections in early childhood. Women are recruited antenatally, and their healthy newborn is followed for the first 2 years of life. Parents keep a daily symptom diary for the study child, collect a weekly anterior nose swab and dirty nappy swab and complete a burden diary when a child meets pre-defined illness criteria. Specimens will be tested for a wide range of viruses by real-time PCR assays. Primary analyses involves calculating incidence rates for acute respiratory illness (ARI) and acute gastroenteritis (AGE) for the cohort by age and seasonality. Control material from children when they are without symptoms will allow us to determine what proportion of ARIs and AGE can be attributed to specific pathogens. Secondary analyses will assess the incidence and shedding duration of specific respiratory and gastrointestinal pathogens.

ETHICS AND DISSEMINATION

This study is approved by The Human Research Ethics Committees of the Children's Health Queensland Hospital and Health Service, the Royal Brisbane and Women's Hospital and The University of Queensland.

TRIAL REGISTRATION

clinicaltrials.gov NCT01304914.

Total population investigation of dental hospitalizations in indigenous children under five years in Western Australia using linked data

BACKGROUND

The aim of this study was to compare dental hospital admissions in a total state birth population of Indigenous and non-Indigenous children aged under five years in Western Australia.

METHODS

Midwives' notification data were linked to databases of deaths, admissions, birth defects and intellectual disability. Births during 1980-1995 were followed until five years of age (n = 383,665). Dental admissions were classified by ICD-9 principal diagnosis categories.

RESULTS

There were 738 dental admissions for 665 children aged up to five years of Indigenous mothers (n = 20,921). Indigenous children comprised 6.3% of all children having a dental admission in this age group; 3.2% of children with Indigenous mothers had a dental admission compared with 2.7% of non-Indigenous children. Overall, 8.7% (n = 58) of Indigenous children with a dental admission had a birth defect and 5.5% (n = 23) had an intellectual disability (compared to 8.8% and 3.2%). Indigenous children were four times more likely to be diagnosed with oral soft tissue diseases than non-Indigenous children, and less likely to be categorized as having diseases of the dental hard tissues. Indigenous children were more likely to have a longer dental admission.

CONCLUSIONS

These analyses provide important findings regarding hospital admissions for Indigenous children. Admissions for disorders of the soft tissues are more common in Indigenous children.

Hospitalisation with infection, asthma and allergy in Kawasaki disease patients and their families: genealogical analysis using linked population data

BACKGROUND

Kawasaki disease results from an abnormal immunological response to one or more infectious triggers. We hypothesised that heritable differences in immune responses in Kawasaki disease-affected children and their families would result in different epidemiological patterns of other immune-related conditions. We investigated whether hospitalisation for infection and asthma/allergy were different in Kawasaki disease-affected children and their relatives.

METHODS/MAJOR FINDINGS

We used Western Australian population-linked health data from live births (1970-2006) to compare patterns of hospital admissions in Kawasaki disease cases, age- and sex-matched controls, and their relatives. There were 295 Kawasaki disease cases and 598 age- and sex-matched controls, with 1,636 and 3,780 relatives, respectively. Compared to controls, cases were more likely to have been admitted at least once with an infection (cases, 150 admissions (50.8%) vs controls, 210 admissions (35.1%); odds ratio (OR) = 1.9, 95% confidence interval (CI) 1.4-2.6, P = 7.2×10⁻⁶), and with asthma/allergy (cases, 49 admissions (16.6%) vs controls, 42 admissions (7.0%); OR = 2.6, 95% CI 1.7-4.2, P = 1.3×10⁻⁵). Cases also had more admissions per person with infection (cases, median 2 admissions, 95% CI 1-5, vs controls, median 1 admission, 95% CI 1-4, P = 1.09×10⁻⁵). The risk of admission with infection was higher in the first degree relatives of Kawasaki disease cases compared to those of controls, but the differences were not significant.

CONCLUSION

Differences in the immune phenotype of children who develop Kawasaki disease may influence the severity of other immune-related conditions, with some similar patterns observed in relatives. These data suggest the influence of shared heritable factors in these families.

A retrospective population-based cohort study identifying target areas for prevention of acute lower respiratory infections in children

BACKGROUND

Acute lower respiratory infections (ALRI) are a major cause of hospitalisation in young children. Many factors can lead to increased risk of ALRI in children and predispose a child to hospitalisation, but population attributable fractions for different risk factors and how these fractions differ between Indigenous and non-Indigenous children is unknown. This study investigates population attributable fractions of known infant and maternal risk factors for ALRI to inform prevention strategies that target high-risk groups or particular risk factors.

METHODS

A retrospective population-based data linkage study of 245,249 singleton births in Western Australia. Population attributable fractions of known maternal and infant risk factors for hospitalisation with ALRI between 1996 and 2005 were calculated using multiple logistic regression.

RESULTS

The overall ALRI hospitalisation rate was 16.1/1,000 person-years for non-Aboriginal children and 93.0/1,000 for Aboriginal children. Male gender, being born in autumn, gestational age <33 weeks, and multiple previous pregnancies were significant risk factors for ALRI in both Aboriginal and non-Aboriginal children. In non-Aboriginal children, maternal smoking during pregnancy accounted for 6.3% (95%CI: 5.0, 7.6) of the population attributable fraction for ALRI, being born in autumn accounted for 12.3% (10.8, 13.8), being born to a mother with three or more previous pregnancies accounted for 15.4% (14.1, 17.0) and delivery by elective caesarean accounted for 4.1% (2.8, 5.3). In Aboriginal children, being born to a mother with three or more previous pregnancies accounted for 16.5% (11.8, 20.9), but remote location at birth accounted for 11.7% (8.5, 14.8), maternal age <20 years accounted for 11.2% (7.8, 14.5), and being in the most disadvantaged socio-economic group accounted for 18.4% (-6.5, 37.4) of the population attributable fraction.

CONCLUSIONS

The population attributable fractions estimated in this study should help in guiding public health interventions to prevent ALRI. A key risk factor for all children is maternal smoking during pregnancy, and multiple previous pregnancies and autumnal births are important high-risk groups. Specific key target areas are reducing elective caesareans in non-Aboriginal women and reducing teenage pregnancies and improving access to services and living conditions for the Aboriginal population.

Incidence of infectious diseases in infants fed follow-on formula containing synbiotics: an observational study

Aim

Infectious diseases in infants are a major public health issue. Synbiotic-enriched formulas (EF) are intended to mimic the beneficial effects of human milk on infectious diseases. We performed an observational study in infants switching to follow-on formula to determine the effects of synbiotic-enriched formula compared to standard formula (SF).

Methods

We recorded family characteristics, medical history and growth data, as well as the symptoms, severity and treatment of infectious diseases. Main outcome measures were compared after adjustments for baseline characteristics.

Results

Between January and June 2007, 771 healthy infants were included in the study; 35.4% experienced at least one infectious disease during the 3-month study period. The most common were upper respiratory tract (24.1%), otitis (6.6%) and gastrointestinal infectious diseases (5.0%). Infants fed synbiotic-enriched formula had fewer infectious diseases overall (EF: 31.0%; SF: 40.6%; p = 0.005) and significantly fewer gastrointestinal infectious diseases (EF: 3.5%; SF: 6.8%; p = 0.03). During follow-up, weight gain was significantly higher (p = 0.0467) in infants fed synbiotic-enriched formula (18.3 ± 8.7 g/day) versus SF (16.9 ± 7.5 g/day).

Conclusions

Supplementation with synbiotics may have beneficial effects on the incidence of infectious disease and growth in infants. Further studies are needed determine optimal doses and composition of synbiotics in infant formula.

Low hospital admission rates for respiratory diseases in children

Background

Population-based data on hospital admissions for children aged 0-17 years concerning all respiratory diseases are scarce. This study examined hospital admissions in relation to the preceding consultations in general practice in this age group.

Methods

Data on children aged 0-17 years with respiratory diseases included in the Second Dutch National Survey of General Practice (DNSGP-2) were linked to all hospital admissions in the Dutch National Medical Registration. Admission rates for respiratory diseases were calculated. Data were analysed using multivariate logistic regression.

Results

Of all 79,272 children within the DNSGP-2, 1.8% were admitted to hospital for any respiratory diagnosis. The highest admission rates per 1000 children were for chronic disease of tonsils and adenoids (12.9); pneumonia and influenza (0.97); and asthma (0.92). Children aged 0-4 years and boys were admitted more frequently. Of children with asthma, 2.3% were admitted for respiratory diseases. For asthma, admission rates varied by urbanisation level: 0.47/1000 children/year in cities with ≤ 30,000 inhabitants, 1.12 for cities with ≥ 50,000 inhabitants, and 1.73 for the three largest cities (p = 0.002). Multivariate logistic regression showed that within two weeks after a GP consultation, younger age (OR 0.81, 95% CI 0.76-0.88) and more severe respiratory diseases (5.55, 95% CI 2.99-8.11) predicted hospital admission.

Conclusions

Children in the general population with respiratory diseases (especially asthma) had very low hospital admission rates. In urban regions children were more frequently admitted due to respiratory morbidity. For effectiveness studies in a primary care setting, hospital admission rates should not be used as quality end-point.

Assessing development of urban Aboriginal infants

AIMS

To determine the appropriateness of using the Griffiths' Mental Developmental Scales (birth - 2 years) to assess development in a cohort of urban Aboriginal children at 12 months of age.

METHODS

The Gudaga study is a prospective longitudinal cohort study assessing the health, development and service use of urban Aboriginal infants residing in south west Sydney. All infants receive a full heath and development assessment (including the Griffiths' Mental Developmental Scales) when they are 12 months of age. This study analyses the results of the first 55 infants.

RESULTS

The distribution of the General Quotient for the first 55 Gudaga infants is normal with a mean of 98.5 (SD 10.5). There is no significant difference between the Gudaga cohort and the Griffiths' standardisation sample for locomotor, personal-social, hearing and language, and eye and hand coordination sub-quotient scores.

CONCLUSION

The Griffiths' Mental Developmental Scales may be an appropriate tool to use for the assessment of development in urban Aboriginal infants.

Rates of radiologically confirmed pneumonia as defined by the World Health Organization in Northern Territory Indigenous children

OBJECTIVE

To determine the burden of hospitalised, radiologically confirmed pneumonia (World Health Organization protocol) in Northern Territory Indigenous children.

DESIGN, SETTING AND PARTICIPANTS

Historical, observational study of all hospital admissions for any diagnosis of NT resident Indigenous children, aged between > or = 29 days and < 5 years, 1 April 1997 to 31 March 2005.

INTERVENTION

All chest radiographs taken during these admissions, regardless of diagnosis, were assessed for pneumonia in accordance with the WHO protocol.

MAIN OUTCOME MEASURE

The primary outcome was endpoint consolidation (dense fluffy consolidation [alveolar infiltrate] of a portion of a lobe or the entire lung) present on a chest radiograph within 3 days of hospitalisation.

RESULTS

We analysed data on 24,115 hospitalised episodes of care for 9492 children and 13,683 chest radiographs. The average annual cumulative incidence of endpoint consolidation was 26.6 per 1000 population per year (95% CI, 25.3-27.9); 57.5 per 1000 per year in infants aged 1-11 months, 38.3 per 1000 per year in those aged 12-23 months, and 13.3 per 1000 per year in those aged 24-59 months. In all age groups, rates of endpoint consolidation in children in the arid southern region of NT were about twice that of children in the tropical northern region.

CONCLUSION

The rates of severe pneumonia in hospitalised NT Indigenous children are among the highest reported in the world. Reducing this unacceptable burden of disease should be a national health priority.

The study protocol for a randomized controlled trial of a family-centred tobacco control program about environmental tobacco smoke (ETS) to reduce respiratory illness in Indigenous infants

BACKGROUND

Acute respiratory illness (ARI) is the most common cause of acute presentations and hospitalisations of young Indigenous children in Australia and New Zealand (NZ). Environmental tobacco smoke (ETS) from household smoking is a significant and preventable contributor to childhood ARI. This paper describes the protocol for a study which aims to test the efficacy of a family-centred tobacco control program about ETS to improve the respiratory health of Indigenous infants in Australia and New Zealand. For the purpose of this paper 'Indigenous' refers to Australia's Aboriginal and Torres Strait Islander peoples when referring to Australian Indigenous populations. In New Zealand, the term 'Indigenous' refers to Māori.

METHODS/DESIGN

This study will be a parallel, randomized, controlled trial. Participants will be Indigenous women and their infants, half of whom will be randomly allocated to an 'intervention' group, who will receive the tobacco control program over three home visits in the first three months of the infant's life and half to a control group receiving 'usual care' (i.e. they will not receive the tobacco control program). Indigenous health workers will deliver the intervention, the goal of which is to reduce or eliminate infant exposure to ETS. Data collection will occur at baseline (shortly after birth) and when the infant is four months and one year of age. The primary outcome is a doctor-diagnosed, documented case of respiratory illness in participating infants.

DISCUSSION

Interventions aimed at reducing exposure of Indigenous children to ETS have the potential for significant benefits for Indigenous communities. There is currently a dearth of evidence for the effect of tobacco control interventions to reduce children's exposure to ETS among Indigenous populations. This study will provide high-quality evidence of the efficacy of a family-centred tobacco control program on ETS to reduce respiratory illness. Outcomes of our study will be important and significant for Indigenous tobacco control in Australia and New Zealand and prevention of respiratory illness in children.

Effectiveness of 7-valent pneumococcal conjugate vaccine against radiologically diagnosed pneumonia in indigenous infants in Australia

OBJECTIVE

To evaluate the effectiveness of the 7-valent pneumococcal conjugate vaccine (PCV7) in preventing pneumonia, diagnosed radiologically according to World Health Organization (WHO) criteria, among indigenous infants in the Northern Territory of Australia.

METHODS

We conducted a historical cohort study of consecutive indigenous birth cohorts between 1 April 1998 and 28 February 2005. Children were followed up to 18 months of age. The PCV7 programme commenced on 1 June 2001. All chest X-rays taken within 3 days of any hospitalization were assessed. The primary endpoint was a first episode of WHO-defined pneumonia requiring hospitalization. Cox proportional hazards models were used to compare disease incidence.

FINDINGS

There were 526 pneumonia events among 10,600 children - an incidence of 3.3 per 1000 child-months; 183 episodes (34.8%) occurred before 5 months of age and 247 (47.0%) by 7 months. Of the children studied, 27% had received 3 doses of vaccine by 7 months of age. Hazard ratios for endpoint pneumonia were 1.01 for 1 versus 0 doses; 1.03 for 2 versus 0 doses; and 0.84 for 3 versus 0 doses.

CONCLUSION

There was limited evidence that PCV7 reduced the incidence of radiologically confirmed pneumonia among Northern Territory indigenous infants, although there was a non-significant trend towards an effect after receipt of the third dose. These findings might be explained by lack of timely vaccination and/or occurrence of disease at an early age. Additionally, the relative contribution of vaccine-type pneumococcus to severe pneumonia in a setting where multiple other pathogens are prevalent may differ with respect to other settings where vaccine efficacy has been clearly established.

Acute and persistent diarrhea

Socially disadvantaged Indigenous infants and children living in western industrialized countries experience high rates of infectious diarrhea, no more so than Aboriginal children from remote and rural regions of Northern Australia. Diarrheal disease, poor nutrition, and intestinal enteropathy reflect household crowding, inadequate water and poor sanitation and hygiene. Acute episodes of watery diarrhea are often best managed by oral glucose-electrolyte solutions with continuation of breastfeeding and early reintroduction of feeding. Selective use of lactose-free milk formula, short-term zinc supplementation and antibiotics may be necessary for ill children with poor nutrition, persistent symptoms, or dysentery. Education, high standards of environmental hygiene, breastfeeding, and immunization with newly licensed rotavirus vaccines are all needed to reduce the unacceptably high burden of diarrheal disease encountered in young children from Indigenous communities.

Chronic respiratory symptoms and diseases among indigenous children

Children from Indigenous populations experience more frequent, severe, and recurrent lower respiratory infections as infants and toddlers. The consequences of these infections are chronic lung disorders manifested by recurrent wheezing and chronic productive cough. These symptoms are aggravated more frequently by active and passive tobacco smoke exposure among Indigenous groups. Therapies for these symptoms, although not specific to children of Indigenous origins, are described as is the evidence for their use.

Indigenous health part 1: determinants and disease patterns

The world's almost 400 million Indigenous people have low standards of health. This poor health is associated with poverty, malnutrition, overcrowding, poor hygiene, environmental contamination, and prevalent infections. Inadequate clinical care and health promotion, and poor disease prevention services aggravate this situation. Some Indigenous groups, as they move from traditional to transitional and modern lifestyles, are rapidly acquiring lifestyle diseases, such as obesity, cardiovascular disease, and type 2 diabetes, and physical, social, and mental disorders linked to misuse of alcohol and of other drugs. Correction of these inequities needs increased awareness, political commitment, and recognition rather than governmental denial and neglect of these serious and complex problems. Indigenous people should be encouraged, trained, and enabled to become increasingly involved in overcoming these challenges.

Twins born following assisted reproductive technology: perinatal outcome and admission to hospital

BACKGROUND

Compared with spontaneously conceived (SC) singletons, adverse perinatal outcome, neonatal intensive care unit (NICU) admission and hospital admission in infancy are more common in those born following Assisted Reproductive Technology (ART). Similar comparisons for twins have shown conflicting results.

METHODS

We investigated perinatal outcome and hospital admission during the first 3 years of life for all twin children born in Western Australia between 1994 and 2000 [700 ART, 4097 SC].

RESULTS

ART twins had a greater risk of adverse perinatal outcome including preterm birth, low birthweight and death compared with SC twins of unlike-sex. In their first year of life, ART twins had a longer birth admission; were 60% more likely to be admitted to a NICU; and had a higher risk of hospital admission. The increased risk of hospital admission continued in the second and third year but was not statistically significant in the third year.

CONCLUSIONS

Couples undertaking ART should be aware that in addition to the known increased perinatal risks associated with a twin birth, ART twins are more likely than SC twins to be admitted to a NICU and hospitalized in the first 3 years of life.

The association of infant feeding with parent-reported infections and hospitalisations in the West Australian Aboriginal Child Health Survey

OBJECTIVE

To examine infant feeding associations with parent-reported infections and hospitalisations in Western Australian Aboriginal infants and children.

METHOD

Families in Western Australia with children under 18 years of Aboriginal or Torres Strait Islander descent were included. A stratified multi-stage sample using an area-based sampling frame was compiled. Survey weights produced unbiased estimates for the population of families with Aboriginal children. Data were collected on demographic variables, maternal and infant characteristics and parent-reported recurring chest, ear and gastrointestinal infections. The data were linked to the Hospital Morbidity System to identify hospitalisations for infections for the same children.

RESULTS

Twenty-seven per cent of Aboriginal children were breastfed for less than three months. Parent-reported recurring chest, ear and gastrointestinal infections were reported in 47% of the 0-3 age group. Hospitalisations due to upper respiratory and gastrointestinal infections were most common in the older children, but wheezing lower respiratory infections were most common in younger children. Breastfeeding for less than three months and birth weight less than 2,500 g were risk factors for parent-reported chest infections and hospitalisations for upper and wheezing lower respiratory infections (p<0.05).

CONCLUSION

Rates of parent-reported chest infections and hospitalisations due to these infections continue to be high in Aboriginal infants and children. Because breastfeeding for less than three months and low birth weight are risk factors for these infections, interventions to reduce the prevalence of low birth weight and to increase breastfeeding rates should be primary health goals in Aboriginal communities for the benefits of Aboriginal infants and children.

Effect of swimming pools on antibiotic use and clinic attendance for infections in two Aboriginal communities in Western Australia

OBJECTIVE

To determine whether installation of swimming pools in remote Aboriginal communities reduces infection-related outpatient attendances and prescription of antibiotics.

DESIGN AND SETTING

Swimming pools were opened in Jigalong and Mugarinya, Western Australia, in September 2000. We examined local clinic records to document illnesses occurring in children and adolescents under 17 years of age between 1998 and 2005. In Jigalong, we examined records of those enrolled in an ongoing study evaluating the effect of swimming pools on health. In Mugarinya, we examined clinic records of those residing there permanently.

MAIN OUTCOME MEASURES

Clinic attendance rates for skin, middle-ear and respiratory tract infections and trauma, and prescription rates for antibiotics were analysed by using a community-based selection method in Jigalong, and a clinic-based selection method in both communities for comparison of the two communities and the two methods.

RESULTS

We examined records of 131 children in Jigalong and 128 children in Mugarinya. After the pools had been installed, clinic attendance rates for skin infections declined by 68% in Jigalong and by up to 77% in Mugarinya. In Jigalong (where the pre-pool prevalence of infections was higher than in Mugarinya), rates of antibiotic prescription declined by 45%, as did clinic attendance for middle-ear infections (61% reduction) and respiratory tract infections (52% reduction).

CONCLUSION

Swimming pools in remote communities are associated with reduced prevalence of skin infections. Where disease prevalence is high, pools are also associated with reduced rates of antibiotic prescriptions and middle-ear and respiratory tract infections. In communities with resident health staff, examination of clinic records is an efficient method of monitoring the effects of public health interventions on the burden of infectious diseases.

Disease burden and health-care clinic attendances for young children in remote aboriginal communities of northern Australia

OBJECTIVE

To determine the frequency of presentations and infectious-disease burden at primary health care (PHC) services in young children in two remote Aboriginal communities in tropical northern Australia.

METHODS

Children born after 1 January 2001, who were resident at 30 September 2005 and for whom consent was obtained, were studied. Clinic records were reviewed for all presentations between 1 January 2002 and 30 September 2005. Data collected included reason for presentation (if infectious), antibiotic prescription and referral to hospital.

FINDINGS

There were 7273 clinic presentations for 174 children aged 0-4.75 years, 55% of whom were male. The median presentation rate per child per year was 16 (23 in the first year of life). Upper-respiratory-tract infections (32%) and skin infections (18%) were the most common infectious reasons for presentation. First presentations for scabies and skin sores peaked at the age of 2 months. By 1 year of age, 63% and 69% of children had presented with scabies and skin sores, respectively.

CONCLUSION

These Aboriginal children average about two visits per month to PHC centres during their first year of life. This high rate is testament to the disease burden, the willingness of Aboriginal people to use health services and the high workload experienced by these health services. Scabies and skin sores remain significant health problems, with this study describing a previously undocumented burden of these conditions commencing within the first few months of life. Appropriate prevention and treatment strategies should encompass early infancy to reduce the high burden of infectious diseases in this population.

Hospitalizations during infancy in three population-based studies in Southern Brazil: trends and differentials

Three cohort studies of children born in the urban area of Pelotas, Southern Brazil, were carried out in 1982, 1993, and 2004. The aim of these studies was to measure the occurrence of hospitalization in the first year of life and to examine the association between hospitalization and the cause of admission and sex, birth weight, and family income. Cause of admission was categorized as "diarrhea" and "all other causes". The frequency of children hospitalized at least once during their first year of life was 19.6% in 1982, 18.1% in 1993, and 19.2% in 2004. There was a marked reduction in hospitalizations due to diarrhea, but the frequency of hospitalization for all causes remained constant. In all three cohorts, infants from poorer families and those born weighing under 2,000g showed the highest frequencies of hospitalization due to diarrhea and all other causes, and the latter also showed a marked increase in hospitalizations due to all causes. These findings could be explained by an epidemic of preterm births in the study population.

Diverging trends for lower respiratory infections in non-Aboriginal and Aboriginal children

AIM

To investigate temporal trends in admission rates for acute lower respiratory infections (ALRI) in a total population birth cohort of non-Aboriginal and Aboriginal children.

METHODS

Retrospective analysis of linked population-based data using the Western Australian Data Linkage System. All singleton live births in Western Australia between 1990 and 2000 were included. Hospital admission rates per 1000 live births for ALRI before age 2 years and linear time trends for ALRI admission rates were investigated.

RESULTS

ALRI admission rates were 7.5 (95% confidence interval (CI) 7.2-7.7) times higher in Aboriginal than non-Aboriginal children (337 vs. 45 per 1000 live births); pneumonia rates were 13.5 (95% CI 12.8-14.4) times higher and bronchiolitis rates were 5.8 (95% CI 5.3-6.0) times higher. ALRI admission rates rose in non-Aboriginal children (<12 months, 6%/year, P<0.002; 12-23 months, 11%/year, P<0.001) but declined in Aboriginal children aged 12-23 months (4%/year, P=0.003). Bronchiolitis rates rose in all children, especially non-Aboriginal infants aged <12 months (13%/year, P<0.001), while pneumonia rates rose in non-Aboriginal children but declined in Aboriginal children. Declines in bronchitis and asthma were also noted.

CONCLUSION

There has been an increase in incidence of bronchiolitis before age 12 months. For children aged 12-23 months a diagnostic shift from asthma and bronchitis to bronchiolitis and changes in health service utilisation are likely explanations for diverging temporal trends. The continuing disparity between Aboriginal and non-Aboriginal children needs to be addressed and appropriate preventative measures for ALRI, and in particular bronchiolitis, are urgently needed.