Impact of participant attrition on child injury outcome estimates: a longitudinal birth cohort study in Australia.

BACKGROUND: Longitudinal research is subject to participant attrition. Systemic differences between retained participants and those lost to attrition potentially bias prevalence of outcomes, as well as exposure-outcome associations. This study examines the impact of attrition on the prevalence of child injury outcomes and the association between sociodemographic factors and child injury. METHODS: Participants were recruited as part of the Environments for Healthy Living (EFHL) birth cohort study. Baseline data were drawn from maternal surveys. Child injury outcome data were extracted from hospital records, 2006-2013. Participant attrition status was assessed up to 2014. Rates of injury-related episodes of care were calculated, taking into account exposure time and Poisson regression was performed to estimate exposure-outcome associations. RESULTS: Of the 2222 participating families, 799 families (36.0%) had complete follow-up data. Those with incomplete data included 137 (6.2%) who withdrew, 308 (13.8%) were lost to follow-up and 978 families (44.0%) who were partial/non-responders. Families of lower socioeconomic status were less likely to have complete follow-up data (p<0.05). Systematic differences in attrition did not result in differential child injury outcomes or significant differences between the attrition and non-attrition groups in risk factor effect estimates. Participants who withdrew were the only group to demonstrate differences in child injury outcomes. CONCLUSION: This research suggests that even with considerable attrition, if the proportion of participants who withdraw is minimal, overall attrition is unlikely to affect the population prevalence estimate of child injury or measures of association between sociodemographic factors and child injury.

Recurrent episodes of injury in children: an Australian cohort study.

Objective The aim of the present study was to compare sociodemographic characteristics of children with single versus recurrent episodes of injury and provide contemporary evidence for Australian injury prevention policy development. Methods Participants were identified from the Environments for Healthy Living: Griffith Birth Cohort Study 2006-11 (n=2692). Demographic data were linked to the child's hospital emergency and admissions data from birth to December 2013. Data were dichotomised in two ways: (1) injured or non-injured; and (2) single or recurrent episodes of injury. Multivariate logistic regression was used for analysis. Results The adjusted model identified two factors significantly associated with recurrent episodes of injury in children aged <3 years. Children born to mothers <25 years were almost fourfold more likely to have recurrent episodes of injury compared with children of mothers aged ≥35 years (adjusted odds ratio (aOR)=3.68; 95% confidence interval (CI) 1.44-9.39) and, as a child's age at first injury increased, odds of experiencing recurrent episodes of injury decreased (aOR=0.97; 95% CI 0.94-0.99). No differences were found in sociodemographic characteristics of children aged 3-7 years with single versus recurrent episodes of injury (P>0.1). Conclusion National priorities should include targeted programs addressing the higher odds of recurrent episodes of injury experienced by children aged <3 years with younger mothers or those injured in the first 18 months of life. What is known about the topic? Children who experience recurrent episodes of injury are at greater risk of serious or irrecoverable harm, particularly when repeat trauma occurs in the early years of life. What does the paper add? The present study identifies key factors associated with recurrent episodes of injury in young Australian children. This is imperative to inform evidence-based national injury prevention policy development in line with the recent expiry of the National Injury Prevention and Safety Promotion Plan: 2004-2014. What are the implications for practitioners? Injury prevention efforts need to target the increased injury risk experienced by families from lower socioeconomic backgrounds and, as a priority, children under 3 years of age with younger mothers and children who are injured in the first 18 months of life. These families require access to education programs, resources, equipment and support, particularly in the child's early years. These programs could be provided as part of the routine paediatric and child health visits available to families after their child's birth or incorporated into hospital and general practitioner injury treatment plans.

Child injury: Does home matter?

This study examined the relationship between home risk and hospital treated injury in Australian children up to five years old. Women with children between two and four years of age enrolled in the Environments for Healthy Living (EFHL): Griffith Birth Cohort Study were invited to complete a Home Injury Prevention Survey from March 2013 to June 2014. A total home risk score (HRS) was calculated and linked to the child's injury related state-wide hospital emergency and admissions data and EFHL baseline demographic surveys. Data from 562 households relating to 566 child participants were included. We found an inverse relationship between home risk and child injury, with children living in homes with the least injury risk (based on the absence of hazardous structural features of the home and safe practices reported) having 1.90 times the injury rate of children living in high risk homes (95% CI 1.15-3.14). Whilst this appears counter-intuitive, families in the lowest risk homes were more likely to be socio-economically disadvantaged than families in the highest risk homes (more sole parents, lower maternal education levels, younger maternal age and lower income). After adjusting for demographic and socio-economic factors, the relationship between home risk and injury was no longer significant (p > 0.05). Our findings suggest that children in socio-economically deprived families have higher rates of injury, despite living in a physical environment that contains substantially fewer injury risks than their less deprived counterparts. Although measures to reduce child injury risk through the modification of the physical environment remain an important part of the injury prevention approach, our study findings support continued efforts to implement societal-wide, long term policy and practice changes to address the socioeconomic differentials in child health outcomes.

Validity of parent's self-reported responses to home safety questions.

The aim of the study was to describe the validity of parent's self-reported responses to questions on home safety practices for children of 2-4 years. A cross-sectional validation study compared parent's self-administered responses to items in the Home Injury Prevention Survey with home observations undertaken by trained researchers. The relationship between the questionnaire and observation results was assessed using percentage agreement, sensitivity, specificity, positive predictive value, negative predictive value and intraclass correlation coefficients. Percentage agreements ranged from 44% to 100% with 40 of the total 45 items scoring higher than 70%. Sensitivities ranged from 0% to 100%, with 27 items scoring at least 70%. Specificities also ranged from 0% to 100%, with 33 items scoring at least 70%. As such, the study identified a series of self-administered home safety questions that have sensitivities, specificities and predictive values sufficiently high to allow the information to be useful in research and injury prevention practice.

Environments For Healthy Living (EFHL) Griffith birth cohort study: characteristics of sample and profile of antenatal exposures.

BACKGROUND: The Environments for Healthy Living (EFHL) study is a repeated sample, longitudinal birth cohort in South East Queensland, Australia. We describe the sample characteristics and profile of maternal, household, and antenatal exposures. Variation and data stability over recruitment years were examined. METHODS: Four months each year from 2006, pregnant women were recruited to EFHL at routine antenatal visits on or after 24 weeks gestation, from three public maternity hospitals. Participating mothers completed a baseline questionnaire on individual, familial, social and community exposure factors. Perinatal data were extracted from hospital birth records. Descriptive statistics and measures of association were calculated comparing the EFHL birth sample with regional and national reference populations. Data stability of antenatal exposure factors was assessed across five recruitment years (2006-2010 inclusive) using the Gamma statistic for ordinal data and chi-squared for nominal data. RESULTS: Across five recruitment years 2,879 pregnant women were recruited which resulted in 2904 live births with 29 sets of twins. EFHL has a lower representation of early gestational babies, fewer still births and a lower percentage of low birth weight babies, when compared to regional data. The majority of women (65%) took a multivitamin supplement during pregnancy, 47% consumed alcohol, and 26% reported having smoked cigarettes. There were no differences in rates of a range of antenatal exposures across five years of recruitment, with the exception of increasing maternal pre-pregnancy weight (p=0.0349), decreasing rates of high maternal distress (p=0.0191) and decreasing alcohol consumption (p<0.0001). CONCLUSIONS: The study sample is broadly representative of births in the region and almost all factors showed data stability over time. This study, with repeated sampling of birth cohorts over multiple years, has the potential to make important contributions to population health through evaluating longitudinal follow-up and within cohort temporal effects.

Environments for Healthy Living (EFHL) Griffith birth cohort study: background and methods.

The health of an individual is determined by the interaction of genetic and individual factors with wider social and environmental elements. Public health approaches to improving the health of disadvantaged populations will be most effective if they optimise influences at each of these levels, particularly in the early part of the life course. In order to better ascertain the relative contribution of these multi-level determinants there is a need for robust studies, longitudinal and prospective in nature, that examine individual, familial, social and environmental exposures. This paper describes the study background and methods, as it has been implemented in an Australian birth cohort study, Environments for Healthy Living (EFHL): The Griffith Study of Population Health. EFHL is a prospective, multi-level, multi-year longitudinal birth cohort study, designed to collect information from before birth through to adulthood across a spectrum of eco-epidemiological factors, including genetic material from cord-blood samples at birth, individual and familial factors, to spatial data on the living environment. EFHL commenced the pilot phase of recruitment in 2006 and open recruitment in 2007, with a target sample size of 4000 mother/infant dyads. Detailed information on each participant is obtained at birth, 12-months, 3-years, 5-years and subsequent three to five yearly intervals. The findings of this research will provide detailed evidence on the relative contribution of multi-level determinants of health, which can be used to inform social policy and intervention strategies that will facilitate healthy behaviours and choices across sub-populations.

Dusk to dawn activity patterns of anopheline mosquitoes in West Timor and Java, Indonesia.

Malaria is a serious health issue in Indonesia. We investigated the dusk to dawn anopheline mosquito activity patterns, host-seeking and resting locations in coastal plain, hilly and highland areas in West Timor and Java. Adult mosquitoes were captured landing on humans or resting in houses or animal barns. Data analyzed were: mosquito night-time activities; period of peak activity; night-time activity in specific periods of time and for mosquito resting locations. Eleven species were recorded; data were sparse for some species therefore detailed analyses were performed for four species only. In Java Anopheles vagus was common, with a bimodal pattern of high activity. In West Timor, its activity peaked around midnight. Other species with peak activity around the middle of the night were An. barbirostris and An. subpictus. Most species showed no biting and resting preference for indoors or outdoors, although An. barbirostris preferred indoors in West Timor, but outdoors in Java. An. aconitus and An. annularis preferred resting in human dwellings; An. subpictus and An. vagus preferred resting in animal barns. An. barbirostris preferred resting in human dwellings in West Timor and in animal barns in Java. The information is useful for planning the mosquito control aspect of malaria management. For example, where mosquito species have peak activity at night indoors, bednets and indoor residual spraying should reduce malaria risk, but where mosquitoes are most active outdoors, other options may be more effective.

Does mosquito control have an effect on mosquito-borne disease? The case of Ross River virus disease and mosquito management in Queensland, Australia.

We examined the relationship between types of mosquito control programs and the mosquito-borne Ross River virus (RRV) disease in Queensland, Australia. Mosquito control information was collected through a survey of the responsible agencies (local governments), and RRV disease notification data were provided by the Queensland state health authority. The study developed a typology of mosquito control programs, based on the approaches used. Based on the analysis of data on RRV disease rates between mosquito control types within 4 climatic regions, each region had different combinations of mosquito control strategies in their programs; there were also general similarities in the relationship between program types and RRV rates between the regions. The long-term RRV disease rates were lower in areas where the mosquito control program included pre-emptive (rather than reactive) surveillance based on an extensive (rather than incomplete) knowledge of mosquito habitats, and where treatment of both saltwater and freshwater habitats (compared to only saltwater habitats, in coastal areas) occurred. The data indicate that mosquito control is an effective public health intervention to reduce mosquito-borne disease; hence, climate change adaptation strategies should ensure that adequate resources are available for effective vector control so as to manage the risk of mosquito-borne diseases.

Relationships between anopheline mosquitoes and topography in West Timor and Java, Indonesia.

BACKGROUND: Malaria is a serious health issue in Indonesia. Mosquito control is one aspect of an integrated malaria management programme. To focus resources on priority areas, information is needed about the vectors and their habitats. This research aimed to identify the relationship between anopheline mosquitoes and topography in West Timor and Java. METHODS: Study areas were selected in three topographic types in West Timor and Java. These were: coastal plain, hilly (rice field) and highland. Adult mosquitoes were captured landing on humans identified to species level and counted. RESULTS: Eleven species were recorded, four of which were significant for malaria transmission: Anopheles aconitus, Anopheles barbirostris, Anopheles subpictus and Anopheles sundaicus. Each species occupied different topographies, but only five were significantly associated: Anopheles annularis, Anopheles vagus and Anopheles subpictus (Java only) with hilly rice fields; Anopheles barbirostris, Anopheles maculatus and Anopheles subpictus (West Timor only) with coastal areas. CONCLUSION: Information on significant malaria vectors associated with specific topography is useful for planning the mosquito control aspect of malaria management.

Impact of biting midges on residential property values in Hervey Bay, Queensland, Australia.

Biting midges (Culicoides spp.) are an important environmental health issue in Hervey Bay, an area of rapid population growth in Australia. It is also the gateway to a World Heritage area (Great Sandy Strait) and a destination for tourists. The spread of housing developments into suburbs close to midge breeding habitats has led to a problem for the local government responsible for managing biting insects in its area. Suburbs with a severe biting midge problem were found to have significantly lower residential property values than less affected suburbs. The gross reduction in value in due to the midge problem was estimated to range from more than AUS dollar 25 million, based on actual sale price, to more than AUS dollar 55 million, based on the perceptions of the most severely affected residents.

Malaria in Indonesia: a summary of recent research into its environmental relationships.

A review of the literature was carried out to evaluate malaria and its environmental relationships. Research, in 6 parts of Indonesia, addressed the relationship between malaria incidence and physical and socioeconomic environmental factors, using longitudinal and cross-sectional approaches. Physical factors, which are generally important for malaria, included rainfall, mosquito breeding and resting sites, their distance from human habitation, and elevation, though the latter was not statistically significant. Housing conditions were occasionally important. Social and economic factors of importance were income, education, use of bednets and pattern of outdoor activities, especially at night. Use of repellents, mosquito coils and sleeping arrangements were significant in some of the studies.

Challenges in using geographic information systems (GIS) to understand and control malaria in Indonesia.

Malaria is a mosquito-borne disease of global concern with 1.5 to 2.7 million people dying each year and many more suffering from it. In Indonesia, malaria is a major public health issue with around six million clinical cases and 700 deaths each year. Malaria is most prevalent in the developing countries of the world. Aid agencies have provided financial and technical assistance to malaria-prone countries in an effort to battle the disease. Over the past decade, the focus of some of this assistance has been in the provision of geographic information systems (GIS) hardware, software and training. In theory, GIS can be a very effective tool in combating malaria, however, in practice there have been a host of challenges to its successful use.This review is based, in part, on the literature but also on our experience working with the Indonesian Ministry of Health. The review identifies three broad problem areas. The first of these relates to data concerns. Without adequate data, GIS is not very useful. Specific problem areas include: accurate data on the disease and how it is reported; basic environmental data on vegetation, land uses, topography, rainfall, etc.; and demographic data on the movement of people. The second problem area involves technology - specifically computer hardware, GIS software and training. The third problem area concerns methods - assuming the previous data and technological problems have been resolved - how can GIS be used to improve our understanding of malaria? One of the main methodological tools is spatial statistical analysis, however, this is a newly developing field, is not easy to understand and suffers from the fact that there is no agreement on standard methods of analysis.The paper concludes with a discussion of strategies that can be used to overcome some of these problems. One of these strategies involves using ArcView GIS software in combination with ArcExplorer (a public domain program that can read ArcView files) to deal with the problem of needing multiple copies of GIS software. Another strategy involves the development of a self-paced training package that can be used to train individuals