Viruses associated with acute respiratory infection in a community-based cohort of healthy New Zealand children.

Acute respiratory infections (ARIs) are a major cause of morbidity among children. Respiratory viruses are commonly detected in both symptomatic and asymptomatic periods. The rates of infection and community epidemiology of respiratory viruses in healthy children needs further definition to assist interpretation of molecular diagnostic assays in this population. Children otherwise healthy aged 1 to 8 years were prospectively enrolled in the study during two consecutive winters, when ARIs peak in New Zealand. Parents completed a daily symptom diary for 8 weeks, during which time they collected a nasal swab from the child for each clinical ARI episode. A further nasal swab was collected by research staff during a clinic visit at the conclusion of the study. All samples were tested for 15 respiratory viruses commonly causing ARI using molecular multiplex polymerase chain reaction assays. There were 575 ARIs identified from 301 children completing the study, at a rate of 1.04 per child-month. Swabs collected during an ARI were positive for a respiratory virus in 76.8% (307 of 400), compared with 37.3% (79 of 212) of swabs collected during asymptomatic periods. The most common viruses detected were human rhinovirus, coronavirus, parainfluenza viruses, influenzavirus, respiratory syncytial virus, and human metapneumovirus. All of these were significantly more likely to be detected during ARIs than asymptomatic periods. Parent-administered surveillance is a useful mechanism for understanding infectious disease in healthy children in the community. Interpretation of molecular diagnostic assays for viruses must be informed by understanding of local rates of asymptomatic infection by such viruses.

Ethnically Disparate Disease Progression and Outcomes among Acute Rheumatic Fever Patients in New Zealand, 1989-2015.

We investigated outcomes for patients born after 1983 and hospitalized with initial acute rheumatic fever (ARF) in New Zealand during 1989-2012. We linked ARF progression outcome data (recurrent hospitalization for ARF, hospitalization for rheumatic heart disease [RHD], and death from circulatory causes) for 1989-2015. Retrospective analysis identified initial RHD patients <40 years of age who were hospitalized during 2010-2015 and previously hospitalized for ARF. Most (86.4%) of the 2,182 initial ARF patients did not experience disease progression by the end of 2015. Progression probability after 26.8 years of theoretical follow-up was 24.0%; probability of death, 1.0%. Progression was more rapid and ≈2 times more likely for indigenous Maori or Pacific Islander patients. Of 435 initial RHD patients, 82.2% had not been previously hospitalized for ARF. This young cohort demonstrated low mortality rates but considerable illness, especially among underserved populations. A national patient register could help monitor, prevent, and reduce ARF progression.

Distribution of Streptococcal Pharyngitis and Acute Rheumatic Fever, Auckland, New Zealand, 2010-2016.

Group A Streptococcus (GAS) pharyngitis is a key initiator of acute rheumatic fever (ARF). In New Zealand, ARF cases occur more frequently among persons of certain ethnic and socioeconomic groups. We compared GAS pharyngitis estimates (1,257,058 throat swab samples) with ARF incidence (792 hospitalizations) in Auckland during 2010-2016. Among children 5-14 years of age in primary healthcare clinics, GAS pharyngitis was detected in similar proportions across ethnic groups (≈19%). Relative risk for GAS pharyngitis was moderately elevated among children of Pacific Islander and Maori ethnicities compared with those of European/other ethnicities, but risk for ARF was highly elevated for children of Pacific Islander and Maori ethnicity compared with those of European/other ethnicity. That ethnic disparities are much higher among children with ARF than among those with GAS pharyngitis implies that ARF is driven by factors other than rate of GAS pharyngitis alone.

Promoting health through housing improvements, education and advocacy: Lessons from staff involved in Wellington's Healthy Housing Initiative.

ISSUE ADDRESSED: Improving the conditions of housing through programs that trigger when children are hospitalised has the potential to prevent further ill-health and re-hospitalisations. Exploring the attitudes and beliefs of staff involved in such a program assists in understanding the advantages and challenges of this approach. METHODS: We interviewed 21 people involved in a regional initiative to improve the health outcomes of children through referral to a housing program. Interviews were recorded and transcribed. Transcripts were subsequently subjected to qualitative thematic analysis. RESULTS: Participants identified a number of factors that were key to the success of the program, such as: visiting the home, having health and energy organisations work together, and an integrated approach that includes interventions as well as education and advocacy. Key challenges to the program's aim of improving health outcomes for children were landlords' reluctance to implement improvements, homeowners' inability to afford improvements, limitations to staff resources, and client stress and income constraints, which meant that some interventions did not necessarily lead to housing improvements. CONCLUSIONS: Efforts to improve health outcomes through housing interventions should be supported by funding and regulatory initiatives that encourage property owners to implement recommended interventions. SO WHAT?: This program represents an encouraging step towards health promotion through housing interventions and education. However, the initiative cannot fully counter structural challenges such as poor quality housing, and lack of housing and energy affordability. This study highlights the potential for a holistic approach to health promotion in housing, which integrates health initiatives with advocacy for regulatory support.

Endotoxin, cat, and house dust mite allergens in electrostatic cloths and bedroom dust.

Environmental exposure to endotoxin, Fel d I (cat) allergen and Der p I (house dust mite) allergen have been associated with asthma symptoms and have been measured in the environment using various sampling methods, including the electrostatic dust collector. The objectives of this study were to investigate whether levels of endotoxin and allergens were detectable in electrostatic dust collectors and to examine the correlation of allergen and endotoxin levels between electrostatic dust collectors and vacuum sampling methods (floor dust and mattress dust). Electrostatic cloths, bedroom floor dust and mattress dust samples from a subset of 60 homes were randomly selected from the Health of Occupants of Mouldy Homes study for allergen and endotoxin analysis. Fel d I and Der p I allergens were analyzed by double monoclonal antibody ELISA and endotoxin by the kinetic Limulus amoebocyte lysate assay. An enhanced ELISA method was used to analyze Der p I in the electrostatic cloths. Endotoxin was detected in all samples, however Fel d I and Der p I were not detected in all electrostatic dust collector samples (detection in 53% and 15% of cloths respectively). No correlations were found between cloth and dust samples for endotoxin or Der p I, but moderate-to-strong correlations were found between all three sampling methods for Fel d I (rs = 0.612-0.715, p < 0.001). Poor correlation was found between floor dust and mattress dust samples for Der p I (rs = 0.256, p = 0.048). Electrostatic dust collectors may provide a way to measure airborne dust and allergen. Given the moderate-to-low correlations with vacuum dust sampling, this may present a unique measurement system which, when collected alongside traditional vacuum dust sampling, could provide additional exposure measures. Further studies are required to correlate endotoxin and allergen levels measured by electrostatic dust collector with air sampling and to explore the relationships between these bioaerosols, environmental factors and asthma.

Indoor visible mold and mold odor are associated with new-onset childhood wheeze in a dose-dependent manner.

Evidence is accumulating that indoor dampness and mold are associated with the development of asthma. The underlying mechanisms remain unknown. New Zealand has high rates of both asthma and indoor mold and is ideally placed to investigate this. We conducted an incident case-control study involving 150 children with new-onset wheeze, aged between 1 and 7 years, each matched to two control children with no history of wheezing. Each participant's home was assessed for moisture damage, condensation, and mold growth by researchers, an independent building assessor and parents. Repeated measures of temperature and humidity were made, and electrostatic dust cloths were used to collect airborne microbes. Cloths were analyzed using qPCR. Children were skin prick tested for aeroallergens to establish atopy. Strong positive associations were found between observations of visible mold and new-onset wheezing in children (adjusted odds ratios ranged between 1.30 and 3.56; P ≤ .05). Visible mold and mold odor were consistently associated with new-onset wheezing in a dose-dependent manner. Measurements of qPCR microbial levels, temperature, and humidity were not associated with new-onset wheezing. The association between mold and new-onset wheeze was not modified by atopic status, suggesting a non-allergic association.

Using preceding hospital admissions to identify children at risk of developing acute rheumatic fever.

AIMS: New Zealand (NZ) Maori and Pacific children have high rates of acute rheumatic fever (ARF). Around 150 new cases arise each year. As part of the national ARF prevention programme, funding is available to improve housing. To obtain maximum benefit from interventions, an effective tool is needed for targeting high-risk children. This study aimed to assess the effectiveness of using hospitalisations for identifying children at risk of subsequent ARF. METHODS: Three potentially avoidable hospitalisation (PAH) groups were investigated, including diseases thought to be influenced by housing. All were developed using expert opinion or systematic reviews. These were: (i) the PAH conditions associated with the housing environment (PAHHE) group; (ii) the Crowding group; and (iii) the Ministry of Health (MoH) group. We analysed NZ public hospital discharge data (2000-2014). The prevalence of ARF among patients hospitalised in each group was calculated to estimate sensitivity and potential effectiveness. The number needed to screen (NNS) to identify one ARF case was estimated as a measure of efficiency. RESULTS: Nearly one-third of ARF patients experienced a PAH as children (before developing ARF). Sensitivity for detecting future ARF ranged from <5% (MoH group) to 27% (PAHHE group). NNS ranged from 502.4 (PAHHE) to 707.5 (MoH). CONCLUSIONS: Because ARF is relatively rare, observing hospitalisations is not particularly efficient for targeting prevention activities for this condition alone. However, housing interventions are likely to improve multiple outcomes; thus, the hospital setting is still useful for identifying at-risk children who could benefit from such programmes.

Cost-benefit analysis of fall injuries prevented by a programme of home modifications: a cluster randomised controlled trial.

BACKGROUND: Injuries due to falls in the home impose a huge social and economic cost on society. We have previously found important safety benefits of home modifications such as handrails for steps and stairs, grab rails for bathrooms, outside lighting, edging for outside steps and slip-resistant surfacing for outside areas such as decks. Here we assess the economic benefits of these modifications. METHODS: Using a single-blinded cluster randomised controlled trial, we analysed insurance payments for medically treated home fall injuries as recorded by the national injury insurer. The benefits in terms of the value of disability adjusted life years (DALYs) averted and social costs of injuries saved were extrapolated to a national level and compared with the costs of the intervention. RESULTS: An intention-to-treat analysis was carried out. Injury costs per time exposed to the modified homes compared with the unmodified homes showed a reduction in the costs of home fall injuries of 33% (95% CI 5% to 49%). The social benefits of injuries prevented were estimated to be at least six times the costs of the intervention. The benefit-cost ratio can be at least doubled for older people and increased by 60% for those with a prior history of fall injuries. CONCLUSIONS: This is the first randomised controlled trial to examine the benefits of home modification for reducing fall injury costs in the general population. The results show a convincing economic justification for undertaking relatively low-cost home repairs and installing safety features to prevent falls. TRIAL REGISTRATION NUMBER: ACTRN12609000779279.

Acute rheumatic fever and exposure to poor housing conditions in New Zealand: A descriptive study.

AIM: Acute rheumatic fever (ARF) is an important public health problem in low- and middle-income countries and in certain populations in high-income countries. Indigenous Australians, and New Zealand Maori and Pacific people, have incidence rates among the highest in the world. We aimed to investigate ARF cases' housing conditions and sore throat treatment to identify opportunities for improving ARF prevention in New Zealand. METHODS: Recently diagnosed cases and their care givers were interviewed. Information was obtained about the cases' demographics, housing circumstances and conditions, and sore throat treatment preceding ARF. RESULTS: We interviewed 55 cases. Most (75%) lived in rental housing and reported multiple measures of deprivation. Common exposures were household crowding (58%), bed-sharing (49%), dampness and mould (76%), cold (82%) and co-habiting with smokers (71%). Experiencing sore throat in the weeks before ARF was recalled by 62%, with 29% seeing a doctor or nurse and 13% of the total sample receiving antibiotics. CONCLUSIONS: The environmental conditions reported could contribute to high group A Streptococcus transmission and susceptibility to infection, thus increasing ARF risk. Sore throat treatment has important limitations as an intervention, particularly as 38% of participants did not recall sore throat preceding the diagnosis. The results support the need to improve rental housing. Interventions promoting minimum enforceable standards in social housing and private rental sectors (such as a housing warrant of fitness) could support these changes. A rigorous investigation, such as a case control study, is needed to explore risk factors further.

Home modifications to reduce injuries from falls in the home injury prevention intervention (HIPI) study: a cluster-randomised controlled trial.

BACKGROUND: Despite the considerable injury burden attributable to falls at home among the general population, few effective safety interventions have been identified. We tested the safety benefits of home modifications, including handrails for outside steps and internal stairs, grab rails for bathrooms, outside lighting, edging for outside steps, and slip-resistant surfacing for outside areas such as decks and porches. METHODS: We did a single-blind, cluster-randomised controlled trial of households from the Taranaki region of New Zealand. To be eligible, participants had to live in an owner-occupied dwelling constructed before 1980 and at least one member of every household had to be in receipt of state benefits or subsidies. We randomly assigned households by electronic coin toss to either immediate home modifications (treatment group) or a 3-year wait before modifications (control group). Household members in the treatment group could not be masked to their assigned status because modifications were made to their homes. The primary outcome was the rate of falls at home per person per year that needed medical treatment, which we derived from administrative data for insurance claims. Coders who were unaware of the random allocation analysed text descriptions of injuries and coded injuries as all falls and injuries most likely to be affected by the home modifications tested. To account for clustering at the household level, we analysed all injuries from falls at home per person-year with a negative binomial generalised linear model with generalised estimating equations. Analysis was by intention to treat. This trial is registered with the Australian New Zealand Clinical Trials Registry, number ACTRN12609000779279. FINDINGS: Of 842 households recruited, 436 (n=950 individual occupants) were randomly assigned to the treatment group and 406 (n=898 occupants) were allocated to the control group. After a median observation period of 1148 days (IQR 1085-1263), the crude rate of fall injuries per person per year was 0.061 in the treatment group and 0.072 in the control group (relative rate 0.86, 95% CI 0.66-1.12). The crude rate of injuries specific to the intervention per person per year was 0.018 in the treatment group and 0.028 in the control group (0.66, 0.43-1.00). A 26% reduction in the rate of injuries caused by falls at home per year exposed to the intervention was estimated in people allocated to the treatment group compared with those assigned to the control group, after adjustment for age, previous falls, sex, and ethnic origin (relative rate 0.74, 95% CI 0.58-0.94). Injuries specific to the home-modification intervention were cut by 39% per year exposed (0.61, 0.41-0.91). INTERPRETATION: Our findings suggest that low-cost home modifications and repairs can be a means to reduce injury in the general population. Further research is needed to identify the effectiveness of particular modifications from the package tested. FUNDING: Health Research Council of New Zealand.

Fatigue in Air Medical Clinicians Undertaking High-acuity Patient Transports.

Abstract Background. Fatigue is likely to be a significant issue for air medical transport clinicians due to the challenging nature of their work, but there is little published evidence for this. Objective. To prospectively assess the levels and patterns of fatigue in air medical transport teams and determine whether specific mission factors influenced clinician fatigue. Methods. Physicians and flight nurses from two intensive care interhospital transport teams routinely completed fatigue report forms before and after patient transport missions over a 4-month period. Data collected included subjective ratings of fatigue (Samn-Perelli and visual analog scale), mission difficulty and performance. Multivariate hierarchical logistic and linear models were used to evaluate the influence of various mission characteristics on post-mission fatigue. Results. Clinicians returned 403 fully complete fatigue report forms at an estimated overall return rate of 73%. Fatigue increased significantly over the course of missions, and on 1 of every 12 fatigue reports returned clinicians reported severe post-mission fatigue (that is, levels of 6 or 7 on the Samn-Perelli scale). Factors that impacted significantly on clinician fatigue were the pre-mission fatigue level of the clinician, night work, mission duration, and mission difficulty. Poorer self-rated performance was significantly associated with higher levels of fatigue (r = -0.4, 95% CI -0.5 to -0.3), and for the 6-month period leading up to the study clinicians reported a total of 22 occasions on which they should have declined a mission due to fatigue. Conclusions. These results suggest that clinicians undertaking interhospital transports of even moderate duration experience high levels of fatigue on a relatively frequent basis. In the unique and challenging environment of air medical transport, prior fatigue, long or difficult missions, and the disadvantageous effect of night work on normal circadian rhythms are a combination where there are minimal safety margins for clinicians' performance capacity. Fatigue prevention or fatigue resistance measures could positively affect air medical clinicians in this context.

Comparison of approaches to rheumatic fever surveillance across Organisation for Economic Co-operation and Development countries.

AIM: Rheumatic fever (RF) prevention, control and surveillance are increasingly important priorities in New Zealand (NZ) and Australia. We compared RF surveillance across Organisation for Economic Co-operation and Development (OECD) member countries to assist in benchmarking and identifying useful approaches. METHODS: A structured literature review was completed using Medline and PubMed databases, investigating RF incidence rates. Surveillance methods were noted. Health department websites were searched to assess whether addressing RF was a Government priority. RESULTS: Of 32 OECD member countries, nine reported RF incidence rates after 1999. Highest rates were seen in indigenous Australians, and NZ Maori and Pacific peoples. NZ and Australian surveillance systems are highly developed, with notification and register data compiled regularly. Only these two Governments appeared to prioritise RF surveillance and control. Other countries relied mainly on hospitalisation data. There is a lack of standardisation across incidence rate calculations. Israel and Italy may have relatively high RF rates among developed countries. CONCLUSIONS: RF lingers in specific populations in OECD member countries. At a minimum, RF registers are needed in higher incidence countries. Countries with low RF incidences should periodically review surveillance information to ensure rates are not increasing.

Effect of repeated freeze/thawing of household dust extracts on ß-(1,3)-glucan levels.

ß-(1,3)-glucan exposure from household dust has been shown to be associated with respiratory symptoms and thus is increasingly being measured in epidemiological studies. Various factors are known to influence its measurement; however, no studies have assessed the effects of sample extract freeze-thawing on ß-(1,3)-glucan. The aim of this study was to assess the effects of repeated freeze-thawing of household dust extracts on levels of ß-(1,3)-glucan. Forty random household dust samples were extracted with 0.3 M NaOH and aliquots of extracts stored at -20 °C were subjected to one, two, and three freeze-thaw cycles. They were analyzed for ß-(1,3)-glucan by the Limulus amoebocyte assay (LAL) and results compared to freshly extracted samples (paired Pearson's t-test on logged values). Initial freezing of house dust extracts results in a significant decline in ß-(1,3)-glucan. However, repeated freeze/thawing (up to three times) does not results in any further decline in ß-(1,3)-glucan levels.

Improving rheumatic fever surveillance in New Zealand: results of a surveillance sector review.

BACKGROUND: The New Zealand (NZ) Government has made a strong commitment to reduce the incidence of rheumatic fever (RF) by two thirds, to 1.4 cases per 100,000, by mid-2017. We reviewed the NZ RF surveillance sector, aiming to identify potential improvements which would support optimal RF control and prevention activities. METHODS: This review used a recently developed surveillance sector review method. Interviews with 36 key informants were used to describe the sector, assess it and identify its gaps. Priorities for improvement and implementation strategies were determined following discussion with these key informants, with policy advisors and within the research team. RESULTS: Key improvements identified included the need for a comprehensive RF surveillance strategy, integrated reporting and an online national RF register. At a managerial level this review provided evidence for system change and built support for this across the surveillance sector. CONCLUSIONS: The surveillance sector review approach can be added to the small set of tools currently available for developing and evaluating surveillance systems. This new approach is likely to prove useful as we confront the challenges of combating new emerging infectious diseases, responding to global environmental changes, and reducing health inequalities.

Warm homes for older people: aims and methods of a randomised community-based trial for people with COPD.

BACKGROUND: Chronic Obstructive Pulmonary Disease (COPD) is of increasing importance with about one in four people estimated to be diagnosed with COPD during their lifetime. None of the existing medications for COPD has been shown to have much effect on the long-term decline in lung function and there have been few recent pharmacotherapeutic advances. Identifying preventive interventions that can reduce the frequency and severity of exacerbations could have important public health benefits. The Warm Homes for Elder New Zealanders study is a community-based trial, designed to test whether a NZ$500 electricity voucher paid into the electricity account of older people with COPD, with the expressed aim of enabling them to keep their homes warm, results in reduced exacerbations and hospitalisation rates. It will also examine whether these subsidies are cost-beneficial. METHODS: Participants had a clinician diagnosis of COPD and had either been hospitalised or taken steroids or antibiotics for COPD in the previous three years; their median age was 71 years. Participants were recruited from three communities between 2009 to early 2011. Where possible, participants' houses were retrofitted with insulation. After baseline data were received, participants were randomised to either 'early' or 'late' intervention groups. The intervention was a voucher of $500 directly credited to the participants' electricity company account. Early group participants received the voucher the first winter they were enrolled in the study, late participants during the second winter. Objective measures included spirometry and indoor temperatures and subjective measures included questions about participant health and wellbeing, heating, medication and visits to health professionals. Objective health care usage data included hospitalisation and primary care visits. Assessments of electricity use were obtained through electricity companies using unique customer numbers. DISCUSSION: This community trial has successfully enrolled 522 older people with COPD. Baseline data showed that, despite having a chronic respiratory illness, participants are frequently cold in their houses and economise on heating. TRIAL REGISTRATION: The clinical trial registration is http://NCT01627418.

Preventing upper respiratory tract infections with prophylactic nasal carrageenan: a feasibility study.

Aim: To observe upper respiratory tract infection (URTI) symptoms, rhinovirus levels and compliance with daily carrageenan nasal spray. Methods: 102 adults were randomized to carrageenan or saline placebo three times daily for 8 weeks and URTI symptoms were recorded. A control group (n = 42) only recorded URTI symptoms. Participants collected nasal swabs when symptomatic. Results: Regular daily carrageenan prophylaxis resulted in consistent but nonsignificant reductions in URTI symptoms versus the placebo group. Saline placebo decreased and increased some cold symptoms compared with no treatment. Conclusion: Daily prophylactic administration of antiviral carrageenan may not significantly reduce URTI symptoms. Due to low compliance, use in a population with specific reasons to avoid URTIs may be more appropriate. Disease-specific outcomes may be more useful than symptom reporting.

Daily vacuuming of mattresses significantly reduces house dust mite allergens, bacterial endotoxin, and fungal ß-glucan.

BACKGROUND AND AIMS: Atopic patients are advised to cover their mattresses with occlusive coverings; however, these are not cheap. We investigated whether daily vacuum cleaning of mattresses significantly reduces content of house dust mite allergens, bacterial endotoxin, and fungal ß-glucan. METHODS: Twenty volunteers vacuumed their mattress daily for 8 weeks. Dust samples collected at two weekly intervals were analyzed for house dust mite allergens (Der p 1 and Der f 1) by double monoclonal antibody ELISA and for endotoxin and ß-glucan by the Limulus amoebocyte lysate kinetic assay. Results are presented as geometric means with 95% confidence interval (CI). RESULTS: Total house dust mite allergens (Der p 1 + Der f 1) significantly reduced from a geometric mean (95% CI) of 4.07 µg (2.44-6.79) at the start to 0.42 µg (0.21-0.81) at week 8. Total endotoxin and ß-glucan were also significantly reduced from 13.6 EU (8.6-21.4) to 3.4 EU (2.3-5.0) and from 94.4 µg (57.1-156.2) to 19.7 µg (10.2-37.9), respectively (p for trend >.0001). Percentage reductions in total house dust mite allergens, endotoxin, and ß-glucan after 8 weeks of daily vacuum cleaning were 85.1% (80.1-90.1), 71.0% (70.4-81.0), and 75.7% (70.4-81.0), respectively. This was mainly due to a 77.7% (70.8-84.7) reduction in total dust. CONCLUSION: Daily vacuum cleaning of mattresses over time significantly reduces house dust mite allergens, endotoxin, and ß-glucan. This gives atopic patients a practical and cheaper alternative to reduce their exposure to indoor house dust mite allergens and microbial bio-contaminants.

Redefining the cast index: the optimum technique to reduce redisplacement in pediatric distal forearm fractures.

BACKGROUND: The aim of this study was to identify the optimal cast index (CI) level that reduces the risk of fracture redisplacement. The CI is the ratio of sagittal to coronal width from the inside edges of the cast at the fracture site. Previous studies have used 0.7 as the standard. METHODS: Case records and radiographs of 1001 children who underwent a manipulation under anesthesia for a displaced fracture of the distal forearm were studied. Redisplacement was defined as > 15 degrees of angulation and/or > 80% of translational displacement on check radiographs at 2 weeks. Angulation (degrees) and translational displacement (%) were measured on the initial and check radiographs. The CI was measured on the check radiographs. The CI has previously been validated in an experimental study. RESULTS: The adequacy of reduction after manipulation was determined by translation and angulation of the radius and ulna in anteroposterior and lateral plain film radiographs. From the 1001 patients who qualified for the study, fracture redisplacement was seen in 107 (10.6%) cases at the 2-week follow-up. A total of 752 (75%) patients had CIs of ≤ 0.8, whereas 249 (25%) had casting indices of ≥ 0.81. In patients with CIs of ≤ 0.8, the displacement rate was only 5.58%. However, in patients with CIs of ≥ 0.81, the displacement rate was 26%. A high CI was the sole factor that was significantly higher in the redisplacement group. No statistically significant difference was seen for age, sex, or surgeon seniority. Statistical differences were not noted in initial angular deformity or initial displacement. DISCUSSION: The CI is a simple reliable radiographic measurement to predict the redisplacement of forearm fractures in children. A plaster with a CI of > 0.81 is prone to redisplacement. High CIs are associated with redisplacement of fractures and should be avoided when molding casts in distal forearm fractures. LEVELS OF EVIDENCE: Level III--retrospective comparative study.

Residential mobility and potentially avoidable hospitalisations in a population-based cohort of New Zealand children.

BACKGROUND: Residential moves are common in early childhood and associations have been found between residential mobility and adverse child health and well-being outcomes. Although there are studies on potentially avoidable hospitalisations (PAH) in children, few have examined PAH in relation to residential mobility. Our aim, therefore, was to investigate residential mobility and PAH in a population-based cohort of New Zealand children. METHODS: Using a retrospective cohort design, we analysed data from the Integrated Data Infrastructure for a cohort of 314 283 children born since the start of 2004, who had at least one residential address recorded by 2 years of age. Residential mobility was derived from address data and PAH were determined from hospital discharge data. RESULTS: Half of the cohort children (52%) experienced at least one residential move by 2 years of age, and 22% experienced two or more moves. Fifteen per cent of the cohort experienced one or more PAH between 2 and 4 years of age. A linear association between residential mobility and PAH was found (relative risk (RR)=1.18, CI 1.17 to 1.19) and this remained robust when adjusting for several covariates. Sensitivity analyses for ambulatory care sensitive hospitalisations (ACSH) and PAH attributable to the housing/physical environment (PAH-HE) produced results very similar to those for PAH (ACSH: adjusted RR (aRR)=1.10, CI 1.09 to 1.11; PAH-HE: aRR=1.11, CI 1.10 to 1.12). CONCLUSION: This study found a linear association between higher residential mobility and an increased likelihood of PAH in young children. Avenues for further investigation are suggested.