Center for Epidemiology and Evidence

North Sydney, Australia

Center for Epidemiology and Evidence

North Sydney, Australia
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Barr M.L.,Center for Epidemiology and Evidence | Barr M.L.,University of Wollongong | Van Ritten J.J.,Center for Epidemiology and Evidence | Steel D.G.,University of Wollongong | Thackway S.V.,Center for Epidemiology and Evidence
BMC Medical Research Methodology | Year: 2012

Background: In Australia telephone surveys have been the method of choice for ongoing jurisdictional population health surveys. Although it was estimated in 2011 that nearly 20% of the Australian population were mobile-only phone users, the inclusion of mobile phone numbers into these existing landline population health surveys has not occurred. This paper describes the methods used for the inclusion of mobile phone numbers into an existing ongoing landline random digit dialling (RDD) health survey in an Australian state, the New South Wales Population Health Survey (NSWPHS). This paper also compares the call outcomes, costs and the representativeness of the resultant sample to that of the previous landline sample. Methods. After examining several mobile phone pilot studies conducted in Australia and possible sample designs (screening dual-frame and overlapping dual-frame), mobile phone numbers were included into the NSWPHS using an overlapping dual-frame design. Data collection was consistent, where possible, with the previous years' landline RDD phone surveys and between frames. Survey operational data for the frames were compared and combined. Demographic information from the interview data for mobile-only phone users, both, and total were compared to the landline frame using χ§ssup§2§esup§ tests. Demographic information for each frame, landline and the mobile-only (equivalent to a screening dual frame design), and the frames combined (with appropriate overlap adjustment) were compared to the NSW demographic profile from the 2011 census using χ§ssup§2§esup§ tests. Results: In the first quarter of 2012, 3395 interviews were completed with 2171 respondents (63.9%) from the landline frame (17.6% landline only) and 1224 (36.1%) from the mobile frame (25.8% mobile only). Overall combined response, contact and cooperation rates were 33.1%, 65.1% and 72.2% respectively. As expected from previous research, the demographic profile of the mobile-only phone respondents differed most (more that were young, males, Aboriginal and Torres Strait Islanders, overseas born and single) compared to the landline frame responders. The profile of respondents from the two frames combined, with overlap adjustment, was most similar to the latest New South Wales (NSW) population profile. Conclusions: The inclusion of the mobile phone numbers, through an overlapping dual-frame design, did not impact negatively on response rates or data collection, and although costing more the design was still cost-effective because of the additional interviews that were conducted with young people, Aboriginal and Torres Strait Islanders and people who were born overseas resulting in a more representative overall sample. © 2012 Barr et al.; licensee BioMed Central Ltd.


Stephens A.S.,NSW Ministry of Health | Bentley J.P.,Center for Epidemiology and Evidence | Taylor L.K.,Center for Epidemiology and Evidence | Arbuckle S.M.,Childrens Hospital at Westmead
Pathology | Year: 2015

We determined brain to liver weight ratio (BLWR) thresholds for fetal growth restriction (FGR) using autopsy information on 395 perinatal deaths comprising stillborn babies who died during labour and neonatal deaths. FGR was defined using two methods: (1) birth weight for gestational age (WGA) less than the 10th percentile; and (2) WGA less than the 10th percentile or discordant birth weight/length. The association between BLWR and FGR was investigated using odds ratios, and classification statistics were calculated for a range of BLWR thresholds. Using WGA, 84 cases (21.3%) were FGR and a further 15 cases (n=99, 25%) had discordant birth weight/length. The BLWR ranged from 1.02 to 7.30 and was positively associated with FGR. BLWR was not associated with FGR for babies with congenital central nervous system or chromosomal abnormalities. Excluding these, for FGR defined using WGA and discordant birth weight/length, a BLWR threshold of 5.0 was 100% predictive of FGR. A BLWR threshold of 3.0 for babies over 28 weeks gestation and 3.7 for more preterm babies optimised case detection while minimising missed and false positive cases. Additional evidence of FGR should be sought for babies with a BLWR of less than 5.0 to confirm FGR. © 2014 Royal College of Pathologists of Australasia.


Bentley J.P.,University of Sydney | Bentley J.P.,Center for Epidemiology and Evidence | Ford J.B.,University of Sydney | Taylor L.K.,Center for Epidemiology and Evidence | And 2 more authors.
BMC Medical Research Methodology | Year: 2012

Background: With the increasing use of probabilistically linked administrative data in health research, it is important to understand whether systematic differences occur between the populations with linked and unlinked records. While probabilistic linkage involves combining records for individuals, population perinatal health research requires a combination of information from both the mother and her infant(s). The aims of this study were to (i) describe probabilistic linkage for perinatal records in New South Wales (NSW) Australia, (ii) determine linkage proportions for these perinatal records, and (iii) assess records with linked mother and infant hospital-birth record, and unlinked records for systematic differences. Methods. This is a population-based study of probabilistically linked statutory birth and hospital records from New South Wales, Australia, 2001-2008. Linkage groups were created where the birth record had complete linkage with hospital admission records for both the mother and infant(s), partial linkage (the mother only or the infant(s) only) or neither. Unlinked hospital records for mothers and infants were also examined. Rates of linkage as a percentage of birth records and descriptive statistics for maternal and infant characteristics by linkage groups were determined. Results: Complete linkage (mother hospital record - birth record - infant hospital record) was available for 95.9% of birth records, partial linkage for 3.6%, and 0.5% with no linked hospital records (unlinked). Among live born singletons (complete linkage = 96.5%) the mothers without linked infant records (1.6%) had slightly higher proportions of young, non-Australian born, socially disadvantaged women with adverse pregnancy outcomes. The unlinked birth records (0.4%) had slightly higher proportions of nulliparous, older, Australian born women giving birth in private hospitals by caesarean section. Stillbirths had the highest rate of unlinked records (3-4%). Conclusions: This study shows that probabilistic linkage of perinatal records can achieve high, representative levels of complete linkage. Records for mother's that did not link to infant records and unlinked records had slightly different characteristics to fully linked records. However, these groups were small and unlikely to bias results and conclusions in a substantive way. Stillbirths present additional challenges to the linkage process due to lower rates of linkage for lower gestational ages, where most stillbirths occur. © 2012 Bentley et al.; licensee BioMed Central Ltd.


Merrifield A.,Center for Epidemiology and Evidence | Schindeler S.,Center for Epidemiology and Evidence | Jalaludin B.,Center for Research | Jalaludin B.,University of New South Wales | Smith W.,Environmental Health Branch
Environmental Health: A Global Access Science Source | Year: 2013

Background: During September 2009, a large dust storm was experienced in Sydney, New South Wales, Australia. Extremely high levels of particulate matter were recorded, with daily average levels of coarse matter (<10 μm) peaking over 11,000 μg/m3 and fine (<2.5 μm) over 1,600 μg/m3. We conducted an analysis to determine whether the dust storm was associated with increases in all-cause, cardiovascular, respiratory and asthma-related emergency department presentations and hospital admissions. Methods. We used distributed-lag Poisson generalized models to analyse the emergency department presentations and hospital admissions adjusted for pollutants, humidity, temperature and day of week and seasonal effects to obtain estimates of relative risks associated with the dust storm. Results: The dust storm period was associated with large increases in asthma emergency department visits (relative risk 1.23, 95% confidence interval 1.10-1.38, p < 0.01), and to a lesser extent, all emergency department visits (relative risk 1.04, 95% confidence interval 1.03-1.06, p < 0.01) and respiratory emergency department visits (relative risk 1.20, 95% confidence interval 1.15-1.26, p < 0.01). There was no significant increase in cardiovascular emergency department visits (p = 0.09) or hospital admissions for any reason. Age-specific analyses showed the dust storm was associated with increases in all-cause and respiratory emergency department visits in the ≥65 year age group; the ≤5 year group had higher risks of all-cause, respiratory and asthma-related emergency department presentations. Conclusions: We recommend public health measures, especially targeting asthmatics, should be implemented during future dust storm events. © 2013 Merrifield et al.; licensee BioMed Central Ltd.


Scandol J.P.,Center for Epidemiology and Evidence | Scandol J.P.,Falls and Injury Prevention Group | Toson B.,Falls and Injury Prevention Group | Close J.C.T.,Falls and Injury Prevention Group | Close J.C.T.,University of New South Wales
Injury | Year: 2013

Introduction: Dementia and fall-related hip fractures both contribute significantly to the burden of illness within elderly populations in Australia and elsewhere. The research presented here uses a large probabilistically linked dataset from NSW, Australia to estimate the prevalence of dementia within hip fracture patients and investigate the impact of dementia on hospitalisation length of stay (LOS) and survival. Method: The cases considered were NSW residents aged 65 years and above who experienced a fall related hip fracture between 1 July 2000 and 30 June 2009. The prevalence of dementia was calculated for the incident hip fracture using two methods to infer dementia status. Cox proportional hazards regression modelling was used to estimate the relative rate of discharge from a hospitalisation episode, and the relative mortality rate of hip fracture patients suffering dementia versus those who were cognitively intact. Additional covariates used in the models included sex, age group at admission, the Charlson Comorbidity Index and separation mode. Results: Of the 44,143 fall-related incident hip fracture cases considered, between 24% (observed diagnosis) to 29% (inferred diagnosis) of these people had dementia. The median LOS for patients with dementia was shorter than those without dementia, but there was a strong interaction with age. The rate of discharge from the fracture-related hospitalisation episode of the cases with dementia was 40% greater (95% CI 1.4-1.5) than the non-demented group. Similarly, the relative mortality rate of those with dementia was greater (2.4, 95% CI 2.3-2.6) than the non-demented group. Both Cox analyses indicated evidence for main effects of age at admission and comorbidity, as well as interaction effects between age group and dementia status. Conclusion: The use of linked datasets with tens of thousands of cases enables the calculation of precise estimates of various parameters. People with dementia constitute a significant proportion of the total population of elderly hip fracture patients in hospitals (up to 29%). Their mortality rate is greater than those without a diagnosis of dementia and their hospital length of stay is shorter, particularly if they are discharged to a residential aged care facility. © 2012 Elsevier Ltd.


Chau J.Y.,University of Sydney | Daley M.,Heart Foundation New South Wales | Dunn S.,Heart Foundation New South Wales | Srinivasan A.,Heart Foundation New South Wales | And 4 more authors.
International Journal of Behavioral Nutrition and Physical Activity | Year: 2014

Prolonged sitting time is detrimental for health. Individuals with desk-based occupations tend to sit a great deal and sit-stand workstations have been identified as a potential strategy to reduce sitting time. Hence, the objective of the current study was to examine the effects of using sit-stand workstations on office workers' sitting time at work and over the whole day.Methods: We conducted a randomized controlled trial pilot with crossover design and waiting list control in Sydney, Australia from September 2011 to July 2012 (n = 42; 86% female; mean age 38 ± 11 years). Participants used a sit-stand workstation for four weeks in the intervention condition. In the time-matched control condition, participants received nothing and crossed over to the intervention condition after four weeks. The primary outcomes, sitting, standing and walking time at work, were assessed before and after using the workstations with ActivPALs and self-report questionnaires. Secondary outcomes, domain-specific sitting over the whole day, were assessed by self-report. Linear mixed models estimated changes in outcomes adjusting for measurement time, study grouping and covariates.Results: Intervention participants significantly reduced objectively assessed time spent sitting at work by 73 min/workday (95% CI: -106,-39) and increased standing time at work by 65 min/workday (95% CI: 47, 83); these changes were significant relative to controls (p = 0.004 and p < 0.001, respectively). Total sitting time significantly declined in intervention participants (-80 min/workday; 95% CI: -155, -4).Conclusions: This study shows that introducing sit-stand workstations in the office can reduce desk-based workers' sitting time at work in the short term. Larger scale studies on more representative samples are needed to determine the public health impact of sit-stand workstations.Trial registration: ACTRN12612000072819. © 2014 Chau et al.; licensee BioMed Central Ltd.


Stewart J.,Center for Epidemiology and Evidence
New South Wales public health bulletin | Year: 2012

A 5-year strategic plan for Aboriginal health research and evaluation has been developed to support the NSW Ministry of Health in its efforts to create the evidence for what works in addressing the health disparity between Aboriginal and non-Aboriginal people. The plan has the following objectives: that all Aboriginal health policies and programs are evidence informed; that programs and strategies are rigorously evaluated and contribute to building the evidence for improving Aboriginal health outcomes; that new research evidence is generated for improving Aboriginal health outcomes; and that robust monitoring and accountability mechanisms in Aboriginal health are in place, with improved data quality. This paper describes the development of the NSW Ministry of Health's Aboriginal Health Research and Evaluation Strategic Plan 2011-15, including a review of the evidence and policy documents, facilitated planning sessions, and consultation with staff within the Population and Public Health Division of the Ministry.


Merrifield A.,Center for Epidemiology and Evidence
New South Wales public health bulletin | Year: 2012

Sample size calculations before conducting a health study or clinical trial are important to provide evidence that the proposed study is capable of detecting real associations between study factors. This review aims to clarify statistical issues related to the calculation of sample sizes and is illustrated with an example of a recent study design to improve health outcomes related to water and sewage in NSW Aboriginal communities. The effect of power, significance level and effect size on sample size are discussed. Calculations of sample sizes for individual-based studies are modified for more complex trial designs by multiplying individual-based estimates by an inflationary factor.


Ding D.,University of Sydney | Do A.,Center for Epidemiology and Evidence | Schmidt H.-M.,Center for Population Health | Bauman A.E.,University of Sydney
PLoS ONE | Year: 2015

Background Socioeconomic inequalities in health outcomes have increased over the past few decades in some countries. However, the trends in inequalities related to multiple health risk behaviours have been infrequently reported. In this study, we examined the trends in individual health risk behaviours and a summary lifestyle risk index in New South Wales, Australia, and whether the absolute and relative inequalities in risk behaviours by socioeconomic positions have changed over time. Methods Using data from the annual New South Wales Adult Population Health Survey during the period of 2002-2012, we examined four individual risk behaviours (smoking, higher than recommended alcohol consumption, insufficient fruit and vegetable intake, and insufficient physical activity) and a combined lifestyle risk indicator. Socioeconomic inequalities were assessed based on educational attainment and postal area-level index of relative socioeconomic disadvantage (IRSD), and were presented as prevalence difference for absolute inequalities and prevalence ratio for relative inequalities. Trend tests and survey logistic regression models examined whether the degree of absolute and relative inequalities between the most and least disadvantaged subgroups have changed over time. Results The prevalence of all individual risk behaviours and the summary lifestyle risk indicator declined from 2002 to 2012. Particularly, the prevalence of physical inactivity and smoking decreased from 52.6% and 22% in 2002 to 43.8% and 17.1% in 2012 (p for trend<0.001). However, a significant trend was observed for increasing absolute and relative inequalities in smoking, insufficient fruit and vegetable consumption, and the summary lifestyle risk indicator. Conclusions The overall improvement in health behaviours in New South Wales, Australia, co-occurred with a widening socioeconomic gap. © 2015 Ding et al.


Bennie J.A.,University of Sydney | Chau J.Y.,University of Sydney | van der Ploeg H.P.,University of Sydney | van der Ploeg H.P.,VU University Amsterdam | And 5 more authors.
International Journal of Behavioral Nutrition and Physical Activity | Year: 2013

Background: Prolonged sitting is an emerging health risk. However, multi-country comparative sitting data are sparse. This paper reports the prevalence and correlates of sitting time in 32 European countries.Methods: Data from the Eurobarometer 64.3 study were used, which included nationally representative samples (n = 304-1,102) from 32 European countries. Face-to-face interviews were conducted during November and December 2005. Usual weekday sitting time was assessed using the International Physical Activity Questionnaire (short-version). Sitting time was compared by country, age, gender, years of education, general health status, usual activity and physical activity. Multivariable-adjusted analyses assessed the odds of belonging to the highest sitting quartile.Results: Data were available for 27,637 adults aged 15-98 years. Overall, mean reported weekday sitting time was 309 min/day (SD 184 min/day). There was a broad geographical pattern and some of the lowest amounts of daily sitting were reported in southern (Malta and Portugal means 194-236 min/day) and eastern (Romania and Hungary means 191-276 min/day) European countries; and some of the highest amounts of daily sitting were reported in northern European countries (Germany, Benelux and Scandinavian countries; means 407-335 min/day). Multivariable-adjusted analyses showed adults with low physical activity levels (OR = 5.10, CI95 = 4.60-5.66), those with high sitting in their main daily activity (OR = 2.99, CI95 = 2.74-3.25), those with a bad/very bad general health state (OR = 1.87, CI95 = 1.63-2.15) and higher education levels (OR = 1.48, CI95 = 1.38-1.59) were more likely to be in the highest quartile of daily sitting time. Adults within Greece (OR = 2.91, CI95 = 2.51-3.36) and Netherlands (OR = 2.56, CI95 = 2.22-2.94) were most likely to be in the highest quartile. High-sit/low-active participants comprised 10.1% of the sample. Adults self-reporting bad/very bad general health state (OR = 4.74, CI95 = 3.97-5.65), those within high sitting in their main daily activities (OR = 2.87, CI95 = 2.52-3.26) and adults aged ≥65 years (OR = 1.53, CI95 = 1.19-1.96) and were more likely to be in the high-sit/low-active group.Conclusions: Weekday sitting time and its demographic correlates varied considerably across European countries, with adults in north-western European countries sitting the most. Sitting is prevalent across Europe and merits attention by preventive interventions. © 2013 Bennie et al.; licensee BioMed Central Ltd.

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