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Many novel infectious diseases have been reported since 1940; most have been zoonoses originating from wildlife (1). Several novel zoonotic viruses, including Hendra virus, Australian bat lyssavirus, and Nipah virus, [...]

Background: This study investigates whether the association of job strain and insecurity with health differs by status. Methods: A cross-sectional study of 2,249 employed workers aged 40-44 years conducted in two regions in south-east Australia in 2000 used a self-completed questionnaire to collect data. Multivariate analyses were used to compare depression, anxiety, physical health and general practitioner (GP) visits over 12 months across categories of job strain and insecurity for three status groups (high, middle and low). Results: High job strain and job insecurity were independently associated with poor mental health, poor physical health and visits to the GP for all status groups when adjusted for confounders. High job strain was associated with depression (OR=2.46, 95% CI 1.96-3.07), anxiety (OR=2.56, 95% CI 2.05-3.20), lower mean physical health scores (-1.11, 95% CI -1.98- -0.23), and more visits to the GP (IRR=1.20, 95% CI 1.05-1.37). High job insecurity also showed significant associations with depression (OR=3.03, 95% CI 2.03-4.53), anxiety (OR=2.66, 95% CI 1.81-3.91), and GP visits (IRR=1.27, 95% CI 1.01-1.60). There were no significant differences by status in the associations of job strain and insecurity with outcomes. Conclusion: High-status workers were just as likely as low-status workers to be exposed to adverse work conditions and both status groups showed similar health effects. Implications: Exposure to insecure and high-strain jobs is likely to rise as economies and labour markets respond to globalisation and political change. High status may not protect employees from either exposure or impact, thus widening the population health consequences of adverse work conditions.

Objective: Data from Q fever pre-vaccination screening were analysed to determine the level of agreement between the two tests of immunity and between disease or vaccination history and immunity, trends in proportion of participants immune to Q fever, and the annual risk of infection. Method: Data from nearly 10,000 screening episodes between July 1988 and June 2001 on Victorian workers at high risk were assessed. Results: Most participants were male (86%) and employed in Victorian abattoirs (81%). Agreement between results of tests for immunity was 'fair' ([kappa]=0.52). Self-reported history of vaccination or infection was a poor predictor of immunity. The proportion of positive blood and skin tests increased with years of exposure to animals/meat, but decreased over the 13-year period with shorter exposures. Hence the percentage requiring vaccination increased from 50% in 1998 to 90% in 2001. The average annual risk of infection among abattoir workers was 45.0 per 1,000 (95% CI 42.3-47.6), and 62.6 per 1,000 (95% CI 57.5-67.7) over the first 10 years of exposure. Conclusions: This is the first Australian study to estimate the annual risk of Q fever infection in abattoir workers. The study confirmed previous findings of poor agreement between screening tests and predictive value of history of vaccination/ exposure. Up to 90% of new entrants in high-risk workplaces will be susceptible to Q fever and require vaccination. Implications: Systematic post-marketing surveillance is needed to monitor adverse events to the vaccine, duration of protection and possible reasons for vaccine failures.

The study conducted to determine the effects of antiretroviral (ARV) use and increase unprotected anal intercourse with casual partners (UAIC) in homosexual men on HIV incidence during 1995-2001 and to project HIV incidence depending on trends in ARV use and UAIC, is presented. Mathematical model suggests that widespread ARV treatment among homosexual men in Australia has some effect in decreasing HIV incidence between 1995-1998.

Deaths from sudden infant death syndrome (SIDS) could possibly be reduced substantially by avoiding certain risk factors. During a two-year period in New Zealand, of all babies who died of SIDS, 127 families provided additional information. This group was compared with statistics on 922 living babies. Risk of SIDS was associated with sleeping on the belly or side, maternal smoking, and combined maternal smoking and bed sharing. The previously seen decrease in SIDS deaths due to a decline in belly sleeping could be further reduced by eliminating these other risk factors., ABSTRACT. Objectives. To identify the risk factors for sudden infant death syndrome (SIDS) following a national campaign to prevent SIDS. Methods. For 2 years (October 1, 1991 through September 30, 1993) data were collected by community child health nurses on all infants born in New Zealand at initial contact and at 2 months. Results. There were 232 SIDS cases in the postneonatal age group (2.0/1000 live births) and these were compared with 1200 randomly selected control subjects. Information was available for 127 cases (54.7%) and 922 (76.8%) of controls. The previously identified modifiable risk factors were examined. The prevalence of prone sleeping position of the infant was very low (0.7% at initial contact and 3.0% at 2 months), but was still associated with an increased risk of SIDS. In addition, the side sleeping position was also found to have an increased risk of SIDS compared with the supine sleeping position (at 2 months: adjusted odds ratio (OR) = 6.57; 95% confidence interval (CI) = 1.71, 25.23). Maternal smoking was found to be the major risk factor for SIDS. Bed sharing was also associated with an increased risk of SIDS. There was an interaction between maternal smoking and bed sharing on the risk of SIDS. Compared with infants not exposed to either bed sharing or maternal smoking, the adjusted OR for infants of mothers who smoked was 5.01 (95% CI = 2.01, 12.46) for bed sharing at the initial contact and 5.02 (95% CI = 1.05, 24.05) for bed sharing at 2 months. In this study breastfeeding was not associated with a statistically significant reduction in the risk of SIDS. The other risk factors for SIDS identified were: unmarried mother, leaving school at a younger age, young mother, greater number of previous pregnancies, late attendance for antenatal care, smoking in pregnancy, male infant, Maori ethnicity, low birth weight, and shorter gestation. Conclusions. After adjustment for potential confounders, prone and side sleeping positions, maternal smoking, and the joint exposure to bed sharing and maternal smoking were associated with statistically significant increased risk of SIDS. A change from the side to the supine sleeping position could result in a substantial reduction in SIDS. Maternal smoking is common in New Zealand and with the reduction in the prevalence of prone sleeping position is now the major risk factor in this country. However, smoking behavior has been difficult to change. Bed sharing is also a major factor but appears only to be a risk to infants of mothers who smoke. Addressing bed sharing among mothers who smoke could reduce SIDS by at least one third. Breast-feeding did not appear to offer a statistically significant reduction in SIDS risk after adjustment of potential confounders, but as breastfeeding rates are comparatively good in New Zealand, this result should be interpreted with caution as the power of this study to detect a benefit is small. Pediatrics 1997;100:835-840; sudden infant death syndrome, prospective study, case-cohort study, risk factors, sleep position, maternal smoking, bed sharing, breastfeeding., ABBREVIATIONS. SIDS, sudden infant death syndrome; OR, odds ratio; PAR, population-attributable risk; CI, confidence interval; SD, standard deviation. Mortality from sudden infant death syndrome (SIDS, or cot death) dropped dramatically [...]

Abstract Background Vitamin D supplementation for fracture prevention is widespread despite conflicting interpretation of relevant randomised controlled trial (RCT) evidence. This study summarises quantitatively the current evidence from RCTs and observational studies regarding vitamin D, parathyroid hormone (PTH) and hip fracture risk. Methods We undertook separate meta-analyses of RCTs examining vitamin D supplementation and hip fracture, and observational studies of serum vitamin D status (25-hydroxyvitamin D (25(OH)D) level), PTH and hip fracture. Results from RCTs were combined using the reported hazard ratios/relative risks (RR). Results from case-control studies were combined using the ratio of 25(OH)D and PTH measurements of hip fracture cases compared with controls. Original published studies of vitamin D, PTH and hip fracture were identified through PubMed and Web of Science databases, searches of reference lists and forward citations of key papers. Results The seven eligible RCTs identified showed no significant difference in hip fracture risk in those randomised to cholecalciferol or ergocalciferol supplementation versus placebo/control (RR = 1.13[95%CI 0.98-1.29]; 801 cases), with no significant difference between trials of 21 (heterogeneity) = 51.02, p < 0.001) and significant heterogeneity was present overall (χ216 (heterogeneity) = 137.9, p < 0.001). Serum PTH levels in hip fracture cases did not differ significantly from controls, based on ten case-control studies with 905 cases (χ29 (heterogeneity) = 149.68, p < 0.001). Conclusions Neither higher nor lower dose vitamin D supplementation prevented hip fracture. Randomised and observational data on vitamin D and hip fracture appear to differ. The reason for this is unclear; one possible explanation is uncontrolled confounding in observational studies. Post-fracture PTH levels are unrelated to hip fracture risk.

Abstract Background There is little empirical evidence regarding the generalisability of relative risk estimates from studies which have relatively low response rates or are of limited representativeness. The aim of this study was to investigate variation in exposure-outcome relationships in studies of the same population with different response rates and designs by comparing estimates from the 45 and Up Study, a population-based cohort study (self-administered postal questionnaire, response rate 18%), and the New South Wales Population Health Survey (PHS) (computer-assisted telephone interview, response rate ~60%). Methods Logistic regression analysis of questionnaire data from 45 and Up Study participants (n = 101,812) and 2006/2007 PHS participants (n = 14,796) was used to calculate prevalence estimates and odds ratios (ORs) for comparable variables, adjusting for age, sex and remoteness. ORs were compared using Wald tests modelling each study separately, with and without sampling weights. Results Prevalence of some outcomes (smoking, private health insurance, diabetes, hypertension, asthma) varied between the two studies. For highly comparable questionnaire items, exposure-outcome relationship patterns were almost identical between the studies and ORs for eight of the ten relationships examined did not differ significantly. For questionnaire items that were only moderately comparable, the nature of the observed relationships did not differ materially between the two studies, although many ORs differed significantly. Conclusions These findings show that for a broad range of risk factors, two studies of the same population with varying response rate, sampling frame and mode of questionnaire administration yielded consistent estimates of exposure-outcome relationships. However, ORs varied between the studies where they did not use identical questionnaire items.

Abstract Background In Australia there is a socioeconomic gradient in morbidity and mortality favouring socioeconomically advantaged people, much of which is accounted for by ischaemic heart disease. This study examines if Australia's universal health care system, with its mixed public/private funding and delivery model, may actually perpetuate this inequity. We do this by quantifying and comparing socioeconomic inequalities in the receipt of coronary procedures in patients with acute myocardial infarction (AMI) and patients with angina. Methods Using linked hospital and mortality data, we followed patients admitted to Western Australian hospitals with a first admission for AMI (n = 5539) or angina (n = 7401) in 2001-2003. An outcome event was the receipt, within a year, of a coronary procedure—angiography, angioplasty and/or coronary artery bypass surgery (CABG). Socioeconomic status was assigned to each individual using an area-based measure, the SEIFA Index of Disadvantage. Multivariable proportional hazards regression was used to model the association between socioeconomic status and procedure rates, allowing for censoring and adjustment of multiple covariates. Mediating models examined the effect of private health insurance. Results In the AMI patient cohort, socioeconomic gradients were not evident except that disadvantaged women were more likely than advantaged women to undergo CABG. In contrast, in the angina patient group there were clear socioeconomic gradients for all procedures, favouring more advantaged patients. Compared with patients in the most disadvantaged quintile of socioeconomic status, patients in the least disadvantaged quintile were 11% (1-21%) more likely to receive angiography, 52% (29-80%) more likely to undergo angioplasty and 30% (3-55%) more likely to undergo CABG. Private health insurance explained some of the socioeconomic variation in rates. Conclusions Australia's universal health care system does not guarantee equity in the receipt of high technology health care for patients with ischaemic heart disease. While such a system might ensure equity for patients with AMI, where guidelines for treatment are relatively well established, this is not the case for angina patients, where health care may be less urgent and more discretionary.