Graeme Tucker

The Effect of Heat Waves on Mental Health in a Temperate Australian City

Objective The goal of this study was to identify mental, behavioral, and cognitive disorders that may be triggered or exacerbated during heat waves, predisposing individuals to heat-related morbidity and mortality. Design Using health outcome data from Adelaide, South Australia, for 1993–2006, we estimated the effect of heat waves on hospital admissions and mortalities attributed to mental, behavioral, and cognitive disorders. We analyzed data using Poisson regression accounting for overdispersion and controlling for season and long-term trend, and we performed threshold analysis using hockey stick regression. Results Above a threshold of 26.7°C, we observed a positive association between ambient temperature and hospital admissions for mental and behavioral disorders. Compared with non–heat-wave periods, hospital admissions increased by 7.3% during heat waves. Specific illnesses for which admissions increased included organic illnesses, including symptomatic mental disorders; dementia; mood (affective) disorders; neurotic, stress related, and somatoform disorders; disorders of psychological development; and senility. Mortalities attributed to mental and behavioral disorders increased during heat waves in the 65- to 74-year age group and in persons with schizophrenia, schizotypal, and delusional disorders. Dementia deaths increased in those up to 65 years of age. Conclusion Our results suggest that episodes of extreme heat pose a salient risk to the health and well-being of the mentally ill. Relevance to Clinical or Professional Practice: Improvements in the management and care of the mentally ill need to be addressed to avoid an increase in psychiatric morbidity and mortality as heat waves become more frequent.

Impact of two recent extreme heat episodes on morbidity and mortality in Adelaide, South Australia: a case-series analysis

BackgroundExtreme heatwaves occurred in Adelaide, South Australia, in the summers of 2008 and 2009. Both heatwaves were unique in terms of their duration (15 days and 13 days respectively), and the 2009 heatwave was also remarkable in its intensity with a maximum temperature reaching 45.7°C. It is of interest to compare the health impacts of these two unprecedented heatwaves with those of previous heatwaves in Adelaide.MethodsUsing case-series analysis, daily morbidity and mortality rates during heatwaves (≥35°C for three or more days) occurring in 2008 and 2009 and previous heatwaves occurring between 1993 and 2008 were compared with rates during all non-heatwave days (1 October to 31 March). Incidence rate ratios (IRRs) were established for ambulance call-outs, hospital admissions, emergency department presentations and mortality. Dose response effects of heatwave duration and intensity were examined.ResultsAmbulance call-outs during the extreme 2008 and 2009 events were increased by 10% and 16% respectively compared to 4.4% during previous heatwaves. Overall increases in hospital and emergency settings were marginal, except for emergency department presentations in 2008, but increases in specific health categories were observed. Renal morbidity in the elderly was increased during both heatwaves. During the 2009 heatwave, direct heat-related admissions increased up to 14-fold compared to a three-fold increase seen during the 2008 event and during previous heatwaves. In 2009, marked increases in ischaemic heart disease were seen in the 15-64 year age group. Only the 2009 heatwave was associated with considerable increases in total mortality that particularly affected the 15-64 year age group (1.37; 95% CI, 1.09, 1.71), while older age groups were unaffected. Significant dose-response relationships were observed for heatwave duration (ambulance, hospital and emergency setting) and intensity (ambulance and mortality).ConclusionsWhile only incremental increases in morbidity and mortality above previous findings occurred in 2008, health impacts of the 2009 heatwave stand out. These findings send a signal that the intense and long 2009 heatwave may have exceeded the capacity of the population to cope. It is important that risk factors contributing to the adverse health outcomes are investigated to further improve preventive strategies.

Risks of adverse outcomes in the next birth after a first cesarean delivery.

OBJECTIVE: To estimate the risks of cesarean first birth, compared with vaginal first birth, for adverse obstetric and perinatal outcomes in the second birth. METHODS: Population-based retrospective cohort study of all singleton, second births in the South Australian perinatal data collection 1998 to 2003 comparing outcomes for 8,725 women who underwent a cesarean delivery for their first birth with 27,313 women who underwent a vaginal first birth. Predictor variables include age, indigenous status, smoking, pregnancy interval, medical and obstetric complications, gestation, patient type, hospital category, and history of ectopic pregnancy, miscarriage, stillbirth or termination of pregnancy. RESULTS: The cesarean delivery cohort had increased risks for malpresentation (odds ratio [OR] 1.84, 95% confidence interval [CI] 1.65–2.06), placenta previa (OR 1.66, 95% CI 1.30–2.11), antepartum hemorrhage (OR 1.23, 95% CI 1.08–1.41), placenta accreta (OR 18.79, 95% CI 2.28–864.6), prolonged labor (OR 5.89, 95% CI 3.91–8.89), emergency cesarean (relative risk 9.37, 95% CI 8.98–9.76) and uterine rupture (OR 84.42, 95% CI 14.64-infinity), preterm birth (OR 1.17, 95% CI 1.04–1.31), low birth weight (OR 1.30, 95% CI 1.14–1.48), small for gestational age (OR 1.12, 95% CI 1.02–1.23), stillbirth (OR 1.56, 95% CI 1.04–2.32), and unexplained stillbirth (OR 2.34, 95% CI 1.26–4.37). The range of the number of primary cesarean deliveries needed to harm included 134 for one additional preterm birth, up to 1,536 for one additional placenta accreta. CONCLUSION: Cesarean delivery is associated with increased risks for adverse obstetric and perinatal outcomes in the subsequent birth. However, some risks may be due to confounding factors related to the indication for the first cesarean. LEVEL OF EVIDENCE: II

Heat and health in Adelaide, South Australia: Assessment of heat thresholds and temperature relationships

BACKGROUND Climate change projections have highlighted the need for public health planning for extreme heat. In Adelaide, South Australia, hot weather is characteristic of summer and heatwaves can have a significant health burden. This study examines the heat thresholds and temperature relationships for mortality and morbidity outcomes in Adelaide. METHODS Daily maximum and minimum temperatures, daily mortality, ambulance call-outs, emergency department (ED) presentations and hospital admissions were obtained for Adelaide, between 1993 and 2009. Heat thresholds for health outcomes were estimated using an observed/expected analysis. Generalized estimating equations were used to estimate the percentage increase in mortality and morbidity outcomes above the threshold temperatures, with adjustment for the effects of ozone (O(3)) and particulate matter<10 μm in mass median aerodynamic diameter (PM(10)). Effect estimates are reported as incidence rate ratios (IRRs). RESULTS Heat-related mortality and morbidity become apparent above maximum and minimum temperature thresholds of 30 °C and 16 °C for mortality; 26 °C and 18 °C for ambulance call-outs; and 34 °C and 22 °C for heat-related ED presentations. Most health outcomes showed a positive relationship with daily temperatures over thresholds. When adjusted for air pollutants, a 10 °C increase in maximum temperature was associated with a 4.9% increase in daily ambulance call-outs (IRR 1.049; 95% CI 1.027-1.072), and a 3.4% increase in mental health related hospital admissions (IRR 1.034; 95% CI 1.009-1.059) for the all-age population. Heat-related ED presentations increased over 6-fold per 10 °C increase in maximum temperature. Daily temperatures were also associated with all-cause and mental health related ED presentations. Associations between temperature over thresholds and daily mortality and renal hospital admissions were not significant when adjusted for ozone and PM(10); however at extreme temperatures mortality increased significantly with increasing heat duration. CONCLUSIONS Heat-attributable mortality and morbidity are associated with elevated summer temperatures in Adelaide, particularly ambulance call-outs, mental health and heat-related illness.

Previous abortion and risk of pre-term birth: a population study.

Objective. This population study was undertaken to determine whether previous abortion is an independent risk factor for pre-term birth and to calculate population-attributable risks for risk factors. Methods. All South Australian first singleton births in 1998–2003 (n = 42 269) were included in a multivariable logistic regression analysis, comparing pre-term births with term births. Results. Risk factors for pre-term birth were found to be: being indigenous, single, a smoker [adjusted odds ratio (AOR) 1.28, 95% confidence interval 1.17–1.41], age 40 years or older, reproductive technology assistance, threatened miscarriage, antepartum haemorrhage, urinary tract infection, pregnancy hypertension and suspected intra-uterine growth restriction. A previous spontaneous abortion was of borderline statistical significance, whereas a previous induced abortion (AOR 1.25, 1.13–1.40) was an independent risk factor. A dose-response relationship was found with increasing number of previous spontaneous or induced abortions. Population-attributable risks were highest for pregnancy hypertension (12.4%) and antepartum haemorrhage (9.2%). Smoking and previous induced abortion had risks of 4.7% and 2.7%, respectively. Among indigenous women, 51% of whom smoked, 16.4% of pre-term birth could be attributed to smoking. Conclusions. A previous induced abortion and smoking during pregnancy (particularly among indigenous women) are preventable risk factors for pre-term birth. Their population-attributable risks are likely to be under-estimates from under-reporting.

Effects of area deprivation on health risks and outcomes: a multilevel, cross-sectional, Australian population study

Objectives:Our aim was to examine the effect of local area socio-economic disadvantage after accounting for individual socio-economic status (SES), and to determine if these differ between various health and risk factor variables.Methods:The North West Adelaide Health Study (NWAHS) is a biomedical representative population study of adults. The Index of Relative Socio-Economic Disadvantage (IRSD), produced from the Australian Bureau of Statistics (ABS) Census data at the level of Collector Districts (200 dwellings) was used as an indicator of local area disadvantage. Multi-level modeling techniques examined the effects of IRSD level on a variety of health outcomes and risk factors, after accounting for individual socio-economic factors.Results:Significant, independent associations were seen between IRSD and obesity, smoking, and health-related quality of life, with 5 % to 7.2 % of the variance located at the neighborhood level. No independent associations were seen between IRSD and estimated cardiovascular disease risk, diabetes, physical activity, or at-risk alcohol use.Conclusions:Aggregated area-level characteristics make modest, but significant independent contributions to smoking, obesity and quality of life, but not for other health outcomes.

Pregnancy outcomes for nulliparous women of advanced maternal age in South Australia, 1998–2008

Child bearing in the later reproductive years has become increasingly common in Australia with potential implications for clinical practice.

Shift to earlier stage at diagnosis as a consequence of the National Bowel Cancer Screening Program

Objective: To assess the impact of the National Bowel Cancer Screening Program (NBCSP) in South Australia.

New Australian population scoring coefficients for the old version of the SF-36 and SF-12 health status questionnaires

PurposeTo compare the relationship of the eight SF-36 v1 subscale scores to the summary scores of the PCS and MCS derived from two different scoring algorithms: one based on the original scoring method (Ware, Kosinski and Keller, SF-36 physical and mental health summary scales: a users manual. The Health Institute, New England Medical Centre, Boston, MA, 1994); and the other based on scoring algorithms that use parameters derived from structural equation modelling. Further, to provide SF-12 scoring algorithms similarly based on structural equation modelling.MethodsThe Australian Bureau of Statistics 1995 Australian National Health Survey dataset was used as the basis for the production of coefficients. There were 18,141 observations with no missing data for all eight SF-36 subscales following imputation of data items, and 17,479 observations with no missing data for the SF-12 data items. Data were analysed in LISREL V8.71. Structural equation models were fit to the data in confirmatory factor analyses producing weighted least squares estimates, which overcame anomalies found in the traditional orthogonal scoring methods.ResultsModels with acceptable fits to the hypothesised factor structure were produced, generating factor score weighting coefficients for use with the SF-36 and SF-12 data items, to produce PCS and MCS summary scores consistent with their underlying subscale scores.ConclusionsThe coefficients generated will score the SF-36 summary PCS and MCS in a manner consistent with their subscales. Previous Australian studies using version 1 of SF-36 or SF-12 can re-score their summary scores using these coefficients.

Functional health literacy mediates the relationship between socio-economic status, perceptions and lifestyle behaviors related to cancer risk in an Australian population

OBJECTIVE To determine if functional health literacy (FHL) mediates the relationship between socio-economic status, and perception of the risk of lifestyle behaviors for cancer. METHODS Cross-sectional, random population survey, 2824 people aged ≥15 years, September-October 2008, included newest vital sign measure of FHL. RESULTS Less than adequate FHL occurred in 45.1%. People who perceived behavioral factors (smoking, diet, obesity, alcohol, physical activity) to be not important, or did not know if they were important cancer risks, were more likely to have inadequate FHL. In a logistic regression model adjusted for age, gender, education, income, occupation, country of birth and area of residence, inadequate FHL was associated with 2-3 (OR=1.9; 95% CI: 1.2-3.0) and 4 or more self-reported lifestyle risk factors (OR=2.8; 95% CI: 1.6-5.0). In a structural equation model of the relationship of socio-economic status, perceptions of risk and behaviors there was significant mediation effect of FHL on the path from SES to health perceptions, estimated 29.4% of the total effect. CONCLUSION A specific focus on the literacy demands made on individuals from health promotion and materials with a view to improving health communication is indicated. PRACTICE IMPLICATIONS Health literacy is important for health promotion.