Monika Nitschke

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.

Health effects of daily indoor nitrogen dioxide exposure in people with asthma

Household gas appliances produce nitrogen dioxide (NO2), which may be associated with an increase in symptoms in asthmatics. The relationship between indoor NO2 exposure, and respiratory symptoms in people with asthma was evaluated. Self-reported asthmatics (n=125) wore lapel badges that measured NO2 daily over 6 weeks at home. Outdoor pollutants, spores and meteorological parameters were measured daily, in addition to smoking status and demographic factors. Seven asthma symptoms were recorded in diaries, for analysis by same day and also with 1 day lag exposures, using a generalized estimating equation. Significant interactions were demonstrated between NO2 at age < or =14 yrs, with respect to the symptoms of chest tightness on the same day (odds ratio (OR): 1.29, 95% confidence interval (CI): 1.16-1.43) and with a 1 day lag (OR: 1.29, 95% CI: 1.14-1.46), breathlessness on exertion with a 1 day lag (OR: 1.13, 95% CI: 1.00-1.28), daytime asthma attacks on the same day (OR: 1.13, 95% CI: 1.02-1.26) night asthma attacks on the same day (OR: 1.16, 95% CI:1.03-1.30) and with a 1 day lag (OR: 1.15, 95% CI; 1.03-1.29) after adjustment for potential confounders. A significant interaction between NO2 and age 35-49 yrs was demonstrated for coughs with a 1 day lag (OR: 1.15, 95% CI: 1.01-1.31). Daily personal exposures to NO2 are associated with asthmatic symptoms in children.

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.

Traffic-related air pollution and health co-benefits of alternative transport in Adelaide, South Australia.

BACKGROUND Motor vehicle emissions contribute nearly a quarter of the worlds energy-related greenhouse gases and cause non-negligible air pollution, primarily in urban areas. Changing peoples travel behaviour towards alternative transport is an efficient approach to mitigate harmful environmental impacts caused by a large number of vehicles. Such a strategy also provides an opportunity to gain health co-benefits of improved air quality and enhanced physical activities. This study aimed at quantifying co-benefit effects of alternative transport use in Adelaide, South Australia. METHOD We made projections for a business-as-usual scenario for 2030 with alternative transport scenarios. Separate models including air pollution models and comparative risk assessment health models were developed to link alternative transport scenarios with possible environmental and health benefits. RESULTS In the study region with an estimated population of 1.4 million in 2030, by shifting 40% of vehicle kilometres travelled (VKT) by passenger vehicles to alternative transport, annual average urban PM2.5 would decline by approximately 0.4μg/m(3) compared to business-as-usual, resulting in net health benefits of an estimated 13deaths/year prevented and 118 disability-adjusted life years (DALYs) prevented per year due to improved air quality. Further health benefits would be obtained from improved physical fitness through active transport (508deaths/year prevented, 6569DALYs/year prevented), and changes in traffic injuries (21 deaths and, 960 DALYs prevented). CONCLUSION Although uncertainties remain, our findings suggest that significant environmental and health benefits are possible if alternative transport replaces even a relatively small portion of car trips. The results may provide assistance to various government organisations and relevant service providers and promote collaboration in policy-making, city planning and infrastructure establishment.

The impact of summer temperatures and heatwaves on mortality and morbidity in Perth, Australia 1994–2008

Climate change projections have drawn attention to the risks of extreme heat and the importance of public health interventions to minimise the impact. The city of Perth, Western Australia, frequently experiences hot summer conditions, with recent summers showing above average temperatures. Daily maximum and minimum temperatures, mortality, emergency department (ED) presentations and hospital admissions data were acquired for Perth for the period 1994 to 2008. Using an observed/expected analysis, the temperature thresholds for mortality were estimated at 34-36°C (maximum) and 20°C (minimum). Generalised estimating equations (GEEs) were used to estimate the percentage increase in mortality and morbidity outcomes with a 10°C increment in temperature, with adjustment for air pollutants. Effect estimates are reported as incidence rate ratios (IRRs). The health impact of heatwave days (three or more days of ≥35°C) was also investigated. A 9.8% increase in daily mortality (IRR 1.098; 95%CI: 1.007-1.196) was associated with a 10°C increase in maximum temperature above threshold. Total ED presentations increased by 4.4% (IRR 1.044; 95%CI: 1.033-1.054) and renal-related ED presentations by 10.2% (IRR 1.102; 95%CI: 1.071-1.135) per 10°C increase in maximum temperature. Heatwave days were associated with increases in daily mortality and ED presentations, while total hospital admissions were decreased on heatwave days. Public health interventions will be increasingly important to minimise the adverse health impacts of hot weather in Perth, particularly if the recent trend of rising average temperatures and more hot days continues as projected.

A cohort study of indoor nitrogen dioxide and house dust mite exposure in asthmatic children

Objective: The purpose of this study was to investigate dose–response relationships between asthma symptoms and indoor nitrogen dioxide (NO2) and house dust mite allergen (HDM) in children. Methods: Asthmatic children from 18 primary schools in Adelaide, Australia, kept a daily symptoms diary over 12 weeks. Home and classroom NO2 levels were measured repeatedly in winter 2000. HDM levels were obtained from beds. Lung function tests were performed at the beginning and at the end of the study period. Results: Data on exposure and respiratory outcomes were gathered for 174 children. For school exposure, the estimated relative symptom rate (RR) for a 10-ppb increase in NO2 for difficulty breathing during the day was 1.09 (95% confidence interval [CI] = 1.03–1.15), at night 1.11 (95% CI = 1.05–1.18), and for chest tightness at night 1.12 (95% CI = 1.07–1.17). Significant symptom rate increases were also found for kitchen NO2 exposure. This was supported by a negative dose–response relationship between percentage predicted forced expiratory volume in 1 second and NO2 (−0.39%; 95% CI = −0.76 to −0.02) for kitchen exposure. Significant threshold effects using a 10-&mgr;g/g cutoff point for HDM exposure were established in the sensitized children for nighttime wheeze (RR = 3.62, 95% CI = 1.49–8.77), daytime cough (RR = 1.64, 95% CI = 1.14–2.36), and daytime asthma attack (RR = 1.95, 95% CI = 1.06–3.60). Conclusion: This study has established reliable risk estimates for exacerbations of asthma symptoms in children based on dose–response investigations of indoor NO2 and HDM.

Vulnerability to extreme heat and climate change: is ethnicity a factor?

Background With a warming climate, it is important to identify sub-populations at risk of harm during extreme heat. Several international studies have reported that individuals from ethnic minorities are at increased risk of heat-related illness, for reasons that are not often discussed. Objective The aim of this article is to investigate the underpinning reasons as to why ethnicity may be associated with susceptibility to extreme heat, and how this may be relevant to Australias population. Design Drawing upon literary sources, the authors provide commentary on this important, yet poorly understood area of heat research. Results Social and economic disparities, living conditions, language barriers, and occupational exposure are among the many factors contributing to heat-susceptibility among minority ethnic groups in the United States. However, there is a knowledge gap about socio-cultural influences on vulnerability in other countries. Conclusion More research needs to be undertaken to determine the effects of heat on tourists, migrants, and refugees who are confronted with a different climatic environment. Thorough epidemiological investigations of the association between ethnicity and heat-related health outcomes are required, and this could be assisted with better reporting of nationality data in health statistics. Climate change adaptation strategies in Australia and elsewhere need to be ethnically inclusive and cognisant of an upward trend in the proportion of the population who are migrants and refugees.Background With a warming climate, it is important to identify sub-populations at risk of harm during extreme heat. Several international studies have reported that individuals from ethnic minorities are at increased risk of heat-related illness, for reasons that are not often discussed. Objective The aim of this article is to investigate the underpinning reasons as to why ethnicity may be associated with susceptibility to extreme heat, and how this may be relevant to Australias population. Design Drawing upon literary sources, the authors provide commentary on this important, yet poorly understood area of heat research. Results Social and economic disparities, living conditions, language barriers, and occupational exposure are among the many factors contributing to heat-susceptibility among minority ethnic groups in the United States. However, there is a knowledge gap about socio-cultural influences on vulnerability in other countries. Conclusion More research needs to be undertaken to determine the effects of heat on tourists, migrants, and refugees who are confronted with a different climatic environment. Thorough epidemiological investigations of the association between ethnicity and heat-related health outcomes are required, and this could be assisted with better reporting of nationality data in health statistics. Climate change adaptation strategies in Australia and elsewhere need to be ethnically inclusive and cognisant of an upward trend in the proportion of the population who are migrants and refugees.

Particulate air pollution and cardiorespiratory hospital admissions in a temperate Australian city: A case-crossover analysis.

BACKGROUND Although ambient air pollution exposure has been linked with poor health in many parts of the world, no previous study has investigated the effect on morbidity in the city of Adelaide, South Australia. OBJECTIVE To explore the association between particulate matter (PM) and hospitalisations, including respiratory and cardiovascular admissions in Adelaide, South Australia. METHODS For the study period September 2001 to October 2007, daily counts of all-cause, cardiovascular and respiratory hospital admissions were collected, as well as daily air quality data including concentrations of particulates, ozone and nitrogen dioxide. Visibility codes for present weather conditions identified days when airborne dust or smoke was observed. The associations between PM and hospitalisations were estimated using time-stratified case-crossover analyses controlling for covariates including temperature, relative humidity, other pollutants, day of the week and public holidays. RESULTS Mean PM(10) concentrations were higher in the warm season, whereas PM(2.5) concentrations were higher in the cool season. Hospital admissions were associated with PM(10) in the cool season and with PM(2.5) in both seasons. No significant effect of PM on all-age respiratory admissions was detected, however cardiovascular admissions were associated with both PM(2.5) and PM(10) in the cool season with the highest effects for PM(2.5) (4.48%, 95% CI: 0.74%, 8.36% increase per 10μg/m(3) increase in PM(2.5)). CONCLUSION These findings suggest that despite the citys relatively low levels of air pollution, PM concentrations are associated with increases in morbidity in Adelaide. Further studies are needed to investigate the sources of PM which may be contributing to the higher cool season effects.

Environmental exposure to carcinogens causing lung cancer: Epidemiological evidence from the medical literature

Objective:  In 2000 there were 1.1 million lung or bronchial cancer deaths worldwide, with relatively limited evidence of causation other than for smoking. We aimed to search and appraise the literature regarding evidence for a causal relationship between air pollution and lung cancer according to the 10 Bradford Hill criteria for causality.