Dino Pisaniello

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.

Health impacts of workplace heat exposure: an epidemiological review.

With predicted increasing frequency and intensity of extremely hot weather due to changing climate, workplace heat exposure is presenting an increasing challenge to occupational health and safety. This article aims to review the characteristics of workplace heat exposure in selected relatively high risk occupations, to summarize findings from published studies, and ultimately to provide suggestions for workplace heat exposure reduction, adaptations, and further research directions. All published epidemiological studies in the field of health impacts of workplace heat exposure for the period of January 1997 to April 2012 were reviewed. Finally, 55 original articles were identified. Manual workers who are exposed to extreme heat or work in hot environments may be at risk of heat stress, especially those in low-middle income countries in tropical regions. At risk workers include farmers, construction workers, fire-fighters, miners, soldiers, and manufacturing workers working around process-generated heat. The potential impacts of workplace heat exposure are to some extent underestimated due to the underreporting of heat illnesses. More studies are needed to quantify the extent to which high-risk manual workers are physiologically and psychologically affected by or behaviourally adapt to workplace heat exposure exacerbated by climate change.

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.

WOOD DUST EXPOSURE DURING FURNITURE MANUFACTURE—RESULTS FROM AN AUSTRALIAN SURVEY AND CONSIDERATIONS FOR THRESHOLD LIMIT VALUE DEVELOPMENT

A survey of time-weighted average (TWA) personal inhalable dust exposures for woodworkers in 15 Australian furniture factories was undertaken. There was significant variation in the individual dust measurements with mean exposures of 3.2, 5.2, and 3.5 mg/m3 for wood machinists, cabinetmakers, and chair framemakers, respectively. Hardwoods, softwoods, and reconstituted woods are used in the industry, but only minor differences in mean exposures or particle size distributions were found for the broad categories. In addition, a modified British Medical Research Council respiratory questionnaire was used to obtain information about work-related symptoms and job activities. Compared with a control group, the woodworkers reported more eye, ear, and nasal problems, with the differences being statistically significant. However, among the woodworkers themselves, with the exception of several nasal symptoms, the prevalences of reported symptoms were poorly correlated with gravimetric measurements of personal dust exposure. The problem of selection bias in cross-sectional studies is discussed. For a mean TWA personal exposure of about 3 mg/m3, hardwood users were more likely to report nasal symptoms than users of reconstituted wood. The question of appropriate exposure standards for woods in general is addressed by reference to those important health effects, besides sino-nasal cancer, that have been investigated. Further exposure guidelines should be formulated for groups of woods that are known to cause a common health effect, such as nasal/respiratory sensitization.

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.

Association between high temperature and work-related injuries in Adelaide, South Australia, 2001–2010

Objectives (1) To investigate the association between temperature and work-related injuries and (2) to identify groups of workers at high risk of work-related injuries in hot environments in Adelaide, South Australia. Methods Workers’ compensation claims in Adelaide, South Australia for 2001–2010 were used. The relationship between temperature and daily injury claims was estimated using a generalised estimating equation model. A piecewise linear spline function was used to quantify the effect of temperature on injury claims below and above thresholds. Results Overall, a 1°C increase in maximum temperature between 14.2°C and 37.7°C was associated with a 0.2% increase in daily injury claims. Specifically, the incidence rate ratios (IRRs) for male workers and young workers aged ≤24 were (1.004, 95% CI 1.002 to 1.006) and (1.005, 95% CI 1.002 to 1.008), respectively. Significant associations were also found for labourers (IRR 1.005, 95% CI 1.001 to 1.010), intermediate production and transport workers (IRR 1.003, 95% CI 1.001 to 1.005) and tradespersons (IRR 1.002, 95% CI 1.001 to 1.005). Industries at risk were agriculture, forestry and fishing (IRR 1.007, 95% CI 1.001 to 1.013), construction (IRR 1.006, 95% CI 1.002 to 1.011), and electricity, gas and water (IRR 1.029, 95% CI 1.002 to 1.058). Conclusions There is a significant association between injury claims and temperature in Adelaide, South Australia, for certain industries and groups. Relevant adaptation and prevention measures are required at both policy and practice levels to address occupational exposure to high temperatures.

Perceptions of Heat-Susceptibility in Older Persons: Barriers to Adaptation

The increase in the frequency of very hot weather that is a predicted consequence of climate change poses an emerging threat to public health. Extreme heat can be harmful to the health of older persons who are known to be amongst the most vulnerable in the community. This study aimed to investigate factors influencing the ability of older persons to adapt to hot conditions, and barriers to adaptation. A qualitative study was conducted in Adelaide, Australia, involving focus groups and interviews with stakeholders including key personnel involved in aged care, community services, government sectors, emergency services and policy making. Findings revealed a broad range of factors that underpin the heat-susceptibility of the aged. These were categorized into four broad themes relating to: physiology and an age-related decline in health; socioeconomic factors, particularly those influencing air conditioning use; psychological issues including fears and anxieties about extreme heat; and adaptive strategies that could be identified as both enablers and barriers. As a consequence, the ability and willingness to undertake behavior change during heatwaves can therefore be affected in older persons. Additionally, understanding the control panels on modern air conditioners can present challenges for the aged. Improving heat-health knowledge and addressing the social and economic concerns of the older population will assist in minimizing heat-related morbidity and mortality in a warming climate.

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.

Stable lead isotope profiles in smelter and general urban communities: a comparison of environmental and blood measures

High-precision lead isotope ratios and lead concentrations have been compared statistically and graphically in women of child-bearing age (n = 77) from two smelter communities and one general urban community to evaluate the relative contributions to blood lead of tissue lead stores and lead from the contemporaneous environment (soil, floor dust, indoor airborne dust, water, food). Blood lead (PbB) contents were generally low (e.g. <10 μg dL−1). Statistically significant isotopic differences in blood and environmental samples were observed between the three cities although isotopic differences in blood for individual subjects living in close proximity (∼200 m radius) was as large as the differences within a city. No single environmental measure dominated the biological isotope profile and in many cases the low levels of blood lead meant that their isotopic profiles could be easily perturbed by relatively small changes of environmental exposure. Apportioning of sources using lead isotopes is possibly not feasible, nor cost effective, when blood lead levels are <5 μg dL−1. Interpretations based on statistical analyses of city-wide data do not give the same conclusions as when the houses are considered individually. Aggregating data from multiple subjects in a study such as this obscures potentially useful information. Most of the measures employed in this study, and many other similar studies, are markers of only short-to-medium integration of lead exposure. Serial sampling of blood and longer sampling times, especially for household variables, should provide more meaningful information.