Elderly men may benefit from vitamin D

Vitamin D deficiency is associated with a myriad of musculoskeletal disorders in the elderly, including osteoporosis, reduced muscle function, falls and fractures. Recent scientific trials, conducted mostly in elderly or institutionalized women, indicate that supplementation with at least 800 IU/d of vitamin D3 or a dose required to raise serum 25(OH) D levels to at least 75 nmol/L, and approximately 1200 mg/d of calcium is most effective for improving many of these musculoskeletal and functional performance measures. While further targeted research is still needed in elderly men, vitamin D supplementation should be considered as a safe and low cost strategy to optimize musculoskeletal health and function in both elderly men and women.<br /

Health effects of bushfire smoke exposure

Bushfires (wildfires) are becoming more frequent and widespread due to the warming climate. The rate of prescribed (fuel reduction) burning has also increased to reduce the intensity of future bushfires. Smoke from bushfires can disperse widely and substantially diminish air quality and is therefore of public health concern. The most important risk related measure of smoke is fine particulate matter (PM2.5 aerodynamic diameter <2.5µm). These particulates are significantly elevated during bushfire smoke episodes and could affect large populations away from the fire source. While there has been substantial research into the impacts of ambient particulate pollution on health outcomes, there has been limited research into the impacts of bushfire smoke, despite the higher exposure levels involved. This thesis aimed to examine the health impacts of bushfire smoke exposure. In particular the thesis investigated the impact of bushfire fine particulate matter exposure (PM2.5) on cardiovascular and respiratory health effects during the Victorian 2006-2007 bushfires. Furthermore, the thesis explored the impact of smoke from prescribed burning on air quality and the potential effects on health. A systematic review was conducted to identify and evaluate studies examining the impact of bushfire particulate matter (PM) on cardiorespiratory morbidity and mortality. The review indicated consistent and positive associations of PM from bushfire smoke with respiratory morbidity and all-cause mortality, and inconsistent associations with cardiovascular morbidity and cause specific mortality. The coarser particulate matter (PM10 aerodynamic diameter <10µm) was most commonly measured, with few studies investigating the effects of bushfire PM2.5. Ground based air quality monitors were a common form of PM measurement in a majority of studies. However, monitored data only provides information from areas surrounding the monitors and therefore cannot adequately represent the bushfire smoke impacts in areas that lack monitoring facilities such as rural/regional areas. This lack of spatially resolved air quality data was a limitation in most studies and an important reason for uncertainties in the health outcomes during bushfire smoke episodes. In order to address the knowledge gaps highlighted in the systematic review, the thesis investigated the association between bushfire PM2.5 exposure and cardiovascular and respiratory health outcomes using modelled air quality data covering a large geographical area. A time stratified case cross-over study investigated associations between daily average PM2.5 concentrations and cardiovascular and respiratory health endpoints during the 2006-2007 Victorian bushfires. The study utilised fine spatially resolved modelled estimates of bushfire PM2.5 data from a blended model (CSIRO’s air pollution model coupled with a chemical transport model). The highly sophisticated modelling technique enabled projections of air quality data from wider geographical areas including areas heavily impacted by bushfire smoke (rural/regional areas). Health data were obtained from comprehensive health based administrative registries. The cardiovascular and respiratory health outcomes examined were out of hospital cardiac arrest, ischaemic heart disease (IHD), acute myocardial infarction, angina, asthma and chronic obstructive pulmonary disease. Conditional logistic regression analysis was conducted controlling for temperature and relative humidity A significant positive association was observed between bushfire PM2.5 exposure and cardiovascular and respiratory health endpoints. An increase in risk was observed for out of hospital cardiac arrests, IHD related hospital admissions and emergency department (ED) visits, and asthma related ED visits. In addition, older adults showed a strong association with cardiorespiratory health outcomes. Men showed a positive association for out of hospital cardiac arrests and women a positive association with hospitalisation for IHD and ED presentations for asthma during the bushfire period. The thesis also explored key issues relating to pollution events during prescribed burning and the potential impacts on human health. The findings from the studies that investigated the impact of smoke from prescribed burning on air quality showed increased PM2.5 concentrations during burning episodes. The annual occurrence of prescribed burning and poor air quality observed during these events need to be investigated in the context of growing evidence of adverse health effects due to bushfire PM exposure. The thesis contributes to this important area of debate. The knowledge and evidence from this thesis will inform policy and practice and help build capacity in the understanding and management of adverse health effects during bushfire smoke events

Fine particulate matter (PM < inf > 2.5 < /inf > ) exposure during a prolonged wildfire period and emergency department visits for asthma

Background and objective: The 2006–2007 wildfire period was one of the most extensive and long lasting fires in Australian history with high levels of fine particulate matter (PM2.5). Large populations were exposed to smoke for over 2 months. The study aimed to investigate the association between wildfire-related PM2.5 exposure and emergency department (ED) visits for asthma. Methods: A time-stratified case-crossover design was used to investigate associations between daily average PM2.5and ED attendances for asthma from December 2006 to January 2007. ED data were obtained from the Victorian Emergency Minimum Dataset. Smoke dispersion during the wildfire event was modelled using a validated chemical transport model. Exposure data (daily average PM2.5, temperature and relative humidity) were modelled for the study period. Various lag periods were investigated. Results: There were 2047 ED attendances for asthma during the study period. After adjusting for temperature and relative humidity, an interquartile range increase in PM2.5 levels of 8.6 μg/m3 was associated with an increase in ED attendances for asthma by 1.96% (95%CI: 0.02, 3.94) on the day of exposure. Lag periods up to 2 days prior did not show any association. A strong association was observed among women 20 years and older (5.08% 95%CI: 1.76, 8.51). Conclusions: Wildfire-related PM2.5 was associated with increased risk of ED attendance for asthma during the wildfire event. It is important to understand the role of wildfire PM2.5 as a trigger for asthma presentations

Health effects of smoke from planned burns: a study protocol

Abstract Background Large populations are exposed to smoke from bushfires and planned burns. Studies investigating the association between bushfire smoke and health have typically used hospital or ambulance data and been done retrospectively on large populations. The present study is designed to prospectively assess the association between individual level health outcomes and exposure to smoke from planned burns. Methods/design A prospective cohort study will be conducted during a planned burn season in three locations in Victoria (Australia) involving 50 adult participants who undergo three rounds of cardiorespiratory medical tests, including measurements for lung inflammation, endothelial function, heart rate variability and markers of inflammation. In addition daily symptoms and twice daily lung function are recorded. Outdoor particulate air pollution is continuously measured during the study period in these locations. The data will be analysed using mixed effect models adjusting for confounders. Discussion Planned burns depend on weather conditions and dryness of ‘fuels’ (i.e. forest). It is potentially possible that no favourable conditions occur during the study period. To reduce the risk of this occurring, three separate locations have been identified as having a high likelihood of planned burn smoke exposure during the study period, with the full study being rolled out in two of these three locations. A limitation of this study is exposure misclassification as outdoor measurements will be conducted as a measure for personal exposures. However this misclassification will be reduced as participants are only eligible if they live in close proximity to the monitors

Impact of fine particulate matter (PM < inf > 2.5 < /inf > ) exposure during wildfires on cardiovascular health outcomes

Background: Epidemiological studies investigating the role of fine particulate matter (PM2.5; aerodynamic diameter < 2.5 μm) in triggering acute coronary events, including out‐of‐hospital cardiac arrests and ischemic heart disease (IHD), during wildfires have been inconclusive. Methods and Results: We examined the associations of out‐of‐hospital cardiac arrests, IHD, acute myocardial infarction, and angina (hospital admissions and emergency department attendance) with PM2.5 concentrations during the 2006–2007 wildfires in Victoria, Australia, using a time‐stratified case‐crossover study design. Health data were obtained from comprehensive health‐based administrative registries for the study period (December 2006 to January 2007). Modeled and validated air exposure data from wildfire smoke emissions (daily average PM2.5, temperature, relative humidity) were also estimated for this period. There were 457 out‐of‐hospital cardiac arrests, 2106 emergency department visits, and 3274 hospital admissions for IHD. After adjusting for temperature and relative humidity, an increase in interquartile range of 9.04 μg/m3 in PM2.5 over 2 days moving average (lag 0‐1) was associated with a 6.98% (95% CI 1.03% to 13.29%) increase in risk of out‐of‐hospital cardiac arrests, with strong association shown by men (9.05%,95%CI 1.63% to 17.02%) and by older adults (aged ≥65 years) (7.25%, 95% CI 0.24% to 14.75%). Increase in risk was (2.07%, 95% CI 0.09% to 4.09%) for IHD‐related emergency department attendance and (1.86%, 95% CI: 0.35% to 3.4%) for IHD‐related hospital admissions at lag 2 days, with strong associations shown by women (3.21%, 95% CI 0.81% to 5.67%) and by older adults (2.41%, 95% CI 0.82% to 5.67%). Conclusion: PM2.5 exposure was associated with increased risk of out‐of‐hospital cardiac arrests and IHD during the 2006–2007 wildfires in Victoria. This evidence indicates that PM2.5 may act as a triggering factor for acute coronary events during wildfire episodes

Vitamin D and health in adults in Australia and New Zealand: A position statement

The prevalence of vitamin D deficiency varies, with the groups at greatest risk including housebound, community-dwelling older and/or disabled people, those in residential care, dark-skinned people (particularly those modestly dressed), and other people who regularly avoid sun exposure or work indoors., Most adults are unlikely to obtain more than 5%-10% of their vitamin D requirement from dietary sources. The main source of vitamin D for people residing in Australia and New Zealand is exposure to sunlight., A serum 25-hydroxyvitamin D (25-OHD) level of ≥50nmol/L at the end of winter (10-20nmol/L higher at the end of summer, to allow for seasonal decrease) is required for optimal musculoskeletal health., Although it is likely that higher serum 25-OHD levels play a role in the prevention of some disease states, there is insufficient evidence from randomised controlled trials to recommend higher targets., For moderately fair-skinned people, a walk with arms exposed for 6-7 minutes mid morning or mid afternoon in summer, and with as much bare skin exposed as feasible for 7-40 minutes (depending on latitude) at noon in winter, on most days, is likely to be helpful in maintaining adequate vitamin D levels in the body., When sun exposure is minimal, vitamin D intake from dietary sources and supplementation of at least 600IU (15μg) per day for people aged ≥70 years and 800IU (20μg) per day for those aged >70 years is recommended. People in high-risk groups may require higher doses., There is good evidence that vitamin D plus calcium supplementation effectively reduces fractures and falls in older men and women

Sub-clinical effects of outdoor smoke in affected communities

Many Australians are intermittently exposed to landscape fire smoke from wildfires or planned (prescribed) burns. This study aimed to investigate effects of outdoor smoke from planned burns, wildfires and a coal mine fire by assessing biomarkers of inflammation in an exposed and predominantly older population. Participants were recruited from three communities in south-eastern Australia. Concentrations of fine particulate matter (PM2.5) were continuously measured within these communities, with participants performing a range of health measures during and without a smoke event. Changes in biomarkers were examined in response to PM2.5 concentrations from outdoor smoke. Increased levels of FeNO (fractional exhaled nitric oxide) (β = 0.500 [95%CI 0.192 to 0.808] p 2.5 levels from outdoor smoke, with effects also shown for wildfire smoke at 4, 12, 24 and 48-h lag periods and coal mine fire smoke at a 4 h lag. Total white cell (β = -0.088 [-0.171 to -0.006] p = 0.036) and neutrophil counts (β = -0.077 [-0.144 to -0.010] p = 0.024) declined in response to a 10 µg/m3 increase in PM2.5. However, exposure to outdoor smoke resulting from wildfires, planned burns and a coal mine fire was not found to affect other blood biomarkers