Outcomes into adulthood of infants born extremely preterm.

As survival of infants born extremely preterm increases, more are now reaching adulthood. It is well documented that survivors born extremely preterm experience more developmental delay and disability in multiple domains compared with term-born controls in early childhood and school age. However, with increasing age, health problems involving physical and mental health become more evident. Despite these challenges, it is reassuring that self-reported quality of life remains good. Future directions of research include development of age-appropriate interventions to optimise health and development of individuals born extremely preterm beyond school age.

Wildfire smoke exposure and respiratory health outcomes in young adults born extremely preterm or extremely low birthweight.

OBJECTIVE: Adults born either extremely preterm (EP, <28 weeks gestation) or extremely low birthweight (ELBW, <1000 g birthweight) have more obstructive airflow than controls of normal birthweight (>2499 g). We compared self-reported adverse respiratory health outcomes in young adults born EP/ELBW with controls following smoke exposure from the 2019/2020 wildfires in the Australian state of Victoria, and explored if any effects were mediated by airway obstruction, reflected in the forced expiratory volume in 1 second (FEV1). METHODS: EP/ELBW participants were derived from all survivors born in the state of Victoria in 1991-92. Contemporaneous controls of normal birthweight (>2499 g) were recruited in the newborn period and matched for sociodemographic variables. Both groups had been assessed at intervals through childhood and into adulthood. Those who participated in the most recent follow-up assessment at 25 years of age, when FEV1 had been measured, were sent a survey when they were approximately 28 years of age asking about respiratory health related outcomes (respiratory symptoms, health services usage, medication uptake) following wildfire smoke exposure over the southern hemisphere summer of 2019-20. RESULTS: A total of 296 participants (166 EP/ELBW; 130 controls) were sent the survey; 44% of the EP/ELBW group and 47% of the control group responded. Compared with controls, EP/ELBW respondents reported more overall respiratory problems (30%vs 20%) and specific respiratory symptoms (breathlessness, wheezing, cough and chest tightness) following wildfire smoke exposure, as well as higher health services usage (e.g. local health clinic, hospital emergency department) and medication uptake for respiratory-related problems. Higher FEV1 values were associated with lower odds of most self-reported respiratory symptoms; adjusting for FEV1 attenuated the differences between EP/ELW and control groups. CONCLUSION: Survivors born EP/ELBW may be at an increased risk of adverse respiratory health outcomes following wildfire smoke exposure in early adulthood, in part related to worse expiratory airflows.

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) (ß = 0.500 [95%CI 0.192 to 0.808] p < 0.001) at a 4 h lag were associated with a 10 µg/m3 increase in PM2.5 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 (ß = -0.088 [-0.171 to -0.006] p = 0.036) and neutrophil counts (ß = -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.

Bone health in young adult survivors born extremely preterm or extremely low birthweight in the post surfactant era.

BACKGROUND: Most infants born extremely preterm (EP; <28 weeks' gestation) or extremely low birthweight (ELBW; <1000 g birthweight) in the post surfactant era (early 1990s) are now surviving into adulthood. Preterm birth/low birthweight are risk factors for reduced bone growth and mineralisation in infants and children. However, little is known about their bone health around peak bone mass and through adult life. OBJECTIVE: To compare bone health (bone mineral measures, bone structure and strength) in young adults born EP/ELBW with controls (>2499 g birthweight), and within the EP/ELBW group examine perinatal and later variables associated with long term bone health. METHODS: A geographic cohort comprising all 297 survivors born EP/ELBW in 1991-92 in the state of Victoria, Australia, and 260 contemporaneous controls (>2499 g birthweight) were recruited into a longitudinal study from birth. At age 25 years, investigations included dual energy X ray absorptiometry and peripheral quantitative computed tomography to measure bone, muscle and soft tissue variables, and fasting blood samples to measure serum 25 hydroxyvitamin D (25(OH)D) and bone turnover markers (BTM). Linear regression analysis, with models fitted using generalised estimating equations, was used to compare outcomes between groups, adjusting for height and weight. RESULTS: Compared with controls (n = 129), young adults born EP/ELBW (n = 162) had lower areal bone mineral density (g/cm2) (mean difference [MD] -0.044; 95% confidence interval [CI] -0.076,-0.013) and Z-scores (MD -0.53; 95% CI -0.75, -0.30) in the femoral neck, and lower total hip Z-score (MD -0.35; 95% CI -0.54, -0.15) after adjusting for height and weight. EP/ELBW males generally displayed more bone and soft tissue deficits than females, compared with their respective controls. Within the EP/ELBW group, early growth, male sex, height and lean mass, muscle measures, 25(OH)D levels, and BTM were independently associated with bone mineral measures, structure or strength. CONCLUSIONS: Young adults born EP/ELBW had evidence of impaired bone health around the age of peak bone mass compared with controls. Further follow-up of the EP/ELBW groups will determine if they have a heightened low-trauma fracture risk in later life.

Cardiovascular Health Profile at Age 25 Years in Adults Born Extremely Preterm or Extremely Low Birthweight.

Being born extremely preterm (EP; <28 weeks' gestation) or extremely low birthweight (ELBW; <1000 g birthweight) may predict increased cardiometabolic risk in adulthood, but other early life predictors are less well described. We aimed to (1) compare cardiovascular health profiles between 165 adults born EP/ELBW and 127 controls at age 25 years, drawn from a prospective longitudinal cohort study, recruited at birth in 1991 to 1992; and (2) in the EP/ELBW group, determine early life associations of cardiovascular health. Cardiovascular health profiles were calculated individually for measures of anthropometry, abdominal visceral fat, blood pressure, fasting plasma glucose, insulin, lipids, C-reactive protein, vascular indices, exercise tolerance and smoking status, and summed for an overall score. Cardiovascular health profiles were compared between groups; using logistic regression (individual scores) and the Mann-Whitney U test (cumulative score). Compared with controls, adults born EP/ELBW had less favorable cardiovascular health profiles; individually for abdominal visceral fat (odds ratio, 0.56 [95% CI, 0.33-0.96], P=0.03), blood pressure (odds ratio 0.38 [95% CI, 0.23-0.63], P<0.001), exercise capacity (odds ratio 0.37 [95% CI, 0.22-0.63], P<0.001), and fasting glucose (odds ratio 0.51 [95% CI, 0.31-0.84], P=0.01) and overall (median [interquartile range] 10 [7-11] versus 11 [9-12], P=0.007). Male sex predicted unfavorable abdominal visceral fat, blood pressure and fasting glucose, and favorable exercise capacity. Greater increases in weight Z scores between 2 and 8, and 8 and 18 years predicted less favorable profiles of exercise capacity and visceral fat. Longer-term follow-up is critical to determine the cardiovascular sequelae of adults born EP/ELBW.

Changing consumption of resources for respiratory support and short-term outcomes in four consecutive geographical cohorts of infants born extremely preterm over 25 years since the early 1990s.

OBJECTIVES: It is unclear how newer methods of respiratory support for infants born extremely preterm (EP; 22-27 weeks gestation) have affected in-hospital sequelae. We aimed to determine changes in respiratory support, survival and morbidity in EP infants since the early 1990s. DESIGN: Prospective longitudinal cohort study. SETTING: The State of Victoria, Australia. PARTICIPANTS: All EP births offered intensive care in four discrete eras (1991-1992 (24 months): n=332, 1997 (12 months): n=190, 2005 (12 months): n=229, and April 2016-March 2017 (12 months): n=250). OUTCOME MEASURES: Consumption of respiratory support, survival and morbidity to discharge home. Cost-effectiveness ratios describing the average additional days of respiratory support associated per additional survivor were calculated. RESULTS: Median duration of any respiratory support increased from 22 days (1991-1992) to 66 days (2016-2017). The increase occurred in non-invasive respiratory support (2 days (1991-1992) to 51 days (2016-2017)), with high-flow nasal cannulae, unavailable in earlier cohorts, comprising almost one-half of the duration in 2016-2017. Survival to discharge home increased (68% (1991-1992) to 87% (2016-2017)). Cystic periventricular leukomalacia decreased (6.3% (1991-1992) to 1.2% (2016-2017)), whereas retinopathy of prematurity requiring treatment increased (4.0% (1991-1992) to 10.0% (2016-2017)). The average additional costs associated with one additional infant surviving in 2016-2017 were 200 (95% CI 150 to 297) days, 326 (183 to 1127) days and 130 (70 to 267) days compared with 1991-1992, 1997 and 2005, respectively. CONCLUSIONS: Consumption of resources for respiratory support has escalated with improved survival over time. Cystic periventricular leukomalacia reduced in incidence but retinopathy of prematurity requiring treatment increased. How these changes translate into long-term respiratory or neurological function remains to be determined.

Using Facebook to Improve Participation Among 25-Year-Olds Enrolled in a Longitudinal Preterm Birth Cohort Study.

OBJECTIVE: Facebook is a popular social media platform used globally to keep connected and informed. The aims of this study were to determine the contribution of Facebook to the participation rate of young adults enrolled in a longitudinal cohort study, and to examine systematic differences in participants recruited through Facebook compared with those recruited through traditional methods. METHODS: Potential participants comprised 297 consecutive survivors born extremely preterm (<28 weeks' gestation) or extremely low birth weight (<1000 g birth weight) in 1991-92 in the state of Victoria, Australia, and 260 contemporaneously recruited normal birth weight (>2499 g birth weight) controls who had participated previously in a prospective cohort study. At 25 years of age participants were approached initially via traditional methods (mail, telephone, texts), and subsequently by Facebook for those difficult to contact or locate. RESULTS: Contact was attempted with 523 young adults via traditional methods and 49% (n = 255) agreed to participate. Of the 208 participants unable to be located or contacted via traditional methods, 153 were subsequently located via Facebook. Of these 82% (n = 125) responded promptly within a day of receiving the Facebook invite, and 41% (n = 63) ultimately participated. The participation rate increased from 49% (255 of 523) to 61% (318 of 523) with the addition of Facebook, an absolute increase of 12%. Participants recruited by Facebook were slightly older, had lower rates of school completion and lower cognitive score at 18 years of age compared with those recruited via traditional methods. CONCLUSIONS: Using Facebook improved participation of young adults enrolled in this longitudinal preterm follow up study, 25 years after original recruitment.

High Blood Pressure in Young Adult Survivors Born Extremely Preterm or Extremely Low Birthweight in the Post Surfactant Era.

More infants born extremely preterm (<28 weeks' gestation) or extremely low birthweight (<1000 g) are surviving into adulthood in recent years. Preterm adolescents have higher blood pressure (BP) than normal birthweight controls, but how their BP changes with increasing age is not known. We compared BP at 25 years and trajectories of BP (change per year) from 18 to 25 years between survivors born <28 weeks/<1000 g and normal birthweight (>2499 g) controls born in the early 1990s, when survival rates began to rise. Participants were derived from 297 consecutive survivors born <28 weeks/<1000 g in 1991 to 1992 in Victoria, Australia, and 260 contemporaneous controls. At age 25 years, ambulatory BP was measured in 151 and 119 participants, respectively. Participants born <28 weeks/<1000 g had higher 24-hour systolic (mean difference 4.5 [95% CI, 1.2-7.7 mm Hg]), diastolic (3.4 [1.5-5.2 mm Hg]), and mean BPs (3.6 [1.4-5.8 mm Hg]) compared with the controls. Similar patterns were observed for both awake and asleep periods. Asleep ambulatory BP between 18 and 25 years increased more in participants born <28 weeks/<1000 g than in controls (systolic 0.56, diastolic 0.41, and mean 0.41 mm Hg increase per year; all P<0.05). Young adults born <28 weeks/<1000 g in the post surfactant era have higher BP and an increased trajectory of ambulatory BP compared with controls. With more survivors born <28 weeks/<1000 g now reaching adulthood, these findings are important for early detection and timely management of hypertension in this high-risk population.

Airway obstruction in young adults born extremely preterm or extremely low birth weight in the postsurfactant era.

BACKGROUND: It is unknown if adults born <28 weeks or <1000 g since surfactant has been available are reaching their full airway growth potential. OBJECTIVE: To compare expiratory airflow at 25 years and from 8 to 25 years of participants born <28 weeks or <1000 g with controls, and within the preterm group to compare those who had bronchopulmonary dysplasia with those who did not. METHODS: All survivors born <28 weeks or <1000 g in 1991-1992 in Victoria, Australia, were eligible. Controls were born contemporaneously, weighing >2499 g. At 8, 18 and 25 years, expiratory airflows were measured and the results converted to z-scores. Outcomes were compared between groups at age 25 years, and trajectories (change in z-scores per year) from childhood were contrasted between groups. RESULTS: Expiratory airflows were measured at 25 years on 164 of 297 (55%) preterm survivors and 130 of 260 (50%) controls. Preterm participants had substantially reduced airflow compared with controls at age 25 years (eg, zFEV1; mean difference -0.97, 95% CI -1.23 to -0.71; p<0.001). Preterm participants had lower airflow trajectories than controls between 8 and 18 years, but not between 18 and 25 years. Within the preterm group, those who had bronchopulmonary dysplasia had worse airflows and trajectories than those who did not. CONCLUSIONS: Young adults born <28 weeks or <1000 g in the surfactant era, particularly those who had bronchopulmonary dysplasia, have substantially reduced airway function compared with controls. Some are destined to develop COPD in later adult life.

Impact of extreme prematurity or extreme low birth weight on young adult health and well-being: the Victorian Infant Collaborative Study (VICS) 1991-1992 Longitudinal Cohort study protocol.

INTRODUCTION: Infants born extremely preterm (EP, <28 weeks' gestation) or with extremely low birth weight (ELBW,<1000 g) in the era when surfactant has been available clinically are at high risk of health and developmental problems in childhood and adolescence. However, how their health and well-being may be affected in adulthood is not well known. This study aims to compare between EP/ELBW and normal birthweight (NBW) controls: (1) physical health, mental health and socioemotional functioning at 25 years of age and (2) trajectories of these outcomes from childhood to adulthood. In addition, this study aims to identify risk factors in pregnancy, infancy, childhood and adolescence for poor physical health and well-being in EP/ELBW young adults. METHODS AND ANALYSIS: The Victorian Infant Collaborative Study (VICS) is a prospective geographical cohort of all EP/ELBW survivors to 18 years of age born in the State of Victoria, Australia, from 1 January 1991 to 31 December 1992 (n=297) and contemporaneous term-born/NBW controls (n=262). Participants were recruited at birth and followed up at 2, 5, 8 and 18 years. This 25-year follow-up includes assessments of physical health (cardiovascular, respiratory and musculoskeletal), mental health and socioemotional functioning. Outcomes will be compared between the birth groups using linear and logistic regression, fitted using generalised estimating equations (GEEs). Trajectories of health outcomes from early childhood will be compared between the birth groups using linear mixed-effects models. Risk factors for adult outcomes will be assessed using linear and logistic regression (fitted using GEEs). ETHICS AND DISSEMINATION: This study was approved by the Human Research Ethics Committees of the Royal Women's Hospital, Mercy Hospital for Women, Monash Medical Centre and the Royal Children's Hospital, Melbourne. Study outcomes will be disseminated through conference presentations, peer-reviewed publications, the internet and social media.

Associations of Preeclampsia with Expiratory Airflows in School-Age Children Born Either at <28 Weeks or Weighing <1000 g.

OBJECTIVES: To assess whether preeclampsia was associated with expiratory airflow at school-age in children born either extremely preterm (<28 weeks of gestation) or extremely low birthweight (ELBW; <1000 g birth weight). STUDY DESIGN: Participants comprised 3 cohorts of children born extremely preterm/ELBW in the state of Victoria, Australia, in 1991-1992, 1997, or 2005. Expiratory airflows were measured at age 8 years, and results converted to z scores. Data were compared between those exposed to preeclampsia with those unexposed to preeclampsia; analyses were then adjusted for confounding perinatal variables. Analyses were repeated within subgroups of extremely preterm only and ELBW only. RESULTS: Respiratory data were available for 544 of 717 (76%) survivors, of whom 95 (17%) had been exposed to preeclampsia. On univariable analysis, those exposed to preeclampsia had better z scores for flows for the forced expired volume in 1 second (zFEV1) (mean difference 0.29, 95% CI 0.04-0.53; P = .022) and zFEV1/forced vital capacity (mean difference 0.33, 95% CI 0.04-0.61; P = .025); the difference persisted for zFEV1 after adjustment for confounding perinatal variables. Analyses confined to those born extremely preterm revealed little evidence for associations between preeclampsia and airflow. In analyses confined to those born ELBW, preeclampsia was associated with better zFEV1, which persisted after adjustment (mean difference 0.33, 95% CI 0.04-0.63; P = .025). CONCLUSIONS: Exposure to maternal preeclampsia was not associated with worse expiratory airflow in children born extremely preterm/ELBW; in fact, some airflows were better.

Health effects of smoke from planned burns: a study protocol.

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.

Fine particulate matter (PM2.5 ) 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 PM2.5 and 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/m(3) 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.

Impact of Fine Particulate Matter (PM2.5) 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/m(3) 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.

Impact of smoke from prescribed burning: Is it a public health concern?

UNLABELLED: Given the increase in wildfire intensity and frequency worldwide, prescribed burning is becoming a more common and widespread practice. Prescribed burning is a fire management tool used to reduce fuel loads for wildfire suppression purposes and occurs on an annual basis in many parts of the world. Smoke from prescribed burning can have a substantial impact on air quality and the environment. Prescribed burning is a significant source of fine particulate matter (PM2.5 aerodynamic diameter<2.5µm) and these particulates are found to be consistently elevated during smoke events. Due to their fine nature PM2.5 are particularly harmful to human health. Here we discuss the impact of prescribed burning on air quality particularly focussing on PM2.5. We have summarised available case studies from Australia including a recent study we conducted in regional Victoria, Australia during the prescribed burning season in 2013. The studies reported very high short-term (hourly) concentrations of PM2.5 during prescribed burning. Given the increase in PM2.5 concentrations during smoke events, there is a need to understand the influence of prescribed burning smoke exposure on human health. This is important especially since adverse health impacts have been observed during wildfire events when PM2.5 concentrations were similar to those observed during prescribed burning events. Robust research is required to quantify and determine health impacts from prescribed burning smoke exposure and derive evidence based interventions for managing the risk. IMPLICATIONS: Given the increase in PM2.5 concentrations during PB smoke events and its impact on the local air quality, the need to understand the influence of PB smoke exposure on human health is important. This knowledge will be important to inform policy and practice of the integrated, consistent, and adaptive approach to the appropriate planning and implementation of public health strategies during PB events. This will also have important implications for land management and public health organizations in developing evidence based objectives to minimize the risk of PB smoke exposure.

Forest Fire Smoke Exposures and Out-of-Hospital Cardiac Arrests in Melbourne, Australia: A Case-Crossover Study.

BACKGROUND: Millions of people can potentially be exposed to smoke from forest fires, making this an important public health problem in many countries. OBJECTIVE: In this study we aimed to measure the association between out-of-hospital cardiac arrest (OHCA) and forest fire smoke exposures in a large city during a severe forest fire season, and estimate the number of excess OHCAs due to the fire smoke. METHODS: We investigated the association between particulate matter (PM) and other air pollutants and OHCA using a case-crossover study of adults (≥ 35 years of age) in Melbourne, Australia. Conditional logistic regression models were used to derive estimates of the percent change in the rate of OHCA associated with an interquartile range (IQR) increase in exposure. From July 2006 through June 2007, OHCA data were collected from the Victorian Ambulance Cardiac Arrest Registry. Hourly air pollution concentrations and meteorological data were obtained from a central monitoring site. RESULTS: There were 2,046 OHCAs with presumed cardiac etiology during our study period. Among men during the fire season, greater increases in OHCA were observed with IQR increases in the 48-hr lagged PM with diameter ≤ 2.5 µm (PM2.5) (8.05%; 95% CI: 2.30, 14.13%; IQR = 6.1 µg/m(3)) or ≤ 10 µm (PM10) (11.1%; 95% CI: 1.55, 21.48%; IQR = 13.7 µg/m(3)) and carbon monoxide (35.7%; 95% CI: 8.98, 68.92%; IQR = 0.3 ppm). There was no significant association between the rate of OHCA and air pollutants among women. One hundred seventy-four "fire-hours" (i.e., hours in which Melbourne's air quality was affected by forest fire smoke) were identified during 12 days of the 2006/2007 fire season, and 23.9 (95% CI: 3.1, 40.2) excess OHCAs were estimated to occur due to elevations in PM2.5 during these fire-hours. CONCLUSIONS: This study found an association between exposure to forest fire smoke and an increase in the rate of OHCA. These findings have implications for public health messages to raise community awareness and for planning of emergency services during forest fire seasons.

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 ≥ 50 nmol/L at the end of winter (10-20 nmol/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 600 IU (15 µg) per day for people aged ≤ 70 years and 800 IU (20 µg) 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.