Effect of extreme temperatures on asthma hospital visits: Modification by event characteristics and healthy behaviors.

Although ambient temperature has been linked to asthma exacerbation, impacts associated with extreme temperature events remain unclear. This study aims to identify the events characteristics that elevate risk of asthma hospital visits, and to assess whether healthy behavior changes due to the COVID-19 prevention and control policy may modify the relationships. Data of asthma hospital visits from all medical facilities in Shenzhen, China during 2016-2020 were assessed in relation to extreme temperature events using a distributed lag model. Stratified analysis was conducted by gender, age and hospital department to identify susceptible populations. Through events defined by various duration days and temperature thresholds, we explored the modification by events intensity, length, occurrence time and healthy behaviors. The cumulative relative risk of asthma during heat waves compared to other days was 1.06 (95%CI: 1.00-1.13) and for cold spells was 1.17 (95%CI: 1.05-1.30), and that of males and school-aged children were generally higher than other sub-groups. There were significant effects of heat waves and cold spells on asthma hospital visits when the mean temperature was above 90th percentile (30 °C) and below 10th percentile (14 °C) respectively, and the relative risks were higher when events lasted longer, became stronger, occurred in daytime and in early summer or winter. During the healthy behaviors maintaining period, the risk of heat waves increased whilst the risk of cold spells reduced. Extreme temperatures may pose considerable impact on asthma and the health effect can be modified by the event characteristics and anti-epidemic healthy behaviors. Strategies of asthma control should consider the heightened threats of the intense and frequent extreme temperature events in the context of climate change.

Climate change, air pollution, and allergic respiratory diseases: a call to action for health professionals.

Rising emissions of greenhouse gases in the atmosphere have warmed the planet substantially and are also accompanied by poor air quality. The increased prevalence of allergic airway disease worldwide can be partially attributed to those global environmental changes. Climate change and air pollution pose adverse impacts on respiratory allergies, and that the mechanisms are complex and interactive. Adverse weather conditions, such as extreme temperatures, can act directly on the respiratory tract to induce allergic respiratory illnesses. Thunderstorms and floods can alter the production and distribution of aeroallergens while wildfires and dust storms increase air pollution, and therefore indirectly enhance health risks. Concentrations of particulate matter and ozone in the air have been projected to increase with climate warming and air stagnation, and the rising temperatures and CO2 increase pollen, molds, and spores, which escalate the risk of allergic respiratory diseases. The synergistic effects of extreme heat and aeroallergens intensify the toxic effect of air pollutants, which in turn augment the allergenicity of aeroallergens. With the Earth's climate change, migration of humans and plants shift the living environments and allergens of susceptible people. Urban residents are exposed to multiple factors while children are sensitive to environmental exposure. Since climate change may pose many unexpected and persistent effects on allergic respiratory diseases, health professionals should advocate for effective mitigation and adaptation strategies to minimize its respiratory health effects.

Area-Level Walkability and the Geographic Distribution of High Body Mass in Sydney, Australia: A Spatial Analysis Using the 45 and Up Study.

Improving the walkability of built environments to promote healthy lifestyles and reduce high body mass is increasingly considered in regional development plans. Walkability indexes have the potential to inform, benchmark and monitor these plans if they are associated with variation in body mass outcomes at spatial scales used for health and urban planning. We assessed relationships between area-level walkability and prevalence and geographic variation in overweight and obesity using an Australian population-based cohort comprising 92,157 Sydney respondents to the 45 and Up Study baseline survey between January 2006 and April 2009. Individual-level data on overweight and obesity were aggregated to 2006 Australian postal areas and analysed as a function of area-level Sydney Walkability Index quartiles using conditional auto regression spatial models adjusted for demographic, social, economic, health and socioeconomic factors. Both overweight and obesity were highly clustered with higher-than-expected prevalence concentrated in the urban sprawl region of western Sydney, and lower-than-expected prevalence in central and eastern Sydney. In fully adjusted spatial models, prevalence of overweight and obesity was 6% and 11% lower in medium-high versus low, and 10% and 15% lower in high versus low walkability postcodes, respectively. Postal area walkability explained approximately 20% and 9% of the excess spatial variation in overweight and obesity that remained after accounting for other individual- and area-level factors. These findings provide support for the potential of area-level walkability indexes to inform, benchmark and monitor regional plans aimed at targeted approaches to reducing population-levels of high body mass through environmental interventions. Future research should consider potential confounding due to neighbourhood self-selection on area-level walkability relations.

Initial group dietary education compared to individual education in gestational diabetes mellitus management: Do outcomes differ?

AIMS: To assess the effectiveness of Initial Group versus Initial Individual GDM dietary education in terms of insulin requirements and pregnancy outcomes. METHODS: A retrospective audit of clinical data was conducted where English speaking women who received initial education in a group setting (01-2-2012 to 01-2-2014) (Group), were compared to women who received initial individual education with a dietitian (1-2-2010 to 31-1-2012) (Individual), all followed by one individual dietitian appointment. The same dietary information was provided in both settings. Data collected included: attendance rates, insulin requirements, maternal weight gain, and rates of adverse birth outcomes. Data were compared by t-test or Chi-squared test. Multivariable logistic regression analysis was conducted to determine independent predictors of insulin therapy. RESULTS: Of 743 women; (362 Group and 381 Individual), Group women had a lower HbA1c at GDM diagnosis 5.3 ±â€¯0.6% versus 5.5 ±â€¯0.5% (34 ±â€¯6.6 mmol/mol versus 37 ±â€¯5.5 mmol/mol p < 0.0001). There were no other differences in baseline characteristics. More Group women required insulin (42.0% versus 34.6%, p = 0.048). Group education was found to be an independent predictor of insulin therapy (OR = 1.9 [1.29, 2.75] p < 0.001). CONCLUSIONS: Despite adjusting for all known potential confounders, unlike Individual education, Group education remained a significant predictor of insulin therapy (but resulted in similar therapeutic and pregnancy outcomes to Individual education).

Does Walkability Contribute to Geographic Variation in Psychosocial Distress? A Spatial Analysis of 91,142 Members of the 45 and Up Study in Sydney, Australia.

Walkability describes the capacity of the built environment to promote walking, and has been proposed as a potential focus for community-level mental health planning. We evaluated this possibility by examining the contribution of area-level walkability to variation in psychosocial distress in a population cohort at spatial scales comparable to those used for regional planning in Sydney, Australia. Data on psychosocial distress were analysed for 91,142 respondents to the 45 and Up Study baseline survey between January 2006 and April 2009. We fit conditional auto regression models at the postal area level to obtain smoothed "disease maps" for psychosocial distress, and assess its association with area-level walkability after adjusting for individual- and area-level factors. Prevalence of psychosocial distress was 7.8%; similar for low (7.9%), low-medium (7.9%), medium-high (8.0%), and high (7.4%) walkability areas; and decreased with reducing postal area socioeconomic disadvantage: 12.2% (most), 9.3%, 7.5%, 5.9%, and 4.7% (least). Unadjusted disease maps indicated strong geographic clustering of psychosocial distress with 99.0% of excess prevalence due to unobserved and spatially structured factors, which was reduced to 55.3% in fully adjusted maps. Spatial and unstructured variance decreased by 97.3% and 39.8% after adjusting for individual-level factors, and another 2.3% and 4.2% with the inclusions of area-level factors. Excess prevalence of psychosocial distress in postal areas was attenuated in adjusted models but remained spatially structured. Postal area prevalence of high psychosocial distress is geographically clustered in Sydney, but is unrelated to postal area walkability. Area-level socioeconomic disadvantage makes a small contribution to this spatial structure; however, community-level mental health planning will likely deliver greatest benefits by focusing on individual-level contributors to disease burden and inequality associated with psychosocial distress.

The contribution of area-level walkability to geographic variation in physical activity: a spatial analysis of 95,837 participants from the 45 and Up Study living in Sydney, Australia.

BACKGROUND: Individual-level studies support a positive relation between walkable built environments and participation in moderate-intensity walking. However, the utility of this evidence for population-level planning is less clear as it is derived at much finer spatial scales than those used for regional programming. The aims of this study were to: evaluate if individual-level relations between walkability and walking to improve health manifest at population-level spatial scales; assess the specificity of area-level walkability for walking relative to other moderate and vigorous physical activity (MVPA); describe geographic variation in walking and other MVPA; and quantify the contribution of walkability to this variation. METHODS: Data on sufficient walking, sufficient MVPA, and high MVPA to improve health were analyzed for 95,837 Sydney respondents to the baseline survey of the 45 and Up Study between January 2006 and April 2010. We used conditional autoregressive models to create smoothed MVPA "disease maps" and assess relations between sufficient MVPA to improve health and area-level walkability adjusted for individual-level demographic, socioeconomic, and health factors, and area-level relative socioeconomic disadvantage. RESULTS: Within-cohort prevalence of meeting recommendations for sufficient walking, sufficient MVPA, and high MVPA were 31.7 (95% CI 31.4-32.0), 69.4 (95% CI 69.1-69.7), and 56.1 (95% CI 55.8-56.4) percent. Prevalence of sufficient walking was increased by 1.20 (95% CrI 1.12-1.29) and 1.07 (95% CrI 1.01-1.13) for high and medium-high versus low walkability postal areas, and for sufficient MVPA by 1.05 (95% CrI 1.01-1.08) for high versus low walkability postal areas. Walkability was not related to high MVPA. Postal area walkability explained 65.8 and 47.4 percent of residual geographic variation in sufficient walking and sufficient MVPA not attributable to individual-level factors. CONCLUSIONS: Walkability is associated with area-level prevalence and geographic variation in sufficient walking and sufficient MVPA to improve health in Sydney, Australia. Our study supports the use of walkability indexes at multiple spatial scales for informing population-level action to increase physical activity and the utility of spatial analysis for walkability research and planning.

Realist theory construction for a mixed method multilevel study of neighbourhood context and postnatal depression.

BACKGROUND: We have recently described a protocol for a study that aims to build a theory of neighbourhood context and postnatal depression. That protocol proposed a critical realist Explanatory Theory Building Method comprising of an: (1) emergent phase, (2) construction phase, and (3) confirmatory phase. A concurrent triangulated mixed method multilevel cross-sectional study design was described. The protocol also described in detail the Theory Construction Phase which will be presented here. METHODS: The Theory Construction Phase will include: (1) defining stratified levels; (2) analytic resolution; (3) abductive reasoning; (4) comparative analysis (triangulation); (5) retroduction; (6) postulate and proposition development; (7) comparison and assessment of theories; and (8) conceptual frameworks and model development. THEORY CONSTRUCTION: The stratified levels of analysis in this study were predominantly social and psychological. The abductive analysis used the theoretical frames of: Stress Process; Social Isolation; Social Exclusion; Social Services; Social Capital, Acculturation Theory and Global-economic level mechanisms. Realist propositions are presented for each analysis of triangulated data. Inference to best explanation is used to assess and compare theories. A conceptual framework of maternal depression, stress and context is presented that includes examples of mechanisms at psychological, social, cultural and global-economic levels. Stress was identified as a necessary mechanism that has the tendency to cause several outcomes including depression, anxiety, and health harming behaviours. The conceptual framework subsequently included conditional mechanisms identified through the retroduction including the stressors of isolation and expectations and buffers of social support and trust. CONCLUSION: The meta-theory of critical realism is used here to generate and construct social epidemiological theory using stratified ontology and both abductive and retroductive analysis. The findings will be applied to the development of a middle range theory and subsequent programme theory for local perinatal child and family interventions.

A novel validated model for the prediction of insulin therapy initiation and adverse perinatal outcomes in women with gestational diabetes mellitus.

AIMS/HYPOTHESIS: Identifying women with gestational diabetes mellitus who are more likely to require insulin therapy vs medical nutrition therapy (MNT) alone would allow risk stratification and early triage to be incorporated into risk-based models of care. The aim of this study was to develop and validate a model to predict therapy type (MNT or MNT plus insulin [MNT+I]) for women with gestational diabetes mellitus (GDM). METHODS: Analysis was performed of de-identified prospectively collected data (1992-2015) from women diagnosed with GDM by criteria in place since 1991 and formally adopted and promulgated as part of the more detailed 1998 Australasian Diabetes in Pregnancy Society management guidelines. Clinically relevant variables predictive of insulin therapy by univariate analysis were dichotomised and included in a multivariable regression model. The model was tested in a separate clinic population. RESULTS: In 3317 women, seven dichotomised significant independent predictors of insulin therapy were maternal age >30 years, family history of diabetes, pre-pregnancy obesity (BMI ≥30 kg/m(2)), prior GDM, early diagnosis of GDM (<24 weeks gestation), fasting venous blood glucose level (≥5.3 mmol/l) and HbA1c at GDM diagnosis ≥5.5% (≥37 mmol/mol). The requirement for MNT+I could be estimated according to the number of predictors present: 85.7-93.1% of women with 6-7 predictors required MNT+I compared with 9.3-14.7% of women with 0-1 predictors. This model predicted the likelihood of several adverse outcomes, including Caesarean delivery, early delivery, large for gestational age and an abnormal postpartum OGTT. The model was validated in a separate clinic population. CONCLUSIONS/INTERPRETATION: This validated model has been shown to predict therapy type and the likelihood of several adverse perinatal outcomes in women with GDM.

Factors influencing workplace violence risk among correctional health workers: insights from an Australian survey.

Little is known about the environmental and organisational determinants of workplace violence in correctional health settings. This paper describes the views of health professionals working in these settings on the factors influencing workplace violence risk. All employees of a large correctional health service in New South Wales, Australia, were invited to complete an online survey. The survey included an open-ended question seeking the views of participants about the factors influencing workplace violence in correctional health settings. Responses to this question were analysed using qualitative thematic analysis. Participants identified several factors that they felt reduced the risk of violence in their workplace, including: appropriate workplace health and safety policies and procedures; professionalism among health staff; the presence of prison guards and the quality of security provided; and physical barriers within clinics. Conversely, participants perceived workplace violence risk to be increased by: low health staff-to-patient and correctional officer-to-patient ratios; high workloads; insufficient or underperforming security staff; and poor management of violence, especially horizontal violence. The views of these participants should inform efforts to prevent workplace violence among correctional health professionals.

Being alone and expectations lost: a critical realist study of maternal depression in South Western Sydney.

The study reported here is part of a critical realist multilevel study. It seeks to identify and explain complex perinatal contextual social and psychosocial mechanisms that may influence the developmental origins of health and disease, with a focus on the role of postnatal depression. The aims of the greater study are to: (1) describe the phenomenon of postnatal depression in South Western Sydney; and (2) identify mechanisms that would add to our understanding of the psycho-social causes of maternal depression. This paper will move beyond our previous quantitative descriptions of individual-level predictors of depressive symptoms by seeking the views of local mothers and practitioners, to explain the mechanisms that might be involved. The study was set in South Western Sydney, New South Wales, Australia. An Explanatory Theory Building Method was used. The previously reported quantitative study was a non-linear principal component analysis and logistic regression study of 15,389 months delivering in 2002 and 2003. This intensive qualitative study used open coding of interviews, of seven practitioners and three naturally occurring mothers groups, to enable maximum emergence. The theoretical concepts identified were: attachment and nurturing, infant temperament, unplanned pregnancy and sole parenthood, support for mothers, access to services, stress, financial hardship, isolation and marginalisation, mothers' "loss of control" and "power", and expectations and dreams. Being alone and expectations lost emerged as possible triggers of stress and depression for mothers. These findings might also apply to others who have their dreams shattered during life's transitions. In these situations social and cultural context can either nurture and support or marginalise and isolate. The challenge for policy and practice is to support mothers and their partners during the transition to parenthood within a challenging social and material context.

A feasibility study using geographic access to general practices and routinely collected data in public health and health services research.

BACKGROUND: Advances in geographic information systems (GIS) and increased availability of routinely collected data have the potential to contribute to public health and health services research. The aim of this feasibility study was to explore the use of GIS to measure access to general practices and its relationship to selected antenatal behaviours. METHODS: We obtained the Perinatal Data Collection, 2004-2008, for South Western Sydney Local Health District from the New South Wales Ministry of Health. Using a GIS, we generated circular and polygon-based 1 km and 2 km road network buffers from a maternal residential address and then calculated the number of general practices within those buffers (density measures). Distances to general practices from maternal residences were also calculated in the GIS as another measure of geographic access to general practices (proximity measures). We used generalised estimating equations logistic regression to examine associations between access to general practices, and smoking during pregnancy and late first antenatal visit. RESULTS: The numbers of general practices within circular buffers were significantly greater than within polygon-based road network buffers. The average distance to the five closest general practices from a mother's residence was 2.3 km ± 3.0 km (median 1.4 km, range 0.05 km to 40.0 km). For two of the five measures of access, a higher number of general practices was associated with increased risk for late first antenatal visit. However, the associations were weak, with odds ratios very close to unity. Choice of metrics of geographic access to general practices did not alter the associations with smoking during pregnancy or late first antenatal visit. CONCLUSION: GIS can be used to quantify measures of geographic access to health services for public health and health services research. Geographic access to general practices was generally not associated with smoking during pregnancy or late first antenatal visit. GIS and routinely collected health data can be used to answer novel questions in public health and health services research.

Are children׳s asthmatic symptoms related to ambient temperature? A panel study in Australia.

OBJECTIVES: To examine the short-term effects of ambient temperature on respiratory symptoms for school children with asthma across Australia. METHODS: A panel of 270 children (7-12 years) with asthma was recruited from six Australian cities. They were asked to record their respiratory symptoms every day in the morning (for night-time symptoms) and evening (for daytime symptoms) for four weeks. Daily ambient temperature, relative humidity and air pollution data were obtained from fixed monitors nearby. A mixed logistic regression model was used to examine the effects of ambient temperature on respiratory symptoms adjusted for children's sex, age, standing height, weight and air pollution. Subjects were specified as random effects. RESULTS: The relationships between ambient temperature and respiratory symptoms were linear. Increasing temperatures induced the risks of children's asthmatic symptoms, especially for "wheeze/chest tightness" and to a lesser extent for "cough/phlegm". The effects were acute and lasted for four days (lag 0-3) in general. With increasing ambient temperature, boys were more at risk than girls. CONCLUSIONS: High ambient temperature is a risk factor for respiratory symptoms in children with asthma. As ambient temperature increases, policies and strategies for rising temperatures will be necessary to protect asthmatic children.

High sitting time or obesity: Which came first? Bidirectional association in a longitudinal study of 31,787 Australian adults.

OBJECTIVE: Evidence on the direction of the association between sitting time and obesity is limited. The prospective associations between baseline total sitting time and subsequent changes in body mass index (BMI), and baseline BMI and subsequent changes in sitting time were examined. METHODS: BMI, from self-reported height and weight, and a single-item measure of sitting time were ascertained at two time points (3.4 ± 0.96 years apart) in a prospective questionnaire-based cohort of 31,787 Australians aged 45-65 years without severe physical limitations. RESULTS: In a fully adjusted model, baseline obesity was associated with increased sitting time among all participants (adjusted odds ratio [aOR] = 1.20 [95% CI, 1.11-1.30]; P < 0.001) and in most subgroups. The association was significant among those who were sitting <4 hours/day (aOR = 1.24 [95% CI, 1.07-1.44]; P = 0.004) and 4-8 hours/day at baseline (aOR=1.18 [95% CI, 1.06-1.32]; P = 0.003), but not in the high sitting groups (P = 0.111 and 0.188 for 8-11 and ≥11 sitting hours/day, respectively). Nonsignificant and inconsistent results were observed for the association between baseline sitting time and subsequent change in BMI. CONCLUSIONS: Our findings support the hypothesis that obesity may lead to a subsequent increase in total sitting time, but the association in the other direction is unclear.

An Australian national panel study of diurnal temperature range and children's respiratory health.

BACKGROUND: It is still uncertain whether diurnal temperature range (DTR) affects children's respiratory function. OBJECTIVE: To examine the effects of DTR on lung function and respiratory symptoms for school children with asthma in Australia. METHODS: A panel of 270 children (ages 7-12 years) with asthma living in 6 Australian cities was recruited. They were asked to perform 3 successive forced expiratory maneuvers using a portable electronic peak flow meter twice daily for 4 weeks. The highest values for peak expiratory flow (PEF) were stored for each session. At the same time, they were asked to record their respiratory symptoms (eg, cough and/or phlegm and wheeze and/or chest tightness) every day in the morning (for nighttime symptoms) and evening (for daytime symptoms). Daily data on different metrics of ambient temperature and air pollution were obtained from fixed monitors nearby. Relative humidity data were downloaded from the Weather Underground website. Mixed models, adjusting for children's individual characteristics and air pollution, were used to examine the effects of DTR on PEF and respiratory symptoms. RESULTS: DTR had linear effects on PEF and respiratory symptoms. An increase in DTR induced a reduction in PEF and increased the occurrence of respiratory symptoms. In general, the effects lasted for 3 days (lag, 0-2 days). The effects occurred for both boys and girls. CONCLUSION: Our findings provide evidence that DTR had significant effects on lung function and respiratory symptoms for children with asthma. These results indicate that it is important and necessary to protect children with asthma from the effect of unstable weather.

Bayesian hierarchical spatial regression of maternal depressive symptoms in South Western Sydney, Australia.

BACKGROUND: There is increasing interest in the role played by maternal depression in mediating the effects of adversity during pregnancy and poor infant outcomes. There is also increasing evidence from multilevel regression studies for an association of area-level economic deprivation and poor individual mental health. The purpose of the study reported here is to explore the spatial distribution of postnatal depressive symptoms in South Western Sydney, Australia, and to identify covariate associations that could inform subsequent multilevel studies. METHODS: Mothers (n = 15,389) delivering in 2002 and 2003 were assessed at 2-3 weeks after delivery for risk factors for depressive symptoms. The individual-level binary outcome variables were Edinburgh Depression Scale (EDS) >9 and >12. The association between social, demographic and ecological factors and aggregated outcome variables were investigated using exploratory factor analysis and multivariate hierarchical Bayesian spatial regression. Relative risks from the final EDS >12 regression model were mapped to visualise the contribution from explanatory covariates and residual components. RESULTS: The exploratory factor analysis identified six factors: neighbourhood adversity, social cohesion, health behaviours, housing quality, social services, and support networks. Variables associated with neighbourhood adversity, social cohesion, social networks, and ethnic diversity were consistently associated with aggregated depressive symptoms. Measures of social disadvantage, lack of social cohesion and lack of social capital were associated with increased depressive symptoms. The association with social disadvantage was not significant when controlling for ethnic diversity and social capital. CONCLUSIONS: The findings support the theoretical proposition that neighbourhood adversity causes maternal psychological distress and depression within the context of social buffers including social networks, social cohesion, and social services. The finding have implications for the distribution of health services including early nurse home visiting which has recently been confirmed to be effective in preventing postnatal depression.

Realist explanatory theory building method for social epidemiology: a protocol for a mixed method multilevel study of neighbourhood context and postnatal depression.

A recent criticism of social epidemiological studies, and multi-level studies in particular has been a paucity of theory. We will present here the protocol for a study that aims to build a theory of the social epidemiology of maternal depression. We use a critical realist approach which is trans-disciplinary, encompassing both quantitative and qualitative traditions, and that assumes both ontological and hierarchical stratification of reality. We describe a critical realist Explanatory Theory Building Method comprising of an: 1) emergent phase, 2) construction phase, and 3) confirmatory phase. A concurrent triangulated mixed method multilevel cross-sectional study design is described. The Emergent Phase uses: interviews, focus groups, exploratory data analysis, exploratory factor analysis, regression, and multilevel Bayesian spatial data analysis to detect and describe phenomena. Abductive and retroductive reasoning will be applied to: categorical principal component analysis, exploratory factor analysis, regression, coding of concepts and categories, constant comparative analysis, drawing of conceptual networks, and situational analysis to generate theoretical concepts. The Theory Construction Phase will include: 1) defining stratified levels; 2) analytic resolution; 3) abductive reasoning; 4) comparative analysis (triangulation); 5) retroduction; 6) postulate and proposition development; 7) comparison and assessment of theories; and 8) conceptual frameworks and model development. The strength of the critical realist methodology described is the extent to which this paradigm is able to support the epistemological, ontological, axiological, methodological and rhetorical positions of both quantitative and qualitative research in the field of social epidemiology. The extensive multilevel Bayesian studies, intensive qualitative studies, latent variable theory, abductive triangulation, and Inference to Best Explanation provide a strong foundation for Theory Construction. The study will contribute to defining the role that realism and mixed methods can play in explaining the social determinants and developmental origins of health and disease.