Establishing subclasses of childhood eczema, their risk factors and prognosis

Background

The heterogeneity of development and progression of eczema suggests multiple underlying subclasses for which aetiology and prognosis may vary. A better understanding may provide a comprehensive overview of eczema development and progression in childhood. Thus, we aimed to determine longitudinal eczema subclasses based on assessments and identify their associations with risk factors and allergic outcomes.

Methods

A total of 619 participants with a family history of allergic disease were assessed at 24 time‐points from birth to 12 years. At each time, eczema was defined as the report of current rash treated with topical steroid‐based preparations. Longitudinal latent class analysis was used to determine eczema subclasses. Subsequent analyses using regression models assessed the associations between eczema subclasses and potential risk factors and allergic outcomes at 18‐ and 25‐year follow‐ups (eczema, allergic rhinitis, asthma and allergic sensitization).

Results

We identified five eczema subclasses ‘early‐onset persistent’, ‘early‐onset resolving’, ‘mid‐onset persistent’, ‘mid‐onset resolving’ and ‘minimal eczema’. Filaggrin null mutations were associated with the early‐onset persistent (OR = 2.58 [1.09–6.08]) and mid‐onset persistent class (OR = 2.58 [1.32–5.06]). Compared with ‘minimal eczema’, participants from early‐onset persistent class had higher odds of eczema (OR = 11.8 [5.20–26.6]) and allergic rhinitis (OR = 3.13 [1.43–6.85]) at 18 and at 25 years eczema (OR = 9.37 [3.17–27.65]), allergic rhinitis (OR = 3.26 [1.07–9.93]) and asthma (OR = 2.91 [1.14–7.43]). Likewise, mid‐onset persistent class had higher odds of eczema (OR = 2.59 [1.31–5.14]), allergic rhinitis (OR = 1.70 [1.00–2.89]) and asthma (OR = 2.00 [1.10–3.63]) at 18 and at 25 years eczema (OR = 6.75 [3.11–14–65]), allergic rhinitis (OR = 2.74 [1.28–5.88]) and asthma (OR = 2.50 [1.25–5.00]). Allergic and food sensitization in early life was more common in those in the persistent eczema subclasses.

Conclusion

We identified five distinct eczema subclasses. These classes were differentially associated with risk factors, suggesting differences in aetiology, and also with the development of allergic outcomes, highlighting their potential to identify high‐risk groups for close monitoring and intervention.

Associations between Body Mass Index Trajectories in the first two years of life and Allergic Rhinitis, Eczema and Food Allergy outcomes up to early adulthood

BACKGROUND

Early life body mass index (BMI) trajectories influence the risk of asthma at 18 years of age. However, it is unclear if these are also associated with other allergic diseases.

OBJECTIVES

We investigated the associations between BMI trajectories and subsequent allergic rhinitis, eczema and food sensitisation/allergies.

METHODS

Parent-reported anthropometric data were collected 18 times in the first two years of life from a cohort of 620 participants in a high-risk cohort. Group-based trajectory modelling was applied to develop BMI trajectories. Associations between trajectories and allergic rhinitis, eczema and food sensitisation at 6, 12 and 18 years of age were assessed using logistic regression models. Potential effect modifications by parental allergic disease, sex and allocated infant formula were assessed.

RESULTS

We identified five BMI trajectories: average, below average, persistently low, early low and catch up, and persistently high. None showed an association with allergic rhinitis. In participants with maternal allergic rhinitis, 'early-low and catch-up' (OR = 2.83;95%CI 1.34-5.96, P_int  = 0.05) and 'below average' trajectories (OR = 2.39; 1.18-7.23, P_int  = 0.02) were associated with allergic rhinitis at 18 years of age compared with the average trajectory. No associations were observed with eczema or food sensitisation.

CONCLUSION

Infants with early-low and catch-up, or below average BMI growth, were at increased risk of allergic rhinitis at 18 years if they had a mother with allergic rhinitis. These results require replication, but suggest that interactions between poor intrauterine growth, failure to thrive and maternal allergies may influence the risk of allergic rhinitis.

Impact of lifetime body mass index trajectories on the incidence and persistence of adult asthma

BACKGROUND

High body mass index trajectories from childhood to adulthood are associated with development of some chronic diseases, but whether such trajectories influence adult asthma has not been investigated to date. Therefore, we investigated associations between body mass index trajectories from childhood to middle age (5-43 years) and incidence, persistence, and relapse of asthma from ages 43 to 53 years.

METHODS

In the Tasmanian Longitudinal Health Study (n= 4194), weight and height were recorded at 8-time points between 5 and 43 years. body mass index trajectories were developed using group-based trajectory modelling. Associations between body mass index trajectories and asthma incidence, persistence, and relapse from 43 to 53 years; bronchial hyper-responsiveness at 50 years; and bronchodilator responsiveness at 53 years were modelled using multiple logistic and linear regression.

RESULTS

Five distinct body mass index trajectories were identified: average, low, high, child high-decreasing, and child average-increasing. Compared to the average trajectory, child average-increasing and high trajectories were associated with increased risk of incident asthma (OR=2.6; 95%CI 1.1, 6.6 and OR=4.4; 1.7, 11.4, respectively) and bronchial hyper-responsiveness in middle age (OR= 2.9; 1.1, 7.5 and OR= 3.5;1.1, 11.4, respectively). No associations were observed for asthma persistence or relapse.

CONCLUSION

Participants with child average-increasing and high body mass index trajectories from childhood to middle age were at higher risk of incident adult asthma. Thus, encouraging individuals to maintain normal body mass index over the life course may help reduce the burden of adult asthma.

Long-term impact of exposure to coalmine fire emitted PM2.5 on emergency ambulance attendances

BACKGROUND

Little is known about the long-term health effects of coalmine fire smoke exposure. The 2014 Hazelwood coalmine fire event in southeast Australia released smoke into surrounding areas for 6 weeks.

OBJECTIVES

We aimed to investigate whether individual-level exposure to coalmine fire-related PM_2.5 was associated with a long-term increase in ambulance attendances following a coalmine fire event.

METHODS

A total of 2223 residents from the most exposed town of Morwell were assessed for ambulance attendances after the Hazelwood event from April 1, 2014 to December 31, 2017. PM_2.5 exposure was estimated for each individual using participant self-reported location diary data during the event and modelled PM_2.5 concentrations. Recurrent event survival analysis was used to evaluate the relationship between PM_2.5 exposure and ambulance attendances.

RESULTS

For each 10 μg/m³ increase in mean coalmine fire-related PM_2.5 exposure, there was a 10% (adjusted hazard ratio [HR]:1.10, 95%CI:1.03-1.17) increase in the overall risk of ambulance attendances within 3.5 years after the coalmine fire. Exposure to PM_2.5 was also associated with increased risk of respiratory (HR: 1.21, 95%CI: 1.02-1.44) and cardiovascular (HR: 1.13, 95%CI: 1.01-1.28) related ambulance attendances.

CONCLUSION

These results demonstrate that exposure to coalmine fire smoke during the Hazelwood event was associated with a long-term health risk post the fire event, specifically for respiratory and cardiovascular conditions. These findings are important for effective implementation of health care services following future extended coalmine fire PM_2.5 events.

The impact of the Hazelwood coal mine fire smoke exposure on asthma

OBJECTIVE

In 2014, a fire at an open cut coal mine in South-eastern Australia burned for about 6 weeks. Residents of the adjacent town were exposed to high levels of fine particulate matter (PM2.5) during this period. Three and a half years after the event, this study aimed to investigate potential long-term impacts of short-term exposure to coal mine fire smoke on asthma.

METHODS

A cross-sectional analysis was undertaken in a group of exposed participants with asthma from Morwell (n = 165) and a group of unexposed participants with asthma from the control town of Sale (n = 64). Exposure was determined by modeled PM2.5 data for the mine fire period. Respiratory symptoms were assessed with a validated respiratory health questionnaire and symptom severity score. Asthma control was assessed with a validated questionnaire. Lung function testing included spirometry, bronchodilator response, and fraction of exhaled nitric oxide.

RESULTS

There was no evidence that exposed participants had more severe asthma symptoms, worse lung function, or more eosinophilic airway inflammation than unexposed participants. However, there was some evidence that Morwell participants had more uncontrolled than well-controlled asthma, compared to the participants from Sale (adjusted relative risk ratio 2.71 95% CI: 1.02, 7.21, p = .046).

CONCLUSION

Three and a half years after exposure, coal mine fire smoke did not appear to be associated with more severe asthma symptoms or worse lung function but might be associated with poorer asthma control.

The effect of long-term radiofrequency exposure on cognition in human observational studies: A protocol for a systematic review

BACKGROUND

The long term effects of exposure to radiofrequency (RF) electromagnetic fields (EMF) for frequencies from 100 kHz to 300 GHz on cognitive performance are best assessed using observational studies. In recent years, the use of mobile (cell) phones has been the main source of RF EMF exposure to the brain, although other sources of exposure may be significant. Cognitive function includes various mental and psychological abilities, which can be measured in a range of domains, such as learning, memory, reasoning, problem solving, decision making and attention. Although effects on cognitive function may be most evident later in life, in the experimental setting acute and immediate effects can only be studied. Observational studies are needed when effects are observed after months or years following short or long-term exposure. The importance of the effects of exposure on children has also been recently identified.

OBJECTIVES

To assess the long-term effects of RF EMF local and whole-body exposure compared to no or a lower level of exposure on indicators of cognition, including complex attention, executive function, learning and memory, perceptual motor ability and social cognition, but excluding cognitive effects caused by neurodegenerative diseases or neurodevelopmental disorders, and to assess if there is evidence of a dose response relationship.

STUDY ELIGIBILITY AND CRITERIA

We will include observational studies that have evaluated cognitive effects of RF energy including a comparator group with a different level of exposure. Studies must report at least one validated measure of cognitive function, including global or domain specific measures, or cognitive impairment, with a minimum follow-up of 6 months. Cohort or case-control studies published in the peer review literature in any language are eligible. We will exclude cross-sectional studies and any that only report brain structure or biomarkers.

STUDY APPRAISAL AND SYNTHESIS METHOD

We will conduct searches of PubMed, Embase, PsycINFO and the EMF-Portal. At least two authors will independently screen the titles/abstracts of all records, with any conflicts resolved by a third reviewer. Full-text screening will also be conducted independently by two authors with conflicts resolved by consensus. Data will be extracted from the studies included, such as identifiers and characteristics of the study design, exposure and comparator groups, participants, outcomes assessed and results. Risk of bias will be assessed with the Office of Health Assessment and Translation (OHAT) tool. We will conduct a meta-analysis of similar studies with a random effects model in STATA or similar software, if two or more studies are available for a given exposure-outcome combination. Confidence in the body evidence will be judged using GRADE methods as adapted by OHAT for reviews of environmental exposures.

Parental preconception BMI trajectories from childhood to adolescence and asthma in the future offspring

BACKGROUND

Recent evidence suggests that parental exposures before conception can increase the risk of asthma in offspring.

OBJECTIVE

We investigated the association between parental preconception Body Mass Index (BMI) trajectories from childhood to adolescence and subsequent risk of asthma in their offspring.

METHODS

Using group-based trajectory modeling from the Tasmanian Longitudinal Health Study (TAHS), we identified BMI trajectories for index participants (parents) when aged 4 to 15 years. Multinomial regression models adjusted for potential confounders were utilized to estimate the association between these early-life parental BMI trajectories and asthma phenotypes in their subsequent offspring.

RESULTS

The main analysis included 1822 parents and 4208 offspring. Four BMI trajectories from age 4 to 15 years were identified as the best fitting model: "low" (8.8%); "normal" (44.1%); "above normal" (40.2%); and "high" (7.0%). Associations were observed between father's "high" BMI trajectory and risk of asthma in offspring before the age of 10 years (RRR=1.70, 95%CI 0.98, 2.93) and also asthma ever (RRR=1.72, 95%CI 1.00, 2.97), especially allergic asthma ever (RRR=2.05, 95%CI 1.12, 3.72). These associations were not mediated by offspring birth weight. No associations were observed for maternal BMI trajectories and offspring asthma phenotypes.

CONCLUSION

This cohort study over six decades of life and across two generations suggests that the "high BMI" trajectory in fathers, well before conception, increased the risk of asthma in their offspring.

Long-term impacts of coal mine fire-emitted PM2.5 on hospitalisation: a longitudinal analysis of the Hazelwood Health Study

BACKGROUND

Little is known about the long-term health impacts of exposures to landscape fire smoke. We aimed to evaluate the association between exposure to coal mine fire-related particulate matter 2.5 μm or less in diameter (PM2.5) and hospitalisation in the 5 years following the 6-week Hazelwood coal mine fire in Australia in 2014.

METHODS

We surveyed 2725 residents (mean age: 58.3 years; 54.3% female) from an exposed and a comparison town. Individual PM2.5 exposures during the event were estimated using modelled PM2.5 concentrations related to the coal mine fire and self-reported location data. The individual exposure and survey data were linked with hospitalisation records between January 2009 and February 2019. Recurrent event survival analysis was used to evaluate relationships between PM2.5 exposure and hospitalisation following mine fire, adjusting for important covariates.

RESULTS

Each 10-µg/m3 increase in mine fire-related PM2.5 was associated with a 9% increased hazard [hazard ratio (HR) = 1.09; 95% confidence interval (CI): 1.01, 1.17] of respiratory hospitalisation over the next 5 years, with stronger associations observed for females (HR = 1.16; 95% CI: 1.06, 1.27) than males (HR = 0.99; 95% CI: 0.89, 1.11). In particular, increased hazards were observed for hospitalisations for asthma (HR = 1.43; 95% CI: 1.19, 1.73) and chronic obstructive pulmonary disease (HR = 1.14; 95% CI: 1.02, 1.28). No such association was found for hospitalisations for cardiovascular diseases, mental illness, injuries, type 2 diabetes, renal diseases or neoplasms.

CONCLUSIONS

A 6-week exposure to coal mine fire-related PM2.5 was associated with increased hazard of respiratory hospitalisations over the following 5 years, particularly for females.

Ten-year prediction model for post-bronchodilator airflow obstruction and early detection of COPD: development and validation in two middle-aged population-based cohorts

Background

Classifying individuals at high chronic obstructive pulmonary disease (COPD)-risk creates opportunities for early COPD detection and active intervention.

Objective

To develop and validate a statistical model to predict 10-year probabilities of COPD defined by post-bronchodilator airflow obstruction (post-BD-AO; forced expiratory volume in 1 s/forced vital capacity<5th percentile).

Setting

General Caucasian populations from Australia and Europe, 10 and 27 centres, respectively.

Participants

For the development cohort, questionnaire data on respiratory symptoms, smoking, asthma, occupation and participant sex were from the Tasmanian Longitudinal Health Study (TAHS) participants at age 41–45 years (n=5729) who did not have self-reported COPD/emphysema at baseline but had post-BD spirometry and smoking status at age 51–55 years (n=2407). The validation cohort comprised participants from the European Community Respiratory Health Survey (ECRHS) II and III (n=5970), restricted to those of age 40–49 and 50–59 with complete questionnaire and spirometry/smoking data, respectively (n=1407).

Statistical method

Risk-prediction models were developed using randomForest then externally validated.

Results

Area under the receiver operating characteristic curve (AUC_ROC) of the final model was 80.8% (95% CI 80.0% to 81.6%), sensitivity 80.3% (77.7% to 82.9%), specificity 69.1% (68.7% to 69.5%), positive predictive value (PPV) 11.1% (10.3% to 11.9%) and negative predictive value (NPV) 98.7% (98.5% to 98.9%). The external validation was fair (AUC_ROC 75.6%), with the PPV increasing to 17.9% and NPV still 97.5% for adults aged 40–49 years with ≥1 respiratory symptom. To illustrate the model output using hypothetical case scenarios, a 43-year-old female unskilled worker who smoked 20 cigarettes/day for 30 years had a 27% predicted probability for post-BD-AO at age 53 if she continued to smoke. The predicted risk was 42% if she had coexistent active asthma, but only 4.5% if she had quit after age 43.

Conclusion

This novel and validated risk-prediction model could identify adults aged in their 40s at high 10-year COPD-risk in the general population with potential to facilitate active monitoring/intervention in predicted ‘COPD cases’ at a much earlier age.

Exposure to mine fire related particulate matter and mortality: A time series analysis from the Hazelwood Health Study

BACKGROUND

In 2014, the Morwell brown coal mine, located in the Latrobe Valley of South eastern Australia, caught fire covering nearby areas in plumes of smoke over a 6-week period.

AIMS

To investigate the association between exposure to mine fire related air pollution and the risk of mortality.

METHODS

Time series models were used to evaluate the risk of mortality during the first 30 days of the mine fire, when the smoke was most intense, and in the following six months. Associations were also investigated between mine fire related PM_2.5 and mortality.

RESULTS

During the 30-day mine fire period, there was an increased risk of death from injury in the most exposed town of Morwell, however no increased risk was observed for all-cause, cardiovascular or respiratory mortality. In the broader Latrobe Valley, males and residents aged 80 and above were at greatest risk of death from injury during the mine fire. In Morwell, during the six months after the mine fire there was an increased risk of all-cause mortality and death from Ischaemic Heart Disease (IHD). Males and residents aged 80 and above in the broader Latrobe Valley, were at increased risk of death from IHD six months after the fire.

CONCLUSIONS

Coal mine fire exposure was associated with an increase in injury deaths during the mine fire and cardiovascular deaths in the six months after the fire. These findings assist in identifying at risk groups, and improving targeted health advice for future air pollution exposures in the community.

Impacts of High Concentration, Medium Duration Coal Mine Fire Related PM2.5 on Cancer Incidence: 5-Year Follow-Up of the Hazelwood Health Study

No studies have investigated the cancer outcomes from high level medium duration coal mine fire fine particulate matter ⩽2.5 µm in diameter (PM_2.5) exposure. We included 2208 Morwell residents (exposed) and 646 Sale residents (unexposed) who participated in the Hazelwood Health Study Adult Survey. Competing risk regression models were used to evaluate relationships between coal mine fire exposure and cancer incidence, adjusting for known confounders. There were 137 cancers in the exposed and 27 in the unexposed over 14 849 person-years of follow-up. A higher risk of cancer incidence was observed for Morwell participants (HR = 1.67 [95% CI 1.05-2.67]), but no evidence to suggest associations between PM_2.5 exposure and incidence of all cancers (HR = 1.02 [95% CI 0.91-1.13]), or site-specific cancers. There is no strong evidence that exposure to high concentrations of mine fire-related PM_2.5 over a prolonged period could explain the higher risk in exposed population in this study.

Normal limits for oscillometric bronchodilator responses and relationships with clinical factors

Introduction

We aimed to determine normal thresholds for positive bronchodilator responses for oscillometry in an Australian general population sample aged ≥40 years, to guide clinical interpretation. We also examined relationships between bronchodilator responses and respiratory symptoms, asthma diagnosis, smoking and baseline lung function.

Methods

Subjects recruited from Sydney, Melbourne and Busselton, Australia, underwent measurements of spirometry, resistance (R_rs6) and reactance (X_rs6) at 6 Hz, before and after inhalation of salbutamol 200 μg. Respiratory symptoms and/or medication use, asthma diagnosis, and smoking were recorded. Threshold bronchodilator responses were defined as the fifth percentile of decrease in R_rs6 and 95th percentile increase in X_rs6 in a healthy subgroup.

Results

Of 1318 participants, 1145 (570 female) were analysed. The lower threshold for ΔR_rs6 was −1.38 cmH₂O·s·L⁻¹ (−30.0% or −1.42 Z-scores) and upper threshold for ΔX_rs6 was 0.57 cmH₂O·s·L⁻¹ (1.36 Z-scores). Respiratory symptoms and/or medication use, asthma diagnosis, and smoking all predicted bronchodilator response, as did baseline oscillometry and spirometry. When categorised into clinically relevant groups according to those predictors, ΔX_rs6 was more sensitive than spirometry in smokers without current asthma or chronic obstructive pulmonary disease (COPD), ∼20% having a positive response. Using absolute or Z-score change provided similar prevalences of responsiveness, except in COPD, in which responsiveness measured by absolute change was twice that for Z-score.

Discussion

This study describes normative thresholds for bronchodilator responses in oscillometry parameters, including intra-breath parameters, as determined by absolute, relative and Z-score changes. Positive bronchodilator response by oscillometry correlated with clinical factors and baseline function, which may inform the clinical interpretation of oscillometry.

Normative values for bronchodilator responses measured by oscillometry were derived. Responsiveness related to clinical factors and baseline function. Reactance was more sensitive in detecting bronchodilator response than spirometry mild airways disease.https://bit.ly/3wtWVeV

Risk factors for chronic cough in adults: A systematic review and meta-analysis

Despite the challenges of diagnosing and managing adult patients with chronic cough, a systematic synthesis of evidence on aetiological risk factor is lacking. We systematically searched PubMed and EMBASE to synthesize the current evidence for longitudinal associations between a wide range of risk factors and chronic cough in the general adult population, following the meta-analysis of observational studies in epidemiology (MOOSE) guidelines. The Newcastle-Ottawa scale was used to assess the quality of the included studies. Fixed-effect meta-analysis was conducted where appropriate. Of 26 eligible articles, 16 domains of risk factors were assessed. There was consistent evidence that asthma (pooled adjusted OR [aOR] = 3.01; 95% CI: 2.33-3.70; I²  = 0%; number of articles [N] = 3) and low education levels/socioeconomic status (SES) (pooled aOR = 1.46; 95% CI: 1.20-1.72; I²  = 0%; N = 3) were associated with an increased risk of chronic cough after adjusting for smoking and other confounders. While continuous smoking was associated with chronic cough (aOR = 1.81; 95% CI: 1.36-2.26; I²  = 57%; N = 3), there was too little evidence to draw conclusions for occupational exposures, outdoor air pollution, early-life exposures, diet, snoring and other chronic conditions, including obesity, chronic obstructive pulmonary disease, gastro-oesophageal reflux disease and chronic pain. Asthma, persistent smoking and lower education/SES were associated with an increased risk of chronic cough. Longitudinal associations between other factors frequently mentioned empirically (i.e., occupational exposures, air pollution and chronic respiratory conditions) need further investigation, ideally with objective and standardized measurement.

Childhood lung function as a determinant of menopause-dependent lung function decline

RATIONALE

The naturally occurring age-dependent decline in lung function accelerates after menopause, likely due to the change of the endocrine balance. Although increasing evidence shows suboptimal lung health in early life can increase adult  susceptibility to insults, the potential effect of poor childhood lung function on menopause-dependent lung function decline has not yet been investigated.

OBJECTIVES

To study whether menopause-dependent lung function decline, assessed as forced vital capacity (FVC) and forced expiratory volume in one second (FEV1), is determined by childhood lung function.

METHODS

The Tasmanian Longitudinal Health Study, a cohort born in 1961, underwent spirometry at age seven.  At ages 45 and 50 serum samples, spirometry and questionnaire data were collected (N = 506). We measured follicle stimulating and luteinizing hormones to determine menopausal status using latent profile analysis. The menopause-dependent lung function decline was investigated using linear mixed models, adjusted for anthropometrics, occupational level, smoking, asthma, asthma medication and study year, for the whole study population and stratified by tertiles of childhood lung function.

MEASUREMENTS AND MAIN RESULTS

The overall menopause-dependent lung function decline was 19.3 mL/y (95%CI 2.2 to 36.3) for FVC and 9.1 mL/y (-2.8 to 21.0) for FEV1. This was most pronounced (pinteraction=0.03) among women within the lowest tertile of childhood lung function [FVC 22.2 mL/y (1.1 to 43.4); FEV1 13.9 mL/y (-1.5 to 29.4)].

CONCLUSIONS

Lung function declines especially rapidly in postmenopausal women who had poor low lung function in childhood. This provides novel insights into respiratory health during reproductive aging and emphasizes the need for holistic public health strategies covering the whole lifespan.

Protein levels, air pollution and vitamin D deficiency: links with allergy

This study provides novel insights into mechanisms of traffic-related air pollution-induced allergy by down-regulation via complement regulators (CFI, PROS1 and PLG) and its interaction with vitamin D deficiency via the complement inhibitor PLG https://bit.ly/3x0jYOw.

Laryngeal hypersensitivity and abnormal cough response during mannitol bronchoprovocation challenge

BACKGROUND AND OBJECTIVE

Inhalational challenge with dry mannitol powder may potentially induce cough by two mechanisms: airway bronchoconstriction or laryngeal irritation. This prospective observational study investigated laryngeal and bronchial components of cough induced by mannitol challenge.

METHODS

We recruited consecutive patients referred for clinical mannitol challenge. The Newcastle Laryngeal Hypersensitivity Questionnaire (LHQ) was administered. Throughout testing, coughs were audio-recorded to derive a cough frequency index per time and dose of mannitol. Relationships between cough indices, laryngeal hypersensitivity and bronchial hyperresponsiveness (BHR) were examined. Participants were classified by cough characteristics with k-means cluster analysis.

RESULTS

Of 90 patients who underwent challenge, 83 completed both the questionnaire and challenge. Cough frequency was greater in patients with abnormal laryngeal hypersensitivity (p = 0.042), but not in those with BHR. There was a moderate negative correlation between coughs per minute and laryngeal hypersensitivity score (r = -0.315, p = 0.004), with lower LHQ scores being abnormal. Cluster analysis identified an older, female-predominant cluster with higher cough frequency and laryngeal hypersensitivity, and a younger, gender-balanced cluster with lower cough frequency and normal laryngeal sensitivity.

CONCLUSION

Cough frequency during mannitol challenge in our cohort reflected laryngeal hypersensitivity rather than BHR. Laryngeal hypersensitivity was more often present among older female patients. With the incorporation of cough indices, mannitol challenge may be useful to test for laryngeal hypersensitivity as well as BHR.

Health and related economic benefits associated with reduction in air pollution during COVID-19 outbreak in 367 cities in China

Due to the COVID-19 outbreak, the Chinese government implemented nationwide traffic restrictions and self-quarantine measures from January 23 to April 8 (in Wuhan), 2020. We estimated how these measures impacted ambient air pollution and the subsequent consequences on health and the health-related economy in 367 Chinese cities. A random forests modeling was used to predict the business-as-usual air pollution concentrations in 2020, after adjusting for the impact of long-term trend and weather conditions. We calculated changes in mortality attributable to reductions in air pollution in early 2020 and health-related economic benefits based on the value of statistical life (VSL). Compared with the business-as-usual scenario, we estimated 1239 (95% CI: 844-1578) PM_2.5-related deaths were avoided, as were 2777 (95% CI: 1565-3995) PM₁₀-related deaths, 1587 (95% CI: 98-3104) CO-related deaths, 4711 (95% CI: 3649-5781) NO₂-related deaths, 215 (95% CI: 116-314) O₃-related deaths, and 1088 (95% CI: 774-1421) SO₂-related deaths. Based on the reduction in deaths, economic benefits for in PM_2.5, PM₁₀, CO, NO₂, O₃, and SO₂ were 1.22, 2.60, 1.36, 4.05, 0.20, and 0.95 billion USD, respectively. Our findings demonstrate the substantial benefits in human health and health-related costs due to improved urban air quality during the COVID lockdown period in China in early 2020.

Lung function trajectory and biomarkers in the Tasmanian Longitudinal Health Study

Background and objective

Different lung function trajectories through life can lead to COPD in adulthood. This study investigated whether circulating levels of biomarkers can differentiate those with accelerated (AD) from normal decline (ND) trajectories.

Methods

The Tasmanian Longitudinal Health Study (TAHS) is a general population study that measured spirometry and followed up participants from ages 7 to 53 years. Based on their forced expiratory volume in 1 s (FEV₁) trajectories from age 7 to 53 years, this analysis included those with COPD at age 53 years (60 with AD and 94 with ND) and controls (n=720) defined as never-smokers with an average FEV₁ trajectory. Circulating levels of selected biomarkers determined at 53 and 45 years of age were compared between trajectories.

Results

Results showed that CC16 levels (an anti-inflammatory protein) were lower and C-reactive protein (CRP) (a pro-inflammatory marker) higher in the AD than in the ND trajectory. Higher CC16 levels were associated with a decreased risk of belonging to the AD trajectory (OR=0.79 (0.63-0.98) per unit increase) relative to ND trajectory. Higher CRP levels were associated with an increased risk of belonging to the AD trajectory (OR=1.07, 95% CI: 1.00-1.13, per unit increase). Levels of CC16 (area under the curve (AUC)=0.69, 95% CI: 0.56-0.81, p=0.002), CRP (AUC=0.63, 95% CI: 0.53-0.72, p=0.01) and the combination of both (AUC=0.72, 95% CI: 0.60-0.83, p<0.001) were able to discriminate between the AD and ND trajectories. Other quantified biomarkers (interleukin (IL)-4, IL-5, IL-6, IL-10 and tumour necrosis factor-α (TNF-α)) were not significantly different between AD, ND and controls.

Conclusions

Circulating levels of CRP and CC16 measured in late adulthood identify different lung function trajectories (AD versus ND) leading to COPD at age 53 years.

Ambient temperature and genome-wide DNA methylation: A twin and family study in Australia

Little is known about the association between ambient temperature and DNA methylation, which is a potential biological process through which ambient temperature affects health. This study aimed to evaluate the association between ambient temperature and DNA methylation across human genome. We included 479 Australian women, including 132 twin pairs and 215 sisters of these twins. Blood-derived DNA methylation was measured using the HumanMethylation450 BeadChip array. Data on average ambient temperature during eight different exposure windows [lag0d (the blood draw day), lag0-7d (the current day and previous seven days prior to blood draw), lag0-14d, lag0-21d, lag0-28d, lag0-90d, lag0-180d, and lag0-365d)] was linked to each participant's home address. For each cytosine-guanine dinucleotide (CpG), we evaluated the association between its methylation level and temperature using generalized estimating equations (GEE), adjusting for important covariates. We used comb-p and DMRcate to identify differentially methylated regions (DMRs). We identified 31 CpGs at which blood DNA methylation were significantly associated with ambient temperature with false discovery rate [FDR] < 0.05. There were 82 significant DMRs identified by both comb-p (Sidak p-value < 0.01) and DMRcate (FDR < 0.01). Most of these CpGs and DMRs only showed association with temperature during one specific exposure window. These CpGs and DMRs were mapped to 85 genes. These related genes have been related to many human chronic diseases or phenotypes (e.g., diabetes, arthritis, breast cancer, depression, asthma, body height) in previous studies. The signals of short-term windows (lag0d and lag0-21d) showed enrichment in biological processes related to cell adhesion. In conclusion, short-, medium-, and long-term exposures to ambient temperature were all associated with blood DNA methylation, but the target genomic loci varied by exposure window. These differential methylation signals may serve as potential biomarkers to understand the health impacts of temperature.

Predictors of lung function trajectories in population-based studies: A systematic review

Despite the growing body of evidence on lung function trajectories over the life course and their risk factors, the literature has not been systematically synthesized. Publications related to lung function trajectories were identified from PubMed, EMBASE and CINAHL databases. Two authors independently identified publications for inclusion according to predefined selection criteria. Studies that modelled lung function trajectories and reported associated exposures were included. Meta-analyses could not be conducted due to heterogeneity in the exposures and methods used to model lung function trajectories. Nine publications were eligible for inclusion of which four used group-based trajectory modelling to model lung function trajectories, while five used latent profile analysis. Studies with repeated lung function measurements over the life course identified more trajectories than others. Only one study spanning from childhood to middle age reported catch-up trajectory. The following childhood risk factors for subnormal lung function trajectories were observed in at least across two studies: low birth weight, early wheezing, asthma, allergic sensitization, eczema, allergic rhinitis, lower respiratory tract infections, family history of asthma and second-hand smoke exposure. Adult active asthma and personal cigarette smoking were observed to be associated with accelerated decline lung trajectories. Our review identified 10 risk factors associated with the growth, catch-up, reduced plateau and decline trajectories of lung function. Intervention directed at childhood asthma and infections, and tobacco smoke exposure at all ages would help promote lung health and prevent subnormal lung function trajectories.

The impacts of long-term exposure to PM2.5 on cancer hospitalizations in Brazil

BACKGROUND

Long-term exposure to PM_2.5 has been linked to cancer incidence and mortality. However, it was unknown whether there was an association with cancer hospitalizations.

METHODS

Data on cancer hospitalizations and annual PM_2.5 concentrations were collected from 1,814 Brazilian cities during 2002-2015. A difference-in-difference approach with quasi-Poisson regression was applied to examine State-specific associations. The State-specific associations were pooled at a national level using random-effect meta-analyses. PM_2.5 attributable burden were estimated for cancer hospitalization admissions, inpatient days and costs.

RESULTS

We included 5,102,358 cancer hospitalizations (53.8% female). The mean annual concentration of PM_2.5 was 7.0 μg/m³ (standard deviation: 4.0 μg/m³). With each 1 μg/m³ increase in two-year-average (current year and previous one year) concentrations of PM_2.5, the relative risks (RR) of hospitalization were 1.04 (95% confidence interval [CI]: 1.02 to 1.07) for all-site cancers from 2002 to 2015 without sex and age differences. We estimated that 33.82% (95%CI: 14.97% to 47.84%) of total cancer hospitalizations could be attributed to PM_2.5 exposure in Brazil during the study time. For every 100,000 population, 1,190 (95%CI: 527 to 1,836) cancer hospitalizations, 8,191 (95%CI: 3,627 to 11,587) inpatient days and US$788,775 (95%CI: $349,272 to $1,115,825) cost were attributable to PM_2.5 exposure.

CONCLUSIONS

Long-term exposure to ambient PM_2.5 was positively associated with hospitalization for many cancer types in Brazil. Inpatient days and cost would be saved if the annual PM_2.5 exposure was reduced.

Residential surrounding greenness and DNA methylation: An epigenome-wide association study

BACKGROUND

DNA methylation is a potential biological mechanism through which residential greenness affects health, but little is known about its association with greenness and whether the association could be modified by genetic background. We aimed to evaluate the association between surrounding greenness and genome-wide DNA methylation and potential gene-greenness interaction effects on DNA methylation.

METHODS

We measured blood-derived DNA methylation using the HumanMethylation450 BeadChip array (Illumina) for 479 Australian women, including 66 monozygotic, 66 dizygotic twin pairs, and 215 sisters of these twins. Surrounding greenness was represented by Normalized Difference Vegetation Index (NDVI) and Enhanced Vegetation Index (EVI) within 300, 500, 1000 or 2000 m surrounding participants' home addresses. For each cytosine-guanine dinucleotide (CpG), the associations between its methylation level and NDVI or EVI were evaluated by generalized estimating equations, after adjusting for age, education, marital status, area-level socioeconomic status, smoking behavior, cell-type proportions, and familial clustering. We used comb-p and DMRcate to identify significant differentially methylated regions (DMRs). For each significant CpG, we evaluated the interaction effects of greenness and single-nucleotide polymorphisms (SNPs) within ±1 Mb window on its methylation level.

RESULTS

We found associations between surrounding greenness and blood DNA methylation for one CpG (cg04720477, mapped to the promoter region of CNP gene) with false discovery rate [FDR] < 0.05, and for another 9 CpGs with 0.05 ≤ FDR < 0.10. For two of these CpGs, we found 33 SNPs significantly (FDR < 0.05) modified the greenness-methylation association. There were 35 significant DMRs related to surrounding greenness that were identified by both comb-p (Sidak p-value < 0.01) and DMRcate (FDR < 0.01). Those CpGs and DMRs were mapped to genes related to many human diseases, such as mental health disorders and neoplasms as well as nutritional and metabolic diseases.

CONCLUSIONS

Surrounding greenness was associated with blood DNA methylation of many loci across human genome, and this association could be modified by genetic variations.

Mortality risk attributable to wildfire-related PM2·5 pollution: a global time series study in 749 locations

BACKGROUND

Many regions of the world are now facing more frequent and unprecedentedly large wildfires. However, the association between wildfire-related PM_2·5 and mortality has not been well characterised. We aimed to comprehensively assess the association between short-term exposure to wildfire-related PM_2·5 and mortality across various regions of the world.

METHODS

For this time series study, data on daily counts of deaths for all causes, cardiovascular causes, and respiratory causes were collected from 749 cities in 43 countries and regions during 2000-16. Daily concentrations of wildfire-related PM_2·5 were estimated using the three-dimensional chemical transport model GEOS-Chem at a 0·25° × 0·25° resolution. The association between wildfire-related PM_2·5 exposure and mortality was examined using a quasi-Poisson time series model in each city considering both the current-day and lag effects, and the effect estimates were then pooled using a random-effects meta-analysis. Based on these pooled effect estimates, the population attributable fraction and relative risk (RR) of annual mortality due to acute wildfire-related PM_2·5 exposure was calculated.

FINDINGS

65·6 million all-cause deaths, 15·1 million cardiovascular deaths, and 6·8 million respiratory deaths were included in our analyses. The pooled RRs of mortality associated with each 10 μg/m³ increase in the 3-day moving average (lag 0-2 days) of wildfire-related PM_2·5 exposure were 1·019 (95% CI 1·016-1·022) for all-cause mortality, 1·017 (1·012-1·021) for cardiovascular mortality, and 1·019 (1·013-1·025) for respiratory mortality. Overall, 0·62% (95% CI 0·48-0·75) of all-cause deaths, 0·55% (0·43-0·67) of cardiovascular deaths, and 0·64% (0·50-0·78) of respiratory deaths were annually attributable to the acute impacts of wildfire-related PM_2·5 exposure during the study period.

INTERPRETATION

Short-term exposure to wildfire-related PM_2·5 was associated with increased risk of mortality. Urgent action is needed to reduce health risks from the increasing wildfires.

FUNDING

Australian Research Council, Australian National Health & Medical Research Council.

Mortality risk attributable to wildfire-related PM2·5 pollution: a global time series study in 749 locations

BACKGROUND

Many regions of the world are now facing more frequent and unprecedentedly large wildfires. However, the association between wildfire-related PM2·5 and mortality has not been well characterised. We aimed to comprehensively assess the association between short-term exposure to wildfire-related PM2·5 and mortality across various regions of the world.

METHODS

For this time series study, data on daily counts of deaths for all causes, cardiovascular causes, and respiratory causes were collected from 749 cities in 43 countries and regions during 2000-16. Daily concentrations of wildfire-related PM2·5 were estimated using the three-dimensional chemical transport model GEOS-Chem at a 0·25° × 0·25° resolution. The association between wildfire-related PM2·5 exposure and mortality was examined using a quasi-Poisson time series model in each city considering both the current-day and lag effects, and the effect estimates were then pooled using a random-effects meta-analysis. Based on these pooled effect estimates, the population attributable fraction and relative risk (RR) of annual mortality due to acute wildfire-related PM2·5 exposure was calculated.

FINDINGS

65·6 million all-cause deaths, 15·1 million cardiovascular deaths, and 6·8 million respiratory deaths were included in our analyses. The pooled RRs of mortality associated with each 10 μg/m3 increase in the 3-day moving average (lag 0-2 days) of wildfire-related PM2·5 exposure were 1·019 (95% CI 1·016-1·022) for all-cause mortality, 1·017 (1·012-1·021) for cardiovascular mortality, and 1·019 (1·013-1·025) for respiratory mortality. Overall, 0·62% (95% CI 0·48-0·75) of all-cause deaths, 0·55% (0·43-0·67) of cardiovascular deaths, and 0·64% (0·50-0·78) of respiratory deaths were annually attributable to the acute impacts of wildfire-related PM2·5 exposure during the study period.

INTERPRETATION

Short-term exposure to wildfire-related PM2·5 was associated with increased risk of mortality. Urgent action is needed to reduce health risks from the increasing wildfires.

FUNDING

Australian Research Council, Australian National Health & Medical Research Council.