Can We Use Lung Function Thresholds and Respiratory Symptoms to Identify Pre-Chronic Obstructive Pulmonary Disease? A Prospective, Population-based Cohort Study.

Rationale: The term "pre-chronic obstructive pulmonary disease" ("pre-COPD") refers to individuals at high risk of developing COPD who do not meet conventional spirometric criteria for airflow obstruction. New approaches to identifying these individuals are needed, particularly in younger populations. Objectives: To determine whether lung function thresholds and respiratory symptoms can be used to identify individuals at risk of developing COPD. Methods: The Tasmanian Longitudinal Health Study comprises a population-based cohort first studied in 1968 (at age 7 yr). Respiratory symptoms, pre- and post-bronchodilator (BD) spirometry, diffusing capacity, and static lung volumes were measured in a subgroup at age 45, and the incidence of COPD was assessed at age 53. For each lung function measure, z-scores were calculated using Global Lung Function Initiative references. The optimal threshold for best discrimination of COPD incidence was determined by the unweighted Youden index. Measurements and Main Results: Among 801 participants who did not have COPD at age 45, the optimal threshold for COPD incidence by age 53 was pre-BD FEV1/FVC z-score less than -1.264, corresponding to the lowest 10th percentile. Those below this threshold had a 36-fold increased risk of developing COPD over an 8-year follow-up period (risk ratio, 35.8; 95% confidence interval, 8.88 to 144), corresponding to a risk difference of 16.4% (95% confidence interval, 3.7 to 67.4). The sensitivity was 88%, and the specificity was 87%. Positive and negative likelihood ratios were 6.79 and 0.14, respectively. Respiratory symptoms, post-BD spirometry, diffusing capacity, and static lung volumes did not improve on the classification achieved by pre-BD FEV1/FVC alone. Conclusions: This is the first study, to our knowledge, to evaluate the discriminatory accuracy of spirometry, diffusing capacity, and static lung volume thresholds for COPD incidence in middle-aged adults. Our findings support the inclusion of pre-BD spirometry in the physiological definition of pre-COPD and indicate that pre-BD FEV1/FVC at the 10th percentile accurately identifies individuals at high risk of developing COPD in community-based settings.

Small for gestational age is associated with reduced lung function in middle age: A prospective study from first to fifth decade of life.

BACKGROUND AND OBJECTIVE: The association between birth weight, particularly relative to gestational age, and adult lung function is uncertain. We investigated the associations between birth weight relative to gestational age and measures of lung function in middle age, and mediation of these associations by adult height. METHODS: Participants in the Tasmanian Longitudinal Health Study who had both known birth weight and lung function assessment at age 45 years were included (n = 849). Linear regression models were fitted to investigate the association between small for gestational age and birth weight with post-bronchodilator lung function measures (forced expiratory volume in 1 second [FEV1 ], forced vital capacity [FVC], FEV1 /FVC, diffusing capacity for carbon monoxide [DL co], residual volume [RV] and total lung capacity [TLC]), adjusting for potential confounders. The contribution of adult height as a mediator of these associations was investigated. RESULTS: Compared with infants born with normal weight for gestational age, those born small for gestational age had reduced FEV1 (coefficient: -191 ml [95%CI: -296, -87]), FVC (-205 ml [-330, -81]), TLC (-292 ml [-492, -92]), RV (-126 ml [-253, 0]) and DL co (-0.42 mmol/min/kPa [-0.79, -0.041]) at age 45 years. However, they had comparable FEV1 /FVC. For every 1 kg increase in birth weight, lung function indices increased by an average of 117 ml (95%CI: 40, 196) for FEV1 , 124 ml (30, 218) for FVC, 215 ml (66, 365) for TLC and 0.36 mmol/min/kPa (0.11, 0.62) for DL co, independent of gestational age, but again not for FEV1 /FVC. These associations were significantly mediated by adult height (56%-90%). CONCLUSION: Small for gestational age was associated with reduced lung function that is likely due to smaller lungs with little evidence of any specific parenchymal impairment.

Risk factors and clinical characteristics of breathlessness in Australian adults: Data from the BOLD Australia study.

BACKGROUND: Breathlessness is a common symptom related to a significant health burden. However, the association of breathlessness with clinical characteristics, especially objective pulmonary test results is scarce. We aimed to identify the characteristics independently associated with breathlessness in Australian adults. METHOD: The analysis used data from BOLD Australia, a cross-sectional study that included randomly selected adults aged ≥40 years from six sites in Australia. Clinical characteristics and spirometry results were compared for breathlessness (modified Medical Research Council [mMRC] grade ≥2). RESULTS: Among all respondents (n = 3321), 252 participants (7.6%) reported breathlessness. The main univariate associations were obesity, chronic respiratory diseases, heart diseases and being Indigenous Australians (odds ratios [ORs] = 2.78, 5.20, 3.77 and 4.38, respectively). Participants with breathlessness had lower pre-and post-bronchodilator lung function than those without. Impaired spirometry results including FVC or FEV1 below 80% predicted, or FEV1/FVC < LLN were independently associated with breathlessness (adjusted ORs = 2.66, 2.94 and 2.34, respectively). CONCLUSIONS: Breathlessness is common among Australian adults and is independently associated with obesity, chronic respiratory diseases, heart diseases, being Indigenous Australians, and impaired spirometry. Multi-disciplinary assessment and comprehensive investigation is needed in clinical practice to address the many factors associated with breathlessness in the population.

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

BACKGROUND: High body mass index (BMI) trajectories from childhood to adulthood are associated with the development of some chronic diseases, but whether such trajectories influence adult asthma has not been investigated to date. Therefore, we investigated associations between BMI 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 eight time-points between 5 and 43 years of age. BMI trajectories were developed using group-based trajectory modelling. Associations between BMI trajectories and asthma incidence, persistence and relapse from age 43 to 53 years, bronchial hyperresponsiveness (BHR) at age 50 years, and bronchodilator responsiveness at age 53 years were modelled using multiple logistic and linear regression. RESULTS: Five distinct BMI trajectories were identified: average, low, child high-decreasing, child average-increasing and high. Compared with 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, 95% CI 1.7-11.4, respectively) and BHR in middle age (OR 2.9, 95% CI 1.1-7.5 and OR 3.5, 95% CI 1.1-11.4, respectively). No associations were observed for asthma persistence or relapse. CONCLUSIONS: Participants with child average-increasing and high BMI trajectories from childhood to middle age were at higher risk of incident adult asthma. Thus, encouraging individuals to maintain a normal BMI over the life course may help reduce the burden of adult asthma.

Phenological sensitivity to climate across taxa and trophic levels.

Differences in phenological responses to climate change among species can desynchronise ecological interactions and thereby threaten ecosystem function. To assess these threats, we must quantify the relative impact of climate change on species at different trophic levels. Here, we apply a Climate Sensitivity Profile approach to 10,003 terrestrial and aquatic phenological data sets, spatially matched to temperature and precipitation data, to quantify variation in climate sensitivity. The direction, magnitude and timing of climate sensitivity varied markedly among organisms within taxonomic and trophic groups. Despite this variability, we detected systematic variation in the direction and magnitude of phenological climate sensitivity. Secondary consumers showed consistently lower climate sensitivity than other groups. We used mid-century climate change projections to estimate that the timing of phenological events could change more for primary consumers than for species in other trophic levels (6.2 versus 2.5-2.9 days earlier on average), with substantial taxonomic variation (1.1-14.8 days earlier on average).

Relationship between concavity of the flow-volume loop and small airway measures in smokers with normal spirometry.

BACKGROUND: There is increasing evidence of small airway abnormalities in smokers despite normal spirometry. The concavity in the descending limb of the maximum expiratory flow curve (MEFV) is a recognised feature of obstruction and can provide information beyond FEV1, and potentially early smoking-related damage. We aimed to evaluate concavity measures compared to known small airway measurements. METHODS: Eighty smokers with normal spirometry had small airway function assessed: multiple breath nitrogen washout (MBNW) from which ventilation heterogeneity in the diffusion-dependent acinar (Sacin) and convection-dependent conductive (Scond) airways were assessed, and impulse oscillometry system (IOS) from which respiratory resistance and reactance at 5 Hz (R5 and X5) were measured. Concavity measures were calculated from the MEFV, partitioned into global and peripheral concavity. RESULTS: We found abnormal peripheral and global concavity as well as acinar ventilation heterogeneity are common in "normal" smokers. Concavity measures were not related to either MBNW or IOS measurements. CONCLUSION: Abnormalities in concavity indices and MBNW or oscillometry parameters are common in smokers despite normal spirometry. However, these measures likely reflect different mechanisms of peripheral airway dysfunction.

Anthropogenic climate change impacts on copepod trait biogeography.

Copepods are among the most abundant marine metazoans and form a key link between marine primary producers, higher trophic levels, and carbon sequestration pathways. Climate change is projected to change surface ocean temperature by up to 4°C in the North Atlantic with many associated changes including slowing of the overturning circulation, areas of regional freshening, and increased salinity and reductions in nutrients available in the euphotic zone over the next century. These changes will lead to a restructuring of phytoplankton and zooplankton communities with cascading effects throughout the food web. Here we employ observations of copepods, projected changes in ocean climate, and species distribution models to show how climate change may affect the distribution of copepod species in the North Atlantic. On average species move northeast at a rate of 14.1 km decade-1 . Species turnover in copepod communities will range from 5% to 75% with the highest turnover rates concentrated in regions of pronounced temperature increase and decrease. The changes in species range vary according to copepod traits with the largest effects found to occur in the cooling, freshening area in the subpolar North Atlantic south of Greenland and in an area of significant warming along the Scotian shelf. Large diapausing copepods (>2.5 mm) which are higher in lipids and a crucial food source for whales, may have an advantage in the cooling waters due to their life-history strategy that facilitates their survival in the arctic environment. Carnivorous copepods show a basin wide increase in species richness and show significant habitat area increases when their distribution moves poleward while herbivores see significant habitat area losses. The trait-specific effects highlight the complex consequences of climate change for the marine food web.

Prevalence of chronic obstructive pulmonary disease with breathlessness in Australia: weighted using the 2016 Australian census.

Access to up-to-date Australian disease prevalence estimates assists health services and consumer organisations to plan and allocate resources. The Burden of Obstructive Lung Disease study was conducted between 2006 and 2012 and provided chronic obstructive pulmonary disease (COPD) (post-bronchodilator airflow limitation) prevalence estimates weighted to the 2006 Australian census. Using the 2016 Australian census, an updated prevalence estimate of all COPD is 8.30% (95% confidence interval = 6.59%-10.01%) for adults aged 40 or more years in Australia and includes 2.52% with mild breathlessness, 0.99% with moderate breathlessness and 0.91% with severe breathlessness.

Prioritizing Beneficial Management Practices for Species at Risk in Agricultural Lands.

Agricultural expansion and intensification are major drivers of ecosystem degradation and loss of biodiversity around the world. Countries are relying on protected areas to conserve habitats and prevent species decline, but these are either too few, too small, or too disconnected to capture and protect the needs of species at risk (SAR). Privately owned and managed lands and agricultural producers are increasingly needed to assist with habitat conservation and SAR recovery. Uptake of environmentally beneficial management practices (BMPs) by producers is often hindered by the lack of awareness of the needs of SAR and of the contribution they can make to their habitats, an actual or perceived negative economic and operational impact of the necessary management changes, the fear of losing management control over their land, and mistrust toward public agencies. We present an eight-step model framework that allows agricultural producers to privately determine the potential SAR occurring in a land parcel of interest and to identify and prioritize mutually compatible and outcome-oriented BMPs relevant to these species. In Alberta, Canada, the framework resulted in the development of a confidential self-served online extension tool tailored to a typical farm-level management unit, and to the geographical and ecological context of the operation. We provide a case study using a land parcel from the agricultural region of Alberta to illustrate the model and the associated tool. This novel approach can alleviate producers concerns, promote uptake of BMPs, and foster voluntary stewardship of SAR habitats on privately owned or managed lands.

Childhood pneumonia, pleurisy and lung function: a cohort study from the first to sixth decade of life.

INTRODUCTION: Adult spirometry following community-acquired childhood pneumonia has variably been reported as showing obstructive or non-obstructive deficits. We analysed associations between doctor-diagnosed childhood pneumonia/pleurisy and more comprehensive lung function in a middle-aged general population cohort born in 1961. METHODS: Data were from the prospective population-based Tasmanian Longitudinal Health Study cohort. Analysed lung function was from ages 7 years (prebronchodilator spirometry only, n=7097), 45 years (postbronchodilator spirometry, carbon monoxide transfer factor and static lung volumes, n=1220) and 53 years (postbronchodilator spirometry and transfer factor, n=2485). Parent-recalled histories of doctor-diagnosed childhood pneumonia and/or pleurisy were recorded at age 7. Multivariable linear and logistic regression were used. RESULTS: At age 7, compared with no episodes, childhood pneumonia/pleurisy-ever was associated with reduced FEV1:FVC for only those with current asthma (beta-coefficient or change in z-score=-0.20 SD, 95% CI -0.38 to -0.02, p=0.028, p interaction=0.036). At age 45, for all participants, childhood pneumonia/pleurisy-ever was associated with a restrictive pattern: OR 3.02 (1.5 to 6.0), p=0.002 for spirometric restriction (FVC less than the lower limit of normal plus FEV1:FVC greater than the lower limit of normal); total lung capacity z-score -0.26 SD (95% CI -0.38 to -0.13), p<0.001; functional residual capacity -0.16 SD (-0.34 to -0.08), p=0.001; and residual volume -0.18 SD (-0.31 to -0.05), p=0.008. Reduced lung volumes were accompanied by increased carbon monoxide transfer coefficient at both time points (z-score +0.29 SD (0.11 to 0.49), p=0.001 and +0.17 SD (0.04 to 0.29), p=0.008, respectively). DISCUSSION: For this community-based population, doctor-diagnosed childhood pneumonia and/or pleurisy were associated with obstructed lung function at age 7 for children who had current asthma symptoms, but with evidence of 'smaller lungs' when in middle age.

Lifeform indicators reveal large-scale shifts in plankton across the North-West European shelf.

Increasing direct human pressures on the marine environment, coupled with climate-driven changes, is a concern to marine ecosystems globally. This requires the development and monitoring of ecosystem indicators for effective management and adaptation planning. Plankton lifeforms (broad functional groups) are sensitive indicators of marine environmental change and can provide a simplified view of plankton biodiversity, building an understanding of change in lower trophic levels. Here, we visualize regional-scale multi-decadal trends in six key plankton lifeforms as well as their correlative relationships with sea surface temperature (SST). For the first time, we collate trends across multiple disparate surveys, comparing the spatially and temporally extensive Continuous Plankton Recorder (CPR) survey (offshore) with multiple long-term fixed station-based time-series (inshore) from around the UK coastline. These analyses of plankton lifeforms showed profound long-term changes, which were coherent across large spatial scales. For example, 'diatom' and 'meroplankton' lifeforms showed strong alignment between surveys and coherent regional-scale trends, with the 1998-2017 decadal average abundance of meroplankton being 2.3 times that of 1958-1967 for CPR samples in the North Sea. This major, shelf-wide increase in meroplankton correlated with increasing SSTs, and contrasted with a general decrease in holoplankton (dominated by small copepods), indicating a changing balance of benthic and pelagic fauna. Likewise, inshore-offshore gradients in dinoflagellate trends, with contemporary increases inshore contrasting with multi-decadal decreases offshore (approx. 75% lower decadal mean abundance), urgently require the identification of causal mechanisms. Our lifeform approach allows the collation of many different data types and time-series across the NW European shelf, providing a crucial evidence base for informing ecosystem-based management, and the development of regional adaptation plans.

Increasing picocyanobacteria success in shelf waters contributes to long-term food web degradation.

Continental margins are disproportionally important for global primary production, fisheries and CO2 uptake. However, across the Northeast Atlantic shelves, there has been an ongoing summertime decline of key biota-large diatoms, dinoflagellates and copepods-that traditionally fuel higher tropic levels such as fish, sea birds and marine mammals. Here, we combine multiple time series with in situ process studies to link these declines to summer nutrient stress and increasing proportions of picophytoplankton that can comprise up to 90% of the combined pico- and nanophytoplankton biomass in coastal areas. Among the pico-fraction, it is the cyanobacterium Synechococcus that flourishes when iron and nitrogen resupply to surface waters are diminished. Our field data show how traits beyond small size give Synechococcus a competitive edge over pico- and nanoeukaryotes. Key is their ability to grow at low irradiances near the nutricline, which is aided by their superior light-harvesting system and high affinity to iron. However, minute size and lack of essential biomolecules (e.g. omega-3 polyunsaturated fatty acids and sterols) render Synechococcus poor primary producers to sustain shelf sea food webs efficiently. The combination of earlier spring blooms and lower summer food quantity and quality creates an increasing period of suboptimal feeding conditions for zooplankton at a time of year when their metabolic demand is highest. We suggest that this nutrition-related mismatch has contributed to the widespread, ~50% decline in summer copepod abundance we observe over the last 60 years. With Synechococcus clades being prominent from the tropics to the Arctic and their abundances increasing worldwide, our study informs projections of future food web dynamics in coastal and shelf areas where droughts and stratification lead to increasing nutrient starvation of surface waters.

Early menarche is associated with lower adult lung function: A longitudinal cohort study from the first to sixth decade of life.

BACKGROUND AND OBJECTIVE: Early menarche is increasing in prevalence worldwide, prompting clinical and public health interest on its links with pulmonary function. We aimed to investigate the relationship between early menarche and lung function in middle age. METHODS: The population-based Tasmanian Longitudinal Health Study (born 1961; n = 8583), was initiated in 1968. The 5th Decade follow-up data (mean age: 45 years) included age at menarche and complex lung function testing. The 6th Decade follow-up (age: 53 years) repeated spirometry and gas transfer factor. Multiple linear regression and mediation analyses were performed to determine the association between age at menarche and adult lung function and investigate biological pathways, including the proportion mediated by adult-attained height. RESULTS: Girls reporting an early menarche (<12 years) were measured to be taller with greater lung function at age 7 years compared with those reporting menarche ≥12 years. By 45 years of age, they were shorter and had lower post-bronchodilator (BD) forced expiratory volume in 1 s (adjusted mean difference: -133 mL; 95% CI: -233, -33), forced vital capacity (-183 mL; 95% CI: -300, -65) and functional residual capacity (-168 mL; 95% CI: -315, -21). Magnitudes of spirometric deficits were similar at age 53 years. Forty percent of these total effects were mediated through adult-attained height. CONCLUSION: Early menarche was associated with reduced adult lung function. This is the first study to investigate post-BD outcomes and quantify the partial role of adult height in this association.

Occupational exposure to solvents and lung function decline: A population based study.

RATIONALE: While cross-sectional studies have shown associations between certain occupational exposures and lower levels of lung function, there was little evidence from population-based studies with repeated lung function measurements. OBJECTIVES: We aimed to investigate the associations between occupational exposures and longitudinal lung function decline in the population-based Tasmanian Longitudinal Health Study. METHODS: Lung function decline between ages 45 years and 50 years was assessed using data from 767 participants. Using lifetime work history calendars completed at age 45 years, exposures were assigned according to the ALOHA plus Job Exposure Matrix. Occupational exposures were defined as ever exposed and cumulative exposure -unit- years. We investigated effect modification by sex, smoking and asthma status. RESULTS: Compared with those without exposure, ever exposures to aromatic solvents and metals were associated with a greater decline in FEV1 (aromatic solvents 15.5 mL/year (95% CI -24.8 to 6.3); metals 11.3 mL/year (95% CI -21.9 to - 0.7)) and FVC (aromatic solvents 14.1 mL/year 95% CI -28.8 to - 0.7; metals 17.5 mL/year (95% CI -34.3 to - 0.8)). Cumulative exposure (unit years) to aromatic solvents was also associated with greater decline in FEV1 and FVC. Women had lower cumulative exposure years to aromatic solvents than men (mean (SD) 9.6 (15.5) vs 16.6 (14.6)), but greater lung function decline than men. We also found association between ever exposures to gases/fumes or mineral dust and greater decline in lung function. CONCLUSIONS: Exposures to aromatic solvents and metals were associated with greater lung function decline. The effect of aromatic solvents was strongest in women. Preventive strategies should be implemented to reduce these exposures in the workplace.

Childhood measles contributes to post-bronchodilator airflow obstruction in middle-aged adults: A cohort study.

BACKGROUND AND OBJECTIVE: Chronic obstructive pulmonary disease (COPD) has potential origins in childhood but an association between childhood measles and post-bronchodilator (BD) airflow obstruction (AO) has not yet been shown. We investigated whether childhood measles contributed to post-BD AO through interactions with asthma and/or smoking in a non-immunized middle-aged population. METHODS: The population-based Tasmanian Longitudinal Health Study (TAHS) cohort born in 1961 (n = 8583) underwent spirometry in 1968 before immunization was introduced. A history of childhood measles infection was obtained from school medical records. During the fifth decade follow-up (n = 5729 responses), a subgroup underwent further lung function measurements (n = 1389). Relevant main associations and interactions by asthma and/or smoking on post-BD forced expiratory volume in 1 s/forced vital capacity (FEV1 /FVC; continuous variable) and AO (FEV1 /FVC < lower limit of normal) were estimated by multiple regression. RESULTS: Sixty-nine percent (n = 950) had a history of childhood measles. Childhood measles augmented the combined adverse effect of current clinical asthma and smoking at least 10 pack-years on post-BD FEV1 /FVC ratio in middle age (z-score: -0.70 (95% CI: -1.1 to -0.3) vs -1.36 (-1.6 to -1.1), three-way interaction: P = 0.009), especially for those with childhood-onset asthma. For never- and ever-smokers of <10 pack-years who had current asthma symptoms, compared with those without childhood measles, paradoxically, the odds for post-BD AO was not significant in the presence of childhood measles (OR: 12.0 (95% CI: 3.4-42) vs 2.17 (0.9-5.3)). CONCLUSION: Childhood measles infection appears to compound the associations between smoking, current asthma and post-BD AO. Differences between asthma subgroups provide further insight into the complex aetiology of obstructive lung diseases for middle-aged adults.

Occupational exposure to pesticides are associated with fixed airflow obstruction in middle-age.

RATIONALE: Population-based studies have found evidence of a relationship between occupational exposures and Chronic Obstructive Pulmonary Disease (COPD), but these studies are limited by the use of prebronchodilator spirometry. Establishing this link using postbronchodilator is critical, because occupational exposures are a modifiable risk factor for COPD. OBJECTIVES: To investigate the associations between occupational exposures and fixed airflow obstruction using postbronchodilator spirometry. METHODS: One thousand three hundred and thirty-five participants were included from 2002 to 2008 follow-up of the Tasmanian Longitudinal Health Study (TAHS). Spirometry was performed and lifetime work history calendars were used to collect occupational history. ALOHA plus Job Exposure Matrix was used to assign occupational exposure, and defined as ever exposed and cumulative exposure unit (EU)-years. Fixed airflow obstruction was defined by postbronchodilator FEV1/FVC <0.7 and the lower limit of normal (LLN). Multinomial logistic regressions were used to investigate potential associations while controlling for possible confounders. RESULTS: Ever exposure to biological dust (relative risk (RR)=1.58, 95% CI 1.01 to 2.48), pesticides (RR=1.74,95% CI 1.00 to 3.07) and herbicides (RR=2.09,95% CI 1.18 to 3.70) were associated with fixed airflow obstruction. Cumulative EU-years to all pesticides (RR=1.11,95% CI 1.00 to 1.25) and herbicides (RR=1.15,95% CI 1.00 to 1.32) were also associated with fixed airflow obstruction. In addition, all pesticides exposure was consistently associated with chronic bronchitis and symptoms that are consistent with airflow obstruction. Ever exposure to mineral dust, gases/fumes and vapours, gases, dust or fumes were only associated with fixed airflow obstruction in non-asthmatics only. CONCLUSIONS: Pesticides and herbicides exposures were associated with fixed airflow obstruction and chronic bronchitis. Biological dust exposure was also associated with fixed airflow obstruction in non-asthmatics. Minimising occupational exposure to these agents may help to reduce the burden of COPD.

Traffic-related air pollution exposure over a 5-year period is associated with increased risk of asthma and poor lung function in middle age.

Current evidence concerning the impact of exposure to traffic-related air pollution (TRAP) on adult respiratory morbidity mainly comes from cross-sectional studies. We sought to establish more robust measures of this association and potential gene-environment interactions using longitudinal data from an established cohort study.Associations between measures of TRAP (nitrogen dioxide (NO2) and distance to major roads) and wheeze, asthma prevalence and lung function were investigated in participants of the Tasmanian Longitudinal Health Study at 45- and 50-year follow-ups. Generalised estimating equations were used to quantify associations and the potential modifying effect of glutathione S-transferase gene variants.Living <200 m from a major road was associated with increased prevalence of current asthma and wheeze, and lower lung function. The association between living <200 m from a major road and current asthma and wheeze was more marked for carriers of the GSTT1 null and GSTP1 val/val or ile/val genotypes. Over the 5-year period, higher NO2 exposures were associated with increased current asthma prevalence. Higher NO2 exposure was associated with lower forced vital capacity for carriers of the GSTT1 null genotype.TRAP exposures were associated with increased risk of asthma, wheeze and lower lung function in middle-aged adults. The interaction with the GSTT1 genotype suggests that deficient antioxidant mechanisms may play a role in these adverse health effects.

Bronchial hyperresponsiveness and obesity in middle age: insights from an Australian cohort.

The association between obesity and bronchial hyperresponsiveness (BHR) is incompletely characterised. Using the 2006 follow-up of the Tasmanian Longitudinal Health Study, we measured the association between obesity and BHR and whether it was mediated by small airway closure or modified by asthma and sex of the patient.A methacholine challenge measured BHR. Multivariable logistic regression measured associations between body mass index (BMI) and BHR, adjusting for sex, asthma, smoking, corticosteroid use, family history and lung function. Mediation by airway closure was also measured.Each increase in BMI of 1 kg·m-2 was associated with a 5% increase in the odds of BHR (OR 1.05, 95% CI 1.01-1.09) and 43% of this association was mediated by airway closure. In a multivariable model, BMI (OR 1.06, 95% CI 1.00-1.16) was associated with BHR independent of female sex (OR 3.26, 95% CI 1.95-5.45), atopy (OR 2.30, 95% CI 1.34-3.94), current asthma (OR 5.74, 95% CI 2.79-11.82), remitted asthma (OR 2.35, 95% CI 1.27-4.35), low socioeconomic status (OR 2.11, 95% CI 1.03-4.31) and forced expiratory volume in 1 s/forced vital capacity (OR 0.86, 95% CI 0.82-0.91). Asthma modified the association with an increasing probability of BHR as BMI increased, only in those with no or remitted asthma.An important fraction of the BMI/BHR association was mediated via airway closure. Conflicting findings in previous studies could be explained by failure to consider this intermediate step.

Preterm birth and low birth weight continue to increase the risk of asthma from age 7 to 43.

BACKGROUND: Perinatal events can influence the development of asthma in childhood but current evidence is contradictory concerning the effects on life-time asthma risk. OBJECTIVE: To assess the relationship between birth characteristics and asthma from childhood to adulthood. METHODOLOGY: All available birth records for the Tasmanian Longitudinal Health Study (TAHS) cohort, born in 1961 were obtained from the Tasmanian State Archives and Tasmanian hospitals. Low birth weight (LBW) was defined as less than 2500 grams. Preterm birth was defined as delivery before 37 weeks' gestation. Small for gestational age (SGA) was defined as a birth weight below the 10th percentile for a given gestational age. Multivariate logistic and cox regression were used to examine associations between birth characteristics and lifetime risk of current and incident asthma, adjusting for confounders. RESULTS: The prevalence of LBW was 5.2%, SGA was 13.8% and preterm was 3.3%. LBW (OR = 1.65, 95%CI 1.12,2.44) and preterm birth (OR = 1.81, 95%CI 0.99, 3.31) were both associated with an increased risk of current asthma between the ages of 7 to 43 years. There was no association between SGA and current asthma risk. However, SGA was associated with incident asthma (HR = 1.32, 95%CI 1.00, 1.74), and there was an interaction with sex (p value = 0.08), with males having a greater risk of incident asthma (HR = 1.70, 95%CI 1.16-2.49) than females (HR = 1.04, 95%CI 0.70-1.54). CONCLUSIONS: Preterm birth and LBW were associated with an increased risk of current asthma into middle-age. These findings are the first to demonstrate the continuing impact of these characteristics on asthma risk into middle-age.