Symptoms and lung function decline in a middle-aged cohort of males and females in Australia

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.

Differences Between Men and Women with Chronic Obstructive Pulmonary Disease

There are many differences between men and women in risk factor vulnerability and impact, symptom development, presentation, clinical manifestations, and outcomes of chronic obstructive pulmonary disease (COPD). These differences have been inadequately explored, which is of particular concern in view of the delay in diagnosis and treatment that occurs for both men and women, and the need to use all therapies in a targeted and tailored way for best clinical gain and least harm. Women are generally underrepresented in randomized trials, as are non-tobacco-related phenotypes of COPD. We must garner the information available to better describe optimal treatment approaches.

Lifetime Risk Factors for Pre- and Post-Bronchodilator Lung Function Decline. A Population-based Study

Rationale: Interactions between early life and adult insults on lung function decline are not well understood, with most studies investigating prebronchodilator (pre-BD) FEV₁ decline.Objectives: To investigate relationships between adult risk factors and pre- and post-BD lung function decline and their potential effect modification by early life and genetic factors.Methods: Multiple regression was used to examine associations between adult exposures (asthma, smoking, occupational exposures, traffic pollution, and obesity) and decline in both pre- and post-BD spirometry (forced expiratory volume in 1 s [FEV₁], forced vital capacity [FVC], and FEV₁/FVC) between ages 45 and 53 years in the Tasmanian Longitudinal Health Study (n = 857). Effect modification of these relationships by childhood respiratory risk factors, including low childhood lung function and GST (glutathione S-transferase) gene polymorphisms, was investigated.Results: Baseline asthma, smoking, occupational exposure to vapors/gases/dusts/fumes, and living close to traffic were associated with accelerated decline in both pre- and post-BD FEV₁. These factors were also associated with FEV₁/FVC decline. Occupational exposure to aromatic solvents was associated with pre-BD but not post-BD FEV₁ decline. Maternal smoking accentuated the effect of personal smoking on pre- and post-BD FEV₁ decline. Lower childhood lung function and having the GSTM1 null allele accentuated the effect of occupational exposure to vapors/gases/dusts/fumes and personal smoking on post-BD FEV₁ decline. Incident obesity was associated with accelerated decline in FEV₁ and more pronounced in FVC.Conclusions: This study provides new evidence for accentuation of individual susceptibility to adult risk factors by low childhood lung function, GSTM1 genotype, and maternal smoking.

Accelerated FEV1 decline and risk of cardiovascular disease and mortality in a primary care population of COPD patients

Accelerated lung function decline has been associated with increased risk of cardiovascular disease (CVD) in a general population, but little is known about this association in chronic obstructive pulmonary disease (COPD). We investigated the association between accelerated lung function decline and CVD outcomes and mortality in a primary care COPD population.

COPD patients without a history of CVD were identified in the Clinical Practice Research Datalink (CPRD)-GOLD primary care dataset (n=36 382). Accelerated decline in forced expiratory volume in 1 s (FEV₁) was defined using the fastest quartile of the COPD population's decline. A Cox regression was used to assess the association between baseline accelerated FEV₁ decline and a composite CVD outcome over follow-up (myocardial infarction, ischaemic stroke, heart failure, atrial fibrillation, coronary artery disease and CVD mortality). The model was adjusted for age, sex, smoking status, body mass index, history of asthma, hypertension, diabetes, statin use, Modified Medical Research Council (mMRC) dyspnoea score, exacerbation frequency and baseline FEV₁ % predicted.

6110 COPD patients (16.8%) had a CVD event during follow-up; median length of follow-up was 3.6 years (interquartile range (IQR) 1.7–6.1 years). Median rate of FEV₁ decline was –19.4 mL·year⁻¹ (IQR –40.5–1.9); 9095 patients (25%) had accelerated FEV₁ decline (> –40.5 mL·year⁻¹), 27 287 (75%) did not (≤ –40.5 mL·year⁻¹). Risk of CVD and mortality was similar between patients with and without accelerated FEV₁ decline (HR_adj 0.98, 95% CI 0.90–1.06). Corresponding risk estimates were 0.99 (95% CI 0.83–1.20) for heart failure, 0.89 (95% CI 0.70–1.12) for myocardial infarction, 1.01 (95% CI 0.82–1.23) for stroke, 0.97 (95% CI 0.81–1.15) for atrial fibrillation, 1.02 (95% CI 0.87–1.19) for coronary artery disease and 0.94 (95% CI 0.71–1.25) for CVD mortality. Rather, risk of CVD was associated with a mMRC score ≤2 and two or more exacerbations in the year prior.

CVD outcomes and mortality were associated with exacerbation frequency and severity and increased mMRC dyspnoea score but not with accelerated FEV₁ decline.

In a primary care population of COPD patients, CVD outcomes and mortality were not associated with accelerated FEV₁ decline but with frequent and severe exacerbations of COPD and increased breathlessnesshttps://bit.ly/35APXL6

Characteristics Associated with Accelerated Lung Function Decline in a Primary Care Population with Chronic Obstructive Pulmonary Disease

Background

Estimates for lung function decline in chronic obstructive pulmonary disease (COPD) have differed by study setting and have not been described in a UK primary care population.

Purpose

To describe rates of FEV₁ and FVC decline in COPD and investigate characteristics associated with accelerated decline.

Patients and Methods

Current/ex-smoking COPD patients (35 years+) who had at least 2 FEV₁ or FVC measurements ≥6 months apart were included using Clinical Practice Research Datalink. Patients were followed up for a maximum of 13 years. Accelerated rate of lung function decline was defined as the fastest quartile of decline using mixed linear regression, and association with baseline characteristics was investigated using logistic regression.

Results

A total of 72,683 and 50,649 COPD patients had at least 2 FEV₁ or FVC measurements, respectively. Median rates of FEV₁ and FVC changes or decline were -18.1mL/year (IQR: -31.6 to -6.0) and -22.7mL/year (IQR: -39.9 to -6.7), respectively. Older age, high socioeconomic status, being underweight, high mMRC dyspnoea and frequent AECOPD or severe AECOPD were associated with an accelerated rate of FEV₁ and FVC decline. Current smoking, mild airflow obstruction and inhaled corticosteroid treatment were additionally associated with accelerated FEV₁ decline whilst women, sputum production and severe airflow obstruction were associated with accelerated FVC decline.

Conclusion

Rate of FEV₁ and FVC decline was similar and showed similar heterogeneity. Whilst FEV₁ and FVC shared associations with baseline characteristics, a few differences highlighted the importance of both lung function measures in COPD progression. We identified important characteristics that should be monitored for disease progression.

Effects of Obesity and Asthma on Lung Function and Airway Dysanapsis in Adults and Children

Obesity increases the risk of developing asthma in children and adults. Obesity is associated with different effects on lung function in children and adults. In adults, obesity has been associated with reduced lung function resulting from a relatively small effect on forced expiratory volume in 1 s (FEV₁) and forced vital capacity (FVC), with the FEV₁/FVC ratio remaining unchanged or mildly increased (restrictive pattern). In contrast, in children, obesity is associated with normal or higher FEV₁ and FVC but a lower FEV₁/FVC ratio (obstructive pattern). This anomaly has recently been associated with a phenomenon known as dysanapsis which results from a disproportionate growth between lung parenchyma size and airway calibre. The mechanisms that promote disproportionate lung parenchyma growth compared with airways in obese children remain to be elucidated. Obesity and dysanapsis in asthma patients might contribute to asthma morbidity by increasing airway obstruction, airway hyper-reactivity and airway inflammation. Obesity and dysanapsis in asthma patients are associated with increased medication use, more emergency department visits, hospitalizations and systemic corticosteroid burst than patients with normal weight. Dysanapsis may explain the reduced response to asthma medications in obese children. Weight loss results in a significant improvement in lung function, airway reactivity and asthma control. Whether these improvements are associated with the changes in the dysanaptic alteration is as yet unclear.

A Dyadic Growth Modeling Approach for Examining Associations Between Weight Gain and Lung Function Decline

The relationship between body weight and lung function is complex. Using a dyadic multilevel linear modeling approach, treating body mass index (BMI; weight (kg)/height (m)2) and lung function as paired, within-person outcomes, we tested the hypothesis that persons with more rapid increase in BMI exhibit more rapid decline in lung function, as measured by forced expiratory volume in 1 second (FEV1), forced vital capacity (FVC), and their ratio (FEV1:FVC). Models included random intercepts and slopes and adjusted for sociodemographic and smoking-related factors. A sample of 9,115 adults with paired measurements of BMI and lung function taken at ≥3 visits were selected from a pooled set of 5 US population-based cohort studies (1983-2018; mean age at baseline = 46 years; median follow-up, 19 years). At age 46 years, average annual rates of change in BMI, FEV1, FVC, and FEV1:FVC ratio were 0.22 kg/m2/year, -25.50 mL/year, -21.99 mL/year, and -0.24%/year, respectively. Persons with steeper BMI increases had faster declines in FEV1 (r = -0.16) and FVC (r = -0.26) and slower declines in FEV1:FVC ratio (r = 0.11) (all P values < 0.0001). Results were similar in subgroup analyses. Residual correlations were negative (P < 0.0001), suggesting additional interdependence between BMI and lung function. Results show that greater rates of weight gain are associated with greater rates of lung function loss.

Lung Function Decline in Farm and Nonfarm Rural Residents of Saskatchewan

OBJECTIVE

This study aims to assess the annual changes in lung function among farm and nonfarm adult residences in rural Saskatchewan, Canada.

METHODS

Data from the Saskatchewan Rural Health Study survey (2010 to 2014) among 724 adults were used.

RESULTS

For forced expiratory volume in 1 second (FEV1) measurements, estimates of annual decline (in milliliters) were highest in older age male (65+ years) (Mean, SD) (-42.63, 21.16); and among old heavy smokers (-57.79, 24.30). Estimates of annual decline in forced vital capacity (FVC) were highest in current smokers without the use of natural gas (-25.78, 14.78) and among old heavy smokers (-33.88, 20.28). Living on a farm is associated with decreased FEV1 and FVC, but not statistically significant by sex and age.

CONCLUSIONS

A complex mix of personal and contextual factors may affect these estimates.

Clinical importance of sex differences in dyspnea and its sex related determinants in asthma and COPD patients

PURPOSE

There is an increasing amount of data regarding the influence of sex on dyspnea perception, however, the influence of sex has not been included in clinical guidelines for asthma and chronic obstructive pulmonary disease (COPD).

MATERIALS AND METHODS

The study included 123 clinically stable subjects. Seventy five patients had COPD, of which 70.6% were men and 29.4% were women. Forty-eight subjects had asthma, comprised of 45.8% and 54.2%, men and women, respectively. Dyspnea was assessed with the use of modified Medical Research Council (mMRC) Visual Analogue Scale VAS, and BORG scale. All patients underwent spirometry with a broncho-reversibility test.

RESULTS

There were no differences in age for neither asthma patients, 56.5 ± 11.6 and 55.0 ± 12.7 (p = 0.5) for males and females, nor for COPD patients, 66.8 ± 9.0 and 66.8 ± 7.7 (p = 0.7) for males and females, respectively. Asthmatic females had more dyspnea than males when assessed with VAS, 1.85 ± 2.24 and 3.84 ± 2.80 (p = 0.01), for males and females, respectively. When assessed with BORGpre 6-MWT, dyspnea results were 0.86 ± 1.83 and 2.43 ± 2.31 (p = 0.005), for males and females, respectively. In the whole group, apart from FEV₁ (for mMRC, VAS, BORGpre) and BMI (BORGpost) the severity of dyspnea was related to female sex when assessed with mMRC (OR=2.83; 95%CI: 1.25-6.42) and VAS (OR = 2.17; 95%CI:1.00-4.73).

CONCLUSIONS

Although more apparent in asthma, it was revealed for the first time, that sex has a strong influence on the magnitude of dyspnea perception, both in asthma and COPD. Therefore, sex related dyspnea sensation should probably be included in clinical assessment and patient treatment.

The long-term rate of change in lung function in urban professional firefighters: a systematic review

BACKGROUND

Despite the known occupational hazards, it is not yet clear whether long-term career firefighting leads to a greater rate of decline in lung function than would normally be expected, and how this rate of change is affected by firefighting exposures and other risk/protective factors.

METHODS

A systematic search of online electronic databases was conducted to identify longitudinal studies reporting on the rate of change in the forced expiratory volume in one second (FEV1) of forced vital capacity (FVC). Included studies were critically appraised to determine their risk of bias using the Research Triangle Institute Item Bank (RTI-IB) on Risk of Bias and Precision of Observational Studies.

RESULTS

Twenty-two studies were identified for inclusion, from four different countries, published between 1974 and 2016. Examined separately, studies were categorised by the type of firefighting exposure. Firefighters experienced variable rates of decline in lung function, which were particularly influenced by cigarette smoking. The influence of routine firefighting exposures is unclear and limited by the methods of measurement, while firefighters exposed to 'non-routine' severe exposures unanimously experienced accelerated declines.

CONCLUSIONS

The data provided by longitudinal studies provide an unclear picture of how the rate of change in lung function of firefighters relates to routine exposures and how it compares to the rate of change expected in a working-age population. Non-smoking firefighters who routinely wear respiratory protection are more likely than otherwise to have a normal rate of decline in lung function. Exposure to catastrophic events significantly increases the rate of decline in firefighter lung function but there is limited evidence detailing the effect of routine firefighting. Future studies will benefit from more robust methods of measuring exposure.

TRIAL REGISTRATION

International Prospective Register of Systematic Reviews (PROSPERO), registration number ( CRD42017058499 ).

Association of physical activity with lung function in lung-healthy German adults: results from the KORA FF4 study

BACKGROUND

In lung disease, physical activity (PA) yields beneficial health effects, but its association with the function of healthy lungs has rarely been studied. We investigated the association of accelerometer-based PA with spirometric indices, maximal inspiratory mouth pressure (PI_max) and lung diffusion capacity in lung-healthy adults.

METHODS

In total, 341 apparently lung-healthy participants from the population-based KORA (Cooperative Health Research in the Region of Augsburg) FF4 cohort study (45% male, aged 48-68 years, 47% never smokers) completed lung function testing and wore ActiGraph accelerometers over a one week period at the hip. In adjusted regression analyses, moderate to vigorous PA (MVPA) was characterized as: sex-specific activity quartiles, achieving ≥ 10 consecutive minutes (yes vs. no), and meeting the WHO PA recommendations (yes vs. no).

RESULTS

Positive associations of MVPA-quartiles with forced expiratory volume in 1 s (FEV₁), forced vital capacity (FVC), and corresponding Global Lung Function Initiative z-scores were found. Subjects in the most active quartile (> 47 or > 50 min/day for females and males, respectively) had 142 ml [95% CI: 23, 260] higher FEV₁ and 155 ml [95% CI: 10, 301] higher FVC than those in the least active quartile (< 17 or < 21 min/day for females and males, respectively); however these associations were stronger among ex-/current smokers. Achieving at least once 10 consecutive minutes of MVPA was only associated with higher PI_max [β-estimate: 0.57 kPa; 95% CI: 0.04, 1.10], remaining significant among never smokers. No associations were found with diffusion capacity or for reaching the WHO-recommended 150 min of MVPA/week in 10-min bouts.

CONCLUSIONS

Although the effects were small, active subjects showed higher spirometric results. The observed associations were more pronounced among ever smokers suggesting a higher benefit of PA for subjects being at a higher risk for chronic lung diseases.