GLI 2012 equations define few spirometric anomalies in the general population: the PneumoLaus study

Reduced sensitivity to thyroid hormones is associated with lung function in euthyroid individuals

Background

The thyroid gland exhibits a subtle interconnection with the lungs. We further investigated the correlation between thyroid hormone sensitivity and lung function in euthyroid individuals.

Methods

Data on spirometry and mortality for participants aged 19-79 years were extracted from the NHANES database. Obstructive lung function was defined as a forced expiratory volume in 1 s to forced vital capacity ratio (FEV1/FVC) < 0.70, while restrictive lung function was considered when FEV1/FVC ≥0.70 and baseline FVC <80 % predicted. Central and peripheral sensitivities to thyroid hormones were mainly evaluated by Thyroid Feedback Quantile-based Index (TFQI) and Free Triiodothyronine/Free thyroxine (FT3/FT4) ratio. Logistic regression and subgroup analysis were used to examine potential associations between thyroid hormone sensitivity and lung function. The association between TFQI and all-cause mortality risk was also investigated.

Results

A total of 6539 participants were analyzed, 900 with obstructive lung function and 407 with restrictive lung function. The prevalence of impaired lung function, both obstructive and restrictive, increased with higher TFQI levels. Logistic regression analysis showed that increased TFQI and decreased FT3/FT4 levels were independent risk factors for obstructive and restrictive lung function (P < 0.05). After adjusting for the impact of lung function, TFQI (HR = 1.25, 95 % CI 1.00-1.56, P = 0.048) was an independent risk factor for all-cause mortality.

Conclusion

Reduced sensitivity to thyroid hormones has been linked to impaired lung function. TFQI and FT3/FT4 are potential epidemiological tools to quantify the role of central and peripheral thyroid resistance in lung function.

Physical activity and lung function association in a healthy community-dwelling European population

BACKGROUND

The association of physical activity (PA) and lung function (LF) varies from no measurable effect to delayed LF decline. We assessed the association between accelerometery-assessed PA and LF in a sample of apparently healthy, community-dwelling subjects.

METHODS

We included two cross-sectional studies using data from the PneumoLaus study (2014-17 and 2018-21), conducted in Lausanne, Switzerland. PA was assessed by accelerometry and categorised as inactivity, light, moderate or vigorous. Forced expiratory volume in 1 second (FEV1), forced volume capacity (FVC) and maximal mid-expiratory flow (MMEF) were measured by spirometry and expressed in percentage of predicted value (PV).

RESULTS

Overall, 1'910 (54.7% women, 62.0 ± 9.7 years) and 1'174 (53.4% women, 65.8 ± 9.5 years) participants were included in the first and the second surveys, respectively. In both surveys, moderate and vigorous PA showed a weak but significant correlation with FEV1 in percentage (PV) (R = 0.106 and 0.132 for the first and 0.111 and 0.125 for the second surveys, p < 0.001). Similar correlations with FVC (p < 0.001) were found. Associations held irrespective of smoking status and remained after multivariable adjustment. Fewer associations were detected between LF and light PA or between MMEF and PA.

CONCLUSION

Moderate and vigorous intensity PA are associated with increased LF regardless of smoking status in apparently healthy community-dwelling European population. These associations are statistically but not clinically significant due to the small correlation coefficients (R < 0.30), corresponding to a weak association.

Associations of Depressive and Anxiety Disorders with Pulmonary Disorders in the Community: The PneumoLaus and PsyCoLaus Studies

INTRODUCTION

Mental health disorders figure among the many comorbidities of obstructive respiratory diseases. The multisystemic characteristics of chronic respiratory disease and its impact on quality of life could affect depressive and/or anxiety disorders. We aimed to evaluate the association of spirometric indices, ventilatory disorders, and self-reported respiratory diseases with psychiatric disorders considering potential confounders.

METHODS

We analysed data from CoLaus|PsyCoLaus, a Swiss population-based cohort study, consisting of 2'774 participants (56% women; mean age: 62.3 (standard deviation = ±9.9) years) who performed spirometry and completed semi-structured psychiatric interviews. We defined ventilatory disorders using GLI-2012 references. Major depressive episode (MDE) and anxiety disorders were defined using the DSM-IV (Diagnostic and Statistical Manual).

RESULTS

630 subjects (22.7%) presented a recent MDE. Reversible obstructive ventilatory disorders were associated with recent MDE (OR = 1.94, 95% confidence interval (95% CI) 1.10-3.43) and recent anxiety disorders (2.21 [1.16-4.22]) only in unadjusted model. Self-reported chronic obstructive pulmonary (COPD) and asthma were associated with MDE with ORs of 2.49 (95% CI, 1.19-5.27) and 1.56 (95% CI, 1.04-2.35) after adjustment, respectively. Possible restrictive ventilatory impairment was positively associated with recent anxiety disorders (OR = 2.46, 1.10-5.51). Z-scores of FEV1, FVC, and maximal mid-expiratory flow were not associated with psychiatric disorders. There was no association between ventilatory disorders and MDE in adjusted models.

CONCLUSIONS

In this cross-sectional population-based study, the association between respiratory disorders and depressive disorders was observed for self-reported COPD and asthma, but not with objective diagnoses based on spirometry. Lung volumes are not associated with psychiatric disorders. Further prospective studies will be necessary to understand the significance of the association.

Prevalence of small airway dysfunction in the Swiss PneumoLaus Cohort

Background

Recent evidence identified exposure to particulate matter of size ≤2.5 µm (PM2.5) as a risk factor for high prevalence of small airway dysfunction (SAD). We assessed the prevalence of SAD in a European region with low air pollution levels.

Methods

SAD was defined as a maximum mid-expiratory flow (MMEF) <65% of predicted value (PV) or MMEF

Results

Among 3351 participants (97.6% Caucasian, 55.7% female sex, mean age 62.7 years), we observed MMEF <65% PV in 425 (12.7%) and MMEF 65 years only. In an area where ambient PM2.5 concentration was <15 µg·m-3 during the observation period (2010 and 2020), ≥72% of participants with SAD were ever-smokers.

Conclusions

The observed low prevalence of SAD of 5.0-12.7% depending on criteria employed may be related to lower PM2.5 exposure. Smoking was the main factor associated with SAD in an area with low PM2.5 exposure. Employing a MMEF threshold <65% PV carries a risk of SAD overdiagnosis in elderly individuals.

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Affiliation(s)

Brice Touilloux Division of Pulmonology, Department of Medicine, Lausanne University Hospital (CHUV) and University of Lausanne (UNIL), Lausanne, Switzerland Division of Pulmonology, Department of Medicine and Specialties, Fribourg Hospital, Fribourg, Switzerland
Cedric Bongard Division of Pulmonology, Department of Medicine, Lausanne University Hospital (CHUV) and University of Lausanne (UNIL), Lausanne, Switzerland
Benoit Lechartier Division of Pulmonology, Department of Medicine, Lausanne University Hospital (CHUV) and University of Lausanne (UNIL), Lausanne, Switzerland
Minh Khoa Truong Division of Pulmonology, Department of Medicine, Lausanne University Hospital (CHUV) and University of Lausanne (UNIL), Lausanne, Switzerland
Pedro Marques-Vidal Division of Internal Medicine, Department of Medicine, CHUV and UNIL, Lausanne, Switzerland
Peter Vollenweider Division of Internal Medicine, Department of Medicine, CHUV and UNIL, Lausanne, Switzerland
Julien Vaucher Division of Internal Medicine, Department of Medicine, CHUV and UNIL, Lausanne, Switzerland Division of Internal Medicine, Department of Medicine and Specialties, Fribourg Hospital, Fribourg, Switzerland University of Fribourg, Fribourg, Switzerland
Alessio Casutt Division of Pulmonology, Department of Medicine, Lausanne University Hospital (CHUV) and University of Lausanne (UNIL), Lausanne, Switzerland Division of Pneumology, Ospedale Regionale di Lugano, Ente Ospedaliero Cantonale, Lugano, Switzerland These authors contributed equally
Christophe von Garnier Division of Pulmonology, Department of Medicine, Lausanne University Hospital (CHUV) and University of Lausanne (UNIL), Lausanne, Switzerland These authors contributed equally

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Evaluation of the Global Lung Function Initiative reference equations in Belgian adults

Background

Over the past decade, the Global Lung Function Initiative (GLI) Network has published all-age reference equations on spirometry, diffusing capacity of the lung for carbon monoxide (D_LCO) and lung volumes.

Methods

We evaluated the appropriateness of these equations in an adult Caucasian population. Retrospective lung function data on subjects who performed tests prior to a diagnostic sleep investigation were analysed. From the medical records, lung healthy, lifetime nonsmoking, nonobese subjects were selected, resulting in a population of 1311 subjects (68% male; age range 18–88 years).

Results

Multiple linear regression analysis revealed that lung function z-scores did not differ between subjects with and without sleep apnoea but did depend on height and age. The average forced expiratory volume in 1 s (FEV₁)/forced vital capacity (FVC) z-score was 0 but exhibited an inverse association with height in both sexes (p<0.01). Values of FEV₁ and FVC in both sexes were larger than predicted (mean±sd z-score +0.30±0.96 or 104±13% pred; p<0.01). Overall, static lung volumes and D_LCO were adequately predicted. However, D_LCO z-scores were inversely associated with height in males and age in females (p<0.01). For all lung function indices, the observed scatter was reduced compared with the prediction. Therefore, for all indices <5% of the data were below the GLI-proposed lower limit of normal (LLN) threshold.

Conclusion

GLI reference equations provide an adequate fit in Belgian adults. However, the GLI-proposed LLN is too low for our Antwerp population, resulting in underdiagnosis of disease. Furthermore, airway obstruction and diffusion disorders might be misclassified due to height and age associations.

Overall, GLI reference equations for lung function appropriately describe the data in Belgian adults. However, airway obstruction and diffusion disorders might be misdiagnosed at age and height extremes, and the GLI LLN was too low in this population.https://bit.ly/3jdauLE

Assessment of comorbidities and prognosis in patients with COPD diagnosed with the fixed ratio and the lower limit of normal: a systematic review and meta-analysis

BACKGROUND

Currently, the diagnosis of chronic obstructive pulmonary disease (COPD) is not uniform, COPD guidelines recommend fixed ratio (FR), whereas ATS and ERS define airflow obstruction based on lower limit of normal (LLN). We aim to determine if there is difference between the two diagnostic criteria for morbidity, mortality, exacerbation.

METHODS

Four databases and all relevant studies from the references were searched from inception to June 25, 2019, to find studies that described the rate of comorbidity, the exacerbation rates, mortality in COPD patients. Data analysis was performed using STATA/SE 14.0 and followed the standard of Cochrane Collaboration. A sensitivity analysis was performed to find the source of heterogeneity.

RESULTS

Thirteen studies and 154,447 participants were finally included in this meta-analysis. The 11 cohort studies and 2 cross-sectional studies were all high-quality. Patients with airflow limitation according to either FR or LLN had higher mortality (HRFR+/LLN- = 1.27, 95% CI = 1.14-1.42; HRFR-/LLN+ = 1.83, 95% CI = 1.17-2.86) than those who met neither criteria. When compared with the FR-/LLN- criteria, those who met the FR criteria were more likely to exacerbate (HR FR+/LLN- = 1.64, 95% CI = 1.09-2.46; HR FR-/LLN+ = 1.58, 95% CI = 0.70-3.55). The meta-analysis for comorbidities showed no significant difference between patients who met neither criteria and those who met LLN or FR criteria.

CONCLUSION

The patients with airflow limitations according to FR were more likely to exacerbate than those with LLN only. Patients that met either FR or LLN were more likely to have higher mortality than FR-/LLN-. There was no difference between the FR+/LLN- and FR-/LLN+ groups for the occurrence of comorbidities.

Mean Oxygen Saturation during Sleep Is Related to Specific Brain Atrophy Pattern

OBJECTIVE

There is much controversy about the neurobiological mechanisms underlying the effects of sleep-disordered breathing on the brain. The aim of this study was to investigate the association between markers of sleep-related hypoxemia and brain anatomy.

METHODS

We used data from a large-scale cohort from the general population (n = 775, 50.6% males, age range = 45-86 years, mean age = 60.3 ± 9.9) that underwent full polysomnography and brain magnetic resonance imaging to correlate respiratory variables with regional brain volume estimates.

RESULTS

After adjusting for age, gender, and cardiovascular risk factors, only mean oxygen saturation during sleep was associated with bilateral volume of hippocampus (right: p = 0.001; left: p < 0.001), thalamus (right: p < 0.001; left: p < 0.001), putamen (right: p = 0.001; left: p = 0.001), and angular gyrus (right: p = 0.011; left: p = 0.001). We observed the same relationship in left hemispheric amygdala (p = 0.010), caudate (p = 0.008), inferior frontal gyrus (p = 0.004), and supramarginal gyrus (p = 0.003). The other respiratory variables-lowest oxygen saturation, percentage of sleep time with oxygen saturation < 90%, apnea-hypopnea index, and oxygen desaturation index-did not show any significant association with brain volumes.

INTERPRETATION

Lower mean oxygen saturation during sleep was associated with atrophy of cortical and subcortical brain areas known for high sensitivity to oxygen supply. Their vulnerability to hypoxemia may contribute to behavioral phenotype and cognitive decline in patients with sleep-disordered breathing. ANN NEUROL 2020;87:921-930.

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PneumoLaus: Prevalence of Lung Function Abnormalities in a Sample of the General Population of Lausanne Abstract. Reduced lung function predicts increased mortality. The prevalence of spirometric abnormalities depends on their definition, the references values used and the use or not of bronchodilation. In the PneumoLaus study, conducted between 2014 and 2017 in a sample of the general population of Lausanne, prevalence of chronic obstruction was 3,8 %, of reversible obstruction 2,5 % and of possible restriction 2,2 %. These numbers are lower than in other population studies. Men had more abnormal spirometry results than women, and ever-smokers more than never-smokers. Two thirds of participants with chronic obstruction, most of which without respiratory symptoms, were not aware of any lung disease.

Advances in spirometry testing for lung function analysis

Introduction: Spirometry, the most common lung function test, is used to evaluate individuals with respiratory complaints or known respiratory disease. However, its underutilization and the misinterpretation of its parameters are causes for concern. Areas covered: This review describes new spirometry-derived metrics, new reference equations, recent recommendations for presentation of results, recent spirometry-based prevalence studies, and technological advances in spirometry equipment. Expert opinion: The underutilization of spirometry can be overcome by increasing access to portable, hand-held, and user-friendly spirometers, together with strategies that increase awareness of the importance of spirometry. New metrics derived from spirometry, together with traditional spirometric criteria, can identify individuals with structural lung disease and respiratory morbidity. Some problems with the reference equations were solved by the Global Lung Function Initiative (GLI), which covers a wider age range and more ethnic groups and provides limits of normality using the z-score. Despite these advantages, the GLI equations lack data from large populations (especially those from Africa, South Asia, and Latin America) and greater representation of older people. Another disadvantage attributed to the GLI is the lack of predicted values for peak expiratory flow and other airflows, limiting the interpretation of the maximal expiratory flow-volume curve.