Real-World Gait Detection Using a Wrist-Worn Inertial Sensor: Validation Study

BACKGROUND

Wrist-worn inertial sensors are used in digital health for evaluating mobility in real-world environments. Preceding the estimation of spatiotemporal gait parameters within long-term recordings, gait detection is an important step to identify regions of interest where gait occurs, which requires robust algorithms due to the complexity of arm movements. While algorithms exist for other sensor positions, a comparative validation of algorithms applied to the wrist position on real-world data sets across different disease populations is missing. Furthermore, gait detection performance differences between the wrist and lower back position have not yet been explored but could yield valuable information regarding sensor position choice in clinical studies.

OBJECTIVE

The aim of this study was to validate gait sequence (GS) detection algorithms developed for the wrist position against reference data acquired in a real-world context. In addition, this study aimed to compare the performance of algorithms applied to the wrist position to those applied to lower back-worn inertial sensors.

METHODS

Participants with Parkinson disease, multiple sclerosis, proximal femoral fracture (hip fracture recovery), chronic obstructive pulmonary disease, and congestive heart failure and healthy older adults (N=83) were monitored for 2.5 hours in the real-world using inertial sensors on the wrist, lower back, and feet including pressure insoles and infrared distance sensors as reference. In total, 10 algorithms for wrist-based gait detection were validated against a multisensor reference system and compared to gait detection performance using lower back-worn inertial sensors.

RESULTS

The best-performing GS detection algorithm for the wrist showed a mean (per disease group) sensitivity ranging between 0.55 (SD 0.29) and 0.81 (SD 0.09) and a mean (per disease group) specificity ranging between 0.95 (SD 0.06) and 0.98 (SD 0.02). The mean relative absolute error of estimated walking time ranged between 8.9% (SD 7.1%) and 32.7% (SD 19.2%) per disease group for this algorithm as compared to the reference system. Gait detection performance from the best algorithm applied to the wrist inertial sensors was lower than for the best algorithms applied to the lower back, which yielded mean sensitivity between 0.71 (SD 0.12) and 0.91 (SD 0.04), mean specificity between 0.96 (SD 0.03) and 0.99 (SD 0.01), and a mean relative absolute error of estimated walking time between 6.3% (SD 5.4%) and 23.5% (SD 13%). Performance was lower in disease groups with major gait impairments (eg, patients recovering from hip fracture) and for patients using bilateral walking aids.

CONCLUSIONS

Algorithms applied to the wrist position can detect GSs with high performance in real-world environments. Those periods of interest in real-world recordings can facilitate gait parameter extraction and allow the quantification of gait duration distribution in everyday life. Our findings allow taking informed decisions on alternative positions for gait recording in clinical studies and public health.

TRIAL REGISTRATION

ISRCTN Registry 12246987; https://www.isrctn.com/ISRCTN12246987.

INTERNATIONAL REGISTERED REPORT IDENTIFIER (IRRID)

RR2-10.1136/bmjopen-2021-050785.

Physical activity and body mass related to catch-up lung function growth in childhood: a population-based accelerated cohort study

OBJECTIVE

The existence of catch-up lung function growth and its predictors is uncertain. We aimed to identify lung function trajectories and their predictors in a population-based birth cohort.

METHODS

We applied group-based trajectory modelling to z-scores of forced expiratory volume in 1 second (zFEV1) and z-scores of forced vital capacity (zFVC) from 1151 children assessed at around 4, 7, 9, 10, 11, 14 and 18 years. Multinomial logistic regression models were used to test whether potential prenatal and postnatal predictors were associated with lung function trajectories.

RESULTS

We identified four lung function trajectories: a low (19% and 19% of the sample for zFEV1 and zFVC, respectively), normal (62% and 63%), and high trajectory (16% and 13%) running in parallel, and a catch-up trajectory (2% and 5%) with catch-up occurring between 4 and 10 years. Fewer child allergic diseases and higher body mass index z-score (zBMI) at 4 years were associated with the high and normal compared with the low trajectories, both for zFEV1 and zFVC. Increased children's physical activity during early childhood and higher zBMI at 4 years were associated with the catch-up compared with the low zFEV1 trajectory (relative risk ratios: 1.59 per physical activity category (1.03-2.46) and 1.47 per zBMI (0.97-2.23), respectively). No predictors were identified for zFVC catch-up growth.

CONCLUSION

We found three parallel-running and one catch-up zFEV1 and zFVC trajectories, and identified physical activity and body mass at 4 years as predictors of zFEV1 but not zFVC catch-up growth.

Mobilise-D insights to estimate real-world walking speed in multiple conditions with a wearable device

This study aimed to validate a wearable device's walking speed estimation pipeline, considering complexity, speed, and walking bout duration. The goal was to provide recommendations on the use of wearable devices for real-world mobility analysis. Participants with Parkinson's Disease, Multiple Sclerosis, Proximal Femoral Fracture, Chronic Obstructive Pulmonary Disease, Congestive Heart Failure, and healthy older adults (n = 97) were monitored in the laboratory and the real-world (2.5 h), using a lower back wearable device. Two walking speed estimation pipelines were validated across 4408/1298 (2.5 h/laboratory) detected walking bouts, compared to 4620/1365 bouts detected by a multi-sensor reference system. In the laboratory, the mean absolute error (MAE) and mean relative error (MRE) for walking speed estimation ranged from 0.06 to 0.12 m/s and - 2.1 to 14.4%, with ICCs (Intraclass correlation coefficients) between good (0.79) and excellent (0.91). Real-world MAE ranged from 0.09 to 0.13, MARE from 1.3 to 22.7%, with ICCs indicating moderate (0.57) to good (0.88) agreement. Lower errors were observed for cohorts without major gait impairments, less complex tasks, and longer walking bouts. The analytical pipelines demonstrated moderate to good accuracy in estimating walking speed. Accuracy depended on confounding factors, emphasizing the need for robust technical validation before clinical application.Trial registration: ISRCTN - 12246987.

Spirometric patterns in young and middle-aged adults: a 20-year European study

BACKGROUND

Understanding the natural history of abnormal spirometric patterns at different stages of life is critical to identify and optimise preventive strategies. We aimed to describe characteristics and risk factors of restrictive and obstructive spirometric patterns occurring before 40 years (young onset) and between 40 and 61 years (mid-adult onset).

METHODS

We used data from the population-based cohort of the European Community Respiratory Health Survey (ECRHS). Prebronchodilator forced expiratory volume in one second (FEV1) and forced vital capacity (FVC) were assessed longitudinally at baseline (ECRHS1, 1993-1994) and again 20 years later (ECRHS3, 2010-2013). Spirometry patterns were defined as: restrictive if FEV1/FVC≥LLN and FVC<10th percentile, obstructive if FEV1/FVC

RESULTS

Among 3502 participants (mean age=30.4 (SD 5.4) at ECRHS1, 50.4 (SD 5.4) at ECRHS3), 2293 (65%) had a normal, 371 (11%) a young restrictive, 301 (9%) a young obstructive, 187 (5%) a mid-adult onset restrictive and 350 (10%) a mid-adult onset obstructive spirometric pattern. Being lean/underweight in childhood and young adult life was associated with the occurrence of the young spirometric restrictive pattern (relative risk ratio (RRR)=1.61 95% CI=1.21 to 2.14, and RRR=2.43 95% CI=1.80 to 3.29; respectively), so were respiratory infections before 5 years (RRR=1.48, 95% CI=1.05 to 2.08). The main determinants for young obstructive, mid-adult restrictive and mid-adult obstructive patterns were asthma, obesity and smoking, respectively.

CONCLUSION

Spirometric patterns with onset in young and mid-adult life were associated with distinct characteristics and risk factors.

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Key Words

• COPD epidemiology
• Clinical Epidemiology

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MESH Headings

• Middle Aged
• Young Adult
• Humans
• Adult
• Pulmonary Disease, Chronic Obstructive
• Spirometry
• Respiratory Function Tests
• Asthma/complications
• Risk Factors
• Forced Expiratory Volume
• Vital Capacity

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Grants

• CEX2018-000806-S Spanish Ministry of Science and Innovation

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Affiliation(s)

Anne-Elie Carsin ISGlobal, Campus mar, Barcelona, Catalunya, Spain Universita Pompeu Fabra (UPF), Barcelona, Spain CIBER Epidemiología y Salud Pública (CIBERESP), Spain, Spain Biometrics, RTI-Health Solutions, Barcelona, Spain
Judith Garcia-Aymerich ISGlobal, Campus mar, Barcelona, Catalunya, Spain Universita Pompeu Fabra (UPF), Barcelona, Spain CIBER Epidemiología y Salud Pública (CIBERESP), Spain, Spain
Simone Accordini Unit of Epidemiology and Medical Statistics, Department of Diagnostics and Public Health, University of Verona, Verona, Italy
Shyamali Dharmage Allergy and Lung Health Unit, School of Population and Global Health, The University of Melbourne, Parkville, Victoria, Australia
Bénédicte Leynaert Université Paris-Saclay, UVSQ, Univ Paris-Sud, Inserm, INSERM, Paris, France
Marti de Las Heras ISGlobal, Campus mar, Barcelona, Catalunya, Spain Universita Pompeu Fabra (UPF), Barcelona, Spain CIBER Epidemiología y Salud Pública (CIBERESP), Spain, Spain
Lidia Casas Social Epidemiology and Health Policy, Department of Family Medicine and Population Health, University of Antwerp, Antwerpen, Belgium Institute for Environment and Sustainable Development (IMDO), University of Antwerp, Antwerpen, Belgium
Seraina Caviezel Epidemiology and Public Health, Swiss Tropical and Public Health Institute, Basel, Switzerland
Pascal Demoly Département de Pneumologie et Addictologie, University Hospital of Montpellier, Montpellier, France IDESP, University of Montpellier - Inserm UMR UA11, Montpellier, France
Bertil Forsberg Department of Public Health and Clinical Medicine, Umeå University, Umeå, Sweden
Thorarinn Gislason Department of Sleep, Landspitali University Hospital, Reykjavik, Iceland Medical Faculty, University of Iceland, Iceland, Iceland
Angelo Guido Corsico Department of Internal Medicine and Therapeutics, University of Pavia, Italy, Italy Division of Respiratory Diseases, Fondazione IRCCS Policlinico San Matteo-University of Pavia, Pavia, Italy
Christer Janson Department of Medical Sciences, Respiratory, Allergy and Sleep Research, Uppsala University, Uppsala, Sweden
Rain Jogi Lung Clinic, Tartu University Hospital, Tartu, Estonia
Jesús Martínez-Moratalla Faculty of Medicine of Albacete, General University Hospital of Albacete, Albacete, Spain
Dennis Nowak Institute and Clinic for Occupational and Environmental Medicine, University Hospital, LMU Munich, Comprehensive Pneumology Centre Munich, member DZL, German Centre for Lung Research, Munich, Germany
Leopoldo Palacios Gómez Distrito Sanitario Huelva-Costa, Huelva, Spain
Isabelle Pin Department of Pediatrics, CHU de Grenoble Alpes, Grenoble, France Inserm, UMR 1209, Institute for Advanced Biosciences, Grenoble, France
Nicole Probst-Hensch Epidemiology and Public Health, Swiss Tropical and Public Health Institute, Basel, Switzerland
Chantal Raherison-Semjen Inserm, UMR 1219, Université de Bordeaux, Bordeaux, France
Giulia Squillacioti Department of Public Health and Pediatrics, University of Turin, Torino, Piemonte, Italy
Cecilie Svanes Centre for International Health, Department of Global Public Health and Primary Care, University of Bergen, Bergen, Norway Department of Occupational Medicine, Haukeland University Hospital, Bergen, Norway
Kjell Torén Department of Occupational and Environmental, School of Public Health and Community Medicine, Institute of Medicine, Sahlgrenska Academy at University of Gothenburg, Gothenburg, Sweden Department of Occupational and Environmental Medicine, Sahlgrenska University Hospital, Gothenburg, Sweden
Isabel Urrutia Pulmonology Department, Galdakao Hospital, Biocruces Bizkaia, Spain
Ismael Huerta Epidemiological Surveillance Section, Directorate General of Public Health, Oviedo, Spain
Josep Maria Anto ISGlobal, Campus mar, Barcelona, Catalunya, Spain Universita Pompeu Fabra (UPF), Barcelona, Spain CIBER Epidemiología y Salud Pública (CIBERESP), Spain, Spain
Debbie Jarvis National Heart and Lung Institute, Imperial College, London, UK
Stefano Guerra ISGlobal, Campus mar, Barcelona, Catalunya, Spain Asthma and Airway Disease Research Center, University of Arizona, Tucson, Arizona, USA

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Ecological validity of a deep learning algorithm to detect gait events from real-life walking bouts in mobility-limiting diseases

Introduction

The clinical assessment of mobility, and walking specifically, is still mainly based on functional tests that lack ecological validity. Thanks to inertial measurement units (IMUs), gait analysis is shifting to unsupervised monitoring in naturalistic and unconstrained settings. However, the extraction of clinically relevant gait parameters from IMU data often depends on heuristics-based algorithms that rely on empirically determined thresholds. These were mainly validated on small cohorts in supervised settings.

Methods

Here, a deep learning (DL) algorithm was developed and validated for gait event detection in a heterogeneous population of different mobility-limiting disease cohorts and a cohort of healthy adults. Participants wore pressure insoles and IMUs on both feet for 2.5 h in their habitual environment. The raw accelerometer and gyroscope data from both feet were used as input to a deep convolutional neural network, while reference timings for gait events were based on the combined IMU and pressure insoles data.

Results and discussion

The results showed a high-detection performance for initial contacts (ICs) (recall: 98%, precision: 96%) and final contacts (FCs) (recall: 99%, precision: 94%) and a maximum median time error of -0.02 s for ICs and 0.03 s for FCs. Subsequently derived temporal gait parameters were in good agreement with a pressure insoles-based reference with a maximum mean difference of 0.07, -0.07, and <0.01 s for stance, swing, and stride time, respectively. Thus, the DL algorithm is considered successful in detecting gait events in ecologically valid environments across different mobility-limiting diseases.

Assessing real-world gait with digital technology? Validation, insights and recommendations from the Mobilise-D consortium

BACKGROUND

Although digital mobility outcomes (DMOs) can be readily calculated from real-world data collected with wearable devices and ad-hoc algorithms, technical validation is still required. The aim of this paper is to comparatively assess and validate DMOs estimated using real-world gait data from six different cohorts, focusing on gait sequence detection, foot initial contact detection (ICD), cadence (CAD) and stride length (SL) estimates.

METHODS

Twenty healthy older adults, 20 people with Parkinson's disease, 20 with multiple sclerosis, 19 with proximal femoral fracture, 17 with chronic obstructive pulmonary disease and 12 with congestive heart failure were monitored for 2.5 h in the real-world, using a single wearable device worn on the lower back. A reference system combining inertial modules with distance sensors and pressure insoles was used for comparison of DMOs from the single wearable device. We assessed and validated three algorithms for gait sequence detection, four for ICD, three for CAD and four for SL by concurrently comparing their performances (e.g., accuracy, specificity, sensitivity, absolute and relative errors). Additionally, the effects of walking bout (WB) speed and duration on algorithm performance were investigated.

RESULTS

We identified two cohort-specific top performing algorithms for gait sequence detection and CAD, and a single best for ICD and SL. Best gait sequence detection algorithms showed good performances (sensitivity > 0.73, positive predictive values > 0.75, specificity > 0.95, accuracy > 0.94). ICD and CAD algorithms presented excellent results, with sensitivity > 0.79, positive predictive values > 0.89 and relative errors < 11% for ICD and < 8.5% for CAD. The best identified SL algorithm showed lower performances than other DMOs (absolute error < 0.21 m). Lower performances across all DMOs were found for the cohort with most severe gait impairments (proximal femoral fracture). Algorithms' performances were lower for short walking bouts; slower gait speeds (< 0.5 m/s) resulted in reduced performance of the CAD and SL algorithms.

CONCLUSIONS

Overall, the identified algorithms enabled a robust estimation of key DMOs. Our findings showed that the choice of algorithm for estimation of gait sequence detection and CAD should be cohort-specific (e.g., slow walkers and with gait impairments). Short walking bout length and slow walking speed worsened algorithms' performances. Trial registration ISRCTN - 12246987.

A multi-sensor wearable system for the assessment of diseased gait in real-world conditions

Introduction: Accurately assessing people's gait, especially in real-world conditions and in case of impaired mobility, is still a challenge due to intrinsic and extrinsic factors resulting in gait complexity. To improve the estimation of gait-related digital mobility outcomes (DMOs) in real-world scenarios, this study presents a wearable multi-sensor system (INDIP), integrating complementary sensing approaches (two plantar pressure insoles, three inertial units and two distance sensors). Methods: The INDIP technical validity was assessed against stereophotogrammetry during a laboratory experimental protocol comprising structured tests (including continuous curvilinear and rectilinear walking and steps) and a simulation of daily-life activities (including intermittent gait and short walking bouts). To evaluate its performance on various gait patterns, data were collected on 128 participants from seven cohorts: healthy young and older adults, patients with Parkinson's disease, multiple sclerosis, chronic obstructive pulmonary disease, congestive heart failure, and proximal femur fracture. Moreover, INDIP usability was evaluated by recording 2.5-h of real-world unsupervised activity. Results and discussion: Excellent absolute agreement (ICC >0.95) and very limited mean absolute errors were observed for all cohorts and digital mobility outcomes (cadence ≤0.61 steps/min, stride length ≤0.02 m, walking speed ≤0.02 m/s) in the structured tests. Larger, but limited, errors were observed during the daily-life simulation (cadence 2.72-4.87 steps/min, stride length 0.04-0.06 m, walking speed 0.03-0.05 m/s). Neither major technical nor usability issues were declared during the 2.5-h acquisitions. Therefore, the INDIP system can be considered a valid and feasible solution to collect reference data for analyzing gait in real-world conditions.

Creatine Kinase Is Decreased in Childhood Asthma

Rationale: The identification of novel molecules associated with asthma may provide insights into the mechanisms of disease and their potential clinical implications. Objectives: To conduct a screening of circulating proteins in childhood asthma and to study proteins that emerged from human studies in a mouse model of asthma. Methods: We included 2,264 children from eight birth cohorts from the Mechanisms of the Development of ALLergy project and the Tucson Children's Respiratory Study. In cross-sectional analyses, we tested 46 circulating proteins for association with asthma in the selection stage and carried significant signals forward to a validation and replication stage. As CK (creatine kinase) was the only protein consistently associated with asthma, we also compared whole blood CK gene expression between subjects with and without asthma (n = 249) and used a house dust mite (HDM)-challenged mouse model to gain insights into CK lung expression and its role in the resolution of asthma phenotypes. Measurements and Main Results: As compared with the lowest CK tertile, children in the highest tertile had significantly lower odds for asthma in selection (adjusted odds ratio, 95% confidence interval: 0.31; 0.15-0.65; P = 0.002), validation (0.63; 0.42-0.95; P = 0.03), and replication (0.40; 0.16-0.97; P = 0.04) stages. Both cytosolic CK forms (CKM and CKB) were underexpressed in blood from asthmatics compared with control subjects (P = 0.01 and 0.006, respectively). In the lungs of HDM-challenged mice, Ckb expression was reduced, and after the HDM challenge, a CKB inhibitor blocked the resolution of airway hyperresponsiveness and reduction of airway mucin. Conclusions: Circulating concentrations and gene expression of CK are inversely associated with childhood asthma. Mouse models support a possible direct involvement of CK in asthma protection via inhibition of airway hyperresponsiveness and reduction of airway mucin.

Long-term effect of asthma on the development of obesity among adults: an international cohort study, ECRHS

INTRODUCTION

Obesity is a known risk factor for asthma. Although some evidence showed asthma causing obesity in children, the link between asthma and obesity has not been investigated in adults.

METHODS

We used data from the European Community Respiratory Health Survey (ECRHS), a cohort study in 11 European countries and Australia in 3 waves between 1990 and 2014, at intervals of approximately 10 years. We considered two study periods: from ECRHS I (t) to ECRHS II (t+1), and from ECRHS II (t) to ECRHS III (t+1). We excluded obese (body mass index≥30 kg/m²) individuals at visit t. The relative risk (RR) of obesity at t+1 associated with asthma at t was estimated by multivariable modified Poisson regression (lag) with repeated measurements. Additionally, we examined the association of atopy and asthma medication on the development of obesity.

RESULTS

We included 7576 participants in the period ECRHS I-II (51.5% female, mean (SD) age of 34 (7) years) and 4976 in ECRHS II-III (51.3% female, 42 (8) years). 9% of participants became obese in ECRHS I-II and 15% in ECRHS II-III. The risk of developing obesity was higher among asthmatics than non-asthmatics (RR 1.22, 95% CI 1.07 to 1.38), and particularly higher among non-atopic than atopic (1.47; 1.17 to 1.86 vs 1.04; 0.86 to 1.27), those with longer disease duration (1.32; 1.10 to 1.59 in >20 years vs 1.12; 0.87 to 1.43 in ≤20 years) and those on oral corticosteroids (1.99; 1.26 to 3.15 vs 1.15; 1.03 to 1.28). Physical activity was not a mediator of this association.

CONCLUSION

This is the first study showing that adult asthmatics have a higher risk of developing obesity than non-asthmatics, particularly those non-atopic, of longer disease duration or on oral corticosteroids.

Design and validation of a multi-task, multi-context protocol for real-world gait simulation

BACKGROUND

Measuring mobility in daily life entails dealing with confounding factors arising from multiple sources, including pathological characteristics, patient specific walking strategies, environment/context, and purpose of the task. The primary aim of this study is to propose and validate a protocol for simulating real-world gait accounting for all these factors within a single set of observations, while ensuring minimisation of participant burden and safety.

METHODS

The protocol included eight motor tasks at varying speed, incline/steps, surface, path shape, cognitive demand, and included postures that may abruptly alter the participants' strategy of walking. It was deployed in a convenience sample of 108 participants recruited from six cohorts that included older healthy adults (HA) and participants with potentially altered mobility due to Parkinson's disease (PD), multiple sclerosis (MS), proximal femoral fracture (PFF), chronic obstructive pulmonary disease (COPD) or congestive heart failure (CHF). A novelty introduced in the protocol was the tiered approach to increase difficulty both within the same task (e.g., by allowing use of aids or armrests) and across tasks.

RESULTS

The protocol proved to be safe and feasible (all participants could complete it and no adverse events were recorded) and the addition of the more complex tasks allowed a much greater spread in walking speeds to be achieved compared to standard straight walking trials. Furthermore, it allowed a representation of a variety of daily life relevant mobility aspects and can therefore be used for the validation of monitoring devices used in real life.

CONCLUSIONS

The protocol allowed for measuring gait in a variety of pathological conditions suggests that it can also be used to detect changes in gait due to, for example, the onset or progression of a disease, or due to therapy.

TRIAL REGISTRATION

ISRCTN-12246987.

Mid-childhood fat mass and airflow limitation at 15 years: The mediating role of insulin resistance and C-reactive protein

BACKGROUND

We previously reported an association of high fat mass levels from age 9 to 15 years with lower forced expiratory flow in 1 s (FEV₁ )/forced vital capacity (FVC) ratio (i.e., increased risk of airflow limitation) at 15 years. Here, we aimed to assess whether insulin resistance and C-reactive protein (CRP) at 15 years partially mediate this association.

METHODS

We included 2263 children from the UK Avon Longitudinal Study of Parents and Children population-based cohort (ALSPAC). Four fat mass index (FMI) trajectories ("low," "medium-low," "medium-high," "high") from 9 to 15 years were previously identified using Group-Based Trajectory Modeling. Data on CRP, glucose, insulin, and post-bronchodilator FEV₁ /FVC were available at 15 years. We defined insulin resistance by the homeostasis model assessment-estimated insulin resistance index (HOMA-IR). We used adjusted linear regression models and a causal mediation analysis to assess the mediating role of HOMA-IR and CRP.

RESULTS

Compared to children in the "low" FMI trajectory, children in the "medium-high" and "high" FMI trajectories had lower FEV₁ /FVC at 15 years. The percentage of the total effect explained by HOMA-IR was 19.8% [-114.1 to 170.0] and 20.4% [1.6 to 69.0] for the "medium-high" and "high" trajectories, respectively. In contrast, there was little evidence for a mediating role of CRP.

CONCLUSION

The association between mid-childhood fat mass and FEV₁ /FVC ratio at 15 years may be partially mediated by insulin resistance.

Changes in Population Health-Related Behaviors During a COVID-19 Surge: A Natural Experiment

Background

The study of impact of lockdowns on individual health-related behaviors has produced divergent results.

Purpose

To identify patterns of change in multiple health-related behaviors analyzed as a whole, and their individual determinants.

Methods

Between March and August 2020, we collected data on smoking, alcohol, physical activity, weight, and sleep in a population-based cohort from Catalonia who had available pre-pandemic data. We performed multiple correspondence and cluster analyses to identify patterns of change in health-related behaviors and built multivariable multinomial logistic regressions to identify determinants of behavioral change.

Results

In 10,032 participants (59% female, mean (SD) age 55 (8) years), 8,606 individuals (86%) modified their behavior during the lockdown. We identified five patterns of behavioral change that were heterogeneous and directed both towards worsening and improvement in diverse combinations. Patterns ranged from “global worsening” (2,063 participants, 21%) characterized by increases in smoking, alcohol consumption, and weight, and decreases in physical activity levels and sleep time, to “improvement” (2,548 participants, 25%) characterized by increases in physical activity levels, decreases in weight and alcohol consumption, and both increases and decreases in sleep time. Being female, of older age, teleworking, having a higher education level, assuming caregiving responsibilities, and being more exposed to pandemic news were associated with changing behavior (all p &lt; .05), but did not discriminate between favorable or unfavorable changes.

Conclusions

Most of the population experienced changes in health-related behavior during lockdowns. Determinants of behavior modification were not explicitly associated with the direction of changes but allowed the identification of older, teleworking, and highly educated women who assumed caregiving responsibilities at home as susceptible population groups more vulnerable to lockdowns.

Urban environment and physical activity and capacity in patients with chronic obstructive pulmonary disease

BACKGROUND

Physical activity and exercise capacity are key prognostic factors in chronic obstructive pulmonary disease (COPD) but their environmental determinants are unknown.

OBJECTIVES

To test the association between urban environment and objective physical activity, physical activity experience and exercise capacity in COPD.

METHODS

We studied 404 patients with mild-to-very severe COPD from a multi-city study in Catalonia, Spain. We measured objective physical activity (step count and sedentary time) by the Dynaport MoveMonitor, physical activity experience (difficulty with physical activity) by the Clinical visit-PROactive (C-PPAC) instrument, and exercise capacity by the 6-min walk distance (6MWD). We estimated individually (geocoded to the residential address) population density, pedestrian street length, slope of terrain, and long-term (i.e., annual) exposure to road traffic noise, nitrogen dioxide (NO₂) and particulate matter (PM_2.5). We built single- and multi-exposure mixed-effects linear regressions with a random intercept for city, adjusting for confounders.

RESULTS

Patients were 85% male, had mean (SD) age 69 (9) years and walked 7524 (4045) steps/day. In multi-exposure models, higher population density was associated with fewer steps, more sedentary time and worse exercise capacity (-507 [95% CI: 1135, 121] steps, +0.2 [0.0, 0.4] h/day and -13 [-25, 0] m per IQR). Pedestrian street length related with more steps and less sedentary time (156 [9, 304] steps and -0.1 [-0.1, 0.0] h/day per IQR). Steeper slope was associated with better exercise capacity (15 [3, 27] m per IQR). Higher NO₂ levels related with more sedentary time and more difficulty in physical activity. PM_2.5 and noise were not associated with physical activity or exercise capacity.

DISCUSSION

Population density, pedestrian street length, slope and NO₂ exposure relate to physical activity and capacity of COPD patients living in highly populated areas. These findings support the consideration of neighbourhood environmental factors during COPD management and the attention to patients with chronic diseases when developing urban and transport planning policies.

Gestational phthalate exposure and lung function during childhood: A prospective population-based study

The potential effect of gestational exposure to phthalates on the lung function levels during childhood is unclear. Therefore, we examined this association at different ages (from 4 to 11 years) and over the whole childhood. Specifically, we measured 9 phthalate metabolites (MEP, MiBP, MnBP, MCMHP, MBzP, MEHHP, MEOHP, MECPP, MEHP) in the urine of 641 gestating women from the INMA study (Spain) and the forced vital capacity (FVC), forced expiratory volume in 1 s (FEV₁) and FEV₁/FVC in their offspring at ages 4, 7, 9 and 11. We used linear regression and mixed linear regression with a random intercept for subject to assess the association between phthalates and lung function at each study visit and for the overall childhood, respectively. We also assessed the phthalate metabolites mixture effect on lung function using a Weighted Quantile Sum (WQS) regression. We observed that the phthalate metabolites gestational levels were consistently associated with lower FVC and FEV₁ at all ages, both when assessed individually and jointly as a mixture, although most associations were not statistically significant. Of note, a 10% increase in MiBP was related to lower FVC (-0.02 (-0.04, 0)) and FEV₁ z-scores (-0.02 (-0.04, -0.01) at age 4. Similar significant reductions in FVC were observed at ages 4 and 7 associated with an increase in MEP and MnBP, respectively, and for FEV₁ at age 4 associated with an increase in MBzP. WQS regression consistently identified MBzP as an important contributor to the phthalate mixture effect. We can conclude that the gestational exposure to phthalates was associated with children's lower FVC and FEV₁, especially in early childhood, and in a statistically significant manner for MEP, MiBP, MBzP and MnBP. Given the ubiquity of phthalate exposure and its established endocrine disrupting effects in children, our findings support current regulations that limit phthalate exposure.

Multisite greenness exposure and oxidative stress in children. The potential mediating role of physical activity

Residential greenness exposure has been reported to positively impact health mainly by reducing overweight/obesity risk, improving mental health and physical activity. Less is known on biological pathways involved in these health benefits. We aimed to investigate the association between multisite greenness exposure and oxidative stress in children and explore the potential mediating role of physical activity in this association. This cross-sectional study involved 323 healthy subjects (8-11 y) from five schools in Asti (Italy). Children's parents filled a questionnaire providing the residential address, parental education, and physical activity frequency. Oxidative stress was quantified in spot urine by isoprostane (15-F_2t-IsoP) using ELISA technique. Residential and scholastic greenness were defined by the Normalized Difference Vegetation Index (NDVI) in buffers with 100, 250, 300, 500 and 1000 m radii, and vegetated portion was also estimated. Multisite exposures were derived accounting for NDVI around home and school, weighted for time spent in each location. Linear mixed models, age-adjusted, with schools as random intercept, tested the association between 500 m-radius buffer multisite grenness variables and log (15-F_2t-IsoP), reporting decreased oxidative stress per interquartile range (IQR) increase in multisite NDVI (β: 012, 95%CI -0.240 to 0.004) and multisite vegetated portion (β: 0.14, 95%CI -0.270 to -0.006). The mediation analysis did not support the hypothesis that physical activity frequency could mediate these associations. Multisite greenness exposure is associated with decreased oxidative stress in children and our data did not support the mediating role of physical activity.

Technical validation of real-world monitoring of gait: a multicentric observational study

INTRODUCTION

Existing mobility endpoints based on functional performance, physical assessments and patient self-reporting are often affected by lack of sensitivity, limiting their utility in clinical practice. Wearable devices including inertial measurement units (IMUs) can overcome these limitations by quantifying digital mobility outcomes (DMOs) both during supervised structured assessments and in real-world conditions. The validity of IMU-based methods in the real-world, however, is still limited in patient populations. Rigorous validation procedures should cover the device metrological verification, the validation of the algorithms for the DMOs computation specifically for the population of interest and in daily life situations, and the users' perspective on the device.

METHODS AND ANALYSIS

This protocol was designed to establish the technical validity and patient acceptability of the approach used to quantify digital mobility in the real world by Mobilise-D, a consortium funded by the European Union (EU) as part of the Innovative Medicine Initiative, aiming at fostering regulatory approval and clinical adoption of DMOs.After defining the procedures for the metrological verification of an IMU-based device, the experimental procedures for the validation of algorithms used to calculate the DMOs are presented. These include laboratory and real-world assessment in 120 participants from five groups: healthy older adults; chronic obstructive pulmonary disease, Parkinson's disease, multiple sclerosis, proximal femoral fracture and congestive heart failure. DMOs extracted from the monitoring device will be compared with those from different reference systems, chosen according to the contexts of observation. Questionnaires and interviews will evaluate the users' perspective on the deployed technology and relevance of the mobility assessment.

ETHICS AND DISSEMINATION

The study has been granted ethics approval by the centre's committees (London-Bloomsbury Research Ethics committee; Helsinki Committee, Tel Aviv Sourasky Medical Centre; Medical Faculties of The University of Tübingen and of the University of Kiel). Data and algorithms will be made publicly available.

TRIAL REGISTRATION NUMBER

ISRCTN (12246987).

Maternal sleep duration and neonate birth weight: A population-based cohort study

OBJECTIVE

To investigate the association between maternal sleep duration (an important health indicator) and neonate birth weight.

METHODS

The study included 2536 mother-neonate pairs of a Spanish birth cohort (2004-2006, INMA project). The exposures were questionnaire-based measures of sleep duration before and during pregnancy. The primary outcome was neonate birth weight score (g) standardized to 40 weeks of gestation.

RESULTS

In women sleeping for <7 h/day before pregnancy, each additional hour of sleep increased birth weight score by 44.7 g (P = 0.049) in the minimally adjusted model, although findings were not statistically significant after considering other potential confounders (P > 0.05). However, increasing sleep duration for the group of mothers who slept for more than 9 h/day decreased birth weight score by 39.2 g per additional hour (P = 0.001). Findings were similar after adjusting for several sociodemographic confounders and maternal depression-anxiety clinical history as an intermediate factor. Similar but attenuated associations were observed with sleep duration in the second trimester of pregnancy.

CONCLUSION

The relationship between maternal sleep duration before and during pregnancy and neonate birth weight is an inverse U-shaped curve. Excessive sleep duration may adversely affect neonate health through its impact on birth weight.

The effect of physical activity on asthma incidence over 10 years: population-based study

Although there are many health benefits from being active, there was no benefit observed in this study from vigorous physical activity in reducing the risk of asthma onset in middle-aged adults https://bit.ly/3bEtHDn.

Regular Physical Activity Levels and Incidence of Restrictive Spirometry Pattern: A Longitudinal Analysis of 2 Population-Based Cohorts

We estimated the association between regular physical activity and the incidence of restrictive spirometry pattern. Forced expiratory volume in 1 second (FEV1), forced vital capacity (FVC), and physical activity were assessed in 2 population-based European cohorts (European Community Respiratory Health Survey: n = 2,757, aged 39-67 years; and Swiss Study on Air Pollution and Lung and Heart Diseases in Adults: n = 2,610, aged 36-82 years) first in 2000-2002 and again approximately 10 years later (2010-2013). Subjects with restrictive or obstructive spirometry pattern at baseline were excluded. We assessed the association of being active at baseline (defined as being physically active at least 2-3 times/week for ≥1 hour) with restrictive spirometry pattern at follow-up (defined as a postbronchodilation FEV1/FVC ratio of at least the lower limit of normal and FVC of <80% predicted) using modified Poisson regression, adjusting for relevant confounders. After 10 years of follow-up, 3.3% of participants had developed restrictive spirometry pattern. Being physically active was associated with a lower risk of developing this phenotype (relative risk = 0.76, 95% confidence interval: 0.59, 0.98). This association was stronger among those who were overweight and obese than among those of normal weight (P for interaction = 0.06). In 2 large European studies, adults practicing regular physical activity were at lower risk of developing restrictive spirometry pattern over 10 years.

Greenness and physical activity as possible oxidative stress modulators in children

Background

Green spaces (greenness) have been reported as beneficial to health, mainly mitigating air pollution, hot spots, noise and promoting socialisation, biodiversity and physical activity (PA). This study aims to examine the association between greenness and oxidative stress (OS) in children and to evaluate interaction with PA.

Methods

The cross-sectional study involved 323 subjects (9-11 yrs.) from five schools in Asti (Italy). Parents completed a questionnaire providing home-address, parental education, and PA of children. Urinary samples were collected to measure OS by isoprostane (15-F2t-IsoP). Time-weighted exposure to greenness was calculated from satellite images (Sentinel2 L2A) by Normalised Difference Vegetation Index (NDVI), within buffers around participants' homes and schools, accounting for the individual multi-site exposure during the day.

Results

Overall 323 subjects were included in the analyses, 50% females. An inverse correlation was found between greenness and OS (Pearson -0.162, p = 0.003). A generalised linear mixed model, age-adjusted with schools as random effect, tested the association between greenness and log-transformed(15-F2t-IsoP), reporting decreased OS levels for each unit of increase in greenness (β: -0.50, 95%CI-0.98 to -0.02, p = 0.041). After adding PA in the model, greenness was no longer significant (β: -0.42, 95%C.I.-0.90 to 0.07, p = 0.092), but children reporting low-PA and high-PA showed the highest increase in OS (β: +0.19, 95%CI 0.04 to 0.43, p = 0.02; β: +0.25, 95%CI 0.04 to 0.46, p = 0.018) compared to those with moderate-PA.

Conclusions

Greenness positively impacts health by reducing OS in children. Our findings suggest that PA is partly mediating this association. Noticeably, this is the first study assessing a multi-site greenness exposure and its association with OS accounting for PA in children. The management of urban greenness should be included as preventive Public Health intervention for health and well-being promotion.

Key messages

Greenness exposure may benefit health by reducing oxidative stress in children. The association between greenness and oxidative stress seems partly mediated by physical activity.

Physical activity and lung function-Cause or consequence?

Concerns exist that the positive association of physical activity with better lung function, which has been suggested in previous longitudinal studies in smokers, is due to reverse causation. To investigate this, we applied structural equation modeling (SEM), an exploratory approach, and marginal structural modeling (MSM), an approach from the causal inference framework that corrects for reverse causation and time-dependent confounding and estimates causal effects, on data from participants in the European Community Respiratory Health Survey (ECRHS, a multicentre European cohort study initiated in 1991–1993 with ECRHS I, and with two follow-ups: ECRHS II in 1999–2003, and ECRHS III in 2010–2014). 753 subjects who reported current smoking at ECRHS II, with repeated data on lung function at ECRHS I, II and III, physical activity at ECRHS II and III, and potential confounders at ECRHS I and II, were included in the analyses. SEM showed positive associations between physical activity and lung function in both directions. MSM suggested a protective causal effect of physical activity on lung function (overall difference in mean β (95% CI), comparing active versus non-active individuals: 58 mL (21–95) for forced expiratory volume in one second and 83 mL (36–130) for forced vital capacity). Our results suggest bi-directional causation and support a true protective effect of physical activity on lung function in smokers, after accounting for reverse causation and time-dependent confounding.

Individual circadian preference (chronotype) is associated with asthma and allergic symptoms among adolescents

Circadian rhythm is an endogenously driven cyclical process that regulates most of our bodily functions, such as sleep–wakefulness cycle, metabolism, and a wide range of cellular, molecular and behavioural processes. Chronotype, or an individual's preferred time of sleep and activity, is one of the major internal cues that helps to harmonise one's biological events according to its circadian timing [1]. Three major variations of chronotype exist among humans, those who prefer to wake up early and sleep early at night (known as morning types or “larks”), those who prefer late sleep at night and late waking up in the morning (referred to as evening type or “owls”) and those who remain in between (intermediate type) [1].

Individual preference of sleep and activity (chronotype) might play an important role on asthma and allergic diseases in adolescents: this link underscores a potential plausible behavioural intervention for asthma and allergic diseases in young populationhttps://bit.ly/2THta9I

Body mass index and weight change are associated with adult lung function trajectories: the prospective ECRHS study

BACKGROUND

Previous studies have reported an association between weight increase and excess lung function decline in young adults followed for short periods. We aimed to estimate lung function trajectories during adulthood from 20-year weight change profiles using data from the population-based European Community Respiratory Health Survey (ECRHS).

METHODS

We included 3673 participants recruited at age 20-44 years with repeated measurements of weight and lung function (forced vital capacity (FVC), forced expiratory volume in 1 s (FEV1)) in three study waves (1991-93, 1999-2003, 2010-14) until they were 39-67 years of age. We classified subjects into weight change profiles according to baseline body mass index (BMI) categories and weight change over 20 years. We estimated trajectories of lung function over time as a function of weight change profiles using population-averaged generalised estimating equations.

RESULTS

In individuals with normal BMI, overweight and obesity at baseline, moderate (0.25-1 kg/year) and high weight gain (>1 kg/year) during follow-up were associated with accelerated FVC and FEV1 declines. Compared with participants with baseline normal BMI and stable weight (±0.25 kg/year), obese individuals with high weight gain during follow-up had -1011 mL (95% CI -1.259 to -763) lower estimated FVC at 65 years despite similar estimated FVC levels at 25 years. Obese individuals at baseline who lost weight (<-0.25 kg/year) exhibited an attenuation of FVC and FEV1 declines. We found no association between weight change profiles and FEV1/FVC decline.

CONCLUSION

Moderate and high weight gain over 20 years was associated with accelerated lung function decline, while weight loss was related to its attenuation. Control of weight gain is important for maintaining good lung function in adult life.

Incidence trends of airflow obstruction among European adults without asthma: a 20-year cohort study

Investigating COPD trends may help healthcare providers to forecast future disease burden. We estimated sex- and smoking-specific incidence trends of pre-bronchodilator airflow obstruction (AO) among adults without asthma from 11 European countries within a 20-year follow-up (ECRHS and SAPALDIA cohorts). We also quantified the extent of misclassification in the definition based on pre-bronchodilator spirometry (using post-bronchodilator measurements from a subsample of subjects) and we used this information to estimate the incidence of post-bronchodilator AO (AOpost-BD), which is the primary characteristic of COPD. AO incidence was 4.4 (95% CI: 3.5-5.3) male and 3.8 (3.1-4.6) female cases/1,000/year. Among ever smokers (median pack-years: 20, males; 12, females), AO incidence significantly increased with ageing in men only [incidence rate ratio (IRR), 1-year increase: 1.05 (1.03-1.07)]. A strong exposure-response relationship with smoking was found both in males [IRR, 1-pack-year increase: 1.03 (1.02-1.04)] and females [1.03 (1.02-1.05)]. The positive predictive value of AO for AOpost-BD was 59.1% (52.0-66.2%) in men and 42.6% (35.1-50.1%) in women. AOpost-BD incidence was 2.6 (1.7-3.4) male and 1.6 (1.0-2.2) female cases/1,000/year. AO incidence was considerable in Europe and the sex-specific ageing-related increase among ever smokers was strongly related to cumulative tobacco exposure. AOpost-BD incidence is expected to be half of AO incidence.

The role of C-reactive protein levels on the association of physical activity with lung function in adults

Objective

Regular physical activity may be associated with improved lung function via reduced systemic inflammation, although studies exploring this mechanism are rare. We evaluated the role of C-reactive protein in blood, which is a common marker of systemic inflammation, on the association of physical activity with forced expiratory volume in one second and forced vital capacity.

Methods

Cross-sectional data on spirometry, C-reactive protein levels and self-reported physical activity (yes/no; ≥2 times and ≥1hr per week of vigorous physical activity) were available in the European Community Respiratory Health Survey (N = 2347 adults, 49.3% male, 28–56 years-old). A subsample was also assessed 10 years later using the International Physical Activity Questionnaire, and tertiles of Metabolic Equivalent of Task—minutes per week spent in vigorous, moderate and walking activities were calculated (N = 671, 49.6% male, 40–67 years-old). Adjusted cross-sectional mixed linear regression models and the “mediate” package in “R” were used to assess the presence of mediation.

Results

Despite positive significant associations between nearly all physical activity metrics with forced expiratory volume in one second and forced vital capacity, there was no evidence that C-reactive protein levels played a role. An influence of C-reactive protein levels was only apparent in the smaller subsample when comparing the medium to low tertiles of moderate activity (mean difference [95% CIs]: 21.1ml [5.2, 41.9] for forced expiratory volume in one second and 17.3ml [2.6, 38.0] for forced vital capacity).

Conclusions

In a population of adults, we found no consistent evidence that the association of physical activity with forced expiratory volume in one second or forced vital capacity is influenced by the level of C-reactive protein in blood.

Effects of smoking bans on passive smoking exposure at work and at home. The European Community respiratory health survey

This longitudinal study investigated whether smoking bans influence passive smoking at work and/or at home in the same subjects. Passive smoking at work and/or at home was investigated in random population samples (European Community Respiratory Health Survey) in 1990-1995, with follow-up interviews in 1998-2003 and 2010-2014. National smoking bans were classified as partial (restricted to public workplaces) or global (extended to private workplaces). Multivariable analysis was accomplished by three-level logistic regression models, where level-1, level-2, and level-3 units were, respectively, questionnaire responses, subjects, and centers. Passive smoking at work was reported by 31.9% in 1990-1995, 17.5% in 1998-2003, and 2.5% in 2010-2014. Concurrently, passive smoking at home decreased from 28.9% to 18.2% and 8.8%. When controlling for sex, age, education, smoking status, and ECHRS wave, the odds of passive smoking at work was markedly reduced after global smoking bans (OR = 0.45, 95% CI 0.25-0.81), particularly among non-smokers, while the protective effect of global smoking bans on passive smoking at home was only detected in non-smokers. Smoking bans both in public and private workplaces were effective in reducing passive smoking at work in Europe. However, given the inefficacy of smoking bans in current smokers' dwellings, better strategies are needed to avoid smoking indoors.

A three-generation study on the association of tobacco smoking with asthma

Background

Mothers’ smoking during pregnancy increases asthma risk in their offspring. There is some evidence that grandmothers’ smoking may have a similar effect, and biological plausibility that fathers’ smoking during adolescence may influence offspring’s health through transmittable epigenetic changes in sperm precursor cells. We evaluated the three-generation associations of tobacco smoking with asthma.

Methods

Between 2010 and 2013, at the European Community Respiratory Health Survey III clinical interview, 2233 mothers and 1964 fathers from 26 centres reported whether their offspring (aged ≤51 years) had ever had asthma and whether it had coexisted with nasal allergies or not. Mothers and fathers also provided information on their parents’ (grandparents) and their own asthma, education and smoking history. Multilevel mediation models within a multicentre three-generation framework were fitted separately within the maternal (4666 offspring) and paternal (4192 offspring) lines.

Results

Fathers’ smoking before they were 15 [relative risk ratio (RRR) = 1.43, 95% confidence interval (CI): 1.01–2.01] and mothers’ smoking during pregnancy (RRR = 1.27, 95% CI: 1.01–1.59) were associated with asthma without nasal allergies in their offspring. Grandmothers’ smoking during pregnancy was associated with asthma in their daughters [odds ratio (OR) = 1.55, 95% CI: 1.17–2.06] and with asthma with nasal allergies in their grandchildren within the maternal line (RRR = 1.25, 95% CI: 1.02–1.55).

Conclusions

Fathers’ smoking during early adolescence and grandmothers’ and mothers’ smoking during pregnancy may independently increase asthma risk in offspring. Thus, risk factors for asthma should be sought in both parents and before conception.

Funding

European Union (Horizon 2020, GA-633212).

DNA Methylation in Inflammatory Pathways Modifies the Association between BMI and Adult-Onset Non-Atopic Asthma

A high body mass (BMI) index has repeatedly been associated with non-atopic asthma, but the biological mechanism linking obesity to asthma is still poorly understood. We aimed to test the hypothesis that inflammation and/or innate immunity plays a role in the obesity-asthma link. DNA methylome was measured in blood samples of 61 non-atopic participants with asthma and 146 non-atopic participants without asthma (non-smokers for at least 10 years) taking part in the Swiss Cohort Study on Air Pollution and Lung and Heart Diseases in Adults (SAPALDIA) study. Modification by DNA methylation of the association of BMI or BMI change over 10 years with adult-onset asthma was examined at each CpG site and differentially methylated region. Pathway enrichment tests were conducted for genes in a priori curated inflammatory pathways and the NLRP3-IL1B-IL17 axis. The latter was chosen on the basis of previous work in mice. Inflammatory pathways including glucocorticoid/PPAR signaling (p = 0.0023), MAPK signaling (p = 0.013), NF-κB signaling (p = 0.031), and PI3K/AKT signaling (p = 0.031) were enriched for the effect modification of BMI, while NLRP3-IL1B-IL17 axis was enriched for the effect modification of BMI change over 10 years (p = 0.046). DNA methylation measured in peripheral blood is consistent with inflammation as a link between BMI and adult-onset asthma and with the NLRP3-IL1B-IL17 axis as a link between BMI change over 10 years and adult-onset asthma in non-atopic participants.

Occupational exposures and incidence of chronic bronchitis and related symptoms over two decades: the European Community Respiratory Health Survey

OBJECTIVES

Chronic bronchitis (CB) is an important chronic obstructive pulmonary disease (COPD)-related phenotype, with distinct clinical features and prognostic implications. Occupational exposures have been previously associated with increased risk of CB but few studies have examined this association prospectively using objective exposure assessment. We examined the effect of occupational exposures on CB incidence in the European Community Respiratory Health Survey.

METHODS

Population samples aged 20-44 were randomly selected in 1991-1993, and followed up twice over 20 years. Participants without chronic cough or phlegm at baseline were analysed. Coded job histories during follow-up were linked to the ALOHA Job Exposure Matrix, generating occupational exposure estimates to 12 categories of chemical agents. Their association with CB incidence over both follow-ups was examined with Poisson models using generalised estimating equations.

RESULTS

8794 participants fulfilled the inclusion criteria, contributing 13 185 observations. Only participants exposed to metals had a higher incidence of CB (relative risk (RR) 1.70, 95% CI 1.16 to 2.50) compared with non-exposed to metals. Mineral dust exposure increased the incidence of chronic phlegm (RR 1.72, 95% CI 1.43 to 2.06). Incidence of chronic phlegm was increased in men exposed to gases/fumes and to solvents and in women exposed to pesticides.

CONCLUSIONS

Occupational exposures are associated with chronic phlegm and CB, and the evidence is strongest for metals and mineral dust exposure. The observed differences between men and women warrant further investigation.

Restrictive spirometry pattern is associated with low physical activity levels. A population based international study

INTRODUCTION

Restrictive spirometry pattern is an under-recognised disorder with a poor morbidity and mortality prognosis. We compared physical activity levels between adults with a restrictive spirometry pattern and with normal spirometry.

METHODS

Restrictive spirometry pattern was defined as a having post-bronchodilator FEV₁/FVC ≥ Lower Limit of Normal and a FVC<80% predicted in two population-based studies (ECRHS-III and SAPALDIA3). Physical activity was measured using the International Physical Activity Questionnaire. The odds of having low physical activity (<1st study-specific tertile) was evaluated using adjusted logistic regression models.

RESULTS

Subjects with a restrictive spirometry pattern (n = 280/4721 in ECRHS, n = 143/3570 in SAPALDIA) reported lower levels of physical activity than those with normal spirometry (median of 1770 vs 2253 MET·min/week in ECRHS, and 3519 vs 3945 MET·min/week in SAPALDIA). Subjects with a restrictive spirometry pattern were more likely to report low physical activity (meta-analysis odds ratio: 1.41 [95%CI 1.07-1.86]) than those with a normal spirometry. Obesity, respiratory symptoms, co-morbidities and previous physical activity levels did not fully explain this finding.

CONCLUSION

Adults with a restrictive spirometry pattern were more likely to report low levels of physical activity than those with normal spirometry. These results highlight the need to identify and act on this understudied but prevalent condition.

The dyspnoea-inactivity vicious circle in COPD: development and external validation of a conceptual model

The vicious circle of dyspnoea-inactivity has been proposed, but never validated empirically, to explain the clinical course of chronic obstructive pulmonary disease (COPD). We aimed to develop and validate externally a comprehensive vicious circle model.We utilised two methods. 1) Identification and validation of all published vicious circle models by a systematic literature search and fitting structural equation models to longitudinal data from the Spanish PAC-COPD (Phenotype and Course of COPD) cohort (n=210, mean age 68 years, mean forced expiratory volume in 1 s (FEV1) 54% predicted), testing both the hypothesised relationships between variables in the model ("paths") and model fit. 2) Development of a new model and external validation using longitudinal data from the Swiss and Dutch ICE COLD ERIC (International Collaborative Effort on Chronic Obstructive Lung Disease: Exacerbation Risk Index Cohorts) cohort (n=226, mean age 66 years, mean FEV1 57% predicted).We identified nine vicious circle models for which structural equation models confirmed most hypothesised paths but showed inappropriate fit. In the new model, airflow limitation, hyperinflation, dyspnoea, physical activity, exercise capacity and COPD exacerbations remained related to other variables and model fit was appropriate. Fitting it to ICE COLD ERIC, all paths were replicated and model fit was appropriate.Previously published vicious circle models do not fully explain the vicious circle concept. We developed and externally validated a new comprehensive model that gives a more relevant role to exercise capacity and COPD exacerbations.

Association between air pollution and rhinitis incidence in two European cohorts

BACKGROUND

The association between air pollution and rhinitis is not well established.

AIM

The aim of this longitudinal analysis was to study the association between modeled air pollution at the subjects' home addresses and self-reported incidence of rhinitis.

METHODS

We used data from 1533 adults from two multicentre cohorts' studies (EGEA and ECRHS). Rhinitis incidence was defined as reporting rhinitis at the second follow-up (2011 to 2013) but not at the first follow-up (2000 to 2007). Annual exposure to NO₂, PM₁₀ and PM_2.5 at the participants' home addresses was estimated using land-use regression models developed by the ESCAPE project for the 2009-2010 period. Incidence rate ratios (IRR) were computed using Poisson regression. Pooled analysis, analyses by city and meta-regression testing for heterogeneity were carried out.

RESULTS

No association between long-term air pollution exposure and incidence of rhinitis was found (adjusted IRR (aIRR) for an increase of 10 μg·m^-3 of NO_2: 1.00 [0.91-1.09], for an increase of 5 μg·m^-3 of PM_2.5: 0.88 [0.73-1.04]). Similar results were found in the two-pollutant model (aIRR for an increase of 10 μg·m^-3 of NO_2: 1.01 [0.87-1.17], for an increase of 5 μg·m^-3 of PM_2.5: 0.87 [0.68-1.08]). Results differed depending on the city, but no regional pattern emerged for any of the pollutants.

CONCLUSIONS

This study did not find any consistent evidence of an association between long-term air pollution and incident rhinitis.

Occupational exposures and 20-year incidence of COPD: the European Community Respiratory Health Survey

BACKGROUND

Occupational exposures have been associated with an increased risk of COPD. However, few studies have related objectively assessed occupational exposures to prospectively assessed incidence of COPD, using postbronchodilator lung function tests. Our objective was to examine the effect of occupational exposures on COPD incidence in the European Community Respiratory Health Survey.

METHODS

General population samples aged 20-44 were randomly selected in 1991-1993 and followed up 20 years later (2010-2012). Spirometry was performed at baseline and at follow-up, with incident COPD defined using a lower limit of normal criterion for postbronchodilator FEV1/FVC. Only participants without COPD and without current asthma at baseline were included. Coded job histories during follow-up were linked to a Job-Exposure Matrix, generating occupational exposure estimates to 12 categories of agents. Their association with COPD incidence was examined in log-binomial models fitted in a Bayesian framework.

FINDINGS

3343 participants fulfilled the inclusion criteria; 89 of them had COPD at follow-up (1.4 cases/1000 person-years). Participants exposed to biological dust had a higher incidence of COPD compared with those unexposed (relative risk (RR) 1.6, 95% CI 1.1 to 2.3), as did those exposed to gases and fumes (RR 1.5, 95% CI 1.0 to 2.2) and pesticides (RR 2.2, 95% CI 1.1 to 3.8). The combined population attributable fraction for these exposures was 21.0%.

INTERPRETATION

These results substantially strengthen the evidence base for occupational exposures as an important risk factor for COPD.

Genetic regulation of IL1RL1 methylation and IL1RL1-a protein levels in asthma

Interleukin-1 receptor-like 1 (IL1RL1) is an important asthma gene. (Epi)genetic regulation of IL1RL1 protein expression has not been established. We assessed the association between IL1RL1 single nucleotide polymorphisms (SNPs), IL1RL1 methylation and serum IL1RL1-a protein levels, and aimed to identify causal pathways in asthma.Associations of IL1RL1 SNPs with asthma were determined in the Dutch Asthma Genome-wide Association Study cohort and three European birth cohorts, BAMSE (Children/Barn, Allergy, Milieu, Stockholm, an Epidemiological survey), INMA (Infancia y Medio Ambiente) and PIAMA (Prevention and Incidence of Asthma and Mite Allergy), participating in the Mechanisms of the Development of Allergy study. We performed blood DNA IL1RL1 methylation quantitative trait locus (QTL) analysis (n=496) and (epi)genome-wide protein QTL analysis on serum IL1RL1-a levels (n=1462). We investigated the association of IL1RL1 CpG methylation with asthma (n=632) and IL1RL1-a levels (n=548), with subsequent causal inference testing. Finally, we determined the association of IL1RL1-a levels with asthma and its clinical characteristics (n=1101).IL1RL1 asthma-risk SNPs strongly associated with IL1RL1 methylation (rs1420101; p=3.7×10^-16) and serum IL1RL1-a levels (p=2.8×10^-56). IL1RL1 methylation was not associated with asthma or IL1RL1-a levels. IL1RL1-a levels negatively correlated with blood eosinophil counts, whereas there was no association between IL1RL1-a levels and asthma.In conclusion, asthma-associated IL1RL1 SNPs strongly regulate IL1RL1 methylation and serum IL1RL1-a levels, yet neither these IL1RL1-methylation CpG sites nor IL1RL1-a levels are associated with asthma.

Leisure-time vigorous physical activity is associated with better lung function: the prospective ECRHS study

OBJECTIVE

We assessed associations between physical activity and lung function, and its decline, in the prospective population-based European Community Respiratory Health Survey cohort.

METHODS

FEV₁ and FVC were measured in 3912 participants at 27-57 years and 39-67 years (mean time between examinations=11.1 years). Physical activity frequency and duration were assessed using questionnaires and used to identify active individuals (physical activity ≥2 times and ≥1 hour per week) at each examination. Adjusted mixed linear regression models assessed associations of regular physical activity with FEV₁ and FVC.

RESULTS

Physical activity frequency and duration increased over the study period. In adjusted models, active individuals at the first examination had higher FEV₁ (43.6 mL (95% CI 12.0 to 75.1)) and FVC (53.9 mL (95% CI 17.8 to 89.9)) at both examinations than their non-active counterparts. These associations appeared restricted to current smokers. In the whole population, FEV₁ and FVC were higher among those who changed from inactive to active during the follow-up (38.0 mL (95% CI 15.8 to 60.3) and 54.2 mL (95% CI 25.1 to 83.3), respectively) and who were consistently active, compared with those consistently non-active. No associations were found for lung function decline.

CONCLUSION

Leisure-time vigorous physical activity was associated with higher FEV₁ and FVC over a 10-year period among current smokers, but not with FEV₁ and FVC decline.

Health-related quality of life and risk factors associated with spirometric restriction

The restrictive spirometric pattern is associated with a substantial morbidity and mortality burden. We sought to determine to what extent spirometric restriction is associated with impaired quality of life.We used data from two large population-based European cohorts: 6698 European Community Respiratory Health Survey (ECRHS) and 6069 Swiss Cohort Study on Air Pollution and Lung and Heart Diseases in Adults (SAPALDIA) adult participants. The restrictive pattern was defined as forced expiratory volume in 1 s (FEV₁)/forced vital capacity (FVC) ≥lower limit of normal (LLN) and FVC <LLN; an obstructive pattern was defined as FEV₁/FVC <LLN independent of FVC. The Physical Component Summary and Mental Component Summary of quality of life were computed using the Short Form-36 questionnaire.In both cohorts, the restrictive pattern was associated with heavy smoking, being underweight or obese and the coexistence of respiratory symptoms. In univariate analyses, compared with the normal group, both the restrictive and obstructive pattern had significant Physical Component Summary deficits (-2.77 and -2.08, respectively, in ECRHS; -3.25 and -2.14, respectively, in SAPALDIA; all p-values <0.001). However, in models adjusted for sex, age, education, body mass index, smoking, comorbidities and respiratory symptoms, only the restrictive pattern remained significantly associated with Physical Component Summary deficits (p=0.004 in ECRHS; p=0.001 in SAPALDIA).The restrictive spirometric pattern is associated with deficits in the physical component of quality of life that are partly independent of the presence of respiratory symptoms.

Socioeconomic position and outdoor nitrogen dioxide (NO2) exposure in Western Europe: A multi-city analysis

BACKGROUND

Inconsistent associations between socioeconomic position (SEP) and outdoor air pollution have been reported in Europe, but methodological differences prevent any direct between-study comparison.

OBJECTIVES

Assess and compare the association between SEP and outdoor nitrogen dioxide (NO₂) exposure as a marker of traffic exhaust, in 16 cities from eight Western European countries.

METHODS

Three SEP indicators, two defined at individual-level (education and occupation) and one at neighborhood-level (unemployment rate) were assessed in three European multicenter cohorts. NO₂ annual concentration exposure was estimated at participants' addresses with land use regression models developed within the European Study of Cohorts for Air Pollution Effects (ESCAPE; http://www.escapeproject.eu/). Pooled and city-specific linear regressions were used to analyze associations between each SEP indicator and NO₂. Heterogeneity across cities was assessed using the Higgins' I-squared test (I²).

RESULTS

The study population included 5692 participants. Pooled analysis showed that participants with lower individual-SEP were less exposed to NO₂. Conversely, participants living in neighborhoods with higher unemployment rate were more exposed. City-specific results exhibited strong heterogeneity (I²>76% for the three SEP indicators) resulting in variation of the individual- and neighborhood-SEP patterns of NO₂ exposure across cities. The coefficients from a model that included both individual- and neighborhood-SEP indicators were similar to the unadjusted coefficients, suggesting independent associations.

CONCLUSIONS

Our study showed for the first time using homogenized measures of outcome and exposure across 16 cities the important heterogeneity regarding the association between SEP and NO₂ in Western Europe. Importantly, our results showed that individual- and neighborhood-SEP indicators capture different aspects of the association between SEP and exposure to air pollution, stressing the importance of considering both in air pollution health effects studies.

Socioeconomic position and outdoor nitrogen dioxide (NO2) exposure in Western Europe: A multi-city analysis

BACKGROUND

Inconsistent associations between socioeconomic position (SEP) and outdoor air pollution have been reported in Europe, but methodological differences prevent any direct between-study comparison.

OBJECTIVES

Assess and compare the association between SEP and outdoor nitrogen dioxide (NO₂) exposure as a marker of traffic exhaust, in 16 cities from eight Western European countries.

METHODS

Three SEP indicators, two defined at individual-level (education and occupation) and one at neighborhood-level (unemployment rate) were assessed in three European multicenter cohorts. NO₂ annual concentration exposure was estimated at participants' addresses with land use regression models developed within the European Study of Cohorts for Air Pollution Effects (ESCAPE; http://www.escapeproject.eu/). Pooled and city-specific linear regressions were used to analyze associations between each SEP indicator and NO₂. Heterogeneity across cities was assessed using the Higgins' I-squared test (I²).

RESULTS

The study population included 5692 participants. Pooled analysis showed that participants with lower individual-SEP were less exposed to NO₂. Conversely, participants living in neighborhoods with higher unemployment rate were more exposed. City-specific results exhibited strong heterogeneity (I²>76% for the three SEP indicators) resulting in variation of the individual- and neighborhood-SEP patterns of NO₂ exposure across cities. The coefficients from a model that included both individual- and neighborhood-SEP indicators were similar to the unadjusted coefficients, suggesting independent associations.

CONCLUSIONS

Our study showed for the first time using homogenized measures of outcome and exposure across 16 cities the important heterogeneity regarding the association between SEP and NO₂ in Western Europe. Importantly, our results showed that individual- and neighborhood-SEP indicators capture different aspects of the association between SEP and exposure to air pollution, stressing the importance of considering both in air pollution health effects studies.