Age and body mass index affect fit of spirometry Global Lung Function Initiative references in schoolchildren

BACKGROUND: References from the Global Lung Function Initiative (GLI) are widely used to interpret children's spirometry results. We assessed fit for healthy schoolchildren. METHODS: LuftiBus in the School was a population-based cross-sectional study undertaken in 2013-2016 in the canton of Zurich, Switzerland. Parents and their children aged 6-17 years answered questionnaires about respiratory symptoms and lifestyle. Children underwent spirometry in a mobile lung function lab. We calculated GLI-based z-scores for forced expiratory volume in 1 s (FEV$_{1}$), forced vital capacity (FVC), FEV$_{1}$/FVC and forced expiratory flow for 25-75% of FVC (FEF$_{25-75}$) for healthy White participants. We defined appropriate fit to GLI references by mean values between +0.5 and -0.5 z-scores. We assessed whether fit varied by age, body mass index, height and sex using linear regression models. RESULTS: We analysed data from 2036 children with valid FEV$_{1}$ measurements, of whom 1762 also had valid FVC measurements. The median age was 12.2 years. Fit was appropriate for children aged 6-11 years for all indices. In adolescents aged 12-17 years, fit was appropriate for FEV$_{1}$/FVC z-scores (mean±sd -0.09±1.02), but not for FEV$_{1}$ (-0.62±0.98), FVC (-0.60±0.98) and FEF$_{25-75}$ (-0.54±1.02). Mean FEV$_{1}$, FVC and FEF$_{25-75}$ z-scores fitted better in children considered overweight (-0.25, -0.13 and -0.38, respectively) than normal weight (-0.55, -0.50 and -0.55, respectively; p-trend <0.001, 0.014 and <0.001, respectively). FEV$_{1}$, FVC and FEF$_{25-75}$ z-scores depended on both age and height (p-interaction 0.033, 0.019 and <0.001, respectively). CONCLUSION: GLI-based FEV$_{1}$, FVC, and FEF$_{25-75}$ z-scores do not fit White Swiss adolescents well. This should be considered when using reference equations for clinical decision-making, research and international comparison

Age and body mass index affect fit of spirometry Global Lung Function Initiative references in schoolchildren.

Background References from the Global Lung Function Initiative (GLI) are widely used to interpret children's spirometry results. We assessed fit for healthy schoolchildren. Methods LuftiBus in the School was a population-based cross-sectional study undertaken in 2013-2016 in the canton of Zurich, Switzerland. Parents and their children aged 6-17 years answered questionnaires about respiratory symptoms and lifestyle. Children underwent spirometry in a mobile lung function lab. We calculated GLI-based z-scores for forced expiratory volume in 1 s (FEV1), forced vital capacity (FVC), FEV1/FVC and forced expiratory flow for 25-75% of FVC (FEF25-75) for healthy White participants. We defined appropriate fit to GLI references by mean values between +0.5 and -0.5 z-scores. We assessed whether fit varied by age, body mass index, height and sex using linear regression models. Results We analysed data from 2036 children with valid FEV1 measurements, of whom 1762 also had valid FVC measurements. The median age was 12.2 years. Fit was appropriate for children aged 6-11 years for all indices. In adolescents aged 12-17 years, fit was appropriate for FEV1/FVC z-scores (mean±sd -0.09±1.02), but not for FEV1 (-0.62±0.98), FVC (-0.60±0.98) and FEF25-75 (-0.54±1.02). Mean FEV1, FVC and FEF25-75 z-scores fitted better in children considered overweight (-0.25, -0.13 and -0.38, respectively) than normal weight (-0.55, -0.50 and -0.55, respectively; p-trend <0.001, 0.014 and <0.001, respectively). FEV1, FVC and FEF25-75 z-scores depended on both age and height (p-interaction 0.033, 0.019 and <0.001, respectively). Conclusion GLI-based FEV1, FVC, and FEF25-75 z-scores do not fit White Swiss adolescents well. This should be considered when using reference equations for clinical decision-making, research and international comparison

Agreement of parent- and child-reported wheeze and its association with measurable asthma traits

Objectives In epidemiological studies, childhood asthma is usually assessed with questionnaires directed at parents or children, and these may give different answers. We studied how well parents and children agreed when asked to report symptoms of wheeze and investigated whose answers were closer to measurable traits of asthma. Methods LuftiBus in the school is a cross-sectional survey of respiratory health among Swiss schoolchildren aged 6–17 years. We applied questionnaires to parents and children asking about wheeze and exertional wheeze in the past year. We assessed agreement between parent–child answers with Cohen's kappa (k), and associations of answers from children and parents with fractional exhaled nitric oxide (FeNO) and forced expiratory volume in 1 s over forced vital capacity (FEV1/FVC), using quantile regression. Results We received questionnaires from 3079 children and their parents. Agreement was poor for reported wheeze (k = 0.37) and exertional wheeze (k = 0.36). Median FeNO varied when wheeze was reported by children (19 ppb, interquartile range [IQR]: 9–44), parents (22 ppb, IQR: 12–46), both (31 ppb, IQR: 16–55), or neither (11 ppb, IQR: 7–19). Median absolute FEV1/FVC was the same when wheeze was reported by children (84%, IQR: 78–89) and by parents (84%, IQR: 78–89), lower when reported by both (82%, IQR: 78–87), and higher when reported by neither (87%, IQR: 82–91). For exertional wheeze findings were similar. Results did not differ by age or sex. Conclusion Our findings suggest that surveying both parents and children and combining their responses can help us to better identify children with measurable asthma traits

Evaluation of the Double-Tracer Gas Single-Breath Washout Test in a Pediatric Field Study

BACKGROUND: The early life origins of chronic pulmonary diseases are thought to arise in peripheral small airways. Predictors of ventilation inhomogeneity, a proxy of peripheral airway function, are understudied in schoolchildren. RESEARCH QUESTION: Is the double-tracer gas single-breath washout (DTG-SBW) measurement feasible in a pediatric field study setting? What are the predictors of the DTG-SBWderived ventilation inhomogeneity estimate in unselected schoolchildren? STUDY DESIGN AND METHODS: In this prospective cross-sectional field study, a mobile lung function testing unit visited participating schools in Switzerland. We applied DTG-SBW, fraction of exhaled nitric oxide (FENO), and spirometry measurements. The DTG-SBW is based on tidal inhalation of helium and sulfur-hexafluoride, and the phase III slope (SIIIHeSF6) is derived. We assessed feasibility, repeatability, and associations of SIIIHe-SF6 with the potential predictors of anthropometrics, presence of wheeze (ie, parental report of one or more episode of wheeze in the prior year), FENO, FEV1, and FEV1/FVC. RESULTS: In 1,782 children, 5,223 DTG-SBW trials were obtained. The DTG-SBW was acceptable in 1,449 children (81.3%); the coefficient of variation was 39.8%. SIIIHe-SF6 was independently but weakly positively associated with age and BMI. In 276 children (21.2%), wheeze was reported. SIIIHe-SF6 was higher by 0.049 g.mol.L-1 in children with wheeze compared with those without and remained associated with wheeze after adjusting for age and BMI in a multivariable linear regression model. SIIIHe-SF6 was not associated with FENO, FEV1, and FEV1/FVC. INTERPRETATION: The DTG-SBW is feasible in a pediatric field study setting. On the population level, age, body composition, and wheeze are independent predictors of peripheral airway function in unselected schoolchildren. The variation of the DTG-SBW possibly constrains its current applicability on the individual level

Physical activity, respiratory physiotherapy practices, and nutrition among people with primary ciliary dyskinesia in Switzerland - a cross-sectional survey.

AIMS OF THE STUDY We know little about the level of physical activity, respiratory physiotherapy practices and nutritional status of people with primary ciliary dyskinesia (PCD), although these are important aspects of patients with chronic respiratory disease. We assessed physical activity, respiratory physiotherapy practices and nutritional status among people with primary ciliary dyskinesia in Switzerland, investigated how these vary by age and identified factors associated with regular physical activity. METHODS We sent a postal questionnaire survey to people with primary ciliary dyskinesia enrolled in the Swiss PCD registry (CH-PCD), based on the standardised FOLLOW-PCD patient questionnaire. We collected information about physical activity, physiotherapy, respiratory symptoms and nutritional status. We calculated the metabolic equivalent (MET) to better reflect the intensity of the reported physical activities. To assess nutritional status, we extracted information from CH-PCD and calculated participants' body mass index (BMI). RESULTS Of the 86 questionnaires we sent, 74 (86% response rate) were returned from 24 children and 50 adults. The median age at survey completion was 23 years (IQR [interquartile range] 15-51), and 51% were female. Among all 74 participants, 48 (65%) performed sports regularly. Children were vigorously active (median MET 9.1; IQR 7.9-9.6) and adults were moderately active (median MET 5.5; IQR 4.3-6.9). Fifty-nine participants (80%) reported performing some type of respiratory physiotherapy. However, only 30% of adults saw a professional physiotherapist, compared with 75% of children. Half of the participants had normal BMI; one child (4%) and two adults (4%) were underweight. People who were regularly physically active reported seeing a physiotherapist more often. CONCLUSIONS Our study is the first to provide patient-reported data about physical activity, respiratory physiotherapy and nutrition among people with primary ciliary dyskinesia. Our results highlight that professional respiratory physiotherapy, exercise recommendations and nutritional advice are often not implemented in the care of people with primary ciliary dyskinesia in Switzerland. Multidisciplinary care in specialised centres by teams including physiotherapists and nutrition consultants could improve the quality of life of people with primary ciliary dyskinesia

Physical activity, respiratory physiotherapy practices, and nutrition among people with primary ciliary dyskinesia in Switzerland – a cross-sectional survey

Aims of the study: We know little about the level of physical activity, respiratory physiotherapy practices and nutritional status of people with primary ciliary dyskinesia (PCD), although these are important aspects of patients with chronic respiratory disease. We assessed physical activity, respiratory physiotherapy practices and nutritional status among people with primary ciliary dyskinesia in Switzerland, investigated how these vary by age and identified factors associated with regular physical activity. Methods: We sent a postal questionnaire survey to people with primary ciliary dyskinesia enrolled in the Swiss PCD registry (CH-PCD), based on the standardised FOLLOW-PCD patient questionnaire. We collected information about physical activity, physiotherapy, respiratory symptoms and nutritional status. We calculated the metabolic equivalent (MET) to better reflect the intensity of the reported physical activities. To assess nutritional status, we extracted information from CH-PCD and calculated participants' body mass index (BMI). Results: Of the 86 questionnaires we sent, 74 (86% response rate) were returned from 24 children and 50 adults. The median age at survey completion was 23 years (IQR [interquartile range] 15-51), and 51% were female. Among all 74 participants, 48 (65%) performed sports regularly. Children were vigorously active (median MET 9.1; IQR 7.9-9.6) and adults were moderately active (median MET 5.5; IQR 4.3-6.9). Fifty-nine participants (80%) reported performing some type of respiratory physiotherapy. However, only 30% of adults saw a professional physiotherapist, compared with 75% of children. Half of the participants had normal BMI; one child (4%) and two adults (4%) were underweight. People who were regularly physically active reported seeing a physiotherapist more often. Conclusions: Our study is the first to provide patient-reported data about physical activity, respiratory physiotherapy and nutrition among people with primary ciliary dyskinesia. Our results highlight that professional respiratory physiotherapy, exercise recommendations and nutritional advice are often not implemented in the care of people with primary ciliary dyskinesia in Switzerland. Multidisciplinary care in specialised centres by teams including physiotherapists and nutrition consultants could improve the quality of life of people with primary ciliary dyskinesia

Respiratory symptoms of Swiss people with primary ciliary dyskinesia

BACKGROUND Mostly derived from chart reviews, where symptoms are recorded in a nonstandardised manner, clinical data about primary ciliary dyskinesia (PCD) are inconsistent, which leads to missing and unreliable information. We assessed the prevalence and frequency of respiratory and ear symptoms and studied differences by age and sex among an unselected population of Swiss people with PCD. METHODS We sent a questionnaire that included items from the FOLLOW-PCD standardised questionnaire to all Swiss PCD registry participants. RESULTS We received questionnaires from 74 (86%) out of 86 invited persons or their caregivers (median age 23 years, range 3-73 years), including 68% adults (≥18 years) and 51% females. Among participants, 70 (94%) reported chronic nasal symptoms; most frequently runny nose (65%), blocked nose (55%) or anosmia (38%). Ear pain and hearing problems were reported by 58% of the participants. Almost all (99%) reported cough and sputum production. The most common chronic cough complications were gastro-oesophageal reflux (n=11; 15%), vomiting (n=8; 11%) and urinary incontinence (n=6; 8%). Only nine (12%) participants reported frequent wheeze, which occurred mainly during infection or exercise, while 49 (66%) reported shortness of breath, and 9% even at rest or during daily activities. Older patients reported more frequent nasal symptoms and shortness of breath. We found no difference by sex or ultrastructural ciliary defect. CONCLUSION This is the first study to describe patient-reported PCD symptoms. The consistent collection of standardised clinical data will allow us to better characterise the phenotypic variability of the disease and study disease course and prognosis