High-altitude alpine therapy and lung function in asthma: systematic review and meta-analysis

Impact of altitude correction on bronchopulmonary dysplasia prevalence: A systematic review and meta-analysis

Bronchopulmonary dysplasia (BPD) presents a significant respiratory challenge in infants born prematurely. Socioeconomic factors and environmental determinants, including altitude, play pivotal roles in shaping respiratory health outcomes among premature infants. This study aimed to investigate the prevalence of BPD among preterm infants based on altitude, considering the impact of altitude correction on prevalence estimates. By examining altitude-related variations in BPD prevalence, the study sought to provide insights essential for guiding interventions aimed at preventing and managing respiratory conditions in this vulnerable population. The study protocol was registered with PROSPERO, and a systematic search of five databases (PubMed, Web of Science, ScienceDirect, ProQuest, and Google Scholar) was conducted without any restrictions on the date of publication. Eligible studies were identified based on predefined inclusion criteria, including retrospective or prospective studies reporting BPD prevalence at different altitudes, the use of standard diagnostic criteria for BPD, and the exclusion of studies involving non-human subjects or those lacking altitude-adjusted data. The risk of bias assessment was conducted using the Critical Appraisal Skills Programme checklist. Statistical analysis included calculating pooled prevalence estimates using a random-effects model, performing subgroup analyses, and assessing heterogeneity and publication bias. The search yielded 339 records, of which ten articles met the inclusion criteria and had a low risk of bias. The altitude-unadjusted BPD prevalence was 41.35% (95% CI 28.62; 55.34%) and ranged from 19.73% (95% CI 16.44; 23.48%) to 71.02% (95% CI 68.33; 73.56%) across different altitude categories. The altitude-adjusted pooled mean BPD prevalence was 26.70% (95% CI 19.60; 35.25%). This systematic review and meta-analysis highlight altitude-related variations in BPD prevalence among preterm infants. Altitude adjustment is crucial for understanding the true prevalence of BPD and guiding tailored interventions in high-altitude regions.

Histopathologic features of chronic rhinosinusitis with nasal polyps in patients from high-altitude Xizang region

BACKGROUND

Chronic rhinosinusitis with nasal polyps (CRSwNP) is a heterogeneous inflammatory disease with varying patterns across regions.

OBJECTIVE

This study aims to investigate the clinical and histopathological features of CRSwNP in Xizang, a high-altitude region in China.

MATERIALS AND METHODS

We retrospectively analyzed the histopathological features of CRSwNP patients from Shanghai and Xizang who underwent functional endoscopic sinus surgery (FESS) between 2017 and 2024. Polyp tissue samples were assessed, and statistical analyses compared features between the two regions in CRSwNP, eosinophilic CRSwNP (eCRSwNP), and noneosinophilic CRSwNP (neCRSwNP) patients.

RESULTS

Twenty-eight patients from Xizang and 35 from Shanghai were analyzed. All Shanghai patients were Han Chinese, and all Xizang patients were Tibetan. Compared to Shanghai, Tibetan patients had significantly lower rates of smoking and asthma. Overall inflammation levels in Xizang were lower, while eosinophil counts were lower in eCRSwNP patients. Neutrophil infiltration, mucosal ulceration, and squamous metaplasia were higher in Xizang patients, while neCRSwNP patients exhibited more neutrophil infiltration and less subepithelial edema.

CONCLUSIONS

The study revealed that Tibetan patients with CRSwNP have lower eosinophilic inflammation but higher neutrophil infiltration and squamous metaplasia compared to Shanghai patients, indicating the impact of high-altitude environments on inflammatory patterns.

Towards travel therapy: addressing the health benefits of international travel

This perspective article discusses the physical, mental and sociocultural benefits of international travel and considers the case for prescribing travel for therapeutic reasons. It also identifies priorities for further research in this neglected area.

The Impact of Climate, Aeroallergens, Pollution, and Altitude on Exercise-Induced Bronchoconstriction

Exercise-induced bronchoconstriction (EIB) with or without underlying asthma is a condition with complex pathophysiology, where many factors play a role in its development and clinical presentation. EIB can be impacted by various environmental factors including climate, environmental allergens, air pollution, and altitude. Although it might be hard to escape one's environment, patients should nevertheless be counseled on how the environment could impact their symptoms. Patient education regarding environmental factors could help overcome impediments to exercise and improve performance.

Tropical high altitude and severe asthma in adults: house dust mite sensitization and phenotypic distribution

BACKGROUND

There is a lack of information on house dust mite (HDM) sensitization and phenotype distribution in patients with severe asthma (SA) living permanently at high-altitude (HA) in tropical regions, which may be different.

OBJECTIVE

The aim of this study was to characterize adults with SA in a tropical high altitude city (2,640 m): Bogotá, Colombia.

MATERIAL AND METHODS

This observational cross-sectional study included severe asthmatic outpatients (n = 129) referred to the ASMAIRE program of the Fundación Neumológica Colombiana in Bogotá (2,640 m). Clinical history, spirometry, total IgE, blood eosinophils, and skin prick test (SPT), including HDM allergens, were performed. Phenotype definitions: Allergic/atopic (AA): IgE ≥100 IU/mL and/or at least one positive SPT; eosinophilic (EOS): blood eosinophils ≥300 cells/µL; type 2-high: AA and/or EOS phenotype; type 2-low: non-AA/non-EOS phenotype (IgE <100 IU/mL, negative SPT, and blood eosinophils <300 cells/µL).

RESULTS

A total of 129 adults with SA were included, 79.8% female. Phenotype distribution: AA: 61.2%; EOS: 37.2%; type 2-high: 72.1%; type 2-low: 27.9%. Among AA patients, HDM sensitization was present in 87% and 34.9% were non-eosinophilic. There was a significant overlap between the phenotypes.

CONCLUSIONS

In contrast to non-tropical high-altitude regions, we found a high frequency of HDM sensitization in patients with AA phenotype living in a tropical high-altitude city. We also found a discrete lower frequency of EOS phenotype with no other significant differences in the phenotypic distribution compared to that described at low altitudes. We propose that tropical location may modify the effect of high altitude on HDM concentrations and allergenicity.

Predictors of Quality-of-Life Improvement at Different Minimum Clinically Important Difference Values in Patients with Chronic Obstructive Pulmonary Disease after Climatic Rehabilitation Treatment

BACKGROUND

The minimum clinically important difference (MCID) for the St George's Respiratory Questionnaire (SGRQ) is debated in chronic obstructive pulmonary disease (COPD) quality-of-life (QoL) assessments. This study aimed to determine whether there is a difference in predictors of clinically significant improvement between the traditional (value of 4) and newly proposed MCID SGRQ (value of 7) after climatic rehabilitation treatment. Climatic rehabilitation treatment consists of two main parts: climatotherapy, which typically involves the controlled exposure of individuals to natural environmental elements, and climatic rehabilitation, which includes other therapeutic factors such as physical activities as well as educating the patient to change their lifestyle.

METHODS

This study included 90 consecutive patients diagnosed with COPD who underwent structured complex pulmonary rehabilitation in High Tatras, part of the Carpathian Mountains. The examination before and after treatment included spirometry, QoL assessment using the SGRQ, 6 min walk test (6-MWT), and the Borg, Beck and Zung scale.

RESULTS

Patients showed statistically significant improvement after the intervention in FEV1, FEV1/FVC, 6-MWT, (p < 0.001), anxiety scores, depression, and improvement in dyspnoea both before and after the 6-MWT (p < 0.001). For both MCID for SGRQ levels 4 and 7, we confirmed the same predictors of clinical improvement for bronchial obstruction grade (spirometry) and exercise capacity (6-MWT), for quality of life in activity score and total score.

CONCLUSION

The results suggest that both the proposed MCID for SGRQ values could be sufficient to assess the clinical significance of the achieved change in health status when assessing the need for pulmonary rehabilitation comprising climatotherapy in patients with COPD.

More airway smooth muscle in males versus females in a mouse model of asthma: A blessing in disguise?

NEW FINDINGS

What is the central question of this study? The lung response to inhaled methacholine is reputed to be greater in male than in female mice. The underpinnings of this sex disparity are ill defined. What is the main finding and its importance? We demonstrated that male airways exhibit a greater content of airway smooth muscle than female airways. We also found that, although a more muscular airway tree in males might contribute to their greater responsiveness to inhaled methacholine than females, it might also curb the heterogeneity in small airway narrowing.

ABSTRACT

Mouse models are helpful in unveiling the mechanisms underlying sex disparities in asthma. In comparison to their female counterparts, male mice are hyperresponsive to inhaled methacholine, a cardinal feature of asthma that contributes to its symptoms. The physiological details and the structural underpinnings of this hyperresponsiveness in males are currently unknown. Herein, BALB/c mice were exposed intranasally to either saline or house dust mite once daily for 10 consecutive days to induce experimental asthma. Twenty-four hours after the last exposure, respiratory mechanics were measured at baseline and after a single dose of inhaled methacholine that was adjusted to trigger the same degree of bronchoconstriction in both sexes (it was twice as high in females). Bronchoalveolar lavages were then collected, and the lungs were processed for histology. House dust mite increased the number of inflammatory cells in bronchoalveolar lavages to the same extent in both sexes (asthma, P = 0.0005; sex, P = 0.96). The methacholine response was also markedly increased by asthma in both sexes (e.g., P = 0.0002 for asthma on the methacholine-induced bronchoconstriction). However, for a well-matched bronchoconstriction between sexes, the increase in hysteresivity, an indicator of airway narrowing heterogeneity, was attenuated in males for both control and asthmatic mice (sex, P = 0.002). The content of airway smooth muscle was not affected by asthma but was greater in males (asthma, P = 0.31; sex, P < 0.0001). These results provide further insights regarding an important sex disparity in mouse models of asthma. The increased amount of airway smooth muscle in males might contribute functionally to their greater methacholine response and, possibly, to their decreased propensity for airway narrowing heterogeneity.

Chronic developmental hypoxia alters rat lung immune cell transcriptomes during allergic airway inflammation

Populations that are born and raised at high altitude develop under conditions of chronic developmental hypoxia (CDH), which results in pulmonary adaptations of increased lung volume and diffusion capacity to increase gas exchange. It is not clear how CDH may alter allergic inflammation in the lung. In this study, we sought to characterize the impact of CDH on immune cell populations in the rat lung during a murine model of asthma. Rats were bred and raised in either hypoxic (15% oxygen, CDH) or normobaric room air (20% oxygen). At 3-weeks of age, animals were sensitized to ovalbumin (OVA) or physiologic saline (phosphate-buffered saline [PBS]) as a control, followed by three consecutive days of intra-nasal OVA or PBS at 6-weeks of age. We then assessed airway reactivity and allergic-associated cytokine levels. This was followed by single-cell transcriptomic profiling of lung cell populations. In scRNA-seq analysis, we assessed differentially expressed genes, differentially enriched functional pathways, immune cell exhaustion/activation markers, and immune cell secretory products. Our results show that while OVA heightened airway reactivity, CDH suppressed airway reactivity in OVA-challenged and control animals. Through scRNA-seq analysis, we further demonstrate that CDH alters the transcriptional landscape in the lung and alters transcriptional programs in immune cells. These data define CDH-dependent changes in the lung that impact airway reactivity.

Climatotherapy for asthma: Research progress and prospect

Asthma affects over 300 million people globally and is a cause of substantial burden of disease, including both premature death and reduced quality of life in people of all ages. Although both genetic and environmental factors play an important role in the pathogenesis of asthma, the rising trend of asthma and other allergic diseases over recent decades is thought to be largely caused by alteration in environmental conditions. Thus, a considerable amount of attention has been paid to environmental modification for the treatment and management of asthma, including household allergen reduction and/or irritant removal. More advanced environmental modification strategies (e.g., health resort medical rehabilitation, high-altitude climate therapy and multiple-hit interventions) have also been suggested. Research advances have been made over the past decades, but major challenges and opportunities coexist in this emerging field. Concerted efforts are required to tackle these formidable challenges.

Healthy worker survival effect at a high-altitude mine: prospective cohort observation

Very little is known about the factors of healthy worker survival effect at high-altitude mines. We conducted this cohort observation of the new hires for a high-altitude gold mine in Kyrgyzstan with the aim to ascertain predictors of survival at work. All new hires in 2009 through 2012 for a high-altitude gold mine (3600–4500 m above sea level) were followed up to January 2022. We tested the association of demographic, physiological predictors and diagnoses at the pre-employment screening with non-survival at work in Cox proportional hazards yielding hazard ratios (HR) with their 95% confidence intervals (CI). The cumulative observation time was 5190 person-years. Blood pressure at pre-employment, lung function, the diagnoses of essential hypertension, chronic obstructive pulmonary disease (COPD) or any other analyzed physiological variables were not associated with non-survival at work. However, smoking (HR 1.55; 95% CI 1.10; 2.17) increased the likelihood of non-survival at work, independent of any diagnosis or lowland residence (HR 1.95; 95% CI 1.31; 2.90). Adjusted for covariates and all diagnoses, having chronic rheumatic fever (HR 10.95; 95% CI 2.92; 33.92), hemorrhoids (HR 1.32; 95% CI 1.01; 3.75), adhesive otitis (HR 1.74; 95% CI 1.05; 2.89) or obesity (HR 1.71; 95% CI 1.01; 2.88) were associated with non-survival at work with time. This prospective observation of new hires for a high-altitude mining operation demonstrated that selected diagnoses, smoking and lowland residence elevated the risk of early exit in prospective workers.

International Olympic Committee (IOC) consensus statement on acute respiratory illness in athletes part 2: non-infective acute respiratory illness

Acute respiratory illness (ARill) is common and threatens the health of athletes. ARill in athletes forms a significant component of the work of Sport and Exercise Medicine (SEM) clinicians. The aim of this consensus is to provide the SEM clinician with an overview and practical clinical approach to non-infective ARill in athletes. The International Olympic Committee (IOC) Medical and Scientific Committee appointed an international consensus group to review ARill in athletes. Key areas of ARill in athletes were originally identified and six subgroups of the IOC Consensus group established to review the following aspects: (1) epidemiology/risk factors for ARill, (2) infective ARill, (3) non-infective ARill, (4) acute asthma/exercise-induced bronchoconstriction and related conditions, (5) effects of ARill on exercise/sports performance, medical complications/return-to-sport (RTS) and (6) acute nasal/laryngeal obstruction presenting as ARill. Following several reviews conducted by subgroups, the sections of the consensus documents were allocated to 'core' members for drafting and internal review. An advanced draft of the consensus document was discussed during a meeting of the main consensus core group, and final edits were completed prior to submission of the manuscript. This document (part 2) of this consensus focuses on respiratory conditions causing non-infective ARill in athletes. These include non-inflammatory obstructive nasal, laryngeal, tracheal or bronchial conditions or non-infective inflammatory conditions of the respiratory epithelium that affect the upper and/or lower airways, frequently as a continuum. The following aspects of more common as well as lesser-known non-infective ARill in athletes are reviewed: epidemiology, risk factors, pathology/pathophysiology, clinical presentation and diagnosis, management, prevention, medical considerations and risks of illness during exercise, effects of illness on exercise/sports performance and RTS guidelines.

Low oxygen levels decrease adaptive immune responses and ameliorate experimental asthma in mice

BACKGROUND

High-altitude therapy has been used as add-on treatment for allergic asthma with considerable success. However, the underlying mechanisms remain unclear. In order to investigate the possible therapeutic effects of high-altitude therapy on allergic asthma, we utilized a new in vivo mouse model.

METHODS

Mice were treated with house dust mite (HDM) extract over 4 weeks and co-exposed to 10% oxygen (Hyp) or room air for the final 2 weeks. Experimental asthma was assessed by airway hyper-responsiveness, mucus hypersecretion and inflammatory cell recruitment. Isolated immune cells from mouse and allergic patients were stimulated in vitro with HDM under Hyp and normoxia in different co-culture systems to analyse the adaptive immune response.

RESULTS

Compared to HDM-treated mice in room air, HDM-treated Hyp-mice displayed ameliorated mucosal hypersecretion and airway hyper-responsiveness. The attenuated asthma phenotype was associated with strongly reduced activation of antigen-presenting cells (APCs), effector cell infiltration and cytokine secretion. In vitro, hypoxia almost completely suppressed the HDM-induced adaptive immune response in both mouse and human immune cells. While hypoxia did not affect effector T-cell responses per-se, it interfered with antigen-presenting cell (APC) differentiation and APC/effector cell crosstalk.

CONCLUSIONS

Hypoxia-induced reduction in the Th2-response to HDM ameliorates allergic asthma in vivo. Hypoxia interferes with APC/T-cell crosstalk and confers an unresponsive phenotype to APCs.

Alpine altitude climate treatment for severe and uncontrolled asthma: An EAACI position paper

Currently available European Alpine Altitude Climate Treatment (AACT) programs combine the physical characteristics of altitude with the avoidance of environmental triggers in the alpine climate and a personalized multidisciplinary pulmonary rehabilitation approach. The reduced barometric pressure, oxygen pressure, and air density, the relatively low temperature and humidity, and the increased UV radiation at moderate altitude induce several physiological and immunological adaptation responses. The environmental characteristics of the alpine climate include reduced aeroallergens such as house dust mites (HDM), pollen, fungi, and less air pollution. These combined factors seem to have immunomodulatory effects controlling pathogenic inflammatory responses and favoring less neuro‐immune stress in patients with different asthma phenotypes. The extensive multidisciplinary treatment program may further contribute to the observed clinical improvement by AACT in asthma control and quality of life, fewer exacerbations and hospitalizations, reduced need for oral corticosteroids (OCS), improved lung function, decreased airway hyperresponsiveness (AHR), improved exercise tolerance, and improved sinonasal outcomes. Based on observational studies and expert opinion, AACT represents a valuable therapy for those patients irrespective of their asthma phenotype, who cannot achieve optimal control of their complex condition despite all the advances in medical science and treatment according to guidelines, and therefore run the risk of falling into a downward spiral of loss of physical and mental health. In the light of the observed rapid decrease in inflammation and immunomodulatory effects, AACT can be considered as a natural treatment that targets biological pathways.

The Effects of Climate Therapy on Cardiorespiratory Fitness and Exercise-Induced Bronchoconstriction in Children with Asthma

We investigated whether a 1-week stay in the mountains may have a positive impact on Exercise-Induced Bronchoconstriction (EIB) and cardiorespiratory endurance in asthmatic children from an urban area. Spirometry was performed before and 10 min after a 20 m shuttle run test (20mSRT) on the first and seventh day of a summer asthma camp in the Italian Alps at 900 m of altitude. Spirometry z-scores were derived from the Global Lung Initiative 2012 prediction equations, and percentiles of the 20mSRT performance were assigned according to De Miguel-Etayo’s and Tomkinson’s predictive equations. A FEV1 decrease ≥10% after the exercise was defined as EIB. Particulate matter pollution was monitored during the camp and in the urban area of provenience. Twenty-four subjects (age range 7–16 years) were included. Frequency of EIB decreased from 58% (14/24) at day-1 to 33% (8/24) at the end of the camp (p = 0.08). Most subjects with a 20mSRT in the lowest quartile at day 1 had EIB (9/11). The proportion of children with a 20mSRT <25° percentile decreased from 45% (11/24) at day-1 to 16% (4/24) at day-7 (p = 0.02). Conclusion: One-week climate therapy in the mountains improved both bronchial hyperreactivity and cardiorespiratory endurance in our cohort of asthmatic children.

Effects of genetics and altitude on lung function

OBJECTIVES

The aim of this work is to present a review on the impact of genetics and altitude on lung function from classic and recent studies.

DATA SOURCE

A systematic search has been carried out in different databases of scientific studies, using keywords related to lung volumes, spirometry, altitude and genetics.

RESULTS

The results of this work have been structured into three parts. First, the relationship between genes and lung function. Next, a review of the genetic predispositions related to respiratory adaptation of people who inhabit high-altitude regions for millennia. Finally, temporary effects and long-term acclimatisation on respiratory physiology at high altitude are presented.

CONCLUSIONS

The works focused on the influence of genetics and altitude on lung function are currently of interest in terms of studying the interactions between genetic, epigenetic and environmental factors in the configuration of the pathophysiological adaptation patterns.

Winter Exercise and Speleotherapy for Allergy and Asthma: A Randomized Controlled Clinical Trial

(1) Background: The prevalence of allergic respiratory diseases is still rising and efforts towards holistic treatments should be made. Although speleotherapy is widely applied in Europe to treat chronic airway diseases, the existing scientific evidence is rather low. Recreational winter exercise has been shown to improve allergic airway inflammation, but little is known about the combined effects of speleotherapy and recreational winter exercise. (2) Methods: In this clinical study we investigated the effects of winter exercise and speleotherapy on adults with allergic rhinitis and/or asthma. The speleotherapy group (n = 23) participated in a ten-day combined winter exercise and speleotherapy program and the exercise group (n = 18) joined a full-day winter sports program. The effects on allergic airway inflammation, quality of life, spirometry and cardiorespiratory fitness were assessed. (3) Results: No significant effects were found for fractional exhaled nitric oxide or nasal nitric oxide. Quality of life (p < 0.001 time effect) and allergic symptoms (p < 0.001 time effect) were improved in the speleotherapy and in the exercise group. (4) Conclusions: Winter exercise alone and winter exercise in combination with speleotherapy improve quality of life and allergic symptoms in adults with allergic rhinitis and/or asthma. Further studies are required to investigate the specific effects of speleotherapy. To our knowledge, this is the first investigation examining speleotherapy in combination with winter exercise. Recreational outdoor winter exercise and speleotherapy may be recommended for highly functioning patients with good disease control.

Effectiveness of pulmonary rehabilitation at high-altitude compared to sea-level in adults with severe refractory asthma

BACKGROUND

Beneficial effects of pulmonary rehabilitation at high-altitude (HAPR) in patients with severe refractory asthma have been reported earlier, but evidence for the effectiveness is limited.

AIM

To investigate the effectiveness of high-altitude pulmonary rehabilitation to comparable treatment at sea-level (LAPR) on patient outcome parameters.

METHODS

Adults with severe refractory asthma living in The Netherlands were included. Treatment consisted of a 12-week personalized multidisciplinary rehabilitation program either at high-altitude (Davos Switzerland) (n = 93) or in a tertiary lung center at sea-level in The Netherlands (n = 45). At baseline, after treatment, and during 12 months follow-up asthma related quality of life (AQLQ), asthma control (ACQ), pulmonary function and OCS-dose were assessed. Patients could not be randomized resulting in different asthma populations. Groups were compared using linear regression analysis (ANCOVA) adjusted for baseline values, in addition to age, atopy, smoking history, BMI and gender.

RESULTS

After treatment, and at 12 months follow-up, improved AQLQ(0.92,p < 0.001 and 0.82,p = 0.001, respectively), ACQ(-0.87,p < 0.001 and -0.69,p = 0.008, respectively) and lower maintenance OCS dose (Unadjusted linear regression analysis-5.29 mg, p = 0.003 and Crude Odds Ratio-1.67, p = 0.003, respectively) were observed in the HAPR-group compared to the LAPR group. Patients receiving HAPR also had less asthma exacerbations (≥1 exacerbation: 20% vs 60%,p < 0.001) and showed improvement in lung function (%predFEV₁ 3.4%,p = 0.014) compared to the LAPR group, but at 12 months no differences between groups were observed.

CONCLUSION

HAPR resulted in a larger improvement in patient outcome parameters compared to LAPR, on the long run the improvement in patient reported symptoms and lower maintenance OCS-dose persists. Underlying factors that explain this observed effect need to be investigated.

Internet-Based Self-Management Support After High-Altitude Climate Treatment for Severe Asthma: Randomized Controlled Trial

BACKGROUND

In patients with severe asthma, high-altitude climate treatment has been shown to improve asthma control. However, asthma symptoms and limitations may increase after finishing inpatient rehabilitation programs and returning to sea level.

OBJECTIVE

We assessed the effectiveness of a patient-tailored, internet-based, self-management strategy in addition to usual care after finishing high-altitude climate treatment.

METHODS

We performed a randomized controlled trial with a 1-year follow-up in patients from a high-altitude asthma center in Davos, Switzerland. At the end of a 12-week multidisciplinary rehabilitation program, 62 adults with asthma were randomized to receive either internet-based self-management support in addition to usual care (n=33) or usual care only after discharge (n=29). The endpoints were changes in asthma-related quality of life according to the Asthma Quality of Life Questionnaire (AQLQ) (a higher score is better) and asthma control according to the Asthma Control Questionnaire (ACQ) (a lower score is better), with a minimally important difference of 0.5 points for both.

RESULTS

Asthma-related quality of life and asthma control declined over time in the usual care strategy group, whereas there was a slower decline in the internet-based strategy group. For both endpoints, mixed-model analysis showed a significant positive effect in favor of internet-based self-management during follow-up (mean AQLQ score difference 0.39, 95% CI 0.092-0.69; P=.01 and ACQ score difference -0.50, 95% CI -0.86 to -0.15; P=.006), which was prominent among patients with uncontrolled asthma at discharge (AQLQ score difference 0.59, 95% CI 0.19-0.99; P=.003 and ACQ score difference -0.73, 95% CI -1.18 to -0.28; P=.002).

CONCLUSIONS

Internet-based self-management support was associated with a smaller decline in quality of life and asthma control as compared with usual care, especially in patients with lower asthma control, after completion of high-altitude climate treatment. Internet-based self-management support in adults with severe asthma seems feasible and effective to maintain quality of life and asthma control.

TRIAL REGISTRATION

The trial is registered in the Netherlands Trial Register (NTR1995).

Dust-mite inducing asthma: what advice can be given to patients?

Introduction: Amongst allergic asthmatics, high allergen exposure increases asthma severity. However, there is no consensus on the role of mite allergen avoidance in the management of asthma, and various guidelines differ in their recommendations. Areas covered: Several systematic reviews/meta-analyses on mite avoidance in the management of asthma have been published, and their findings have been used for a call to provide a recommendation in British guidelines that dust-mite control measures should not be recommended. However, there are several problems with such analysis (such as combining studies in adults and children), and we question whether these are appropriate tools to evaluate available evidence about mite allergen avoidance, and whether it is correct to rely disproportionately on the results of meta-analyses/systematic reviews to inform clinical practice in this area. Recent evidence in children suggests that mite-impermeable bed encasings reduce emergency hospital attendance with severe asthma exacerbations. Expert opinion: The practical questions include how to achieve a sufficient real-life reduction allergen exposure, and how to identify patients who will benefit from effective intervention. The intervention should start early in the natural history of asthma, and consideration for choosing patients should include using the titre of allergen-specific IgE antibodies or the size of skin test wheal as an indicator.

Winter Exercise Reduces Allergic Airway Inflammation: A Randomized Controlled Study

Background: Physical exercise is often recommended as additional treatment for people suffering from allergic rhinitis and/or asthma, but less is known about the specific effects of recreational winter outdoor exercise on allergic airway inflammation. Methods: We performed a longitudinal, randomized controlled intervention study to investigate the effects of recreational winter exercise on allergic airway inflammation, quality of life, spirometry and cardiorespiratory fitness in adults suffering from allergic rhinitis and/or asthma. The exercise group participated in a ten-day winter sports program. The control group did not receive any intervention. Results: A significant improvement of fractional oral exhaled nitric oxide (FeNO; p = 0.008, day 10) and a significant decrease in FeNO after a single 4 h hiking tour (p < 0.001, time effect) were observed for the exercise group. The nasal eosinophilic cell count revealed a short-term reduction (p = 0.021, treatment effect) in the exercise group and for the visual analogue scale sustainable improvements in allergic symptoms (p < 0.001, day 60) were found. No adverse effects of outdoor winter exercise were observed. Conclusion: Recreational winter exercise at moderately cold temperatures reduces allergic airway inflammation measured as FeNO, nasal eosinophilic cell count and induces sustainable improvements in allergic symptoms.

Human exposure to airborne pollen and relationships with symptoms and immune responses: Indoors versus outdoors, circadian patterns and meteorological effects in alpine and urban environments

Pollen exposure is a major cause of respiratory allergies worldwide. However, it is unclear how everyday exposure is related to symptoms and how allergic patients may be affected spatially and temporally. Hence, we investigated the relationship of pollen, symptoms and immune responses under a controlled regime of 'high-low-moderate' pollen exposure in urban versus alpine environment. The research was conducted in 2016 in two locations in Germany: urban Augsburg (494 m) and Schneefernerhaus (UFS) on Zugspitze mountain (2656 m). Monitoring of airborne pollen took place using Hirst-type volumetric traps. On UFS, both indoor and outdoor samples were taken. Grass pollen allergic human volunteers were monitored daily during the peak of the grass pollen season, in Augsburg, on UFS, then again in Augsburg. Nasal biosamples were obtained throughout the study to investigate immune responses. All symptoms decreased significantly during the stay on UFS and remained low even after the return to Augsburg. The same was observed for nasal total IgE and IgM levels and for nasal type 2 cytokines and chemokines. Augsburg showed higher pollen concentrations than those on UFS. At all sites, pollen were present throughout each day, but were more abundant in Augsburg during morning. On UFS, outdoor pollen levels were up to 6-fold higher than those indoors. Nasal, ocular and pulmonary symptoms correlated with current and previous days' pollen concentrations and relative humidity. Stays in low-exposure environments during the peak pollen season can be an efficient means of reducing allergic symptoms and immune responses. However, in alpine environments, even occasional pollen exposure during short intervals may still trigger symptoms because of the additional environmental stress posed onto allergics. This highlights the need for the consideration of additional environmental factors, apart from symptom diaries and immune responses, so as to efficiently predict high-risk allergy periods.

High prevalence of house dust mite sensitization in children with severe asthma living at high altitude in a tropical country

BACKGROUND

Some studies, mainly in Europe, have shown a low level of sensitization to house dust mite (HDM) allergens at high altitude (HA). Differently, some others in tropical countries have shown a higher level. The aim of this study was to evaluate allergens sensitization, including HDM, in children with severe asthma (SA), residents at HA in a tropical middle-income developing country.

METHODS

Observational, analytical, cross-sectional study in children aged 6-15 years old with SA at HA (2640 m). Skin prick tests (SPT), serum IgE, exhaled fraction of nitric oxide (FE_NO ), spirometry, and asthma questionnaire (ACT) were performed. Associations were explored by Pearson or Spearman coefficients.

RESULTS

We included 61 children. Most patients were male (61.3%), median age: 10 years (Interquartile range [IQR]: 8-12), median BMI: 17 kg/m² (IQR: 16-20); Median of positive SPT: 2 (IQR: 2-3). At least one SPT was positive in 88.7% of patients and 87.9% were positive for at least one HDM. Serum IgE: 348 UI/mL (IQR: 154-760) and FE_NO : 22 ppb (IQR: 9-41). Prebronchodilator values were (% predicted): FVC: 109.7% (±15.5%), FEV₁ : 98.4% (±16.3); FEV₁ /FVC: 82% (±8%). SPT were inversely correlated with the FEV₁ /FVC (Rho: -0.34; 95% CI: -0.55 a -0.09; P = 0.008).

CONCLUSIONS

These children with SA living at HA in a tropical middle-income developing country have a high prevalence of HDM sensitization. One explanation for this might be that tropical conditions, such as temperature and humidity, could modify the effect of the altitude on asthma.

The Effect of Pulmonary Rehabilitation in Mountain Environment on Exercise Capacity and Quality of Life in Patients with Chronic Obstructive Pulmonary Disease (COPD) and Chronic Bronchitis

BACKGROUND We aimed to test the effectiveness of the pulmonary rehabilitation in a mountain environment on the pulmonary function, physical performance, dyspnea, affective factors, and quality of life (QoL) in patients with chronic obstructive pulmonary disease (COPD) and chronic bronchitis (CB), as well as to determine predictors of clinical improvement. MATERIAL AND METHODS 128 consecutive patients (90 diagnosed with COPD and 38 diagnosed with CB) underwent comprehensive pulmonary rehabilitation for a duration of 3 weeks in one of 3 mountain health resorts in the High Tatras. The examination included spirometry (FEV1 and FEV1/FVC), 6-minute walk test (6MWT), Borg scale of dyspnea, and assessment of depression (Zung score), anxiety (Beck score), and QoL using the SF-36 scales. RESULTS After the study intervention, all patients in both monitored groups demonstrated significant improvements in objective measurements in which large treatment effect was achieved (for FEV1 η²=0.218, for 6MWT η²=0.771). Similarly, in subjective measurements a large effect was achieved (for the Beck score: η²=0.599, for the Zung score: η²=0.536). QoL improved after the intervention in all the monitored SF-36 scales in both groups (P<0.001 for all). In patients with COPD, the improvement of exercise capacity was positively correlated with baseline 6MWT and FEV1, and negatively with the Beck anxiety score and the Borg dyspnea score, whereas, only improvement in the mental summary component of QoL was negatively correlated with baseline 6MWT and FEV1 (P<0.05 for all). CONCLUSIONS Rehabilitation in a mountain environment has proven to be effective in both the reported diagnoses of COPD and CB. Improvements in both functional and subjective indicators were observed. These findings support the use of this treatment modality.

Altitude above 1500 m is a major determinant of asthma incidence. An ecological study

BACKGROUND

Previous studies suggest an inverse correlation between asthma and altitude. In the present work, we performed an in-depth analysis of asthma incidence in the 758 Mexican counties covered by the largest medical institution in the country (∼37.5 million insured subjects), and evaluated its relationships with altitude and other factors.

METHODS

Asthma incidence in each county was calculated from new cases diagnosed by family physicians. Other variables in the same counties, including selected diseases, geographical variables, and socioeconomic factors, were also obtained and their association with asthma was evaluated through bivariate and multivariate analyses.

RESULTS

Median asthma incidence was 296.2 × 100,000 insured subjects, but tended to be higher in those counties located on or near the coast. When asthma incidence was plotted against altitude, a two-stage pattern was evident: asthma rates were relatively stable in counties located below an altitude of ∼1500 m, while these rates progressively decreased as altitude increased beyond this level (r_S = -0.51, p < .001). Multivariate analysis showed that, once each variable was adjusted by the potential influence of the others, asthma incidence was inversely correlated with altitude (standardized β coefficient, -0.577), helminthiasis (-0.173), pulmonary tuberculosis (-0.130), and latitude (-0.126), and was positively correlated with acute respiratory tract infection (0.382), pneumonia (0.289), type 2 diabetes (0.138), population (0.108), and pharyngotonsillitis (0.088), all with a p ≤ .001.

CONCLUSION

Our study showed that altitude higher than ∼1500 m comprises a major factor in determining asthma incidence, with the risk of new-onset asthma decreasing as altitude increases. Other less influential conditions were also identified.

Perception of climate change in patients with chronic lung disease

BACKGROUND

Climate change affects human health. The respective consequences are predicted to increase in the future. Patients with chronic lung disease are particularly vulnerable to the involved environmental alterations. However, their subjective perception and reactions to these alterations remain unknown.

METHODS

In this pilot study, we surveyed 172 adult patients who underwent pulmonary rehabilitation and 832 adult tourists without lung disease in the alpine region about their perception of being affected by climate change and their potential reaction to specific consequences. The patients' survey also contained the COPD Assessment Test (CAT) to rate the severity of symptoms.

RESULTS

Most of the patients stated asthma (73.8%), COPD (9.3%) or both (11.0%) as underlying disease while 5.8% suffered from other chronic lung diseases. Patients and tourists feel equally affected by current climate change in general, while allergic subjects in both groups feel significantly more affected (p = 0.04). The severity of symptoms assessed by CAT correlates with the degree of feeling affected (p<0.01). The main disturbing consequences for patients are decreased air quality, increasing numbers of ticks and mosquitos and a rising risk for allergy and extreme weather events such as thunderstroms, while tourists are less disturbed by these factors. Increasing number of heat-days is of little concern to both groups.

CONCLUSION

Overall patients are more sensitive to health-related consequences of climate change. Yet, the hazard of heat-days seems underestimated and awareness should be raised.

Morbidity in the Mountainous Province of Kyrgyzstan: Results from a Population-Based Cross-Sectional Study

Brimkulov, Nurlan, Louis Louton, Salima Sydykova, Denis Vinnikov, and Farida Imanalieva. Morbidity in the mountainous Province of Kyrgyzstan: Results from a population-based cross-sectional study. High Alt Med Biol 18:338-342, 2017.-The aim of this study was to identify the main causes of using primary care facilities in the mountainous Naryn Province of Kyrgyzstan to set resources allocation priorities. We collected data on all admissions to family doctors in three Family Medical Centers (FMCs) in Naryn Province: (1) the city of Naryn (2200 meters above sea level [MASL]); (2) the town of At-Bashy (3200 MASL); and the town of Kochkor (1800 MASL) by using an original questionnaire during one full week (5 days) in spring 2016. Within 1 week, we recorded 1136 cases in Naryn and 782 cases in Bishkek after exclusion of missing data. The top three reasons for admissions were respiratory (23% of all in Naryn and 36% in Bishkek), nonspecific general (19% and 17%), and neurological (13% and 9%). Naryn residents were 3.84 times (confidence interval [95% CI] 2.07-7.11) more likely to apply with musculoskeletal and 3.05 times (95% CI 1.02-9.12) more likely to apply with cardiovascular conditions. This first population-based study in Naryn stresses the need to prioritize cardiovascular and rheumatological care in these mountainous conditions.

Respiratory Health Benefits and Risks of Living at Moderate Altitude

Grissom, Colin K., and Barbara E. Jones. Respiratory health benefits and risks of living at moderate altitude. High Alt Med Biol 19:109-115, 2018.-The respiratory system plays a critical role in the series of physiologic responses that occur at high altitude and allows individuals to adapt to and tolerate hypobaric hypoxia. Persons with underlying lung disease may have complications, but sometimes derive benefits, related to residence at high altitude. This review will focus on health benefits and risks of patients with underlying asthma, chronic obstructive pulmonary disease, pulmonary hypertension, or obstructive sleep apnea, who live at altitudes of 1500 to 4500 m. We will also discuss maladaptive responses of the respiratory system at high altitude in previously healthy persons, including development of pulmonary hypertension and sleep-disordered breathing.