Cold temperature and sudden temperature drop as novel risk factors of asthma exacerbation: a longitudinal study in 18 Chinese cities

Designing and validating an experimental protocol to induce airway narrowing in older adults with and without asthma

BACKGROUND

Persons with asthma may experience excessive airway narrowing due to exercise or exposure to cold air, worsening their daily functionality. Exercise has several benefits for asthma control, but it may induce airway narrowing in some persons with asthma. When combined with cold temperatures, it introduces another layer of challenges. Therefore, managing this interaction is crucial to increase the quality of life in individuals with asthma. The purpose of this study was to develop a reliable experimental protocol to assess the effects of exercise and cold air on airway narrowing in adults with asthma in a controlled and safe environment.

METHODS

This study was a randomized cross-over study in adults with and without asthma. Participants underwent a protocol involving a 10-min seated rest, followed by a 10-min cycling on a stationary bike in different temperatures of 0, 10, or 20 ∘ C. The sequence of room temperatures was randomized, and there was a 30-min interval for recovery between each temperature transition. In each temperature, to measure lung function and respiratory symptoms, oscillometry and a questionnaire were used at 0 min (baseline), after 10 min of sitting and before starting biking (pre-exercise), and after 10 min of biking (post-exercise). At each room temperature, the changes in airway mechanics and asthma symptoms among baseline, pre-exercise, and post-exercise were compared with one-way repeated measures ANOVA or Friedman Rank Test. Within each arm, cardiac and thoraco-abdominal motion respiration signals were also measured continuously using electrodes and calibrated respiratory inductance plethysmographs, respectively.

RESULTS

A total of 23 persons with asthma (11 females, age: 56.3 ± 10.9 years, BMI: 27.4 ± 5.7 kg/m2) and 6 healthy subjects (3 females, age: 61.8 ± 9.1 years, BMI: 28.5 ± 3.1 kg/m2) were enrolled in the study. Cold temperature of 0∘ C induced airway narrowing in those with and without asthma after 10 and 20 min, respectively. Exercise intervention had significant changes in airway narrowing in participants with asthma in the range of 10-20∘ C. Our results showed that in asthma, changes in subjective respiratory symptoms were due to both cold temperatures of 0 and 10∘ C and exercise in the 0-20∘ C range. Respiratory symptoms were not noticed among the healthy participants.

CONCLUSION

In conclusion, our findings suggest that exposure to cold temperatures of 0∘ C could serve as a reliable method in the experimental protocol for inducing airway narrowing in asthma. The impact of exercise on airway narrowing was more variable among participants. Understanding these triggers in the experimental protocol is essential for the successful management of asthma in future studies.

The combined effect of oxidative stress and TRPV1 on temperature-induced asthma: Evidence in a mouse model

Temperature is one of the possible activators for asthma. As global warming continues, the health hazard of high temperatures is increasing. It is unclear, nevertheless, how high temperatures affect asthma. The research aims to examine how asthma is affected by high temperatures and underlying molecular mechanisms. The BALB/c mice were adopted in a model of asthma. The mice were exposed at 24 °C, 38 °C and 40 °C for 4h on weekdays from day 1 to day 30. After the experiment, the lung function was measured in vivo, and then serum protein, pulmonary inflammation and immunohistochemistry assay was assessed in vitro. As the temperature increased from 24 °C to 40 °C, there was a significant increase in serum protein, while there is no discernible difference in serum protein of OVA-sIgE and OVA-sIgG between the OVA (38 °C) group and OVA (24 °C) group. The immunohistochemistry assay showed a change in the pro-inflammatory cytokines. The histopathological analysis exhibited the change of airway structure after high-temperature exposure, especially for exposure at 40 °C. The results of signals protein showed a remarkable rise of TRPV1 for OVA+40 °C. Our results revealed that high temperatures may make asthmatic airway dysfunction severe, and the higher the temperature, the more serious asthma. The oxidative stress and TRPV1 receptor can be a potential drug target for asthma. It will provide a new tool for precision medicine in asthma.

Impact of ambient temperature on respiratory disease: a case-crossover study in Seoul

BACKGROUND

Respiratory diseases contribute to global morbidity and mortality, and temperature is a significant factor. We investigated the association between ambient temperature and emergency department (ED) visits for various respiratory diseases in Seoul, South Korea.

METHODS

Using data from the National Emergency Department Information System (2008-2017), we analysed 1,616,644 ED visits for respiratory diseases, categorised according to the Korean Standard Classification of Diseases 7th revision codes (J00-J99). Using a time-stratified case-crossover design and a distributed lag nonlinear model, we investigated the effect of temperature exposure on ED visits for respiratory diseases, calculating the relative risk (RR) for the maximum risk temperature (MaxRT) of both cold and hot extremes compared to the minimum risk temperature (MinRT).

RESULTS

Cold temperatures (MaxRT: -9.0 °C) resulted in a 2.68-fold increase (RR = 2.68, 95% CI = 2.26-3.14) in ED visits for total respiratory diseases, while hot temperatures (MaxRT: 29.4 °C) led to a 1.26-fold increase (RR = 1.26, 95% CI = 1.11-1.42) compared to the MinRT (24.8 °C). Cold temperatures increased the risk of most respiratory diseases, except interstitial lung disease, whereas hot temperatures increased ED visits for acute upper respiratory infections and influenza. Cold temperatures increased ED visits for all age groups, especially those aged 18-64 (RR = 3.54, 95% CI = 2.90-4.33), while hot temperatures significantly affected those < 18 (RR = 1.45, 95% CI = 1.27-1.66). The risk levels were similar in both males and females, regardless of hot and cold temperatures.

CONCLUSION

Our findings underscore the significant impact of both cold and heat exposure on ED visits for respiratory diseases, with varying intensities and risk profiles across different population groups.

The impact of outdoor pollution and extreme temperatures on asthma-related outcomes: A systematic review for the EAACI guidelines on environmental science for allergic diseases and asthma

Air pollution is one of the biggest environmental threats for asthma. Its impact is augmented by climate change. To inform the recommendations of the EAACI Guidelines on the environmental science for allergic diseases and asthma, a systematic review (SR) evaluated the impact on asthma-related outcomes of short-term exposure to outdoor air pollutants (PM2.5, PM10, NO2 , SO2 , O3 , and CO), heavy traffic, outdoor pesticides, and extreme temperatures. Additionally, the SR evaluated the impact of the efficacy of interventions reducing outdoor pollutants. The risk of bias was assessed using ROBINS-E tools and the certainty of the evidence by using GRADE. Short-term exposure to PM2.5, PM10, and NO2 probably increases the risk of asthma-related hospital admissions (HA) and emergency department (ED) visits (moderate certainty evidence). Exposure to heavy traffic may increase HA and deteriorate asthma control (low certainty evidence). Interventions reducing outdoor pollutants may reduce asthma exacerbations (low to very low certainty evidence). Exposure to fumigants may increase the risk of new-onset asthma in agricultural workers, while exposure to 1,3-dichloropropene may increase the risk of asthma-related ED visits (low certainty evidence). Heatwaves and cold spells may increase the risk of asthma-related ED visits and HA and asthma mortality (low certainty evidence).

Effects of air pollutants and temperature on the number of asthma outpatient visits in Hohhot, China

Although numerous studies have linked asthma to air temperature and pollution, few studies have examined their interactive effects on asthma outpatient visits. This study investigated how air pollutants and their interactions with temperature affect asthma outpatient visits in a city in northern Chinaduring the time period 2018 - 2020 . . As the results, 24,163 asthma outpatients were recorded, a 10-μg/m3 increase in PM10, PM2.5, SO2, and NO2 concentrations was associated with significant increases in visits of 3.47% (95% CI: 2.35%-4.60%), 0.83% (95% CI: 0.36%-1.30%), 3.17% (95% CI: 1.47%-4.90%), and 8.90% (95% CI: 6.09%-11.79%), respectively. The effect was stronger in females than males, and stronger in the elderly (≥65 years) than among the young. The interaction between low temperatures and high air pollution levels significantly increased the number of asthma outpatient visits. This study emphasizesthe importance of reducing air pollution in order to lessen the effects of cold.

Impact of air pollution changes and meteorology on asthma outpatient visits in a megacity in North China Plain

The effects of air pollution and meteorology on asthma is less studied in North China Plain. In the last decade, air quality in this region is markedly mitigated. This study compared the short-term effects of air pollutants on daily asthma outpatient visits (AOV) within different sex and age groups from 2014 to 2016 and 2017-2019 in Tianjin, with the application of distributed lag nonlinear model. Moreover, relative humidity (RH) and temperature as well as the synergistic impact with air pollutants were assessed. Air pollutants-associated risk with linear (different reference values were used) and non-linear assumptions were compared. In 2014-2016, PM10 and PM2.5 exhibited a larger impact on AOV, with the corresponding cumulative excess risks (ER) for every 10 μg/m3 increase at 1.04 % (95%CI:0.67-1.40 %, similarly hereafter) and 0.79 % (0.35-1.23 %), as well as increased to 43 % (26-63 %) and 20 % (10-31 %) at severe pollution. In 2017-2019, NO2 and MDA8 O3 exhibited a larger impact on AOV, with a cumulative ER for every 10 μg/m3 increase at 1.0 (0.63-1.4 %) and 0.36 % (0.15-0.57 %), with corresponding values of 7.9 % (4.8-11 %) and 5.6 % (2.3-9.0 %), at severe pollution. SO2 associated risk was only significant from 2014 to 2016. Cold effect, including extremely low temperature exposure and sharp temperature drop could generate a pronounced increase in AOV at 9.6 % (3.8-16 %) and 24 % (9.1-41 %), respectively. Moderate low temperature combined with air pollutants can enhance AOV during winter. Higher temperature in spring and autumn could trigger asthma by increasing pollen levels. Low RH resulted in AOV increase by 4.6 % (2.4-6.9), while higher RH generated AOV increase by 3.4 % (1.6-5.3). Females, children, and older adults tended to have a higher risk for air pollution, non-optimum temperature, and RH. As air pollution-associated risks on AOV tends to be weaker due to air quality improvement in recent years, the impact of extreme meteorological condition amidst climate change on asthma visits warrants further attention.

Effects of climate and environment on migratory old people with allergic diseases in China: Protocol for a Sanya cohort study

Background

Several studies have reported that the mountain climate can alleviate asthma, however, the effect of tropical climate on migratory elderly, especially in people with respiratory or allergic diseases is unknown.

Objectives

This cohort study aims to explore impact of climate and environmental changes on allergic diseases in migratory old people.

Methods

In this prospective cohort study, we recruited 750 older migratory people, the majority of whom were homeowners to minimize the risk of loss to follow up. The study's inclusion criteria were elderly individuals had moved from northern China to Sanya and suffered from either asthma or allergic diseases. Prior to participation, these individuals provided informed consent and underwent baseline assessment. Subsequently, they will be followed for three years. A face-to-face interview was conducted to gather information regarding their living environment and habits. Trained investigators administered the questionnaires and performed physical examinations including height, weight, and blood pressure, while a professional respiratory doctor conducted pulmonary function tests. Blood samples were promptly tested routine blood test, liver function, kidney function, glucose, triglyceride, allergens, and inflammatory factors. Climate and environmental data were obtained from Sanya Meteorological Bureau and Ecological Environment Bureau, respectively. We primarily compared the differences of participants with asthma or allergic diseases between northern China and Sanya in southern China by Chi-square test, t-test or Wilcoxon rank-sum test.

Findings

A total of 750 participants were recruited in this cohort from fourteen communities. All participants were surveyed questionnaires about health and family environment, underwent physical examinations, and collected biological samples for laboratory examinations.

Novelty

This is the first study to evaluate the effects of tropical climate and environment on elderly migrants from cold regions. This study has important implication for the health tourism and aging health, especially for the elderly migrants who suffered the respiratory and allergic diseases. Furthermore, this cohort study establishes a solid foundation for investigating the influence of environmental changes on elderly migrants with allergic diseases.

Socioeconomic and environmental determinants of asthma prevalence: a cross-sectional study at the U.S. County level using geographically weighted random forests

BACKGROUND

Some studies have established associations between the prevalence of new-onset asthma and asthma exacerbation and socioeconomic and environmental determinants. However, research remains limited concerning the shape of these associations, the importance of the risk factors, and how these factors vary geographically.

OBJECTIVE

We aimed (1) to examine ecological associations between asthma prevalence and multiple socio-physical determinants in the United States; and (2) to assess geographic variations in their relative importance.

METHODS

Our study design is cross sectional based on county-level data for 2020 across the United States. We obtained self-reported asthma prevalence data of adults aged 18 years or older for each county. We applied conventional and geographically weighted random forest (GWRF) to investigate the associations between asthma prevalence and socioeconomic (e.g., poverty) and environmental determinants (e.g., air pollution and green space). To enhance the interpretability of the GWRF, we (1) assessed the shape of the associations through partial dependence plots, (2) ranked the determinants according to their global importance scores, and (3) mapped the local variable importance spatially.

RESULTS

Of the 3059 counties, the average asthma prevalence was 9.9 (standard deviation ± 0.99). The GWRF outperformed the conventional random forest. We found an indication, for example, that temperature was inversely associated with asthma prevalence, while poverty showed positive associations. The partial dependence plots showed that these associations had a non-linear shape. Ranking the socio-physical environmental factors concerning their global importance showed that smoking prevalence and depression prevalence were most relevant, while green space and limited language were of minor relevance. The local variable importance measures showed striking geographical differences.

CONCLUSION

Our findings strengthen the evidence that socio-physical environments play a role in explaining asthma prevalence, but their relevance seems to vary geographically. The results are vital for implementing future asthma prevention programs that should be tailor-made for specific areas.

Effect of extreme temperatures on asthma hospital visits: Modification by event characteristics and healthy behaviors

Although ambient temperature has been linked to asthma exacerbation, impacts associated with extreme temperature events remain unclear. This study aims to identify the events characteristics that elevate risk of asthma hospital visits, and to assess whether healthy behavior changes due to the COVID-19 prevention and control policy may modify the relationships. Data of asthma hospital visits from all medical facilities in Shenzhen, China during 2016-2020 were assessed in relation to extreme temperature events using a distributed lag model. Stratified analysis was conducted by gender, age and hospital department to identify susceptible populations. Through events defined by various duration days and temperature thresholds, we explored the modification by events intensity, length, occurrence time and healthy behaviors. The cumulative relative risk of asthma during heat waves compared to other days was 1.06 (95%CI: 1.00-1.13) and for cold spells was 1.17 (95%CI: 1.05-1.30), and that of males and school-aged children were generally higher than other sub-groups. There were significant effects of heat waves and cold spells on asthma hospital visits when the mean temperature was above 90th percentile (30 °C) and below 10th percentile (14 °C) respectively, and the relative risks were higher when events lasted longer, became stronger, occurred in daytime and in early summer or winter. During the healthy behaviors maintaining period, the risk of heat waves increased whilst the risk of cold spells reduced. Extreme temperatures may pose considerable impact on asthma and the health effect can be modified by the event characteristics and anti-epidemic healthy behaviors. Strategies of asthma control should consider the heightened threats of the intense and frequent extreme temperature events in the context of climate change.

Low ambient temperature and temperature drop as novel risk factors of acute glaucoma: a case-crossover study

The prevalence of glaucoma has seasonal variation in population, but the role of ambient temperature and its variation remains unclear in this seasonal trend. So, we conducted a time-stratified case-crossover study to examine the association of ambient temperature and temperature change between neighboring days (TCN) with the risk of acute glaucoma. Data on meteorological parameters and glaucoma outpatient visit between 2015 and 2021 covered all districts of Shanghai. Conditional logistic regression with distributed lag nonlinear model was applied to estimate the association of temperature or TCN with the risk of acute glaucoma. A total of 7,746 patients diagnosed with acute primary angle-closure glaucoma (APACG) were included in this analysis. We observed a significant increase in the risk of acute glaucoma with cold temperature and temperature drop. Compared with the referent temperature (32℃), moderate low (12 °C) and extreme low (4 °C) temperature exposures were associated with higher risk of acute glaucoma outpatient visit, with the highest cumulative OR of 1.46 (95% CI: 1.11, 1.91) and 1.50 (95% CI: 1.09, 2.06) over lag 0-2 days. Temperature drop (TCN =  - 4 °C) also increases the risk of acute glaucoma (OR = 1.34, 95% CI: 1.07, 1.67) over lag 0-7 days, comparing with no temperature change. Patients of female and above age 65 were more vulnerable to cold exposure and temperature drop. This case-crossover study provided novel and robust individual-level evidence that low ambient temperature and temperature drop significantly increase the acute glaucoma risk. The findings provide protective strategies for glaucoma patient, especially for female and the old, under cold exposure and sudden temperature decline.

Assessing the national burden of allergic asthma by web-search data, pollen counts, and drug prescriptions in Germany and Sweden

Background

Asthma and its main phenotype allergic asthma are prevalent, chronic, and complex diseases affecting 4% of the population. One main trigger for allergic asthma exacerbations is pollen. Online health information search behavior by people is increasing, and analysis of web-search data can provide valuable insight into disease burden and risk factors of a population.

Objectives

We sought to perform a web-search data analysis and correlation to climate factors and pollen in 2 European countries.

Methods

We analyzed the national web-search volume for allergic asthma-related keywords in Germany and Sweden from 2018 to 2021 and correlated it to local pollen counts, climatic factors, and drug prescription rates.

Results

Per capita, more searches were conducted in Sweden than in Germany. A complex geographic stratification within the countries was observed. Search results were seasonal with a peak in spring and correlated with pollen counts in both countries. However, anti-asthmatic drug prescription rates in Sweden, as well as temperature and precipitation in both countries, did not correlate with search volume.

Conclusion

Our analysis offers population-level insights about this complex disease by reporting its needs and establishing the correlation to pollen counts, which enables a targeted approach in the public health management of allergic asthma. Local pollen counts, as opposed to temperature or precipitation, might be good predictors of allergic asthma disease burden.

Seasonal characteristics of ambient temperature variation (DTR, TCN, and TV0-t) and air pollutants on childhood asthma attack in a dry and cold city in China

Very few researches have concentrated on a variety of time scales to evaluate the association between temperature variation (TV) and childhood asthma (CA), and the evidence for the interaction of air pollutants on this association is lacking. In this study, we aim to estimate the relative risks (RRs) of CA due to TV by following metrics: diurnal temperature range (DTR), temperature changes between neighboring days (TCN), and temperature variability (TV_0-t); to quantify the seasonal attributable fraction (AF) and number (AN) of CA due to TV; to examine the interactive effects of the TV and air pollutants on CA in different seasons. We mainly applied distributed lagged nonlinear model (DLNM) and conditional Poisson models to evaluate the associations between TV and outpatient visits for CA during 2014-2019 in Lanzhou, China. Additionally, the bivariate response surface model was used to examine the interplay effect of air pollutants. We found that in warm season, the risks of DTR maximum at lag5 (RR = 1.073, 95% CI: 1.017-1.133); TCN showed protective effect. In cold season, the risks of DTR peaked at lag8 (RR = 1.063, 95% CI: 1.027-1.100); the risks of TCN maximum at lag0 (RR = 1.058 95% CI: 1.009-1.109); the estimation of total cases maximized at TV_0-4 in cold season (RR = 1.039 at TV_0-3, 95% CI: 1.001, 1.077) and was the lowest at TV_0-1 in warm season (RR = 0.999, 95% CI: 0.969, 1.030). In addition, the response surface model graphically pictured ambient air pollutants enhanced the DTR/TV_0-4-CA effect for girls. In conclusion, the RRs of CA are markedly increased by TV exposure, particularly during the colder months. A combined evaluation of DTR, TCN, TV_0-5∼TV_0-6, NO₂, SO₂, and PM_2.5 should be used to identify the adverse effects of TV on CA.

Short-term exposure to ozone and asthma exacerbation in adults: A longitudinal study in China

Background

The relationships between short-term ozone exposure and the acute exacerbations of asthma in adults have not been fully studied. Existing studies commonly ignored the effects of ozone on mild or early asthma exacerbations.

Objective

To investigate the associations between short-term ozone exposure and asthma exacerbations in Chinese adults.

Methods

We administered health management for adult asthma patients through the Respiratory Home Platform and required them to monitor their lung function every morning and evening by themselves. Finally, a total of 4,467 patients in 18 Chinese cities were included in the current analyses, with 79,217 pairs of lung function records. The maximum daily 8-h average ozone concentrations were collected from fixed-site air quality monitoring stations. We calculated diurnal peak expiratory flow (PEF) variation using morning and evening measurements of PEF and then defined different severity of asthma exacerbations with diurnal PEF variations >10, 15, and 20%, respectively. A binomial distributed generalized additive mixture model combined with distribution non-linear models was applied to examine the association of ozone with asthma exacerbations. We further conducted stratified analyses by sex, age, season of lung function tests, and region.

Measurements and results

We found that short-term ozone exposure was independently associated with an elevated risk of asthma exacerbations defined by lung function and the effects could last for about 2 days. At lag 0-2 days, each 10 μg/m3 increment in ozone concentration was associated with odds ratios of 1.010 [95% confidence interval (CI): 1.003, 1.017], 1.014 (95% CI: 1.005, 1.023), and 1.017 (95% CI: 1.006, 1.028) for asthma exacerbations that were defined by diurnal PEF variation over 10, 15, and 20%, respectively. The associations remained significant after adjusting for other pollutants, and became unstable when using 24-h average ozone concentration. We also found that the associations were relatively stronger in males, those aged 45 years and older, and in the warm season.

Conclusions

Our results suggest that short-term ozone exposure can increase the risk of asthma exacerbations, even in the early stage of exacerbation. Male and older asthma patients may be more vulnerable to ozone air pollution, especially in the warm season.

Geoclimatic risk factors for childhood asthma hospitalization in southwest of Iran

BACKGROUND

Asthma is a chronic respiratory disease resulting from a complex interaction between genetic and environmental factors. Among environmental factors, climatic and geographical variations have an important role in increasing asthma hospitalization. The current study aimed to investigate the effect of geoclimatic factors on the occurrence of childhood asthma hospitalization in Fars province, southwest Iran.

METHOD

We mapped the addresses of 211 hospitalized patients with childhood asthma (2016-2019) and investigated the effects of different temperature models, mean annual rainfall and humidity, number of frosty and rainy days, evaporation, slope, and land covers on the occurrence of childhood asthma hospitalization using a geographical information system. The Kriging and Spline methods have been used for generating interpolated models. Data were analyzed using logistic regression.

RESULTS

In the multivariate model, urban setting was recognized as the most important childhood asthma hospitalization predictor (p < 0.001, odds ration [OR] = 35.044, confidence interval [CI] = 9.096-135.018). The slope was considered the determinant of childhood asthma hospitalization when analyzed independently and its increase was associated with decreased childhood asthma hospitalization (p  = 0.01, OR = 0.914, CI = 0.849-0.984).

CONCLUSION

In the current study, the urban setting was the most important risk factor associated with increased childhood asthma hospitalization.