Associations between ambient temperature and adult asthma hospitalizations in Beijing, China: a time-stratified case-crossover study

Abstract

Background Studies on the associations between ambient temperature and asthma hospitalizations are limited, and the results are controversial. We aimed to assess the short-term effects of ambient temperature on the risk of asthma hospitalizations and quantify the hospitalization burdens of asthma attributable to non-optimal temperature in adults in Beijing, China. Methods We collected daily asthma hospitalizations, meteorological factors and air quality data in Beijing from 2012 to 2015. We applied a time-stratified case-crossover design and fitted a distributed lag non-linear model with a conditional quasi-Poisson regression to explore the association between ambient temperature and adult asthma hospitalizations. The effect modifications of these associations by gender and age were assessed by stratified analyses. We also computed the attributable fractions and numbers with 95% empirical confidence intervals (eCI) of asthma hospitalizations due to extreme and moderate temperatures. Results From 2012 to 2015, we identified a total of 18,500 hospitalizations for asthma among adult residents in Beijing, China. Compared with the optimal temperature (22 °C), the cumulative relative risk (CRR) over lag 0–30 days was 2.32 with a 95% confidence interval (CI) of 1.57–3.42 for extreme cold corresponding to the 2.5th percentile (− 6.5 °C) of temperature distribution and 2.04 (95% CI 1.52–2.74) for extreme heat corresponding to the 97.5th percentile (29 °C) of temperature distribution. 29.1% (95% eCI 17.5–38.0%) of adult asthma hospitalizations was attributable to non-optimum temperatures. Moderate cold temperatures yielded most of the burdens, with an attributable fraction of 20.3% (95% eCI 9.1–28.7%). The temperature-related risks of asthma hospitalizations were more prominent in females and younger people (19–64 years old). Conclusions There was a U-shaped association between ambient temperature and the risk of adult asthma hospitalizations in Beijing, China. Females and younger patients were more vulnerable to the effects of non-optimum temperatures. Most of the burden was attributable to moderate cold. Our findings may uncover the potential impact of climate changes on asthma exacerbations.

Non-optimum temperature increases risk and burden of acute myocardial infarction onset: A nationwide case-crossover study at hourly level in 324 Chinese cities

“…This approach accounts for the potentially complex temporal patterns of exposure–response relationships to provide more appropriate estimates for the disease burden, and thus has been widely used in previous studies within the framework of DLNM. 7 , 17 , 22 , 25 The formulas of backward attributable fraction (AF) and number (AN) at time t were as follows 24 : …”

“… 24 The corresponding 2.5 th and 97.5 th percentiles of the distributions by simulating 5000 random samples were interpreted as the 95% eCIs. 22 , 24 , 25 …”

Exposure to outdoor artificial light at night increases risk and burden of metabolic disease in Ningxia, China

“…In addition, Monte Carlo simulations were used to calculate empirical confidence intervals (eCIs) by assuming a multivariate normal distribution of point estimates and a variance matrix derived from the regression model (Gasparrini and Leone 2014). A random sample of 1000 was simulated, corresponding to 2.5th and 97.5th was interpreted as 95% eCIs (Chen et al 2022;Gasparrini and Leone 2014;Tian et al 2016).…”

“…As metabolic disease fractions attributable to outdoor ALAN, using the backward method from a previous study, we quantified the presence of metabolic disease due to outdoor ALAN (Gasparrini and Leone 2014), and exposures from the past 30 days could be summarized in this way. This approach takes into account potentially complex temporal patterns of exposure-response relationships, thus providing a more appropriate estimate of disease burden, and has therefore been used extensively in previous studies within the DLNM framework (Chen et al 2022;Fu et al 2018;Tian et al 2016;Yang et al 2017). We calculated the attribution fractions (AF) for metabolic disease at outdoor ALAN exposure of 0, 10, 20 nWcm −2 sr −1 for different sex and age groups, respectively.…”

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

“… 25 , 26 Another study found a complex U-shaped association between asthma disease burden and temperature. 27 Small real-world studies demonstrated that increased pollen exposure was associated with an increased prevalence of asthma exacerbations. 28 …”