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Overview information of cold spells under different definitions
Source publication
Objectives
Our work aimed at exploring the relationship between cold spells and acute exacerbation of chronic obstructive pulmonary disease (AECOPD) hospitalisations in Beijing, China, and assessing the moderating effects of the intensities and the durations of cold spells, as well as identifying the vulnerable.
Design
A time-series study.
Settin...
Contexts in source publication
Context 1
... Table 2 shows the overview information of cold spells under different definitions. More days were defined as cold spell days with higher temperature thresholds and shorter duration. ...Similar publications
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Citations
... The OR in this study was close to the estimated values in other studies, such as in Shanghai at 1.26 (95% CI: 1.14, 1.38) [37], Shanxi at 1.232 (1.090, 1.394) [23], Beijing at 1.811 (1.229-2.667) [38], and Nanjing at 1.54 (1.16, 2.04) [39]. These results indicate that the hazards of cold waves should receive sufficient attention. ...
Background
Extreme weather events like heatwaves and fine particulate matter (PM2.5) have a synergistic effect on mortality, but research on the synergistic effect of cold waves and PM2.5 on outpatient visits for respiratory disease, especially at high altitudes in climate change-sensitive areas, is lacking.
Methods
we collected time-series data on meteorological, air pollution, and outpatient visits for respiratory disease in Xining. We examined the associations between cold waves, PM2.5, and outpatient visits for respiratory disease using a time-stratified case-crossover approach and distributional lag nonlinear modeling. Our analysis also calculated the relative excess odds due to interaction (REOI), proportion attributable to interaction (AP), and synergy index (S). We additionally analyzed cold waves over time to verify climate change.
Results
Under different definitions of cold waves, the odds ratio for the correlation between cold waves and outpatient visits for respiratory disease ranged from 0.95 (95% CI: 0.86, 1.05) to 1.58 (1.47, 1.70). Exposure to PM2.5 was significantly associated with an increase in outpatient visits for respiratory disease. We found that cold waves can synergize with PM2.5 to increase outpatient visits for respiratory disease (REOI > 0, AP > 0, S > 1), decreasing with stricter definitions of cold waves and longer durations. Cold waves’ independent effect decreased over time, but their interaction effect persisted. From 8.1 to 21.8% of outpatient visits were due to cold waves and high-level PM2.5. People aged 0–14 and ≥ 65 were more susceptible to cold waves and PM2.5, with a significant interaction for those aged 15–64 and ≥ 65.
Conclusion
Our study fills the gap on how extreme weather and PM2.5 synergistically affect respiratory disease outpatient visits in high-altitude regions. The synergy of cold waves and PM2.5 increases outpatient visits for respiratory disease, especially in the elderly. Cold wave warnings and PM2.5 reduction have major public health benefits.
... Consequently, this study opts for the mean daily temperature indicator and delineates multiple definitions for heat waves and cold spells through three threshold temperatures and three durations, attempting to find out the optimal definition of heat waves and cold waves associated with changes in blood parameters in Tianjin. We found that in most cases, the effect of heat waves (or cold spells) increases with the increase (or decrease) of threshold temperature and increased duration, which has been confirmed by previous studies [38][39][40]. In addition, we found that the definitions with the best model fit were HW05 (the 97th percentile and duration of at least 3 days) and CS07 (the 10th percentile threshold and duration of at least 2 days). ...
Background: With the increasing occurrence of extreme temperature events due to climate change, the attention has been predominantly focused on the effects of heat waves and cold spells on morbidity and mortality. However, the influence of these temperature extremes on blood parameters has been overlooked.
Methods: We conducted a cohort study involving 2,752 adult blood donors in Tianjin, China, between January 18, 2013, and June 25, 2021. The generalized additive mixed model was used to investigate the effects and lagged effects of heat waves and cold spells on six blood parameters of blood donors, including alanine aminotransferase (ALT), white blood cell count (WBC), red blood cell count (RBC), hemoglobin (HB), hematocrit (HCT), and platelet count (PLT). Subgroup analyses were stratified by sex, age, and BMI.
Results: Heat waves and cold spells are associated with changes in blood parameters, particularly HB and PLT. Heat waves increased HB and PLT, while cold spells increased HB and decreased PLT. The effect of heat waves is greater than that of cold spells. The largest effect of heat waves on HB and PLT occurred at lag1 with 2.6 g/L (95% CI: 1.76 to 3.45) and lag7 with 9.71 × 10^9/L (95% CI: 6.26 to 13.17), respectively, while the largest effect of cold spells on HB and PLT occurred at lag0 with 1.02 g/L (95% CI: 0.71 to 1.33) and lag2 with −3.85 × 10^9/L (95% CI: −5.00 to −2.70), respectively. In subgroup analysis, the effect of cold spells on ALT was greater in the 40–49 age group.
Conclusion: We indicated that heat waves and cold spells can impact hemoglobin and platelet counts in the human body. These findings provide evidence linking heat waves or cold spells to diseases and may reduce health risks caused by extreme temperature events.
... In particular, individuals with bronchial asthma report exacerbation of symptoms when exposed to cold weather (Hyrkäs-Palmu et al. 2018). There is evidence that the number of hospitalisations due to asthma and chronic obstructive pulmonary disease increase in very cold days (Chen et al. 2022;Liu et al. 2021). Some studies showed a reduction of the forced expiratory capacity in one second (FEV 1 ) in spirometry after cold air exposure in both healthy subjects and individuals with known asthma or COPD (Koskela and Tukiainen 1995;Koskela et al. 1996). ...
Objective
The aim of this study is to investigate whether there is an association between brief but repeated exposures to extremely cold temperatures over many years and pulmonary function.
Methods
We performed a retrospective analysis of the data collected over 10 years in the context of the extended medical examinations of storeworkers exposed to extremely cold temperatures. We considered forced vital capacity (FVC), forced expiratory volume in one second (FEV1), Tiffeneau-Pinelli index (FEV1/FVC), CO diffusion capacity (DL,CO) and Krogh-factor (CO diffusion capacity relative to recorded alveolar volume, DL,CO/VA) reported as %-predicted. We analysed trends in outcome parameters with linear mixed models.
Results
46 male workers participated in at least two extended medical examinations between 2007 and 2017. Overall 398 measure points were available. All lung function parameters had values above the lower limit of normality at the first examination. In the multivariate model including smoking status and monthly intensity of cold exposure (≤ 16 h/month vs. > 16 h/month) FEV1%-predicted and FVC %-predicted had a statistically significant positive slope (FEV1, 0.32% 95% CI 0.16% to 0.49% p < 0.001; FVC 0.43% 95% CI 0.28% to 0.57% p < 0.001). The other lung function parameters (FEV1/FVC %-predicted, DL,CO %-predicted, DL,CO/VA %-predicted) showed no statistically significant change over time.
Conclusions
Long term intermittent occupational exposure to extreme cold temperatures (-55 °C) does not appear to cause irreversible deleterious changes in lung function in healthy workers, thus the development of obstructive or restrictive lung diseases is not expected.
... We conducted a case-crossover study of the associations between season-specific cold spells and the risk of stroke in the city of Kaunas, Lithuania, 2000-2015. The study protocol for the WHO MONICA study was approved by the Lithuanian Bioethics Committee (No. [14][15][16][17][18][19][20][21][22][23][24][25][26][27] and the study complies with the Declaration of Helsinki. STROBE guidelines were followed in the reporting. ...
... where Z denotes the Z-test; E 1 and E 2 are the effect estimates (i.e. ln (RR)) of two subgroups; SE(E 1 ) and SE(E 2 ) are corresponding Standard Errors of E 1 and E 2 [23]. ...
Background
Cold winter weather increases the risk of stroke, but the evidence is scarce on whether the risk increases during season-specific cold weather in the other seasons. The objective of our study was to test the hypothesis of an association between personal cold spells and different types of stroke in the season-specific context, and to formally assess effect modification by age and sex.
Methods
We conducted a case-crossover study of all 5396 confirmed 25–64 years old cases with stroke in the city of Kaunas, Lithuania, 2000–2015. We assigned to each case a one-week hazard period and 15 reference periods of the same calendar days of other study years. A personal cold day was defined for each case with a mean temperature below the fifth percentile of the frequency distribution of daily mean temperatures of the hazard and reference periods. Conditional logistic regression was applied to estimate odds ratios (OR) and 95% confidence intervals (95% CI) representing associations between time- and place-specific cold weather and stroke.
Results
There were positive associations between cold weather and stroke in Kaunas, with each additional cold day during the week before the stroke increases the risk by 3% (OR 1.03; 95% CI 1.00–1.07). The association was present for ischemic stroke (OR 1.05; 95% CI 1.01–1.09) but not hemorrhagic stroke (OR 0.98; 95% CI 0.91–1.06). In the summer, the risk of stroke increased by 8% (OR 1.08; 95% CI 1.00–1.16) per each additional cold day during the hazard period. Age and sex did not modify the effect.
Conclusions
Our findings show that personal cold spells increase the risk of stroke, and this pertains to ischemic stroke specifically. Most importantly, cold weather in the summer season may be a previously unrecognized determinant of stroke.
... Extreme weather events show a trend of increasing intensity, frequency, and duration. 1 According to the Global Burden of Disease Report 2019, air pollution and nonoptimal temperature rank as the fourth and eighth risk factors for mortality in China, respectively. 2 A large amount of epidemiological evidence suggests that air pollution and low temperatures are important factors contributing to increased mortality from cardiovascular and respiratory diseases, premature births, and increased prevalence of mental health disorders in humans. ...
... Therefore, there is a need for a warning system with local characteristics. According to the Q-AIC, the best definition of all-cause mortality was P2T4, the threshold of which was the same as cold spell research in China processed by Chen et al., 22,32 and the air pollution research processed by Zhang et al. 1,20,28,45 However, the combined event defined by P1T5 showed the highest cumulative relative risk, which means that an early warning should be triggered on the first exposure day when the temperature is lower than the 2.5th percentile and lasts for at least 48 h. The stricter definition showed a higher relative risk, but the protective ability was quite limited. ...
... 7,12,15,45 When exposed to cold temperature or air pollution, the airway epithelium is irritated, which causes the body to respond with coughing, bronchoconstriction, and mucosal secretion. 1,46 Cold stress and PM 2.5 experiments in adulthood of mice showed that coexposure may promote the deterioration of asthma symptoms by increasing inflammatory cytokines, ROS formation, Th2/Th1 imbalance, and suppressing the differentiation of Th17 toward Treg cells. 47,48 Further deaths from respiratory disease will occur in sensitive individuals (e.g., elderly people, etc.). ...
In this study, a total of 90 definitions were set up based on six air pollution definitions, five cold spell definitions, and three combined exposure scenarios. The relative risks (RRs) on all-cause, circulatory, and respiratory mortality were explored by a model combining a distributed linear lag model with quasi-Poisson regression. The definition in which daily PM 2.5 increases more than 75 μg/m 3 for at least 2 days and the average temperature falls below the 10th percentile for at least 2 days produced the best model fit performance in all-cause mortality. The high peaks of the health effect were generally observed around the lag days 6−9. The cumulative relative risks (CRRs) were more significant in the simultaneous-exposure scenario and higher in respiratory mortality, where the highest CRR (12.15, 3.69−40.03) was observed in definition P1T5, in which daily PM 2.5 increases more than 75 μg/m 3 , and the average temperature falls below the 2.5th percentile for at least two days. For relative risk due to interaction (RERI), we found positive additive interactions (RERI > 0) between PM 2.5 pollution and cold spell, especially in respiratory mortality. Clarifying the definition of combined events can help policymakers to capture health risks and construct more effective risk warning systems.
... The lag-response associations for lag days up to 21 days were modeled with a natural cubic spline with three df and one knot placed equally in the log scale. We considered lag days up to 21 days because previous studies have reported that cold exposure effects last for similar periods (Chen et al., 2019;Liu et al., 2021;Ma et al., 2021). Furthermore, our preliminary analyses for lag-specific associations using the distributed lag models generally supported the choice of a lag period of 21 days as well ( Fig. S2; Fig. S3). ...
Background:
Emerging evidence supports an association between heat exposure and acute kidney injury (AKI). However, there is a paucity of studies on the association between cold exposure and AKI.
Objective:
We aimed to investigate the associations of cold exposure with hospital admission and mortality due to AKI and to explore whether these associations were influenced by age and sex.
Methods:
Information on daily counts of hospital admission and mortality due to AKI in 16 regions of Korea during the cold seasons (2010-2019) was obtained from the National Health Insurance Service (a single national insurer providing universal health coverage) and Statistics Korea. Daily mean temperature and relative humidity were calculated from hourly data obtained from 94 monitoring systems operated by the Korean Meteorological Administration. Associations of low temperatures (<10th percentile of daily mean temperature) and cold spells (≥2 consecutive days with <5th percentile of daily mean temperature) up to 21 days with AKI were estimated using quasi-Poisson regression models adjusted for potential confounders (e.g., relative humidity and air pollutants) with distributed lag models and univariate meta-regression models.
Results:
Low temperatures were associated with hospital admission due to AKI [relative risk (RR) = 1.12, 95 % confidence interval (CI): 1.09, 1.16]. Cold spells were associated with hospital admission (RR = 1.87, 95 % CI: 1.46, 2.39) and mortality due to AKI (RR = 4.84, 95 % CI: 1.30, 17.98). These associations were stronger among individuals aged ≥65 years than among those aged <65 years.
Conclusion:
Our results underscore the need for the general population, particularly the elderly, physicians, and other healthcare providers to be more vigilant to cold exposure, given the risk of AKI. Government agencies need to develop specific strategies for the prevention and early detection of cold exposure-related AKI.
... Evidence of the harmful effects of cold spells on respiratory diseases has been accumulating (Chen et al., 2019;Chen et al., 2021;Liu et al., 2021b;Ma et al., 2011;Ma et al., 2013;Song et al., 2018). However, the majority of the previous studies have mainly focused on morbidity, mortality, and hospitalizations, and few studies explored the effects on length of hospital stay (LoS) and hospitalization expenses (Sun et al., 2022). ...
... In the cumulative lagged structure, we found significant and positive associations between cold spells and hospitalization for respiratory diseases. The largest cumulative RR of cold spells on total respiratory diseases in our study was consistent with the estimates reported previously such as studies conducted in Shanghai (Liu et al., 2021a;Liu et al., 2021b;Ma et al., 2011). The persistent significant lag periods of cumulative cold spell effects observed in our study were similar to the previous research which found the harmful effect of the cold spell could last 2-3 weeks (Chai et al., 2020;Chen et al., 2019). ...
... (Dai et al., 2018;Ianevski et al., 2019;Li et al., 2011). Moreover, cold exposure may suppress the immune response, and thus increase the susceptibility to respiratory infection (Liu et al., 2021b;Song et al., 2018). ...
Background:
Previous studies have revealed the relationship between cold spells and morbidity and mortality due to respiratory diseases, while the detrimental effects of cold spells on the length of hospital stay and hospitalization expenses remain largely unknown.
Methods:
We collected hospitalization data for respiratory diseases in 11 cities of Shanxi, China during 2017-2019. In each case, exposure to meteorological variables and air pollution was estimated by the bilinear interpolation approach and inverse distance weighting method, respectively, and then averaged at the city level. Cold spells were defined as the daily mean temperature below the 10th, 7.5th, or 5th percentiles for at least 2 to 5 consecutive days. We applied distributed lag non-linear models combined with generalized additive models to assess cumulative effects and harvesting effects.
Results:
There were significant associations between cold spells and hospital admissions, length of hospital stay, and hospital expenses for respiratory diseases. Compared with the non-cold spell period, the overall (lag 0-21) cumulative risk of hospitalization for total respiratory diseases was 1.232 (95 % CI: 1.090, 1.394) on cold spell days, and the increased length of hospital stay and hospitalization expenses were 112.793 (95 % CI: 10.755, 214.830) days and 127.568 (95 % CI: 40.513, 214.624) thousand Chinese yuan. The overall cumulative risks of cold spells on total respiratory diseases and pneumonia were statistically significant. We further observed harvesting effects in the associations between cold spells and hospital admission, length of hospital stay, and hospitalization expenses for respiratory diseases.
Conclusions:
Cumulative cold-spell exposure for up to three weeks is associated with hospitalization, length of hospital stay, and hospital expenses for respiratory diseases. The observed harmful effects of cold spells on respiratory diseases can be partly attributable to harvesting effects.
... Stratified analysis by sex, age, and cause of mortality were also conducted to identify sensitive diseases and vulnerable populations. Second, the attributable fractions (AFs) were estimated according to the associations between cold spells and mortality to evaluate the attributable mortality burden of cold spells (6). In addition, the stability of the model was validated by conducting sensitivity analysis (Supplementary Table S1, available in http://weekly.chinacdc.cn/). ...
What is already known about this topic?:
In recent years, climate change may lead to an increase in cold spells in the middle latitudes, and there is a positive correlation between cold spells and population mortality.
What is added by this report?:
The acute response period and the vulnerable population were identified under the optimal definition of cold spells, and the mortality burden caused by cold spells was estimated.
What are the implications for public health practice?:
This research would provide evidence on the acute mortality effects of cold spells in southern China. Therefore, vulnerable populations, especially the elderly, should take timely measures to reduce the health damage caused by cold spells, especially in the first week after cold waves.
... One more limitation of this study is that we did not analyze the importance of air pollution on stroke because air pollutants can be seen as interim variables in the pathway from different weather to stroke (Liu et al. 2021). Adjusting for the interim variables would lead to the underestimation of the real effect. ...
The aim of this study was to determine the association between the daily number of cases of ischemic stroke (IS) and hemorrhagic stroke (HS) in patients aged 25–64 years and the El Niño-Southern Oscillation (ENSO) events during 2000–2015. As an indicator of the effect of the ENSO, the monthly NIÑO 3.4 index (Equatorial Pacific Sea Surface Temperature) was used. During the 5844-day study period, 5600 cases of stroke (3170 (56.61%) in men and 2430 (43.39%) in women) were analyzed. Of these, 4354 (77.8%) cases were IS, and 1041 (18.6%) cases were HS. In 3496 (62.2%) cases, stroke occurred in the age group of 55–64 years. In the analysis, we used the following categories of the ENSO events: strong La Niña, moderate La Niña, moderate El Niño, and strong El Niño. The effect of the ENSO was examined by using the multivariate Poisson regression adjusting for weather variables. The highest risk of both strokes (BS) was observed on days of strong and moderate La Niña (rate ratio ( RR ) 1.27, 95% CI 1.13–1.42) and RR = 1.15 (1.07–1.23), respectively), while the risk for IS was the highest on days of moderate El Niño ( RR = 1.11(1.02–1.20)). A lower risk for BS was found on days of strong El Niño ( RR = 0.77(0.62–0.97)). We found that ENSO events affected the occurrence of BS and IS in all age groups, and the strongest effect was observed among females. The results of this study provide new evidence that ENSO events may affect the risk of stroke, especially the risk of IS.
