Effect Of Diurnal Temperature Range Research Articles

Effects of diurnal temperature range on diarrhea in the subtropical megacity of Dhaka, Bangladesh

IntroductionWhile numerous studies have assessed the association of diarrhea with temperature, few have addressed the relationship between within-day variation of temperature and diarrhea. Materials and methodsWe investigated the association between diurnal temperature range (DTR) and daily counts of hospitalizations for all-cause diarrhea in Dhaka, Bangladesh using time series regression analysis employing distributed lag-linear models. Defining DTRs below 10th, 5th and 1st percentiles as low, very low and extremely low DTR, and DTRs above 90th, 95th and 99th percentiles as high, very high and extremely high DTRs, we additionally analyzed the effects of extreme DTR on diarrhea hospitalization. Effects were assessed for all ages, under-5 children and by gender. ResultsAlthough we did not find any significant effects of overall DTR and large DTRs, we detected significant effects of small DTRs on diarrhea hospitalization in all subgroups. A unit rise in low, very low and extremely low DTR was associated with a 4.9 % (95 % CI: 3.6 – 6.2), 7.1 % (95 % CI: 5.4 – 8.9) and 11.8 % (95 % CI: 8.3 – 15.5) increase in all-cause diarrhea hospitalization in all ages, respectively. A unit increase in low, very low and extremely low DTR was associated with a 4.9 %, 5.1 % and 18.4 % increase in all-cause diarrhea hospitalization in children under 5 years of age, respectively. The impact of extremely low DTR varied by gender (16.2 % in females versus 10.1 % in males). The effect of extremely low DTR was most pronounced in children under 5 years of age. ConclusionLess variation in within-day temperatures is a risk factor for diarrhea hospitalization in Dhaka, Bangladesh. Further research is needed to elucidate the causal pathways and identify the preventive measures necessary to mitigate the impacts of lowering DTRs on diarrhea.

[Effect of Diurnal Temperature Range on the Number of Residents Hospitalized Due to Stroke in Lanzhou].

Objective To analyze the relationship between diurnal temperature range (DTR) and the hospitalization of stroke in Lanzhou,so as to provide a scientific basis for probing into the mechanism of temperature changes in inducing stroke and formulating comprehensive prevention and control measures for stroke by relevant departments.Methods The information of the patients hospitalized due to stroke in Lanzhou during January 2014 to December 2019 and the air pollutants (PM10,SO2,and NO2) and meteorological data in the same period were collected for statistical analysis.Spearman rank correlation analysis was performed to analyze the correlations between air pollutants and meteorological factors.The distributed lag nonlinear model was adopted to fit the relationship between DTR and the number of stroke inpatients,and three-dimensional diagrams and the correlation diagrams of DTR against stroke risk were established.The stratified analysis was performed according to gender and age (< 65 years and ≥65 years).Results From 2014 to 2019,a total of 92 812 stroke patients were hospitalized in Lanzhou,with a male-to-female ratio of 1.35:1.There was a nonlinear relationship between DTR and the number of stroke inpatients in Lanzhou,which presented a lag effect.The low DTR at 4.5 ℃ had the largest RR value of 1.25 (95%CI=1.16-1.35) for stroke inpatients at a cumulative lag of 18 d.The effect of high DTR (18.5 ℃) on the hospitalization of stroke patients peaked at a cumulative lag of 21 d,with an RR value of 1.09 (95%CI=1.01-1.18).The stratified analysis results suggested that low levels of DTR had greater effects on the hospitalization of male stroke patients and stroke patients <65 years.Conclusions Short-term exposure to different levels of DTR had an impact on the number of stroke inpatients,and low levels of DTR had a slightly greater impact on stroke inpatients than high levels of DTR.Importance should be attached to the protection of males and people aged <65 years at low levels of DTR.

The effects of diurnal temperature range on mortality and emergency department presentations in Victoria state of Australia: A time-series analysis

State of Victoria, Australia (SVA) has a wide variation of diurnal temperatures (DTR). DTR has been reported to be associated with risk of mortality and morbidity. We examined the association between exposure to DTR and risk of all-cause mortality and emergency department (ED) presentations in the SVA. We obtained data on daily counts of deaths and ED presentations, and weather data from 1 st January 2000─2019. We applied a quasi-Poisson time-series regression analysis to examine the association between daily DTR exposures and risk of mortality and ED presentations. The analyses were queried by age, sex, seasons, ED presentations triages, and departure status. Risk of mortality and ED presentation increased by 0.33% (95% CI: 0.24%–0.43%), and 0.094% (95% CI: 0.077%–0.11%) in relation to one degree increase in the daily DTR. The association between DTR and ED presentations was stronger in children (0–15 years) (0.38% [95% CI: 0.34%–0.42%]) and the elderly (75+ years) (0.34% [95% CI: 0.29%–0.39%]). Resuscitation, which was consistently accounted for the highest vulnerability to DTR variation, increased by 0.79% (95% CI: 0.60%–0.99%). This study suggests that the risk of mortality and ED presentations associates with the increase of DTR. Children, the elderly, and their caregivers need to be made aware of the health risk posed by DTR.

Impact of diurnal temperature range on rhinitis in Lanzhou, China: Accounting for COVID-19 effects

Rhinitis is a global public health issue. A distributed lag non-linear model (DLNM) was used to examine the impact of diurnal temperature range (DTR) on nonallergic rhinitis (NAR) and allergic rhinitis (AR) in Lanzhou, China. Stratified analyses by age, gender, seasons, and the COVID-19 period were conducted, alongside extreme-DTR and attributable risk analyses. Using 37,225 cases, we found:1.The nonlinear DTR-rhinitis relationship: high- and low-DTR acutely impacted AR, while primarily high DTR moderately affected NAR during full and pre-COVID-19 periods.2.COVID-19 transformed the adverse impact of low-DTR into protective effects.3.In full study period, AR showed age heterogeneity, and NAR displayed age and gender differences. In pre-COVID-19 study period, AR had age and gender variations. The age < 18 group, vulnerable to NAR and AR, requires concerns.4.Low-DTR exhibits protective effects during cold seasons, while it poses adverse effects and increased risks in warm seasons.5.Moderate high DTR contributed most to rhinitis outpatients.In conclusion, NAR and AR demonstrate distinct responses to short-term DTR exposure, which may be influenced by COVID-19 and seasonal factors. Future research is essential to assess the long-term impacts of DTR and COVID-19 effects on NAR and AR.

Temporal variation of the relationships between rice yield and climate variables since 1925.

Long-term time-series datasets of crop yield and climate variables are necessary to study the temporal variation of climate effects on crops. The aim of this study was to broadly assess assessment of the effects of climate on rice, and the associated temporal variations of the effects during the long-term period. We conducted field experiments in Taiwan from 1925 to 2019 to collect and analyze rice yield data and evaluate the impacts of changes in average temperature, diurnal temperature range (DTR), rainfall, and sunshine duration on rice yield during cool and warm cropping seasons. We then estimated the relationships between annual grain yield and the climate variables using the time series of their first difference values. We also computed the total relative and annual actual yield changes using regression coefficients for each climate variable for the intervals 1925-1944, 1945-1983, and 1996-2019 to reveal the impacts of climate change on yields and the associated temporal variations during the overall experimental period. The annual daily average temperature calculated from the trend of the regression lines increased by 0.94-1.03 °C during the 95-year period. The maximum temperature remained steady while the minimum temperature increased, leading to decreased DTR. The total annual rainfall decreased by 237-352 mm and the annual total sunshine duration decreased by 93.9-238.9 h during the experimental period. We observed that during the cool cropping season, yield response to temperature change decreased, while that to DTR and rainfall changes increased. During the warm cropping season, all the yield responses to temperature, DTR, and rainfall changes were negative throughout the experimental period. In recent years (1996-2019) the estimated annual actual rice yield changes during the cool cropping season were negatively affected by climate variables (except for sunshine duration), and slightly positively affected (except for temperature) during the warm cropping season. Compared to the effects of temperature and DTR, those of rainfall and sunshine duration on rice yield changes were weak. This study contributes to provide impacts of climate change on rice yield and associated long-term temporal variations over nearly a century.

[Effect of diurnal temperature range on the number of elderly inpatients with ischemic stroke in Hunan Province].

Objective: To study the effect of diurnal temperature range on the number of elderly inpatients with ischemic stroke in Hunan Province. Method: Demographic and disease data, meteorological data, air quality data, population, economic and health resource data of elderly inpatients with ischemic stroke were collected in 122 districts/counties of Hunan Province from January to December 2019. The relationships between the diurnal temperature range and the number of elderly inpatients with ischemic stroke were analyzed by using the distributed lag non-linear model, including the cumulative lag effect of the diurnal temperature range in different seasons, extremely high diurnal temperature range and extremely low diurnal temperature range. Results: In 2019, 152 875 person-times were admitted to the hospital for ischemic stroke in the elderly in Hunan Province. There was a non-linear relationship between the diurnal temperature range and the number of elderly patients with ischemic stroke, with different lag periods. In spring and winter, with the decrease in diurnal temperature range, the risk of admission of elderly patients with ischemic stroke increased (Ptrend<0.001, Ptrend=0.002);in summer, with the increase in diurnal temperature range, the risk of admission of elderly patients with ischemic stroke increased (Ptrend=0.024);in autumn, the change in the diurnal temperature range would not cause a change in admission risk (Ptrend=0.089). Except that the lag effect of the extremely low diurnal temperature range in autumn was not obvious, the lag effect occurred in other seasons under extremely low and extremely high diurnal temperature ranges. Conclusion: The high diurnal temperature range in summer and the low diurnal temperature range in spring and winter will increase the risk of admission of elderly patients with ischemic stroke, and the risk of admission of elderly patients with ischemic stroke will lag under the extremely low and extremely high diurnal temperature ranges in the above three seasons.

Diurnal temperature range and hospital admission due to cardiovascular and respiratory diseases in Dezful, a city with hot climate and high DTR fluctuation in Iran: an ecological time-series study.

The results of previous studies have indicated the effects of temperature changes on health status. The present study was conducted to investigate the effects of diurnal temperature range (DTR) and hospital admission on cardiovascular and respiratory diseases in Dezful, in Iran. In this ecological time-series study, data related to hospital admissions based on ICD-10, meteorological, and climatological data were gathered over a period of six years from 2014 to 2019. A distributed lag nonlinear model combined with a quasi-Poisson regression was then used to assess the impact of DTR on cardiovascular and respiratory hospital admissions. Potential confounders, including wind speed, air pollution, seasonality, time trend, weekends and holidays, days of week, and humidity were controlled. In extreme low DTRs, the cumulative effects of cardiovascular admissions significantly increased in total, and in warm and cold seasons (Lag0-21, P ≤ 0.05). In addition, in extreme high DTRs, the cumulative effects of cardiovascular significantly decreased in total (Lag0-13 and Lag0-21, P ≤ 0.05), and in warm (Lag0-21, P ≤ 0.05) and cold seasons (Lag0-21, P ≤ 0.05). Moreover, respiratory admissions significantly decreased in total (Lag0-21, P ≤ 0.05) and in warm season (Lag0-21, P ≤ 0.05).Our result indicates that extreme low DTRs could increase the risk of daily cardiovascular admissions, and extreme high DTRs may cause a protective effect on daily respiratory and cardiovascular admissions in some regions with high fluctuations in DTR.

Larger diurnal temperature range undermined later autumn leaf senescence with warming in Europe

AbstractAimClimate change regulates autumn leaf senescence date (LSD), exhibiting a strong phenological control of plant carbon uptake. Unlike the delaying effect of daily mean temperature (Tmean) on LSD, the impact of warming asymmetry in daytime and nighttime, as evidenced by variations of the diurnal temperature range (DTR), remains elusive. The objectives of this study were to investigate physiological and ecological impacts of DTR on LSD using long‐term in situ observations and to predict the future trends of LSD under warming.LocationEurope.Time period1950–2015.Major taxa studiedPlant phenology.MethodsWe used partial correlation analysis, multiple linear regression and ridge regression to explore the impacts of DTR on LSD. To quantify the importance of potential drivers of LSD, we trained random forest models and applied the SHapley Additive exPlanations method to isolate the marginal contributions of each predictor on LSD. For LSD modelling and projection, we first evaluated two temperature‐driven LSD models [i.e., cooling‐degree‐day (CDD, without DTR effect) and day–night‐temperature CDD (DNCDD, with DTR effect)], then applied them to predict future LSDs.ResultsWe found that observational increases in Tmean and DTR had contrasting effects on LSD. Increased Tmean delayed the LSD, whereas larger DTR overall had an advancing effect. Considering the DTR effect, the Tmean sensitivity of LSD was 14% lower than presently estimated (2.4 vs. 2.8 days °C−1). Warming asymmetry‐related drought stress and plant functional traits (i.e., plant isohydricity and water‐use efficiency) potentially explained the advancing effect of DTR on LSD. We found that current projections of future LSD are overestimated because the DTR effect is discounted, suggesting the need for an adequate understanding of how plant phenology responds to warming asymmetry.Main conclusionsOur findings highlight the importance of DTR in controlling LSD variations with an advancing‐dominant effect and call for the improvement of phenology modelling incorporating the DTR effect. Given that DTR showed a globally narrowing trend over the last several decades, more efforts are needed to understand the potential ecological impacts of warming asymmetry and vegetation response to climate change.

The non-linear and interactive effects of meteorological factors on the transmission of COVID-19: A panel smooth transition regression model for cities across the globe

The ongoing pandemic created by COVID-19 has co-existed with humans for some time now, thus resulting in unprecedented disease burden. Previous studies have demonstrated the non-linear and single effects of meteorological factors on viral transmission and have a question of how to exclude the influence of unrelated confounding factors on the relationship. However, the interactions involved in such relationships remain unclear under complex weather conditions. Here, we used a panel smooth transition regression (PSTR) model to investigate the non-linear interactive impact of meteorological factors on daily new cases of COVID-19 based on a panel dataset of 58 global cities observed between Jul 1, 2020 and Jan 13, 2022. This new approach offers a possibility of assessing interactive effects of meteorological factors on daily new cases and uses fixed effects to control other unrelated confounding factors in a panel of cities. Our findings revealed that an optimal temperature range (0°C–20 °C) for the spread of COVID-19. The effect of RH (relative humidity) and DTR (diurnal temperature range) on infection became less positive (coefficient: 0.0427 to −0.0142; p < 0.05) and negative (coefficient: −0.0496 to −0.0248; p < 0.05) with increasing average temperature(T). The highest risk of infection occurred when the temperature was −10 °C and RH was >80% or when the temperature was 10 °C and DTR was 1 °C. Our findings highlight useful implications for policymakers and the general public.

Impact of diurnal temperature range on hospital admissions for cerebrovascular disease among farmers in Northwest China

Diurnal temperature range (DTR) is an appropriate indicator for reflecting climate change. Many previous studies have examined the relationship between DTR and mortality. Cerebrovascular disease (CVD) have a higher mortality than other diseases, with mortality from CVD higher in rural areas than in urban areas. A distributed lag non-linear model (DLNM) was used to analyze the exposure-effect relationship between DTR and hospital admissions for CVD from 2018 to 2020 in the population living in rural areas of Tianshui, Gansu Province, China. We investigated the effects of extreme DTR in groups stratified according to gender and age. A U-shape relationship was observed between DTR and hospital admissions for CVD. Both high DTR (19 °C) and low DTR (3 °C) were significantly associated significantly with CVD hospital admissions. When the lag period was 0–21 days, the impact of high DTR (1.595 [95% CI 1.301–1.957]) was slightly more significant than that of a low DTR (1.579 [95% CI − 1.202 to 2.075]). The effect of DTR on CVD varied in different populations. Males and adults were more sensitive to DTR than females and elderly people. It is necessary to make preventive measures to protect vulnerable populations from the adverse effects of extreme DTR.

Effects of diurnal temperature range on atopic dermatitis: Findings from a northwestern Chinese city with temperate continental climate

BackgroundClimate change contributes to the increasing incidence of AD, diurnal temperature range (DTR) is a pivotal indicator for monitoring climate change, however, the effects of DTR on AD remains unknown in regions with a temperate continental climate. ObjectiveThis study aims to explore effects of DTR on AD in Lanzhou, China. MethodA Poisson generalized linear regression model combined with a distributed lag non-linear model (DLNM) was used to analyze data. ResultsThe effect of DTR on AD outpatient visits is nonlinear and presents J-shaped. For every 1 °C increase in DTR, the risk of AD outpatient visits increased by 2.6% (95% CI: 0.2%, 5.2%) at lag 21 when DTR was 17 °C. Harmful effect of extremely high DTR is significant, it is observed on lag 9 days and lasted for 12 days. The maximum effect of extremely high DTR emerged on lag 0–21 days and the relative risk was 1.470 (95% CI: 1.119, 1.932). Females and children aged 0–14 years were vulnerable to extremely high DTR. ConclusionThe present study suggests that high DTR is a risk factor for AD outpatient visits and provides a theoretical basis and practical guidelines for the prevention of AD.

A comparison of the effect of diurnal temperature range and apparent temperature on cardiovascular disease among farmers in Qingyang, Northwest China.

Climate change is increasing the incidence of extreme weather events which have a significant impact on public health. Cardiovascular diseases (CVDs) are the number one cause of death globally (40%). Apparent temperature (AT) and diurnal temperature range (DTR) have been extensively used to evaluate the effects of temperature on cardiovascular disease (CVD). However, the relevant information is quite limited from analysis and comparison of effects and differing pathogenesis of DTR and AT on CVD especially in less-developed, rural areas of China. This is the first attempt to analyze different effects between AT and DTR on CVD using distributed lag nonlinear modeling (DLNM) in rural area. Data on CVD hospital admission in Qingyang (Northwest China) in 2014-2017 originated from the New Rural Cooperative Medical System (NRCMS) of Gansu Province, and meteorological variables were provided by the Meteorological Science Data Sharing Service. Both AT and DTR had significant nonlinear and delayed impacts on hospital admissions for CVD. DTR had a stronger and more persistent effect on CVD incidence than AT. Females were more affected by high AT and low DTR than were males, while males were more vulnerable to low AT and high DTR. Temperature effects were not significantly different between people above and below 65years of age. These findings provide local public health authorities with reference concerning sensitive temperature indices for susceptible populations with a view to improve CVD preventive strategies in rural areas.

Effect of diurnal temperature range on bioleaching of sulfide ore by an artificial microbial consortium

Temperature is considered to be one of the main factors affecting bioleaching, but few studies have assessed the effects of diurnal temperature range (DTR) on the bioleaching process. This study investigates the effects of different bioleaching temperatures (30 and 40 °C) and DTR on the bioleaching of metal sulfide ores by microbial communities. The results showed that DTR had an obvious inhibitory effect on the bioleaching efficiency of the artificial microbial community, although this effect was mainly concentrated in the early and middle stages (0–18 days) of exposure, gradually decreasing until almost disappearing in the late stage (18–24 days). Extracellular polymeric substance (EPS) analysis showed that DTR did not change the composition of the EPS matrix (humic acid-like substances, polysaccharides and protein-like substances), but had a significant effect on the generative behavior of EPS, inhibiting the secretion of EPS during the early and middle stages of the bioleaching process. However, the continual increase in EPS secretion in the bioleaching system gradually reduced the adverse effects of DTR on mineral dissolution. X-ray diffraction (XRD), Fourier transform infrared (FTIR) and Scanning electron microscopy- energy dispersive spectrometry (SEM-EDS) analysis of the bioleached residue showed that DTR had no obvious effect on the mineralogical characteristics of sulfide ore. Therefore, in industrial sulfide ore bioleaching applications, in order to accelerate the artificial microbial community start-up process, temperature control measures should be increased in the bioleaching process to reduce the adverse effects of DTR on mineral dissolution.

Diurnal Temperature Ranges in Relation to Lower Limb Amputation Rate of Diabetic Foot in South Korea: A Population Based Nationwide Study.

The evidence for the association between diurnal temperature range (DTR) and diabetic foot amputations is limited. We aimed to investigate the region-specific association between DTR and the amputation rate of diabetic foot in Korean national-wide data. Daily data on DTR and the rate of diabetic foot amputations from 16 provincial capital cities in Korea were obtained (2011–2018). In this study, the latitude ranged from 33°11′ N to 38°61′ N, and we classified each region according to latitude. Region 1, which was located at a relatively high latitude, included Seoul, Incheon, Gyeonggi-do, and Gangwon-do. Region 2, which was located at a relatively low latitude, included Busan, Ulsan, Gyeonsannam-do, Gwangju, Jeollanam-do, Jeollabuk-do, and Jeju-do. The region-specific DTR effects on the amputation rate were estimated based on a quasi-Poisson generalized linear model, combined with a distributed lag non-linear model based on the self-controlled case series design. The DTR impacts were generally limited to a period of nine days, while significant effects during lag days 7–14 were only found in the cities of Seoul, Incheon, and Gyeonggi-do (10th lag day: RR [95% CI]; Seoul: 1.015, [1.001–1.029]; Incheon: 1.052 [1.006–1.101]; Gyeonggi-do: 1.018 [1.002–1.034]). In the subgroup analysis (according to the latitude), an increase of 1 °C in DTR was associated with the risk of diabetic foot in relatively high latitude regions. DTR has considerable effects on the risk of diabetic foot amputation in various provinces in Korea, and it was particularly affected by latitude. The results can inform the decisions on developing programs to protect vulnerable subpopulations from adverse impacts.

The association between diurnal temperature range and clinic visits for upper respiratory tract infection among college students in Wuhan, China.

The effects of daily mean temperature on health outcomes have been discussed in many previous studies, but few have considered the adverse impacts on upper respiratory tract infection (URTI) due to variance of temperature in one day. Diurnal temperature range (DTR) was a novel indicator calculated as maximum temperature minus minimum temperature on the same day. In this study, generalized additive model (GAM) with quasi-Poisson distribution was used to investigate the association between DTR and the number of daily outpatient visits for URTI among college students. Data about meteorological factors and air pollutants were provided by Hubei Meteorological Bureau and Wuhan Environmental Protection Bureau, respectively. Outpatient visits data were collected from the Hospital of Wuhan University from January 1, 2016, to December 31, 2018. Short-term exposure to DTR was associated with the increased risk of outpatient for URTI among all college students. Per 1 °C increased in DTR was associated with 0.73% (95%CI: 0.24, 1.21) increased in outpatient visits of all college students for URTI at lag 0 day. The greatest effect values were observed in males [1.35% (95%CI: 0.33,2.39)] at lag 0-6 days, and in females [0.86% (95%CI: 0.24, 1.49)] at lag 0-1 days. DTR had more adverse health impact in autumn and winter. Public health departments should consider the negative effect of DTR to formulate more effective prevention and control measures for protecting vulnerable people.

Effects of diurnal temperature range on cardiovascular disease hospital admissions in farmers in China's Western suburbs.

Cardiovascular disease (CVD), reported to relate with climate change, is the leading cause of global mortality and morbidity. Since the relevant information is quite limited from suburbs and countryside in developing and underdeveloped countries, there are no studies that focused on morbidity through diurnal temperature range (DTR) for these regions. This is the first study to evaluate the short-term effect of DTR on CVD hospital admission in suburban farmers, as well as to identify vulnerable subpopulations. Daily time series data of CVD hospital admissions on suburban farmers of Qingyang, China, and meteorological data from 2011 to 2015 were collected, and a distributed lag non-linear model (DLNM) combined with a quasi-Poisson generalized additive regression model (GAM) was used to examine the exposure-response relationship and delayed effect between DTR and CVD hospital admissions. Stratified analyses by age and gender were performed and extreme DTR effects were examined. Non-linear relation between DTR and CVD hospital admissions was observed, and whether DTR lower or higher than the reference (13 °C, 50th percentile) had adverse effect while lower DTR have slightly higher impact. Also, both extreme low and extreme high DTR had adverse effect. Besides, adults (age < 65) and males were more vulnerable to the effects of DTR compared with the old (age ≥ 65) and females, respectively. This study provides evidence that not only high DTR but also low DTR had adverse effects on CVD which should be paid attention to. Adults and males were more vulnerable among suburban farmers. The results are inconsistent with the studies from urban and indicate differences between urban and suburban residents. Multiple factors such as occupations, risk awareness, and lifestyles could have a significant influence on CVD morbidity, and further study is needed to explore more evidence.

Effect of daily temperature fluctuations on virus lifetime

Epidemiological studies based on statistical methods indicate inverse correlations between virus lifetime and both (i) daily mean temperature and (ii) diurnal temperature range (DTR). While thermodynamic models have been used to predict the effect of constant-temperature surroundings on virus inactivation rate, the relationship between virus lifetime and DTR has not been explained using first principles. Here, we model the inactivation of viruses based on temperature-dependent chemical kinetics with a time-varying temperature profile to account for the daily mean temperature and DTR simultaneously. The exponential Arrhenius relationship governing the rate of virus inactivation causes fluctuations above the daily mean temperature during daytime to increase the instantaneous rate of inactivation by a much greater magnitude than the corresponding decrease in inactivation rate during nighttime. This asymmetric behavior results in shorter predicted virus lifetimes when considering DTR and consequently reveals a potential physical mechanism for the inverse correlation observed between the number of cases and DTR reported in statistical epidemiological studies. In light of the ongoing COVID-19 pandemic, a case study on the effect of daily mean temperature and DTR on the lifetime of SARS-CoV-2 was performed for the five most populous cities in the United States. In Los Angeles, where mean monthly temperature fluctuations are low (DTR ≈ 7 °C), accounting for DTR decreases predicted SARS-CoV-2 lifetimes by only 10%; conversely, accounting for DTR for a similar mean temperature but larger mean monthly temperature fluctuations in Phoenix (DTR ≈ 15 °C) decreases predicted lifetimes by 50%. The modeling framework presented here provides insight into the independent effects of mean temperature and DTR on virus lifetime, and a significant impact on transmission rate is expected, especially for viruses that pose a high risk of fomite-mediated transmission.

Effect of diurnal temperature range on emergency room visits for acute upper respiratory tract infections

BackgroundAn acute upper respiratory tract infection (URI) is the most common disease worldwide, irrespective of age or sex. This study aimed to evaluate the short-term effect of diurnal temperature range (DTR) on emergency room (ER) visits for URI in Seoul, Korea, between 2009 and 2013.MethodsDaily ER visits for URI were selected from the National Emergency Department Information System, which is a nationwide daily reporting system for ER visits in Korea. URI cases were defined according to International Classification of Diseases, 10thRevision codes J00–J06. The search for DTR effects associated with URI was performed using a semi-parametric generalized additive model approach with log link.ResultsThere were 529,527 ER visits for URI during the study period, with a daily mean of 290 visits (range, 74–1942 visits). The mean daily DTR was 8.05 °C (range, 1.1–17.6 °C). The cumulative day (lag 02) effect of DTR above 6.57 °C per 1 °C increment was associated with a 1.42% (95% confidence interval [CI] 0.04–2.82) increase in total URI. Children (≤ 5 years of age) were affected by DTR above 6.57 °C per 1 °C, with 1.45% (95% CI 0.32–2.60) at lag 02, adults (19–64 years) with 2.77% (95% CI 0.39–5.20) at lag 07. When the DTR (lag02) was 6.57 °C to 11.03 °C, the relative risk was significant at 6.01% (95% CI 2.45–9.69) for every 1 °C increase in youth subjects aged for 6 to 18 years.ConclusionsDTR was associated with a higher risk for ER visits for URI. In addition, the results suggested that the lag effects and relative risks of DTR on URI were quite different according to age.

The effect and prediction of diurnal temperature range in high altitude area on outpatient and emergency room admissions for cardiovascular diseases.

Diurnal temperature range (DTR) is a meteorological indicator closely associated with global climate change. Thus, we aim to explore the effects of DTR on the outpatient and emergency room (O&ER) admissions for cardiovascular diseases (CVDs), and related predictive research. The O&ER admissions data for CVDs from three general hospitals in Jinchang of Gansu Province were collected from 2013 to 2016. A generalized additive model (GAM) with Poisson regression was employed to analyze the effect of DTR on the O&ER admissions for all cardiovascular diseases, hypertension, ischemic heart disease (IHD) and stoke. GAM was also used to preform predictive research of the effect of DTR on the O&ER admissions for CVDs. There were similar positive linear relationships between DTR and the O&ER visits with the four cardiovascular diseases. And the cumulative lag effects were higher than thesingle lag effects. A 1°C increase in DTR corresponded to a 1.30% (0.99-1.62%) increase in O&ER admissions for all cardiovascular diseases. Males and elderly were more sensitivity to DTR. The estimates in non-heating season were higher than in heating season. The trial prediction accuracy rate of CVDs based on DTR was between 59.32 and 74.40%. DTR has significantly positive association with O&ER admissions for CVDs, which can be used as a prediction index of the admissions of O&ER with CVDs.

Assessing the effects of non-optimal temperature on risk of gestational diabetes mellitus in a cohort of pregnant women in Guangzhou, China

Previous observational studies have shown that exposure to ambient temperature and air pollution were associated with the incidence of gestational diabetes mellitus (GDM). However, the susceptible time window of non-optimal temperature on GDM is still unknown, and the interaction with air pollution has not been examined. We conducted a prospective cohort study in Guangzhou, China to investigate the windows of susceptibility of temperature extremes and variability on the risk of GDM and to explore any interaction effect with air pollution. Daily maximum (Tmax), minimum temperature (Tmin) and diurnal temperature range (DTR) were obtained from Guangdong Meteorological Service. Distributed lag non-linear models with a logistic regression were applied to assess the effect of temperature extremes and DTR in different weeks of gestation on GDM. To examine the interaction effect, relative excess risk due to interaction index, attributable proportion and synergy index were calculated. There were 5,165 pregnant women enrolled, of which 604 were diagnosed with GDM (11.7%). Compared with a reference temperature (50th percentile of Tmax), we found that extreme high temperature (99th percentile of Tmax) exposure during 21st and 22nd gestational weeks was associated with an increased risk of GDM. Extreme low temperature (1st percentile of Tmax) exposure during 14th to 17th weeks increased the risk of GDM. We observed that per 1 °C increment of DTR during 21st to 24th weeks was associated with an elevated GDM risk. No interaction effect of temperature extremes or variability with air pollution on GDM were observed. Our results suggested that non-optimal temperature is an independent risk factor of GDM. The time window of susceptibility for extreme temperatures and DTR exposure on the risk of GDM generally occurred in second trimester of pregnancy. In the context of climate change, our study has important implications for reproductive health and justifies more research in different climate zones.