The association between weather conditions and stroke admissions in Turkey

Forecasting extremely high ischemic stroke incidence using meteorological time serie

MOTIVATION

The association between weather conditions and stroke incidence has been a subject of interest for several years, yet the findings from various studies remain inconsistent. Additionally, predictive modelling in this context has been infrequent. This study explores the relationship of extremely high ischaemic stroke incidence and meteorological factors within the Slovak population. Furthermore, it aims to construct forecasting models of extremely high number of strokes.

METHODS

Over a five-year period, a total of 52,036 cases of ischemic stroke were documented. Days exhibiting a notable surge in ischemic stroke occurrences (surpassing the 90th percentile of historical records) were identified as extreme cases. These cases were then scrutinized alongside daily meteorological parameters spanning from 2015 to 2019. To create forecasts for the occurrence of these extreme cases one day in advance, three distinct methods were employed: Logistic regression, Random Forest for Time Series, and Croston's method.

RESULTS

For each of the analyzed stroke centers, the cross-correlations between instances of extremely high stroke numbers and meteorological factors yielded negligible results. Predictive performance achieved by forecasts generated through multivariate logistic regression and Random Forest for time series analysis, which incorporated meteorological data, was on par with that of Croston's method. Notably, Croston's method relies solely on the stroke time series data. All three forecasting methods exhibited limited predictive accuracy.

CONCLUSIONS

The task of predicting days characterized by an exceptionally high number of strokes proved to be challenging across all three explored methods. The inclusion of meteorological parameters did not yield substantive improvements in forecasting accuracy.

Short-Term Effect of Ambient Temperature in Acute Ischemic Stroke with Endovascular Treatment Due to Large Vessel Occlusion

Purpose

Acute ischemic stroke (AIS) stands as the primary cause of mortality and extended disability globally. While prior studies have examined the connection between stroke and local weather, they have produced conflicting results. Our goal was to examine the correlation between temperature and functional prognosis in patients with large vessel occlusion (LVO) undergoing endovascular therapy (EVT).

Patients and methods

This study included a total of 1809 patients. Temperatures from stroke onset to groin puncture were categorized into Cold (10th percentile of temperature), Cool (10th-50th percentile of temperature), Warm (50th-90th percentile of temperature), and Hot (90th percentile of temperature) groups. The primary efficacy result was the modified Rankin Scale (mRS) score at 90 days. Safety outcomes included mortality, symptomatic intracranial hemorrhage (sICH) and complications after cerebral infarction.

Results

The primary efficacy results demonstrated a statistical enhancement in functional outcomes at 90 days for patients in the Warm group compared to the Cold group (adjusted common odds ratio [OR]: 1.386; 95% confidence interval [CI]: 1.024-1.878, P=0.035). Secondary efficacy results showed that temperature was associated with a higher rate of 90-day functional independence (adjusted OR: 1.016; 95% CI: 1.004-1.029; P=0.009), which was higher in the Warm group compared with patients in the Cold group (adjusted OR: 1.646; 95% CI: 1.107-2.448, P=0.014). There were no significant differences between groups in terms of sICH, 90-day mortality, and post-infarction complications.

Conclusion

Compared with Cold temperature, Warm temperature is associated with better functional outcomes and reduced mortality risk without increasing the risk of sICH.

Impact of desert dust storms, PM10 levels and daily temperature on mortality and emergency department visits due to stroke

Objective

It is known that the inhalation of air pollutants adversely affects human health. These air pollutants originated from natural sources such as desert storms or human activities including traffic, power generating, domestic heating, etc. This study aimed to investigate the impacts of desert dust storms, particulate matter ≤10 μm (PM10) and daily maximum temperature (MT) on mortality and emergency department (ED) visits due to stroke in the city of Gaziantep, Southeast Turkey.

Method

The data on mortality and ED visits due to stroke were retrospectively recruited from January 1, 2009, to March 31, 2014, in Gaziantep City Centre.

Results

PM10 levels did not affect ED visits or mortality due to stroke; however, MT increased both ED visits [adjusted odds ratio (OR) = 1.002, 95% confidence interval (CI) = 1.001-1.003] and mortality (OR = 1.006, 95% CI = 0.997-1.014) due to stroke in women. The presence of desert storms increased ED visits due to stroke in the total population (OR = 1.219, 95% CI = 1.199-1.240), and all subgroups. It was observed that desert dust storms did not have an increasing effect on mortality.

Conclusion

Our findings suggest that MT and desert dust storms can induce morbidity and mortality due to stroke.

Climate and human health: a review of publication trends in the International Journal of Biometeorology

The climate-health nexus is well documented in the field of biometeorology. Since its inception, Biometeorology has in many ways become the umbrella under which much of this collaborative research has been conducted. Whilst a range of review papers have considered the development of biometeorological research and its coverage in this journal, and a few have reviewed the literature on specific diseases, none have focused on the sub-field of climate and health as a whole. Since its first issue in 1957, the International Journal of Biometeorology has published a total of 2183 papers that broadly consider human health and its relationship with climate. In this review, we identify a total of 180 (8.3%, n = 2183) of these papers that specifically focus on the intersection between meteorological variables and specific, named diagnosable diseases, and explore the publication trends thereof. The number of publications on climate and health in the journal increases considerably since 2011. The largest number of publications on the topic was in 2017 (18) followed by 2021 (17). Of the 180 studies conducted, respiratory diseases accounted for 37.2% of the publications, cardiovascular disease 17%, and cerebrovascular disease 11.1%. The literature on climate and health in the journal is dominated by studies from the global North, with a particular focus on Asia and Europe. Only 2.2% and 8.3% of these studies explore empirical evidence from the African continent and South America respectively. These findings highlight the importance of continued research on climate and human health, especially in low- and lower-middle-income countries, the populations of which are more vulnerable to climate-sensitive illnesses.

Effect of ambient temperature and other environmental factors on stroke emergency department visits in Beijing: A distributed lag non-linear model

Background

Most studies have focused on the relationship between ambient temperature and stroke mortality, but studies on the relationship between ambient temperature and stroke occurrence are still limited and inconsistent.

Objective

This study aimed to analyze the effect of ambient temperature and other environmental factors on emergency stroke visits in Beijing.

Methods

Our study utilized stroke visit data from the Beijing Red Cross Emergency Medical Center during 2017-2018, and applied a generalized additive model (GAM) as well as a distributed lag non-linear model (DLNM), respectively, regarding the direct, lagged, and cumulative effects of ambient temperature alone and with correction for other environmental factors on stroke occurrence.

Results

With a total of 26,984 emergency stroke patients in 2017-2018, both cold and hot effects were observed and weakened after correction for other environmental factors. Compared to the reference temperature, in the multi-factor model, extreme cold (-10°C) reached a maximum relative risk (RR) of 1.20 [95% Confidence Interval (CI): 1.09, 1.32] at lag 14 days, and extreme hot (30°C) had a maximum RR of 1.07 (95% CI: 1.04, 1.11) at lag 6 days. The cumulative effect of extreme cold reached a maximum of 2.02 (95% CI: 1.11, 3.67) at lag 0-14 days, whereas the cumulative effect of extreme hot temperature is greatest at lag 0-10 days, but no statistically significant effect was found. In addition, ischemic stroke patients, the elderly, and males were more susceptible to the effects of cold temperature.

Conclusions

There is a non-linear relationship between ambient temperature and stroke occurrence, with cold temperature having a greater and longer-lasting impact than hot temperature.

Relationship between diurnal temperature range and emergency ambulance dispatches due to stroke in Guangzhou, China

BACKGROUND

The evidence between diurnal temperature range (DTR) and stroke remains controversial and sparse. We aimed to assess the relationship between DTR and emergency ambulance dispatches (EADs) due to stroke, and to explore whether there were effect modifications to the relationship.

METHODS

A Quasi-Poisson generalized linear regression combined with a distributed lag non-linear model was used to examine the relationship between DTR and EADs for stroke between January 1st 2011 and June 30th 2018 in Guangzhou, China. We estimated the effects of the low DTR and high DTR (defined as DTR below and above 10 °C respectively) on EADs. The effects of minimum, maximum, 5th, 25th, 50th, 75th, and 95th percentiles of DTR compared with the DTR of 10 °C were also analyzed.

RESULTS

A total of 20,275 EADs for stroke were included for analyses, among which 17,556 EADs were used in the model further adjusted for age and sex. A quasi-U-shaped relationship between DTR and EADs over lag0-2 days was observed. For the low DTR, per 1 °C decrease in DTR was significantly associated with an increase of 2.64% (RR = 1.03, 95% CI: 1.01-1.04) for EADs, while per 1 °C increase for the high DTR was non-significantly related with an increased risk of EADs (RR = 1.01, 95% CI: 0.90-1.13). Significant effects of the 5th and 25th percentiles of DTR on EADs were found when compared with the DTR of 10 °C. No significant effect modifications by age, sex or season were found to the association between DTR and EADs.

CONCLUSIONS

We found a quasi-U-shaped relationship between DTR and EADs due to stroke in this study, while age, sex or season did not significantly modify the association between DTR and EADs. More high-quality evidence is needed to further explore and validate the relationship between DTR and stroke.

The Influence of Selected Meteorological Factors on the Prevalence and Course of Stroke

Background: The objective of this study was to evaluate the impact of weather factors on stroke parameters. Methods: This retrospective study analyzed the records of stroke patients concerning the influence of meteorological conditions and moon phases on stroke parameters. Results: The study group consisted of 402 patients aged between 20 and 102; women constituted 49.8% of the subjects. Ischaemic stroke was diagnosed in 90.5% of patients and hemorrhagic stroke was diagnosed in 9.5% of patients. The highest number of hospitalizations due to stroke was observed in January (48 events); the lowest number was observed in July (23 events). There was no statistically significant correlation between the meteorological parameters on the day of onset and the preceding day of stroke and the neurological status (NIHSS) of patients. Mean air temperature on the day of stroke and the day preceding stroke was significantly lower in the group of patients discharged with a very good functional status (≤2 points in modified Rankin scale (mRS)) compared to the patients with a bad functional status (>2 points in mRS); respectively: 7.98 ± 8.01 vs. 9.63 ± 7.78; p = 0.041 and 8.13 ± 7.72 vs. 9.70 ± 7.50; p = 0.048). Humidity above 75% on the day of stroke was found to be a factor for excellent functional state (RR 1.61; p = 0.016). The total anterior circulation infarcts (in comparison with stroke in the other localization) were more frequent (70%) during a third quarter moon (p = 0.011). The following parameters had a significant influence on the number of stroke cases in relation to autumn having the lowest number of onsets: mean temperature (OR 1.019 95% CI 1.014–1.024, p < 0.000), humidity (OR 1.028, CI 1.023–1.034, p < 0.0001), wind speed (OR 0.923, 95% CI 0.909–0.937, p < 0.0001), insolation (OR 0.885, 95% CI 0.869–0.902, p < 0.0001), precipitation (OR 0.914, 95% CI 0.884–0.946, p < 0.0001). Conclusion: Air humidity and air temperature on the day of stroke onset as well as air temperature on the day preceding stroke are important for the functional status of patients in the acute disease period. A combination of the following meteorological parameters: lowered mean temperature and low sunshine, high humidity and high wind speed all increase the risk of stroke during the winter period. High humidity combined with high precipitation, low wind speed and low sunshine in the autumn period are associated with the lowest stroke incidence risk. A possible relationship between phases of the moon and the incidence requires further investigation.

Global warming and neurological practice: systematic review

Background

Climate change, including global warming, will cause poorer global health and rising numbers of environmental refugees. As neurological disorders account for a major share of morbidity and mortality worldwide, global warming is also destined to alter neurological practice; however, to what extent and by which mechanisms is unknown. We aimed to collect information about the effects of ambient temperatures and human migration on the epidemiology and clinical manifestations of neurological disorders.

Methods

We searched PubMed and Scopus from 01/2000 to 12/2020 for human studies addressing the influence of ambient temperatures and human migration on Alzheimer’s and non-Alzheimer’s dementia, epilepsy, headache/migraine, multiple sclerosis, Parkinson’s disease, stroke, and tick-borne encephalitis (a model disease for neuroinfections). The protocol was pre-registered with PROSPERO (2020 CRD42020147543).

Results

Ninety-three studies met inclusion criteria, 84 of which reported on ambient temperatures and nine on migration. Overall, most temperature studies suggested a relationship between increasing temperatures and higher mortality and/or morbidity, whereas results were more ambiguous for migration studies. However, we were unable to identify a single adequately designed study addressing how global warming and human migration will change neurological practice. Still, extracted data indicated multiple ways by which these aspects might alter neurological morbidity and mortality soon.

Conclusion

Significant heterogeneity exists across studies with respect to methodology, outcome measures, confounders and study design, including lack of data from low-income countries, but the evidence so far suggests that climate change will affect the practice of all major neurological disorders in the near future. Adequately designed studies to address this issue are urgently needed, requiring concerted efforts from the entire neurological community.

Weather conditions associated with subarachnoid hemorrhage: a multicenter case-crossover study

BACKGROUND

Most spontaneous subarachnoid hemorrhages (SAH) occur unexpectedly and independently of classical risk factors. In the light of increasing climate variability and change, we investigated weather and rapid weather changes as possible short-term risk factors for SAH.

METHODS

Seven hundred ninety one patients admitted to three major hospitals in Germany for non-traumatic SAH with a determinable onset of SAH symptoms were included in this hospital-based, case-crossover study. The effects of atmospheric pressure, relative air humidity, and ambient temperature and their 24 h changes on the onset of SAH under temperate climate conditions were estimated.

RESULTS

There was no association between the risk of SAH and 24 h weather changes, mean daily temperature or mean relative air humidity in the overall population. For every 11.5 hPa higher mean daily atmospheric pressure, the risk of SAH increased by 15% (OR 1.15, 95% confidence interval (CI) 1.01-1.30) in the entire study population with a lag time of three days.

CONCLUSION

Our results suggest no relevant association between 24 h-weather changes or absolute values of ambient temperature and relative humidity and the risk of SAH. The medical significance of the statistically weak increase in SAH risk three days after exposure to high atmospheric pressure is unclear. However, as the occurrence of stable high-pressure systems will increase with global warming and potentially affect SAH risk, we call for confirming studies in different geographical regions to verify our observations.

A time series analysis of the relationship between ambient temperature and ischaemic stroke in the Ljubljana area: immediate, delayed and cumulative effects

BACKGROUND

Stroke is a major health problem around the world. Several studies have examine the influence of ambient temperature on incidence of stoke, but they reported different results for different types of stroke and different geographical regions. Hence, effect of ambient temperature is still much of interest, when focusing on ischemic stroke (IS) in regions that have not been examined yet. The aim of our study is to analyse association between IS incidences and short, delayed and cumulative effect of average daily ambient temperature, humidity and pressure in central Europe. To the best of our knowledge, this is the first IS study conducted between 45° and 50° latitude where large part of Central European population resides.

METHODS

We linked daily hospitals' admission data for whole population and separately for two specific age groups with ambient temperature data. We considered patients coming from Ljubljana basin and its immediate surrounding. Data were gathered daily from January 2012 to December 2017. To measure the effect of average ambient temperature, humidity and pressure we used generalized linear model with a log-link-function and a Poisson distribution.

RESULTS

The results of our study show a statistically significant immediate, delayed and cumulative effects of ambient temperatures on IS incidence for the whole population and the population older than 65 years. Specifically, 1 °C reduction in ambient temperature on a given day (Lag 0) increases the IS risk for approximately 5‰ (all population) or 6‰ (population older than 65 years). Similar effects were found for lags from 1 to 6. Analysis of time windows from 0 to 1 days up to 0-28 days also show statistically significant cumulative effect for the same two age groups. IS incidence was not found to be significantly related to pressure or humidity in any group.

CONCLUSION

The findings of this study may help healthcare authorities in central Europe improve existing stroke prevention measures and raise public awareness.

The effect of meteorological variables on suicide

We aimed to reveal the relationship between the meteorological variables and suicide rates (completed suicides and suicide attempts) independently of the seasonal cycle and holiday effects. This is an observational retrospective study. We collected the data on age, gender, and suicide method of all suicide cases transferred to hospitals from the scene by emergency medical services as well as those cases in which the victim died on the scene between January 1, 2017 and June 30, 2019. We also collected data on maximum, minimum, and average temperatures (°C), average humidity (%), and average actual pressure (hPa) measured daily in Ankara. The total number of cases due to suicide between the given dates was 6777. The suicide method in 60.1% of the cases was drug poisoning, which was the most common suicide method. Investigating the effect of meteorological variables on suicide cases (suicide attempts and completed suicides), the present study found that after smoothing the effect of the day of the week and seasonality, an increase in the minimum temperature on the day of the application by 1 unit (1°C degree) leads to an increase in the number of suicides by 0.01 point (0.01 ± 0.005, p = 0.046). There was no significant change in the variables other than the minimum temperature. We believe that the results of the present study will contribute to growing body literature about the epidemiology of suicide. We also believe that there is a need for large-scale studies that include individual data to reveal causality.

Potential Impacts of Meteorological Variables on Acute Ischemic Stroke Onset

Purpose

The effects of meteorological parameters on stroke occurrence remain debated. The aim of the study was to assess the association between meteorological parameters and ischemic stroke onset in cold seasons in Tianjin.

Patients and Methods

Patients with acute ischemic stroke (946) were identified by standard sampling from one stroke unit in the Second Hospital of Tianjin Medical University, Tianjin, China, from 10/1/2014 to 4/30/2019. Generalized linear Poisson regression models were used to explore the effect of meteorological parameters (air temperature, barometric pressure, and relative humidity) on daily ischemic stroke onset after adjusting for air pollutants, day of week, and public holiday.

Results

The results showed that ischemic stroke onset was positively associated with the diurnal variation of temperature (β coefficient: 0.020, 95% CI [0.001, 0.038] p<0.05). Significant positive correlation between ischemic stroke onset and barometric pressure (mean, minimum) was found (β coefficient: 0.010, 95% CI [0.001,0.019] p<0.05; 0.010, 95% CI [0.001,0.019] p<0.05). The subgroup analysis considering age and gender difference showed that the older and the female were more vulnerable to weather conditions.

Conclusion

Our study demonstrated that there was a measurable effect of weather parameters on daily ischemic stroke onset in colder seasons, suggesting that meteorological variables may, at least in part, play as risk factors for ischemic stroke onset, especially for the aging and female population.

Deciphering the stroke-built environment nexus in transitional cities: Conceptual framework, empirical evidence, and implications for proactive planning intervention

Adverse lifestyle-associated health outcomes, and stroke in particular, have been aggravated in transitional countries under high-speed urbanisation. Against this backdrop, deciphering the nexus between built environments (BEs) and lifestyle-associated health outcomes is of importance for crafting proactive interventions. The existing literature on this topic, however, fails to sufficiently capture the multiplicity of health-related BEs and, in turn, the complexity of such a nexus, largely challenging the applicability of established frameworks and the reliability of relevant findings. Looking at the case of stroke in Wuhan, China, this research aims to flesh out the understanding of the nexus between multidimensional BEs and lifestyle-associated health outcomes in transitional cities, with regards to conceptual framework and empirical evidence. To this end, we clarified stroke-related BE elements and integrated them into one conceptual framework. We then visualised stroke risk and examined its BE determinants using the Bayesian conditional autoregressive model. The visualisation results showed that stroke risks exhibited significant clustering in the high-density urban core. The statistical analysis found that, after the data were controlled for sociodemographic characteristics, net population density and building density were positively associated with stroke risk. In contrast, an abundance of public parks and institutional land use and access to medical care facilities have presented negative correlations with stroke risk, regardless of urban density. Our research reveals that compact urban developments might not be a silver bullet for health promotion in transitional cities, calling for an urgent need to scrutinise their applicability. To offset the adverse effects of increasingly dense urban environments, more efforts should also be made to provide better access to the identified salubrious resources. Furthermore, we argue that the establishment of comprehensive conceptual frameworks that connect BEs and lifestyle-associated health outcomes deserves to be highlighted in further research, planning intervention schemes, and health impact assessment projects.

Differences of hemorrhagic and ischemic strokes in age spectra and responses to climatic thermal conditions

The risks of emergency room (ER) visits for cerebral infarction (CI) and intracerebral hemorrhage (ICH) is found to differ in different age groups under different climatic thermal environments. Based on CI and ICH related ER-visit records from three major hospitals in Beijing, China, from 2008 to 2012, the advanced Universal Thermal Climate Index (UTCI), was adopted in this study to assess the climatic thermal environment. Particularly, daily mean UTCI was used as a predictor for the risk of ER visits for CI and ICH. A generalized quasi-Poisson additive model combined with a distributed lag non-linear model was performed to quantify their association. The results indicated that (i) the highest growth rate of ER visits for ICH occurred in age 38 to 48, whereas an increasing ER admissions for CI maintained at age 38 to 78. (ii) The frequency distribution of UTCI in Beijing peaked at -8 and 30 °C, corresponding to moderate cold stress and moderate heat stress, respectively. (iii) Correlation analysis indicated that ICH morbidity was negatively correlated with UTCI, whereas occurrence of CI showed no significant association with UTCI. (iv) The estimated relative risk of ER visits corresponding to 1 °C change in UTCI, which was then stratified by age and gender, indicated that all sub-groups of ICH patients responded similarly to thermal stress. Namely, there is an immediate ICH risk (UTCI = -13 °C, RR = 1.35, 95% CIs: 1.11-1.63) from cold stress on the onset day, but non-significant impact from heat stress. As for CI occurrences, no effect from cold stress was identified, except for only those aged 45 to 65 were threatened by heat stress (UTCI = 38 °C, RR = 1.64, 95% CIs: 1.10-2.44) on lag 0-2 d.

Stroke: Temporal Trends and Association with Atmospheric Variables and Air Pollutants in Northern Spain

Stroke, the second cause of death and the most frequent cause of severe disability among adults in developed countries, is related to a large variety of risk factors. This paper assesses the temporal patterns in stroke episodes in a city in Northern Spain during a 12-year period and analyzes the possible effects that atmospheric pollutants and meteorological variables may have on stroke on a daily scale. Our results show that there is an increase in stroke admissions (r = 0.818, p = 0.001) especially in patients over 85 years old. On a weekly scale, the number of hospital admissions due to stroke remains stable from Monday to Friday, whereas it abruptly decreases during the weekends, reaching its minimum values on Sunday (p < 0.005); however, mortality in patients admitted to the hospital is higher on Sundays than on other days of the week. Finally, a statistically significant positive correlation between the number of stroke hospital admissions and NO₂ levels (p = 0.012) and an inverse correlation with relative humidity (p = 0.032) were found. The analysis of the relationship between ischemic strokes and atmospheric circulation shows a higher frequency of the former in Santander with enhanced negative air pressure anomalies over western Spain; the fact that under these conditions the region studied registers very low values of relative humidity is in line with the aforementioned inverse correlation, which has not been described elsewhere in the literature. This study could be a first step for implementing stroke alert protocols depending on air pollution levels and circulation patterns forecasts.

Relationship of Meteorological and Air Pollution Parameters with Pneumonia in Elderly Patients

Background and Purpose

In this study, we aimed to evaluate the relationship between pneumonia and meteorological parameters (temperature, humidity, precipitation, airborne particles, sulfur dioxide (SO₂), carbon monoxide (CO), nitrogen dioxide (NO₂), nitrite oxide (NO), and nitric oxide (NOX)) in patients with the diagnosis of pneumonia in the emergency department.

Methods

Our study was performed retrospectively with patients over 65 years of age who were diagnosed with pneumonia. The meteorological variables in the days of diagnosing pneumonia were compared with the meteorological variables in the days without diagnosis of pneumonia. The sociodemographic characteristics, complete blood count of the patients, and meteorological parameters (temperature, humidity, precipitation, airborne particles, SO2, CO, NO2, NO, and NOX) were investigated.

Results

When the temperature was high and low, the number of days consulted due to pneumonia was related to low air temperature (p < 0.05). During the periods when PM 10, NO, NO2, NOX, and CO levels were high, the number of days referred for pneumonia was increased (p < 0.05).

Conclusion

As a result, climatic (temperature, humidity, pressure levels, rain, etc.) and environmental factors (airborne particles, CO, NO, and NOX) were found to be effective in the number of patients admitted to the hospital due to pneumonia.

The cold effect of ambient temperature on ischemic and hemorrhagic stroke hospital admissions: A large database study in Beijing, China between years 2013 and 2014-Utilizing a distributed lag non-linear analysis

The effects of ambient temperature on stroke death in China have been well addressed. However, few studies are focused on the attributable burden for the incident of different types of stroke due to ambient temperature, especially in Beijing, China. We purpose to assess the influence of ambient temperature on hospital stroke admissions in Beijing, China. Data on daily temperature, air pollution, and relative humidity measurements and stroke admissions in Beijing were obtained between 2013 and 2014. Distributed lag non-linear model was employed to determine the association between daily ambient temperature and stroke admissions. Relative risk (RR) with 95% confidence interval (CI) and Attribution fraction (AF) with 95% CI were calculated based on stroke subtype, gender and age group. A total number of 147, 624 stroke admitted cases (including hemorrhagic and ischemic types of stroke) were documented. A non-linear acute effect of cold temperature on ischemic and hemorrhagic stroke hospital admissions was evaluated. Compared with the 25th percentile of temperature (1.2 °C), the cumulative RR of extreme cold temperature (first percentile of temperature, -9.6 °C) was 1.51 (95% CI: 1.08-2.10) over lag 0-14 days for ischemic type and 1.28 (95% CI: 1.03-1.59) for hemorrhagic stroke over lag 0-3 days. Overall, 1.57% (95% CI: 0.06%-2.88%) of ischemic stroke and 1.90% (95% CI: 0.40%-3.41%) of hemorrhagic stroke was attributed to the extreme cold temperature over lag 0-7 days and lag 0-3 days, respectively. The cold temperature's impact on stroke admissions was found to be more obvious in male gender and the youth compared to female gender and the elderly. Exposure to extreme cold temperature is associated with increasing both ischemic and hemorrhagic stroke admissions in Beijing, China.

The Effects of Various Weather Conditions as a Potential Ischemic Stroke Trigger in Dogs

Stroke is the fifth leading cause of death in the United States, and is the leading cause of serious, long-term disability worldwide. There are at least 795,000 new or recurrent strokes each year, and approximately 85% of all stroke occurrences are ischemic. Unfortunately, companion animals are also at risk for ischemic stroke. Although the exact incidence of ischemic stroke in companion animals is unknown, some studies, and the veterinary information network (VIN), report that approximately 3% of neurological case referrals are due to a stroke. There is a long list of predisposing factors associated with the risk of ischemic stroke in both humans and canines; however, these factors do not explain why a stroke happens at a particular time on a particular day. Our understanding of these potential stroke “triggers” is limited, and the effect of transient environmental exposures may be one such “trigger”. The present study investigated the extent to which the natural occurrence of canine ischemic stroke was related to the weather conditions in the time-period immediately preceding the onset of stroke. The results of the present study demonstrated that the change in weather conditions could be a potential stroke trigger, with the strokes evaluated occurring after periods of rapid, large fluctuations in weather conditions. There are currently no epidemiological data on the seasonal variability of ischemic stroke in dogs, and determining whether canine stroke parallels human stroke would further validate the use of companion dogs as an appropriate naturally occurring model.

Relationship between weather conditions and admissions for ischemic stroke and subarachnoid hemorrhage

AIM

To assess impacts of different weather conditions on hospitalizations of patients with ischemic strokes and subarachnoid hemorrhages (SAH) in South Florida.

METHODS

Diagnostic data of patients with spontaneous SAH and strokes were recorded between June 2010 and July 2013. Daily synchronous forecast charts were collected from the National Weather Service and the whole data were matched prospectively. The incidence rate ratio (IRR) was calculated.

RESULTS

Increased incidence rate of ischemic stroke was consistent with the daily lowest and highest air pressure (IRR 1.03, P=0.128 and IRR 0.98, P=0.380, respectively), highest air temperature (IRR 0.99, P=0.375), and presence of hurricanes or storms (IRR 0.65, P=0.054). Increased incidence of SAH cases was consistent with daily lowest and highest air pressure (IRR 0.87, P<0.001 and IRR 1.08, P=0.019, respectively) and highest air temperature (IRR 0.98, P<0.001). Presence of hurricanes and/or tropical storms did not influence the frequency of SAH. We found no relationship between the presence of fronts and the admissions for ischemic stroke or SAH.

CONCLUSION

Higher number of ischemic stroke and SAH cases can be expected with the daily lowest and highest air pressure, highest air temperature. Presence of hurricanes or tropical storms increased the risk of ischemic stroke but not the SAH. These findings can help to develop preventive health plans for cerebrovascular diseases.

Revealing the association between cerebrovascular accidents and ambient temperature: a meta-analysis

The association between cerebrovascular accidents (CVA) and weather has been described across several studies showing multiple conflicting results. In this paper, we aim to conduct a meta-analysis to further clarify this association, as well as to find the potential sources of heterogeneity. PubMed, EMBASE, and Google Scholar were searched from inception through 2015, for articles analyzing the correlation between the incidence of CVA and temperature. A pooled effect size (ES) was estimated using random effects model and expressed as absolute values. Subgroup analyses by type of CVA were also performed. Heterogeneity and influence of covariates-including geographic latitude of the study site, male percentage, average temperature, and time interval-were assessed by meta-regression analysis. Twenty-six articles underwent full data extraction and scoring. A total of 19,736 subjects with CVA from 12 different countries were included and grouped as ischemic strokes (IS; n = 14,199), intracerebral hemorrhages (ICH; n = 3798), and subarachnoid hemorrhages (SAH; n = 1739). Lower ambient temperature was significantly associated with increase in incidence of overall CVA when using unadjusted (pooled ES = 0.23, P < 0.001) and adjusted data (pooled ES = 0.03, P = 0.003). Subgroup analyses showed that lower temperature has higher impact on the incidence of ICH (pooled ES = 0.34, P < 0.001), than that of IS (pooled ES = 0.22, P < 0.001) and SAH (pooled ES = 0.11, P = 0.012). In meta-regression analysis, the geographic latitude of the study site was the most influencing factor on this association (Z-score = 8.68). Synthesis of the existing data provides evidence supporting that a lower ambient temperature increases the incidence of CVA. Further population-based studies conducted at negative latitudes are needed to clarify the influence of this factor.

Relationship of meteorological factors and acute stroke events in Kaunas (Lithuania) in 2000-2010

Some researchers have hypothesised that meteorological factors may have an impact on acute cerebrovascular diseases. The aim of this study was to determine an impact of some meteorological factors on occurrence of acute cerebrovascular events in the middle-aged Kaunas population. Kaunas stroke register data were used. Data on meteorological factors for the time period from 2000 to 2010 were obtained from the Lithuanian Hydrometeorological Service Kaunas Meteorological Station. We analysed 4038 cases with stroke. Ischemic strokes composed 80.4% and haemorrhagic strokes-19.6%. According to Poisson regression analysis, significant negative correlation between ischemic, haemorrhagic and all types of stroke and ambient air temperature was found (β coefficient - 0.007, -0.016, -0.009, p < 0.001, respectively). Results of ARIMA showed that ambient temperature of the day of stroke onset was associated with the occurrence of ischemic, haemorrhagic and all types of stroke: when temperature was lower, the risk of stroke was higher (-0.006, -0.003, -0.009, p < 0.001, respectively). Low temperature on the event day and 1 and 2 days before the event was associated with higher incidence of haemorrhagic stroke in women. Low ambient temperature on the event day increased incidence of haemorrhagic stroke in subjects 55-64 years. High wind speed on the event day was associated with higher incidence of ischemic stroke in older subjects. Meteorological factors may have some impact on the risk of acute cerebrovascular events. Health care providers should focus on preventive measures, which can reduce these risks.

Oceanic Meteorological Conditions Influence Incidence of Aneurysmal Subarachnoid Hemorrhage

OBJECTIVE

Publications concerning the weather pattern of occurrence of the subarachnoid hemorrhage have produced controversial results. We chose to study subarachnoid hemorrhage occurring in oceanic climate with deep variations focusing on partial oxygen volume (pO₂) and patient history.

METHODS

Seventy-one patients had been successively recruited from a single center 45 km from the Atlantic shore. Climate conditions had been analyzed from 72 hours before subarachnoid hemorrhage to 24 hours after. According to Dalton's law, climate conditions influence pO_2, recalculated with Dupré's formula, and patient history analyzed and scored according to the induced oxidative stress.

RESULTS

Subarachnoid hemorrhage risk is highest during spring and autumn, lowest between midnight and 6:00 a.m. Risk is highest after a period of atmospheric pressure higher than 1010 hPa (83%) and high pO₂ and lowest for atmospheric pressure lower than 990 hPa and pO₂ lower than 20.6_. According to the medical history, 2 groups of patients could be identified: patients without history (22%), women (62%), high atmospheric pressure, and relatively lower pO₂; and patients with a medical history, relatively lower atmospheric pressure, and higher pO₂. Atmospheric pressure decreased significantly before disruption (994 hPa) but with a constant pO₂. Subarachnoid hemorrhages during high atmospheric pressure were preceded by a decrease of pO₂ despite a highly stable period of high atmospheric pressure.

DISCUSSION

Atmospheric O₂ changes and the subsequent oxidative stress could be the local ultimate trigger of subarachnoid hemorrhage that could result in the "ideal" fit of patient's health conditions with the meteorological environment.

Ambient Temperature and Stroke Occurrence: A Systematic Review and Meta-Analysis

Biologically plausible associations exist between climatic conditions and stroke risk, but study results are inconsistent. We aimed to summarize current evidence on ambient temperature and overall stroke occurrence, and by age, sex, and variation of temperature. We performed a systematic literature search across MEDLINE, Embase, PsycINFO, CINAHL, Web of Science, and GEOBASE, from inception to 16 October 2015 to identify all population-based observational studies. Where possible, data were pooled for meta-analysis with Odds ratios (OR) and corresponding 95% confidence intervals (CI) by means of the random effects meta-analysis. We included 21 studies with a total of 476,511 patients. The data were varied as indicated by significant heterogeneity across studies for both ischemic stroke (IS) and intracerebral hemorrhage (ICH). Pooled OR (95% CI) in every 1 degree Celsius increase in ambient temperature was significant for ICH 0.97 (0.94–1.00), but not for IS 1.00 (0.99–1.01) and subarachnoid hemorrhage (SAH) 1.00 (0.98–1.01). Meta-analysis was not possible for the pre-specified subgroup analyses by age, sex, and variation of temperature. Change in temperature over the previous 24 h appeared to be more important than absolute temperature in relation to the risk of stroke, especially in relation to the risk of ICH. Older age appeared to increase vulnerability to low temperature for both IS and ICH. To conclude, this review shows that lower mean ambient temperature is significantly associated with the risk of ICH, but not with IS and SAH. Larger temperature changes were associated with higher stroke rates in the elderly.

Short-Term Effect of Ambient Temperature and the Risk of Stroke: A Systematic Review and Meta-Analysis

BACKGROUND AND PURPOSE

The relationship between stroke and short-term temperature changes remains controversial. Therefore, we conducted a systematic review and meta-analysis to investigate the association between stroke and both high and low temperatures, and health assessment.

METHODS

We searched PubMed, Embase, Cochrane, China National Knowledge Infrastructure (CNKI) and Wanfang Data up to 14 September 2014. Study selection, quality assessment, and author-contractions were steps before data extraction. We converted all estimates effects into relative risk (RR) per 1 °C increase/decrease in temperature from 75th to 99th or 25th to 1st percentiles, then conducted meta-analyses to combine the ultimate RRs, and assessed health impact among the population.

RESULTS

20 articles were included in the final analysis. The overall analysis showed a positive relationship between 1 °C change and the occurrence of major adverse cerebrovascular events (MACBE), 1.1% (95% confidence intervals (CI), 0.6 to 1.7) and 1.2% (95% CI, 0.8 to 1.6) increase for hot and cold effects separately. The same trends can be found in both effects of mortality and the cold effect for morbidity. Hot temperature acted as a protective factor of hemorrhage stroke (HS), -1.9% (95% CI, -2.8 to -0.9), however, it acted as a risk factor for ischemic stroke (IS), 1.2% (95% CI, 0.7 to 1.8).

CONCLUSION

Short-term changes of both low and high temperature had statistically significant impacts on MACBE.