Various meteorological conditions exhibit both immediate and delayed influences on the risk of stroke events: The HEWS-stroke study

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.

Association of ambient temperature on acute ischemic stroke in Yancheng, China

BACKGROUND

Acute ischemic stroke (AIS) is a major global public health issue. There is limited research on the relationship between ambient temperature and AIS hospital admissions, and the results are controversial. Our objective is to assess the short-term impact of ambient temperature on the risk of AIS hospital admissions in Yancheng, China.

METHODS

We collected data on daily AIS hospital admissions, meteorological factors, and air quality in Yancheng from 2014 to 2019. We used Poisson regression to fit generalized linear models and distributed lag non-linear models to explore the association between ambient temperature and AIS hospital admissions. The effects of these associations were evaluated by stratified analysis by sex and age.

RESULTS

From 2014 to 2019, we identified a total of 13,391 AIS hospital admissions. We observed that the influence of extreme cold and heat on admissions for AIS manifests immediately on the day of exposure and continues for a duration of 3-5 days. Compared to the optimal temperature (24.4 °C), the cumulative relative risk under extreme cold temperature (-1.3 °C) conditions with a lag of 0-5 days was 1.88 (95%CI: 1.28, 2.78), and under extreme heat temperature (30.5 °C) conditions with a lag of 0-5 days was 1.48 (95%CI: 1.26, 1.73).

CONCLUSIONS

There is a non-linear association between ambient temperature and AIS hospital admission risk in Yancheng, China. Women and older patients are more vulnerable to non-optimal temperatures. Our findings may reveal the potential impact of climate change on the risk of AIS hospital admissions.

Influence of Meteorological Parameters on the Prevalence of TEE Detected Left Atrial Appendage Thrombi

(1) Background: Meteorological factors seem to exert various effects on human health, influencing the occurrence of diseases such as thromboembolic events and strokes. Low atmospheric pressure in summer may be associated with an increased likelihood of ischemic stroke. The aim of this study was to investigate the potential impact of meteorological conditions on left atrial appendage (LAA) thrombus formation. (2) Methods: A total of 131 patients were included, diagnosed with a first instance of thrombus via 3D transesophageal echocardiography (TEE) between February 2009 and February 2019. Months with frequent thrombus diagnoses of at least 10 thrombi per month were categorized as frequent months (F-months), while months with fewer than 10 thrombus diagnoses per month were labelled as non-frequent months (N-months). The analysis focused on differences in meteorological parameters in two-week and four-week periods before the diagnosis. (3) Results: F-months were predominantly observed in spring and summer (April, May, June, and July), as well as in February and November. During F-months, a higher absolute temperature difference, lower relative humidity, longer daily sunshine duration, and greater wind speed maximum were observed in the two- and four-week periods rather than for N-months. In the two-week period, average temperatures, equivalent temperatures, and temperature maxima were also significantly higher during F-months than N-months. (4) Conclusion: Thrombi in the left atrial appendage are more prevalent during periods characterized by high absolute temperature differences, low relative humidity, and long daily sunshine duration.

Potential role of ambient temperature as a trigger for intracerebral hemorrhage: a time-stratified case-crossover study in Tianjin, China

The adverse effects of ambient temperature on human health are receiving increasing attention, yet evidence of its impact on intracerebral hemorrhage (ICH) onset is limited. Here, the relationship between ambient temperature and ICH was evaluated. A time-stratified case-crossover analysis was performed based on 4051 ICH patients admitted to five stroke units in Tianjin between January 2014 and December 2020. Conditional logistic regression was applied to evaluate the associations between the daily mean temperature (Tm) or daily temperature range (DTR) and ICH onset. We found a negative association between Tm and ICH onset (OR = 0.977, 95% CI 0.968-0.987) but not between DTR and ICH onset. In stratified analyses, men and individuals aged ≥ 60 years were more susceptible to low-ambient temperature effects; corresponding adjusted ORs were 0.970 (95% CI 0.956-0.983) and 0.969 (95% CI 0.957-0.982), respectively. Tm significantly affected patients with deep ICH (OR = 0.976, 95% CI 0.965-0.988), but had no effect on lobar ICH. There was also seasonal heterogeneity in the effect of Tm on ICH onset, with Tm being negatively associated with ICH onset only in the warm season (OR = 0.961, 95% CI 0.941-0.982). Results suggest that the low-ambient temperature might trigger ICH onset, especially for the male and elderly population, providing important health guidance to prevent cold exposure-induced ICH.

Risk of ischemic and hemorrhagic stroke in relation to cold spells in four seasons

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.

Association between El Niño-Southern Oscillation events and stroke: a case-crossover study in Kaunas city, Lithuania, 2000-2015

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.

Daily Meteorological Parameters Influence the Risk of Intracerebral Hemorrhage in a Subtropical Monsoon Basin Climate

Background and Purpose

The correlation between meteorological parameters and intracerebral hemorrhage (ICH) occurrence is controversial. Our research explored the effect of daily meteorological parameters on ICH risk in a subtropical monsoon basin climate.

Methods

We retrospectively analyzed patients with ICH in a teaching hospital. Daily meteorological parameters including temperature (TEM), atmospheric pressure (PRE), relative humidity (RHU), and sunshine duration (SSD) were collected, with the diurnal variation (daily maximum minus minimum) and day-to-day variation (average of the day minus the previous day) calculated to represent their fluctuation. We adopted a time-stratified case-crossover approach and selected conditional logistic regression to explore the effect of meteorological parameters on ICH risk. The influence of monthly mean temperature proceeded via stratified analysis. Air pollutants were gathered as covariates.

Results

Our study included 1052 eligible cases with ICH. In a single-factor model, the risk of ICH decreased by 5.9% (P<0.001) for each 1°C higher of the daily mean TEM, and the risk increased by 2.4% (P=0.002) for each 1hPa higher of the daily mean PRE. Prolongation of daily SSD inhibited the risk of ICH, and OR was 0.959 (P=0.007). The risk was raised by 7.5% (P=0.0496) with a 1°C increment of day-to-day variation of TEM. In a two-factor model, the effect of daily mean TEM or daily SSD on ICH risk was still statistically significant after adjusting another factor. The influence of meteorological parameters on ICH risk continued in cold months but disappeared in warm months after stratified analysis.

Conclusion

This research indicates daily TEM and SSD had an inverse correlation to ICH risk in a subtropical monsoon basin climate. They were independent when adjusted by another factor. Daily PRE and day-to-day TEM variation were positively related to ICH risk. The correlation of daily meteorological factors on ICH risk was affected by the monthly thermal background.

A prehospital diagnostic algorithm for strokes using machine learning: a prospective observational study

High precision is optimal in prehospital diagnostic algorithms for strokes and large vessel occlusions. We hypothesized that prehospital diagnostic algorithms for strokes and their subcategories using machine learning could have high predictive value. Consecutive adult patients with suspected stroke as per emergency medical service personnel were enrolled in a prospective multicenter observational study in 12 hospitals in Japan. Five diagnostic algorithms using machine learning, including logistic regression, random forest, support vector machine, and eXtreme Gradient Boosting, were evaluated for stroke and subcategories including acute ischemic stroke with/without large vessel occlusions, intracranial hemorrhage, and subarachnoid hemorrhage. Of the 1446 patients in the analysis, 1156 (80%) were randomly included in the training (derivation) cohort and cohorts, and 290 (20%) were included in the test (validation) cohort. In the diagnostic algorithms for strokes using eXtreme Gradient Boosting had the highest diagnostic value (test data, area under the receiver operating curve 0.980). In the diagnostic algorithms for the subcategories using eXtreme Gradient Boosting had a high predictive value (test data, area under the receiver operating curve, acute ischemic stroke with/without large vessel occlusions 0.898/0.882, intracranial hemorrhage 0.866, subarachnoid hemorrhage 0.926). Prehospital diagnostic algorithms using machine learning had high predictive value for strokes and their subcategories.

Visualization of lenticulostriate artery by intracranial dark-blood vessel wall imaging and its relationships with lacunar infarction in basal ganglia: a retrospective study

OBJECTIVES

There is close relationship between lenticulostriate arteries (LSAs) and lacunar infarctions (LIs) of the basal ganglia. The study aims to visualize the LSAs using high-resolution vessel wall imaging (VWI) on 3T system and explore the correlation between LSAs and LIs.

METHODS

Fifty-six patients with LIs in basal ganglia, and 44 age-matched control patients were enrolled and analyzed retrospectively. The raw VWI images were reformatted into coronal slices in minimum intensity projection for further observation of LSAs. The risk factors of LIs in basal ganglia were analyzed by univariate and multivariate logistic regression. The correlation and linear regression analysis between the LSAs and LIs, ipsilateral MCA-M1 plaques were investigated.

RESULTS

The total number (p < 0.01) and length (p < 0.01) of LSAs were statistically different between basal ganglias with and without LIs. The total number of LSAs and ipsilateral MCA-M1 plaques were independently related to LIs in basal ganglias. The mean length of LSAs were negatively correlated with number (r = - 0.33, p = 0.002) and volume (r = - 0.37, p = 0.001) of LIs. Age, drinking history, and mean length of LSAs were associated with LI occurrence in basal ganglia, and mean length of LSAs was correlated with larger volume of LIs.

CONCLUSIONS

Number of LSA reduction and ipsilateral MCA-M1 plaques were associated with the presence of LIs in basal ganglias. Age increasing, drinking history, and shorter LSAs were correlated with the increasing of LIs.

KEY POINTS

• Patients with LIs tend to have shorter LSAs. • The characteristics of LSAs and ipsilateral MCA-M1 plaques are associated with LIs in basal ganglias. • Age, drinking history, and mean length of LSAs are correlated with LI features in basal ganglias.

Preliminary development of a prediction model for daily stroke occurrences based on meteorological and calendar information using deep learning framework (Prediction One; Sony Network Communications Inc., Japan)

BACKGROUND

Chronologically meteorological and calendar factors were risks of stroke occurrence. However, the prediction of stroke occurrences is difficult depending on only meteorological and calendar factors. We tried to make prediction models for stroke occurrences using deep learning (DL) software, Prediction One (Sony Network Communications Inc., Tokyo, Japan), with those variables.

METHODS

We retrospectively investigated the daily stroke occurrences between 2017 and 2019. We used Prediction One software to make the prediction models for daily stroke occurrences (present or absent) using 221 chronologically meteorological and calendar factors. We made a prediction models from the 3-year dataset and evaluated their accuracies using the internal cross-validation. Areas under the curves (AUCs) of receiver operating characteristic curves were used as accuracies.

RESULTS

The 371 cerebral infarction (CI), 184 intracerebral hemorrhage (ICH), and 53 subarachnoid hemorrhage patients were included in the study. The AUCs of the several DL-based prediction models for all stroke occurrences were 0.532-0.757. Those for CI were 0.600-0.782. Those for ICH were 0.714-0.988.

CONCLUSION

Our preliminary results suggested a probability of the DL-based prediction models for stroke occurrence only by meteorological and calendar factors. In the future, by synchronizing a variety of medical information among the electronic medical records and personal smartphones as well as integrating the physical activities or meteorological conditions in real time, the prediction of stroke occurrence could be performed with high accuracy, to save medical resources, to have patients care for themselves, and to perform efficient medicine.

Association between stroke occurrence and changes in atmospheric circulation

Background

The impact of weather on morbidity from stroke has been analysed in previous studies. As the risk of stroke was mostly associated with changing weather, the changes in the daily stroke occurrence may be associated with changes in atmospheric circulation. The aim of our study was to detect and evaluate the association between daily numbers of ischaemic strokes (ISs) and haemorrhagic strokes (HSs) and the teleconnection pattern.

Methods

The study was performed in Kaunas, Lithuania, from 2000 to 2010. The daily numbers of ISs, subarachnoid haemorrhages (SAHs), and intracerebral haemorrhages (ICHs) were obtained from the Kaunas Stroke Register. We evaluated the association between these types of stroke and the teleconnection pattern by applying Poisson regression and adjusting for the linear trend, month, and other weather variables.

Results

During the study period, we analysed 4038 cases (2226 men and 1812 women) of stroke. Of these, 3245 (80.4%) cases were ISs, 533 (13.2%) cases were ICHs, and 260 (6.4%) cases were SAHs. An increased risk of SAH was associated with a change in mean daily atmospheric pressure over 3.9 hPa (RR = 1.49, 95% CI 1.14–1.96), and a stronger El Niño event had a protective effect against SAHs (RR = 0.34, 95% CI 0.16–0.69). The risk of HS was positively associated with East Atlantic/West Russia indices (RR = 1.13, 95% CI 1.04–1.23). The risk of IS was negatively associated with the Arctic Oscillation index on the same day and on the previous day (RR = 0.97, p < 0.033). During November–March, the risk of HS was associated with a positive North Atlantic Oscillation (NAO) (RR = 1.29, 95% CI 1.03–1.62), and the risk of IS was negatively associated with the NAO index (RR = 0.92, 95% CI 0.85–0.99).

Conclusions

The results of our study provide new evidence that the North Atlantic Oscillation, Arctic Oscillation, East Atlantic/West Russia, and El Niño-Southern Oscillation pattern may affect the risk of stroke. The impact of these teleconnections is not identical for various types of stroke. Emergency services should be aware that specific weather conditions are more likely to prompt calls for more severe strokes.

Optimal Antihypertensive Medication Adherence Reduces the Effect of Ambient Temperature on Intracerebral Hemorrhage Occurrence: A Case-Crossover Study

BACKGROUND AND PURPOSE

The role of antihypertensive medication adherence in reducing the effect of ambient temperature (TEM) on intracerebral hemorrhage (ICH) pathogenesis is unclear. We aimed to study the influence of ambient TEM on the ICH occurrence in hypertensive patients with different medication adherence.

METHODS

We enrolled consecutive ICH patients with a definite history of hypertension in a teaching hospital over a period of six years. Medication adherence was calculated using the proportion of prescription days covered (PDC) to antihypertensive mediation in the last month before the ICH attack. Optimal medication adherence (OMA) was the PDC > 80%, and non-optimal medication adherence (non-OMA) was ≤80%. Daily ambient TEM and its variation were collected as the explanatory variables, and dominant air pollutants were gathered as covariates. We adopted a time-stratified case-crossover approach to minimize individual confounders. Conditional logistic regression was conducted to calculate the odds ratio (OR) of daily ambient TEM on ICH occurrence.

RESULTS

We recruited a total of 474 patients in this study. The number of participants with OMA and non-OMA was 249 and 225. Daily mean and max TEM in lag0 to lag2, as well as daily min TEM in lag0 to lag1, were significantly related to ICH onset in all enrolled patients and non-OMA cases. However, only daily TEM in lag0 was meaningfully associated with ICH onset in the OMA cases. The risk of ICH in OMA patients, respectively, changed by 7.9% (OR = 0.921, [0.861, 0.985]) or 6.3% (OR = 0.937, [0.882, 0.995]) when daily mean or max TEM was altered by 1°C in lag0, but the change raised by 10.4% (OR = 0.896, [0.836, 0.960]) or 7.5% (OR = 0.925, [0.868, 0.986]) in non-OMA patients. And the risk varied (OR = 0.933, [0.882, 0.988]) only in non-OMA patients when daily min TEM was altered by 1°C in lag1.

CONCLUSION

Our results indicate that OMA to antihypertensive drugs reduces the influence of ambient TEM on ICH occurrence in hypertensive patients.

Impact of temperature decline from the previous day as a trigger of spontaneous subarachnoid hemorrhage: case-crossover study of prefectural stroke database

OBJECTIVE

Several environmental factors have been reported to correlate with incidence of spontaneous subarachnoid hemorrhage (SAH). However, because of different patient selection and study designs among these studies, meteorological factors that trigger the incidence of SAH in a short hazard period remain unknown. Among meteorological factors, daily temperature changes may disrupt and violate homeostasis and predispose to cerebrovascular circulatory disturbances and strokes. The authors aimed to investigate whether a decline in the temperature from the highest of the previous day to the lowest of the event day (temperature decline from the previous day [TDP]) triggers SAH in the prefecture-wide stroke database.

METHODS

All 28 participating institutions with primary or comprehensive stroke centers located throughout Kochi Prefecture, Japan, were included in the study. Data collected between January 2012 and December 2016 were analyzed, and 715 consecutive SAH patients with a defined date of onset were enrolled. Meteorological data in this period were obtained from the Kochi Local Meteorological Observatory. A case-crossover study was performed to investigate association of TDP and other environmental factors with onset of SAH.

RESULTS

The increasing TDP in 1°C on the day of the SAH event was associated with an increased incidence of SAH (OR 1.041, 95% CI 1.007-1.077) after adjustment for other environmental factors. According to the stratified analysis, a significant association between TDP and SAH was observed in women, patients < 65 years old, and patients with weekday onset. Among these factors, increasing TDP had a great impact on SAH onset in patients < 65 years old (p = 0.028, Mann-Whitney U-test).

CONCLUSIONS

TDP, temperature decline from the highest of the previous day to the lowest of the day, was correlated with the incidence of spontaneous SAH, particularly in younger patients < 65 years old.

Warm Front Passage on the Previous Day Increased Ischemic Stroke Events

BACKGROUND AND PURPOSE

The influence of a weather front passage is rarely evaluated on stroke events. We hypothesized that a weather front passage on the stroke onset day or during the previous days may play an important role in the incidence of stroke.

METHODS

A multicenter retrospective study was conducted to evaluate the frequency of stroke events and their interaction with weather front passages. Consecutive acute stroke patients (n = 3935, 73.5 ± 12.4 years, 1610 females) who were admitted to 7 stroke hospitals in 3 cities from January 2012 to December 2013 were enrolled in this study. Multivariate Poisson regression models involving time lag variables were used to compare the daily rates of stroke events with the day of a weather front passage and the previous 6 days, adjusting for considerable influences of ambient temperature and atmospheric pressure.

RESULTS

There were a total of 33 cold fronts and 13 warm fronts that passed over the 3 cities during the study period. The frequency of ischemic stroke significantly increased when a warm front passed on the previous day (risk ratio 1.34, 95% confidence interval 1.07-1.69, P= .016).

CONCLUSIONS

This study indicated that a weather front passage on the previous days may be associated with the occurrence of stroke.