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.

Background/Aims: An influence of climate upon stroke risk is biologically plausible and supported by epidemiological evidence. We aimed to determine whether air pressure (AP) and humidity are associated with hospital stroke admission. Methods: We searched MEDLINE, Embase, PsycINFO, CINAHL, Web of Science, and GEOBASE, from inception to 16 October 2015 to identify relevant 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-effect method. Results: We included 11 studies with a total of 314,385 patients. The effect of AP was varied across studies for ischemic stroke (IS) and subarachnoid haemorrhage (SAH). Pooled ORs (95%CI) associated with 1 hPa increase in AP for the risk of IS, intracerebral hemorrhage (ICH) and SAH were 1.00 (0.99–1.01), 1.01 (0.99–1.02) and 1.02 (0.97–1.07) respectively. The pooled ORs (95%CI) associated with 1 percent increase in humidity for the risk of IS and ICH were 1.00 (1.00–1.01) and 1.00 (0.99–1.01) respectively. Conclusion: This review shows that there is no evidence of a relationship between AP or humidity and the occurrence of hospital admission for stroke. Further research is needed to clarify the extent and nature of any relationship between AP, humidity and stroke in different geographical areas.

High white blood cell (WBC) count and high blood glucose level are risk factors for mortality and pneumonia after acute ischemic stroke (AIS). We investigated the combined effect of high WBC count and high blood glucose level on hospital admission and in-hospital mortality and pneumonia in acute AIS patients. A total of 3124 AIS patients enrolled from December 2013 to May 2014 across 22 hospitals in Suzhou city were included in the present study. We divided patients into four groups according to their level of WBC count and blood glucose: NWNG (normal WBC count and normal glucose), NWHG (normal WBC count and higher glucose), HWNG (higher WBC count and normal glucose), and HWHG (higher WBC count and higher glucose). Cox proportional hazard model and logistic regression model were used to estimate the combined effect of WBC count and blood glucose on all-cause in-hospital mortality and pneumonia in AIS patients. HWHG was associated with a 2.22-fold increase in the risk of in-hospital mortality in comparison to NWNG (adjusted hazard ratio [HR] 2.22; 95% confidence interval [CI], 1.21–4.07; P trend = 0.003). The risk of pneumonia was significantly higher in patients with HWHG compared to those with NWNG (adjusted odds ratio [OR] 2.61; 95% CI, 1.66–4.10; P trend < 0.001). The C-statistic for the combined WBC count and blood glucose was higher than WBC count or blood glucose alone for prediction of in-hospital mortality and pneumonia (all p < 0.01). High WBC count combined with high blood glucose level at admission was independently associated with in-hospital mortality and pneumonia in AIS patients. Moreover, the combination of WBC count and blood glucose level appeared to be a better predictor than WBC count or blood glucose alone.

There is uncertainty surrounding the differences in outcomes after intracerebral haemorrhage (ICH) between men and women. This study aimed to investigate the sex differences in clinical characteristics, severity and outcomes of Chinese ICH patients. The Nanjing First Hospital stroke registry was a hospital-based registry of stroke patients with 1-year prospective follow-up. From 2004 to 2008, a total of 651 consecutively recruited patients with acute ICH were enrolled. Primary outcome was death or dependency defined as a modified Rankin Scale score of 3-6 at 12 months. Multivariable logistic regression analyses were performed to determine whether there were sex differences in clinical outcomes after ICH. Clinically important and biologically plausible risk factors of death or dependency were selected from available variables. A total of 615 ICH patients were enrolled. There was no significant difference in age (63.5 ± 14.0 vs. 62.7 ± 12.7, p = 0.500) between women and men. At baseline, men were more likely to be current smokers (46.1% vs. 3.6%, P < 0.001) or current drinkers (35.4% vs. 3.6%, P < 0.001), but women had higher admission National Institute of Health Stroke Scale (NIHSS) scores than men (10 vs. 8, P = 0.039). Women also had higher rates of death or dependency at 3, 6, and 12 months (61.2% vs. 46.8%, P = 0.001; 56.7% vs. 45.3%, P = 0.009; and 51.8% vs. 44.1%, P = 0.065; respectively). After adjustment for age, existing hypertension and diabetes, prior stroke, previous ischemic heart disease, previous atrial fibrillation, current smoking and alcohol consumption status, pre-stroke dependency, onset-to-door time, admission NIHSS score, admission systolic blood pressure and location of bleeding, the association between the female gender and death or dependency remained statistical significant at 3 months [odds ratio (OR): 1.76; 95% confidence interval (CI): 1.07-2.89], but did not reach statistical significance at 6 months (OR: 1.59; 95% CI: 0.99-2.54) and 12 months (OR: 1.22; 95% CI: 0.77-1.95). In a Chinese population, women are more likely to be dead or dependent early after ICH than men. However, this gender difference gradually attenuates over the period of 12 months.

Background: Stroke is the second leading cause of death and the third leading cause of disability in the general population worldwide. However, the changing trend of ischemic stroke burden attributable to various dietary risk factors has not been fully revealed and may contribute to a better understanding of stroke epidemiology. Aims: Our article aimed to evaluate the temporal trend of diet-related ischemic stroke burden to inform future research and policy-making. Methods: This analysis was based on the data from the Global Burden of Disease (GBD) Study 2019 (spanning years 1990 to 2019), and we used the joinpoint regression to model temporal trends in diet-related ischemic stroke burden across countries and regions of the world during the study period. Six specific dietary factors known to influence stroke risk, including sodium, red meat, fiber, vegetables, whole grains, and fruits, were evaluated in the GBD study to determine their individual and joint impact on ischemic stroke. The changing trend was primarily measured by the average annual percent change (AAPC). Age-standardized rates (ASRs) of mortality and years lived with disability (YLD) per 100,000 population were used to evaluate disease burden. Finally, the socioeconomic background, which was quantified as sociodemographic index (SDI), and its association with diet-related ischemic stroke burden were also explored with the Pearson correlation coefficient. Results: During the study period, the ischemic stroke ASR of mortality attributable to overall dietary risk decreased by an average of 1.6% per year, while the ASR of YLD decreased by an average of 0.2% per year. High sodium diet was still a key driver of diet-related ischemic stroke, accounting for 8.4% and 11.0% of deaths and disabilities, respectively, in 2019. In addition, we found a negative association between temporal evolution of stroke burden and socioeconomic background ( r = −0.6603 for mortality and r = −0.4224 for disability, P < 0.001), which suggested that the developing countries with weak social and economic foundation faced greater challenges from the ongoing burden of diet-related strokes compared with developed countries. Conclusions: Our study found declining trends and revealed the current status of diet-related ischemic stroke mortality and disability. Interdisciplinary countermeasures involving the development of effective food policies, evidence-based guidelines, and public education are needed in the future to combat this global epidemic. Data access statement: The data used for analysis were open-access and can be obtained from https://vizhub.healthdata.org/gbd-results/ .