Diversity of risk factors for stroke: The putative roles and mechanisms of depression and air pollution

Oxidative stress and the cardiovascular effects of air pollution

Cardiovascular causes have been estimated to be responsible for more than two thirds of the considerable mortality attributed to air pollution. There is now a substantial body of research demonstrating that exposure to air pollution has many detrimental effects throughout the cardiovascular system. Multiple biological mechanisms are responsible, however, oxidative stress is a prominent observation at many levels of the cardiovascular impairment induced by pollutant exposure. This review provides an overview of the evidence that oxidative stress is a key pathway for the different cardiovascular actions of air pollution.

The effect of air pollution on hospitalization of individuals with respiratory and cardiovascular diseases in Jinan, China

To analyze the short-term effects of air pollution on the hospitalization rates of individuals with acute exacerbation of chronic obstructive pulmonary disease (AECOPD), stroke, and myocardial infarction (MI) after adjusting for confounding factors including weather, day of the week, holidays, and long-term trends in Jinan, China.Hospitalization information was extracted based on data from the primary class 3-A hospitals in Jinan from 2013 to 2015. The concentrations of PM2.5, PM10, SO2, NO2, and O3 were obtained from Jinan Environment Monitoring Center. The relative risk and 95% confidence intervals of AECOPD, stroke, and MI were estimated using generalized additive models with quasi-Poisson distribution in the mgcv package, using R software, version 1.0.136.The incremental increased concentrations of particulate pollutants including PM2.5 and PM10 were significantly associated with increased risk of hospitalization of AECOPD, stroke, and MI, and the adverse influences of PM2.5 on these diseases were generally stronger than that of PM10. The incremental increased concentrations of gaseous pollutants including SO2, NO2, and O3 were significantly associated with increased risk of hospitalization of stroke and MI in this population.Air pollution has significant adverse effects on hospitalization rates of individuals with AECOPD, stroke, and MI in Jinan, China.

Sulfur dioxide and emergency department visits for stroke and seizure

The purpose of this study was to assess an association between ambient sulfur dioxide and the number of emergency department (ED) visits for ischemic stroke and seizure. The study used data collected in a Vancouver (Canada) hospital in the years 1999–2003. Daily ED visits diagnosed as ministroke, stroke, or seizure were investigated using the case-crossover technique. Conditional logistic regression models were applied to estimate the odds ratios (ORs) and their respective 95% confidence intervals (CIs). The models included temperature and relative humidity in the form of natural splines. The results were reported for an increase in interquartile range ((IQR), IQR = 1.9 ppb for SO₂). Positive and statistically significant associations were obtained for SO₂ and ischemic stroke for all patients (OR = 1.12; CI 1.02, 1.23; lag 3) and for female patients (OR = 1.17; CI 1.01, 1.33; lag 0). In the case of ED visits for seizure, for female patients the results were also statistically significant (OR = 1.15; CI 1.02, 1.28; lag 1 and OR = 1.18; CI 1.05, 1.32; lag 2). These findings suggest that cases of ischemic cerebrovascular accidents are associated with acute exposure to ambient sulfur dioxide.

An analysis of admissions from 155 United States hospitals to determine the influence of weather on stroke incidence

Weather is the most frequently proposed factor driving apparent seasonal trends in stroke admissions. Here, we present the largest study of the association between weather and ischemic stroke in the USA to date. We consider admissions to 155 United States hospitals in 20 states during the five-year period from 2004 to 2008. The data set included 196,439 stroke admissions, which were classified as ischemic (n=98,930), hemorrhagic (n=18,960), or transient ischemic attack (n=78,549). Variations in stroke admissions were tested to determine if they tracked seasonal and transient weather patterns over the same time period. Using autocorrelation analyses, no significant seasonal changes in stroke admissions were observed over the study period. Using time-series analyses, no significant association was observed between any weather variable and any stroke subtype over the five-year study. This study suggests that seasonal associations between weather and stroke are highly confounded, and an association between weather and stroke is virtually non-existent. Therefore, previous studies reporting an association between specific weather patterns and stroke should be interpreted with caution.

Severely depressed young patients have over five times increased risk for stroke: a 5-year follow-up study

BACKGROUND

This study aims to estimate the risk of developing stroke within 5 years of discharge among young patients ages 18 to approximately 44 who were hospitalized for depressive disorders.

METHODS

Our study design features a study cohort and a comparison cohort. The study cohort included patients ages 18 to approximately 44 who were hospitalized with a principal diagnosis of depressive disorder (n = 827), whereas the comparison cohort consisted of 4,135 patients selected randomly (five for every depressed patient) and matched with the study group in terms of gender, age, and date of discharge. Each patient was tracked for 5 years after their discharge in 1998. Cox proportional hazard regressions were performed to compute the 5-year stroke-free survival rates after adjusting for possible confounding factors.

RESULTS

During the 5-year follow-up period, 50 depressed patients (6.05% of the study cohort) and 48 non-depressed subjects (1.16% of the comparison cohort) developed strokes. The adjusted hazard of stroke was 5.43 (95% confidence interval = 3.47-8.51, p < .001) times greater for depressed patients than for non-depressed subjects.

CONCLUSIONS

Our findings show young patients ages 18 to approximately 44 who were hospitalized for depressive disorders were at over five times greater risk of developing stroke within 5 years of discharge compared with non-depressed age- and gender-matched subjects.