Background Data on the association between air pollution and cerebrovascular disease in the US are limited. The objective of this study was to investigate the association between short-term exposure to ambient air pollution and risk of ischemic cerebrovascular events in a US community. Methods Daily counts of ischemic strokes/TIAs (2001–2005) were obtained from the population-based Brain Attack Surveillance in Corpus Christi (BASIC) Project. Daily particulate matter <2.5μm in diameter (PM2.5), ozone (O3), and meteorological data were obtained from Texas Commission on Environmental Quality. To examine the association between PM2.5 and stroke/TIA risk, Poisson regression was used. Separate models included same day PM2.5, PM2.5 lagged 1–5 days, and an averaged lag effect. All models were adjusted for temperature, day of week and temporal trends in stroke/TIA. The effects of O3 were also investigated. Results Median PM2.5 was 7.0 μg/m3 (Inter Quartile Range (IQR): 4.8–10.0). There were borderline significant associations between same day (RR=1.03, 95% CI:0.99–1.07 for an IQR increase in PM2.5) and previous day (RR=1.03, 95% CI:1.00–1.07) PM2.5 and stroke/TIA risk. These associations were independent of O3, which demonstrated similar associations with stroke/TIA risk (same day RR=1.02, 95% CI: 0.97–1.08 and previous day RR=1.04, 95% CI: 0.99–1.09) in two pollutant models. Inference We observed associations between recent PM2.5 and O3 exposure and ischemic stroke/TIA risk even in this community with relatively low pollutant levels. This study provides data on environmental exposures and stroke risk in the US and suggests future research on ambient air pollution and stroke is warranted.

No abstract

The authors explored whether neighborhood-level characteristics are associated with ischemic stroke and whether the association differs by ethnicity, age, and gender. Using data from the Brain Attack Surveillance in Corpus Christi Project (January 2000-June 2003), they identified cases of ischemic stroke (n = 1,247) from both hospital and out-of-hospital sources. Census tracts served as proxies for neighborhoods, and neighborhood socioeconomic status scores were constructed from census variables (higher scores represented less disadvantage). In Poisson regression analyses comparing the 90th percentile of neighborhood score with the 10th, the relative risk of stroke was 0.49 (95% confidence interval (CI): 0.41, 0.58). After adjustment for age, gender, and ethnicity, this association was attenuated (relative risk (RR) = 0.79, 95% CI: 0.63, 1.00). There was no ethnic difference in the association of score with stroke (p for interaction = 0.79). Significant effect modification was found for age (p for interaction < 0.001) and gender (p for interaction = 0.04), with increasing scores being protective against stroke in men and younger persons. Associations were attenuated after adjustment for education (men: RR = 0.77, 95% CI: 0.55, 1.07; persons aged <65 years: RR = 0.65, 95% CI: 0.41, 1.02). Neighborhood characteristics may influence stroke risk in certain gender and age groups. Mechanisms for these associations should be examined.

Objective To investigate the association between the number of fast food restaurants and ischemic stroke in neighborhoods. Methods This work was a pre-specified part of the Brain Attack in Corpus Christi (BASIC) project. Ischemic stroke cases were prospectively ascertained in Nueces County, Texas. Home addresses were geocoded and used to establish the census tract for each stroke case. Census tracts were used as proxies for neighborhoods (n=64). Using a standard definition, fast food restaurants were identified from a commercial list. Poisson regression was used to study the association between the number of fast food restaurants in the neighborhood, using a 1-mile buffer around each census tract, and the risk of stroke in the neighborhood. Models were adjusted for demographics and neighborhood socioeconomic status (SES). Results There were 1,247 completed ischemic strokes from January 2000 through June 2003 and 262 fast food restaurants. The median number of fast food restaurants per census tract including buffer was 22 (IQR 12–33). Adjusting for neighborhood demographics and SES, the association of fast food restaurants with stroke was significant (p=0.02). The association suggested that the risk of stroke in a neighborhood increased by 1% for every fast food restaurant (RR 1.01 95% CI: 1.00–1.01). The relative risk of stroke comparing neighborhoods in the 75th to the 25th percentile of the distribution of fast food restaurants was 1.13 (95% CI: 1.02–1.25). Interpretation Controlling for demographic and SES factors, there was a significant association between fast food restaurants and stroke risk in neighborhoods in this community-based study.

No abstract