Location of the study area in China.

<p>Location of the study area in China.</p

Plot of RR by relative humidity at specific lags (left), RR by lag at specific daily relative humidity (right) in Jinan.

<p>Reference at 58% of relative humidity.</p

Three-D plot of RR along temperature and lags with 15°C as reference (left); and relative humidity and lags with 57.5% as reference (right).

<p>Three-D plot of RR along temperature and lags with 15°C as reference (left); and relative humidity and lags with 57.5% as reference (right).</p

Summary statistics of daily weather conditions and ischemic stroke hospital admission in Jinan, China.

<p>Abbreviation: Min, minimum; Max, maximum; SD, standard deviation.</p

The time series of monthly ischemic stroke hospital admission in Jinan, 1990–2009.

<p>The time series of monthly ischemic stroke hospital admission in Jinan, 1990–2009.</p

Spearman's correlations between daily weather variables in Jinan, 1990–2009.

<p>P<0.05 for all.</p

Ischemic Stroke Hospital Admission Associated with Ambient Temperature in Jinan, China

<div><p>Background</p><p>This study estimated the effects of ambient temperature and relative humidity on hospital admissions for ischemic stroke during 1990–2009 in Jinan, China.</p><p>Methods</p><p>To account for possible delayed effects and harvesting effect, we examined the impact of meteorological factors up to 30 days before each admission using a distributed lag non-linear model; we controlled for season, long-term trend, day of week and public holidays in the analysis. Stratified analyses were also done for summer and winter.</p><p>Results</p><p>A total of 1,908 ischemic stroke hospital admissions were observed between 1990 and 2009. We found a strong non-linear acute effect of daily temperatures on ischemic stroke hospital admission. With the mean temperature 15°C as the reference, the relative risk (RR) was 1.43 (95% confidence interval (CI): 1.10–1.85) for 0°C daily temperature on the same day, and 0.43 (95% CI: 0.31–0.59) for 30°C daily temperature on the same day, respectively. The effect of ambient temperature was similar in summer and winter. No significant association was observed between relative humidity and ischemic stroke hospitalization.</p><p>Conclusions</p><p>Low temperature might be a risk factor for ischemic stroke, and high temperature might be protective factor of ischemic stroke occurrence in Jinan, China.</p></div

The time series of daily weather variables in Jinan, 1990–2009.

<p>The time series of daily weather variables in Jinan, 1990–2009.</p

Plot of RR by daily mean temperature at specific lags (left), RR by lag at specific daily mean temperature (right) in Jinan.

<p>Reference at 15°C daily mean temperature.</p