Potential Impacts of Meteorological Variables on Acute Ischemic Stroke Onset

Figures & data

Table 1 Baseline Characteristics of Study Subjects

Characteristics	n (%)
Age
<75	553 (58.5%)
≥75	393 (41.5%)
Gender
Male	558 (59.0%)
Female	388 (41.0%)
Smoking	343 (36.3%)
Alcohol drinking	208 (22.0%)
Presence of medical history
Stroke history	336 (35.5%)
Hypertension	659 (69.7%)
Diabetes mellitus	305 (32.2%)
Hyperlipidemia	220 (23.3%)
Hyperhomocysteinemia	364 (38.5%)
Atrial fibrillation	115 (12.2%)
Coronary artery disease	300 (31.7%)
Lung diseases	109 (11.5%)
Infectious diseases	120 (12.7%)
hsCRP (mg/L), median (IQR)	3.2 (1.4–8.1)
NIHSS, median (IQR)	3 (2–6)

Abbreviations: hsCRP, high-sensitivity c-reactive protein; IQR, interquartile range; NIHSS, National Institutes of Health Stroke Scale.

Table 2 Descriptive Statistics of Meteorological Variables

Variables	Mean±SD	Range
Temperature mean (°C)	7.2±7.4	(−12.9, 26.9)
Minimum temperature (°C)	3.1±6.8	(−14.5, 19.7)
Maximum temperature (°C)	11.6±8.3	(−11.6, 34.0)
Diurnal variation of temperature (°C)	8.6±3.6	(0.8, 20.5)
Barometric pressure mean (hPa)	1023.0±7.5	(999.4, 1043.3)
Minimum barometric pressure (hPa)	1020.1±7.8	(993.8, 1041.8)
Maximum barometric pressure (hPa)	1026.1±7.4	(1003.7, 1045.5)
Diurnal variation of barometric pressure (hPa)	6.1±2.9	(1.8, 23.7)
Relative humidity (%)	44.1±18.4	(7.6, 94.8)

Abbreviation: SD, standard deviation.

Table 3 Association Analysis Between the Meteorological Variables and Ischemic Stroke Hospitalization

Meteorological Variables	Estimate (95% CI)
	All Patients (n=946)	Male (n=558)	Female (n=388)	<75 Years Old (n=553)	≥75 Years Old (n=393)
Temperature mean	−0.006 (−0.015, 0.003)	−0.003 (−0.017, 0.011)	−0.008 (−0.020, 0.004)	−0.002 (−0.014, 0.009)	−0.011 (−0.025, 0.003)
Minimum temperature	−0.010 (−0.019, 0.000)	−0.009 (−0.024, 0.006)	−0.010 (−0.023, 0.003)	−0.005 (−0.018, 0.007)	−0.009 (−0.021, 0.002)
Maximum temperature	−0.003 (−0.011, 0.005)	0.002 (−0.011, 0.014)	−0.006 (−0.016, 0.005)	0.000 (−0.010, 0.011)	−0.007 (−0.020, 0.005)
Diurnal variation of temperature	0.020* (0.001, 0.038)	0.005 (−0.019, 0.029)	0.041** (0.012, 0.069)	0.012 (−0.002, 0.017)	0.016* (0.005, 0.028)
Barometric pressure mean	0.010* (0.001, 0.019)	0.000 (−0.014, 0.014)	0.017** (0.005, 0.029)	0.007 (−0.004, 0.019)	0.012* (0.003, 0.020)
Minimum barometric pressure	0.010* (0.001, 0.019)	0.000 (−0.014, 0.013)	0.017** (0.006, 0.029)	0.008 (−0.004, 0.019)	0.014* (0.001, 0.027)
Maximum barometric pressure	0.008 (−0.001, 0.017)	0.000 (−0.014, 0.015)	0.013* (0.001, 0.025)	0.005 (−0.008, 0.017)	0.012 (−0.002, 0.027)
Diurnal variation of barometric pressure	0.012 (0.000, 0.023)	0.000 (−0.019, 0.018)	0.020* (0.004, 0.035)	0.012 (−0.003, 0.028)	0.017* (0.004, 0.027)
Relative humidity	−0.002 (−0.006, 0.002)	−0.003 (−0.009, 0.002)	0.000 (−0.007, 0.006)	−0.003 (−0.008, 0.002)	−0.001 (−0.008, 0.005)

Notes: Models are fitted separately for each meteorological parameter after adjusting for day of week, public holiday and air quality index using generalized linear Poisson regression; *p<0.05, **p<0.01.

Abbreviation: CI, confidence interval.

Table 4 Delayed Effect of Mean Temperature on Ischemic Stroke Hospitalization

Temperature	Estimate (95% CI)
	All Patients (n=946)	Male (n=558)	Female (n=388)	<75 Years Old (n=553)	≥75 Years Old (n=393)
Day 0	−0.006 (−0.015, 0.003)	−0.008 (−0.020, 0.004)	−0.010 (−0.028, 0.002)	−0.002 (−0.014, 0.009)	−0.011 (−0.025, 0.003)
Day 1	−0.008 (−0.017, 0.001)	−0.007 (−0.024, 0.004)	−0.012 (−0.029, 0.003)	−0.004 (−0.015, 0.008)	−0.013 (−0.027, 0.001)
Day 2	−0.009* (−0.018, −0.001)	−0.011 (−0.023, 0.001)	−0.013* (−0.025, −0.002)	−0.006 (−0.018, 0.006)	−0.014* (−0.028, −0.001)
Day 3	−0.007 (−0.016, 0.002)	−0.009 (−0.020, 0.003)	−0.010 (−0.023, 0.004)	−0.002 (−0.014, 0.009)	−0.012 (−0.027, 0.002)

Notes: Models are fitted separately for each meteorological variable after adjusting for day of week, public holiday and air quality index using generalized linear Poisson regression; *p<0.05.

Abbreviation: CI, confidence interval.