Table 2.

Hazard Ratios and 95% Confidence Intervals for Associations Between Stroke Occurrence and Geomagnetic Storm Severity Adjusted for Weather Parameters (Daily Mean Ambient Temperature [°C], Atmospheric Pressure [kPa], and Relative Humidity [%])

Environmental FactorAge Group, yIschemic Stroke (n=6915)Intracerebral Hemorrhage (n=1187)Subarachnoid Hemorrhage (n=479)All Strokes Combined (n=11 453)
Moderate geomagnetic activity16–641.20 (0.97–1.47)1.19 (0.76–1.86)1.65 (1.00–2.70)1.27 (1.08–1.48)
64–751.13 (0.95–1.34)0.90 (0.59–1.37)1.63 (0.51–5.18)1.18 (1.04–1.34)
≥750.86 (0.71–1.05)0.57 (0.31–1.05)0.77 (0.10–5.92)1.03 (0.89–1.20)
Total1.02 (0.92–1.14)0.90 (0.68–1.17)1.61 (1.04–2.51)1.15 (1.06–1.25)
Strong geomagnetic activity16–641.40 (0.95–2.07)1.55 (0.82–2.93)1.39 (0.83–2.35)1.52 (1.19–1.92)
64–751.03 (0.76–1.39)1.25 (0.40–3.90)0.80 (0.20–3.31)1.03 (0.82–1.29)
≥751.35 (0.94–1.93)1.08 (0.34–3.39)Model did not converge1.92 (1.53–2.40)
Total1.22 (1.00–1.49)1.46 (0.89–2.39)1.12 (0.69–1.82)1.36 (1.19–1.56)
Severe/extreme geomagnetic activity16–641.34 (0.95–1.89)2.14 (1.05–4.36)2.50 (1.39–4.48)1.52 (1.19–1.94)
64–751.27 (0.96–1.66)1.30 (0.70–2.44)0.51 (0.07–3.66)1.15 (0.94–1.41)
≥750.79 (0.56–1.12)1.18 (0.48–2.89)Model did not converge1.01 (0.79–1.29)
Total1.10 (0.92–1.32)1.45 (0.96–2.19)1.84 (1.06–3.21)1.13 (0.99–1.29)
All geomagnetic storms16–641.26 (1.06–1.48)1.40 (1.00–1.96)1.70 (1.23–2.34)1.37 (1.21–1.54)
64–751.13 (0.99–1.30)1.01 (0.72–1.42)0.95 (0.41–2.19)1.15 (1.04–1.27)
≥750.91 (0.77–1.06)0.72 (0.45–1.15)0.24 (0.03–1.80)1.16 (1.03–1.30)
Total1.07 (0.98–1.17)1.06 (0.86–1.31)1.44 (1.08–1.94)1.19 (1.11–1.27)