Table 5.

Incidence per 1000 person-years and the HRs (95% CI) for Alzheimer’s disease and vascular dementia.

Variables	N	Cases	Incidence	Unadjusted HR (95% CI)	Adjusted HR (95% CI)
Alzheimer’s disease
Non-anesthesia	12,400	546	6.1	1.00 (ref.)	1.00 (ref.)
General anesthesia	3100	178	7.7	1.69 (1.41–2.02) ***	1.52 (1.27–1.82) ***
Vascular dementia
Non-anesthesia	12,400	124	1.4	1.00 (ref.)	1.00 (ref.)
General anesthesia	3100	49	2.1	1.85 (1.31–2.61) ***	1.64 (1.15–2.33) **

HR, hazard ratio; CI, confidence interval. ** p < 0.01 and *** p < 0.001.