Table 4.

Associations between age at surgical menopause and all-cause dementia, Alzheimer's disease (AD), and vascular dementia (VD).

Dementia	Years	Women	Dementia	Incidence rate (per 10 000 person-years)	Model 1	Model 2	Model 3	Model 4
					HR (95% CI)	HR (95% CI)	HR (95% CI)	HR (95% CI)
All-cause dementia	≤40	2862	64	18.5	2.23 (1.59, 3.13)	2.08 (1.48, 2.92)	1.98 (1.41, 2.79)	1.94 (1.38, 2.73)
	41–45	4945	53	8.9	1.06 (0.74, 1.50)	1.02 (0.72, 1.46)	1.00 (0.70, 1.42)	1.00 (0.70, 1.42)
	46–50	6238	79	10.5	1	1	1	1
	51–55	3754	58	12.9	1.19 (0.85, 1.68)	1.20 (0.85, 1.70)	1.20 (0.85, 1.68)	1.16 (0.82, 1.63)
	>55	3728	106	24.1	1.74 (1.29, 2.35)	1.74 (1.29, 2.34)	1.80 (1.33, 2.42)	1.65 (1.21, 2.24)
Alzheimer's disease (AD)	≤40	2862	30	8.7	2.34 (1.44, 3.82)	2.25 (1.38, 3.67)	2.24 (1.37, 3.66)	2.16 (1.32, 3.54)
	41–45	4945	19	3.2	0.81 (0.47, 1.42)	0.80 (0.46, 1.39)	0.78 (0.45, 1.37)	0.78 (0.45, 1.37)
	46–50	6238	37	4.9	1	1	1	1
	51–55	3754	34	7.6	1.44 (0.90, 2.30)	1.46 (0.91, 2.33)	1.44 (0.90, 2.31)	1.38 (0.86, 2.21)
	>55	3728	43	9.8	1.45 (0.93, 2.27)	1.46 (0.93, 2.28)	1.54 (0.99, 2.42)	1.37 (0.87, 2.17)
Vascular dementia (VD)	≤40	2862	11	3.2	2.42 (1.06, 5.50)	2.24 (0.98, 5.14)	1.84 (0.80, 4.22)	1.79 (0.78, 4.11)
	41–45	4945	8	1.3	1.02 (0.42, 2.49)	0.97 (0.40, 2.39)	0.91 (0.37, 2.23)	0.91 (0.37, 2.22)
	46–50	6238	12	1.6	1	1	1	1
	51–55	3754	11	2.4	1.43 (0.63, 3.25)	1.47 (0.65, 3.33)	1.45 (0.64, 3.28)	1.40 (0.62, 3.20)
	>55	3728	22	5.0	2.12 (1.04, 4.31)	2.11 (1.04, 4.31)	2.11 (1.03, 4.31)	1.95 (1.04, 4.02)

Model 1: age at baseline, ethnicity, BMI, education level, and income level were adjusted; Model 2: leisure activities, cigarette smoking, and alcohol drinking were further adjusted based on Model 1; Model 3: cardiovascular disease (CVD) and APOE (apolipoprotein E) were further adjusted based on Model 2; Model 4: ever-used menopausal hormone therapy (MHT) at baseline was further adjusted based on Model 3. HR, hazard ratio.