Table 2.

Unadjusted Association Between Secondhand Smoke Exposure, Vascular Measures, and Dementia Incidence in the Cardiovascular Health Cognition Study From 1991 to 1999^a

Characteristic	Dementia		No Dementia		CIRb	95% CI
	No.c	%	No.	%
Secondhand smoke exposure
0–15 years	95	15.8	505	84.2	Ref
16–25 years	17	13.8	106	86.2	0.87	0.54, 1.41
>25 years	36	14.6	211	85.4	0.92	0.65, 1.31
Clinical vascular disease
Absent	138	15.9	728	84.1	Ref
Present	10	9.6	94	90.4	0.60	0.33, 1.11
Subclinical MRI measures
Large infarcts ≥3 mm
Absent	94	13.2	616	86.8	Ref
Present	52	20.2	205	79.8	1.53	1.12, 2.08
Small infarcts <3 mm
Absent	117	14.0	720	86.0	Ref
Present	29	22.3	101	77.7	1.60	1.11, 2.29
White matter disease
Absent	64	9.7	595	90.3	Ref
Present	81	27.0	219	73.0	2.78	2.06, 3.74
Subclinical carotid artery measures
Internal artery thickness >80th percentile
Absent	103	13.4	667	86.6	Ref
Present	42	22.0	149	78.0	1.64	1.19, 2.27
Common artery thickness >80th percentile
Absent	105	13.5	671	86.5	Ref
Present	40	21.6	145	78.4	1.60	1.15, 2.22
Stenosis >25%
Absent	83	13.8	518	86.2	Ref
Present	62	17.3	297	82.7	1.25	0.92, 1.69

Abbreviations: CI, confidence interval; CIR, cumulative incidence ratio; MRI, magnetic resonance imaging; Ref, referent.

^aFor various characteristics, 0–10 values are missing.

^bUnadjusted value based on dementia status at the last follow-up visit.

^cThe 148 dementia cases included 94 with Alzheimer's disease only, 41 with vascular dementia, 10 with mixed vascular dementia/Alzheimer's disease, and 3 with other types of dementia.