Table 1.
Baseline Characteristicsa of 970 Nonsmokers by Level of Secondhand Smoke Exposure, Cardiovascular Health Cognition Study, 1991–1994
| Variable | Level of Exposure |
P Valueb | ||
| 0–15 Years (n = 600) | 16–25 Years (n = 123) | >25 Years (n = 247) | ||
| Demographics | ||||
| Age, years | 75.0 (4.9) | 73.9 (4.3) | 73.8 (4.3) | <0.001 |
| Gender: female | 68.7 | 82.1 | 83.0 | <0.001 |
| Education (≥high school diploma) | 76.6 | 84.3 | 78.7 | 0.12 |
| Clinical vascular disease | 11.3 | 9.8 | 9.7 | 0.74 |
| Subclinical MRI measures | ||||
| Large infarcts | 28.8 | 22.8 | 23.1 | 0.14 |
| Small infarcts | 13.6 | 16.3 | 11.7 | 0.48 |
| White matter disease | 32.1 | 24.6 | 32.7 | 0.23 |
| Subclinical carotid artery measures | ||||
| Internal artery thickness >80th percentile | 20.2 | 18.7 | 19.6 | 0.92 |
| Common artery thickness >80th percentile | 21.8 | 13.8 | 15.9 | 0.04 |
| Stenosis >25% | 39.0 | 35.0 | 34.7 | 0.42 |
Abbreviation: MRI, magnetic resonance imaging.
a
Values are expressed as mean (standard deviation) or %.
b
Based on the F test for continuous data and the χ2 test for categorical data.