Table 4.
Hazard ratios for cotinine group and risk of stroke over 20 years of follow up
Cotinine concentration (ng/ml)
|
||||||
---|---|---|---|---|---|---|
≤0.7 | 0.8-1.4 | 1.5-2.7 | 2.8-14.0 | Active smokers (1-9/day) | Test for trend* | |
All men | ||||||
Mean (SD) cotinine (ng/ml) | 0.4 (0.2) | 1.1 (0.2) | 2.0 (0.4) | 4.9 (2.1) | 138.4 (149.3) | |
No of men | 575 | 508 | 506 | 516 | 192 | |
No of events | 35 | 22 | 27 | 28 | 17 | |
Person years | 10 552 | 9162 | 9159 | 9112 | 3316 | |
Stroke rate/1000 person years) | 3.32 | 2.40 | 2.95 | 3.07 | 5.13 | |
Hazard ratios (95% Cl)†: | ||||||
Adjustment 1 | 1.00 | 0.76 (0.44 to 1.31) | 0.83 (0.50 to 1.40) | 0.87 (0.52 to 1.47) | 1.48 (0.81 to 2.69) | 0.73 |
Adjustment 2 | 1.00 | 0.81 (0.47 to 1.41) | 0.87 (0.51 to 1.47) | 0.78 (0.45 to 1.35) | 1.39 (0.74 to 2.60) | 0.91 |
Adjustment 3 | 1.00 | 0.83 (0.46 to 1.47) | 0.94 (0.54 to 1.64) | 0.77 (0.42 to 1.41) | 1.45 (0.71 to 2.96) | 0.99 |
Excluding former smokers | ||||||
Mean (SD) cotinine (ng/ml) | 0.4 (0.2) | 1.1 (0.2) | 2.0 (0.4) | 5.0 (2.4) | 138.4 (149.3) | |
No of men | 308 | 249 | 197 | 191 | 192 | |
No of events | 14 | 10 | 6 | 11 | 17 | |
Person years | 5804 | 4610 | 3625 | 3458 | 3316 | |
Stroke rate/person years) | 2.41 | 2.17 | 1.66 | 3.18 | 5.13 | |
Hazard ratios (95% Cl)† | ||||||
Adjustment 1 | 1.00 | 1.01 (0.43 to 2.35) | 0.66 (0.25 to 1.78) | 1.25 (0.54 to 2.89) | 1.95 (0.90 to 4.22) | 0.52 |
Adjustment 2 | 1.00 | 1.14 (0.48 to 2.71) | 1.08 (0.38 to 3.02) | 1.34 (0.54 to 3.31) | 2.04 (0.91 to 4.57) | 0.23 |
Adjustment 3 | 1.00 | 1.34 (0.53 to 3.40) | 1.39 (0.48 to 4.04) | 2.16 (0.80 to 5.80) | 2.69 (1.07 to 6.75) | 0.11 |
P values from tests for linear trend between log (cotinine) and stroke hazard across passive smoking groups.
For stroke hazard ratios: adjustment 1 stratified by town and adjusted for age; adjustment 2 additionally adjusted for systolic blood pressure, diastolic blood pressure, total cholesterol, HDL cholesterol, FEV1, height, and pre-existing CHD; adjustment 3 additionally adjusted for BMI, triglycerides, white cell count, diabetes, physical activity (none, occasional, light, moderate or more), alcohol intake (none/occasional, light/moderate, heavy), and social class (I, II, III non-manual, III manual, IV, V, and Armed Forces).