Table 2. Parkinson Disease and Cigarette Smoking: Conditional Logistic Regression Analysis on Data of Patients and Hospital Controls.
| Cases | Controls | Crude | Adjusteda | |
| No. (%) | No. (%) | OR (95% CI) | OR (95% CI) | |
| Total smoking (pack-years) | ||||
| Never smokers | 207 (46.6) | 243 (27.7) | 1 | 1 |
| >0–7.8 | 86 (19.4) | 161 (18.4) | 0.58 (0.42–0.82) | 0.58 (0.42–0.82) |
| >7.8–17.5 | 67 (15.1) | 155 (17.7) | 0.45 (0.32–0.65) | 0.46 (0.32–0.66) |
| >17.5–29.4 | 45 (10.1) | 160 (18.3) | 0.28 (0.18–0.42) | 0.28 (0.18–0.42) |
| >29.4–103 | 39 (8.8) | 157 (17.9) | 0.26 (0.17–0.40) | 0.27 (0.18–0.42) |
| P value for trendb | <0.0001/0.0004 | <0.0001/0.0006 | ||
| Smoking intensity (cigarettes/day) | ||||
| Never smokers | 207 (46.6) | 243 (27.7) | 1 | 1 |
| >0–7.0 | 77 (17.3) | 158 (18.0) | 0.53 (0.37–0.75) | 0.53 (0.38–0.76) |
| >7.0–12.7 | 54 (12.2) | 159 (18.2) | 0.37 (0.25–0.53) | 0.37 (0.25–0.54) |
| >12.7–19.2 | 50 (11.3) | 158 (18.0) | 0.33 (0.23–0.49) | 0.34 (0.23–0.51) |
| >19.2–60.0 | 56 (12.6) | 158 (18.0) | 0.38 (0.26–0.54) | 0.39 (0.27–0.57) |
| P value for trendb | <0.0001/0.16 | <0.0001/0.20 | ||
| Smoking duration (years) | ||||
| Never smokers | 207 (46.6) | 243 (27.7) | 1 | 1 |
| >0–18 | 98 (22.1) | 165 (18.8) | 0.66 (0.48–0.91) | 0.66 (0.48–0.91) |
| >18–28 | 56 (12.6) | 152 (17.4) | 0.37 (0.25–0.54) | 0.36 (0.24–0.53) |
| >28–41 | 48 (10.8) | 166 (18.9) | 0.29 (0.19–0.43) | 0.29 (0.20–0.44) |
| >41–66 | 35 (7.9) | 150 (17.1) | 0.24 (0.15–0.37) | 0.25 (0.16–0.39) |
| P value for trendb | <0.0001/<0.0001 | <0.0001/<0.0001 | ||
| Time-since-cessation (years) | ||||
| Never smokers | 207 (46.6) | 243 (27.7) | 1 | 1 |
| >31–53 | 93 (20.9) | 158 (18.0) | 0.67 (0.47–0.95) | 0.65 (0.46–0.93) |
| >19–31 | 68 (15.3) | 147 (16.8) | 0.52 (0.36–0.76) | 0.53 (0.36–0.77) |
| >0–19 | 54 (12.2) | 166 (18.9) | 0.35 (0.24–0.51) | 0.36 (0.25–0.52) |
| 0 | 22 (5.0) | 162 (18.5) | 0.15 (0.09–0.24) | 0.15 (0.09–0.25) |
| P value for trendb | n.a./<0.0001 | n.a./<0.0001 |
Abbreviations: OR = odds ratio, CI = confidence interval.
a
The adjusted model includes coffee consumption (in quartiles).
b
The first P value for trend was based on analyses with the exposure as a continuous variable including the persons from the reference category. The second p value for trend was based on analysis whereby the persons from the reference category are excluded.