Table 2 Relationship between ever coffee drinking/cigarette smoking and dystonia, analysed according to the median number of cups of coffee/packs of cigarettes per day.
| Cases (%) | Control subjects (%) | Adjusted OR (95% CI), p value | |
|---|---|---|---|
| Case vs hospital control subjects | |||
| Ever coffee drinking | |||
| Never | 39 (24) | 24 (11) | 1 (reference) |
| ⩽2 cups/day | 97 (58) | 121 (52) | 0.44 (0.26 to 0.80), 0.009 |
| >2 cups/day | 25 (15) | 78 (34) | 0.23 (0.11 to 0.48), <0.0001* |
| Missing data | 5 (3) | 5 (2) | |
| Ever cigarette smoking | |||
| Never | 111 (67) | 116 (51) | 1 (reference) |
| ⩽0.75 packs/day | 29 (18) | 61 (27) | 0.68 (0.38 to 1.3), 0.2 |
| >0.75 packs/day | 22 (13) | 44 (19) | 0.58 (0.3 to 1.2), 0.13 |
| Missing data | 3 (2) | 7 (3) | |
| Case vs population control subjects | |||
| Ever coffee drinking | |||
| Never | 39 (24) | 20 (11) | 1 (reference) |
| ⩽2 cups/day | 97 (58) | 105 (56) | 0.49 (0.24 to 0.99) 0.046 |
| >2 cups/day | 25 (15) | 57 (33) | 0.19 (0.1–0.45), <0.0001* |
| Missing data | 5 (3) | 0 | |
| Ever cigarette smoking | |||
| Never | 111 (67) | 105 (56) | 1 (reference) |
| ⩽0.75 packs/day | 29 (18) | 48 (26) | 0.93 (0.5 to 1.8), 0.8 |
| >0.75 packs/day | 22 (13) | 34 (18) | 0.72 (0.4 to 1.6), 0.4 |
| Missing data | 3 (2) | 0 |
OR were adjusted for age, sex, referral centre, duration of disease, years of schooling and ever coffee drinking/cigarette smoking, as appropriate.
*t test for trend.