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Encoding of some prognostic factors.
| Prognostic factor | Coding | |||||
|---|---|---|---|---|---|---|
| Sex | 0 (Male) | 1 (Female) | ||||
| Residence | 0 (Urban) | 1 (Semiurban) | 2 (Rural) | |||
| Season of the symptoms | 0 (None) | 1 (Winter) | 2 (Autumn) | 3 (Spring) | 4 (Summer) | 5 (>2 Seasons) |
| Type of heating | 0 (Central heating) |
1 (Wood stove) |
2 (Oil stove) |
3 (Fireplace) | 4 (Central heating + Fireplace) |
|
| Pregnancy duration in weeks | 0 (<37) | 1 (37-38) | 2 (>38) | |||
| Allergens | 0 (0) | 1 (3.5–6 mm) | 2 (>6 mm) | |||
