Table 3.
Risk factors for development of Legionnaires' disease (LD) or Pontiac fever (PF) instead of remaining unaffected, buildings A and B cohorts
| Characteristic | No. (%) with LD | No. (%) with PF | No. (%) unaffected | Univariate RR of LD (95% CI) | Univariate RR of PF (95% CI) | LD aOR (95% CI) | PF aOR (95% CI) |
|---|---|---|---|---|---|---|---|
| Building A occupant* | 16 (14) | 18 (16) | 78 (70) | 6·3 (2·2–18·4) | 4·7 (1·9–11·5) | 6·9 (2·2–22) | 5·5 (2·1–14·5) |
| Building B occupant* | 4 (3) | 6 (4) | 145 (94) | Referent | Referent | Referent | Referent |
| Male | 14 (8) | 14 (8) | 150 (84) | 1·1 (0·4–2·8) | 0·7 (0·3–1·5) | n.a. | n.a. |
| Female | 6 (7) | 10 (11) | 73 (82) | Referent | Referent | n.a. | n.a. |
| Age ⩾50 years* | 13 (14) | 12 (13) | 69 (73) | 3·6 (1·5–8·8) | 2 (1·0–4·4) | 2·7 (0·9–8·0) | 1·7 (0·7–4·4) |
| Age <50 years* | 7 (4) | 12 (7) | 154 (89) | Referent | Referent | Referent | Referent |
| Current smoker | 7 (13) | 6 (11) | 41 (76) | 2·2 (0·9–5·2) | 1·4 (0·6–3·4) | n.a. | n.a. |
| Current non-smoker | 13 (6) | 18 (8) | 182 (85) | Referent | Referent | n.a. | n.a. |
| Reported history of any chronic disease* | 10 (13) | 10 (12) | 60 (75) | 2·5 (1·1–5·7) | 1·8 (0·8–3·9) | 1·9 (0·7–5·7) | 1·7 (0·6–4·4) |
| No reported history of chronic disease* | 10 (5) | 14 (7) | 163 (87) | Referent | Referent | Referent | Referent |
RR, Relative risk; CI, confidence interval; aOR, adjusted odds ratio; n.a., not applicable.
PF cases were excluded from the calculations of whether characteristics were associated with an increased risk of developing LD instead of remaining unaffected and LD cases were excluded from the equivalent calculations for PF.
*
Characteristic used in multivariate models calculating aORs for whether individuals with specified characteristics developed LD instead of remaining unaffected or developed PF instead of remaining unaffected.