Table 2.
Legionnaires’ disease attack rates and relative risks among residents of an apartment complex for seniors (n = 143 respondents)
| Characteristics | No. of LD patients | No. of non-patients | Attack rate | Relative risk* (95% confidence interval) |
|---|---|---|---|---|
|
Overall |
8 |
135 |
4.7%† |
-- |
|
Potable water exposures |
|
|
|
|
| Any showering |
8 |
90 |
8.2% |
7.02 (0.45–128.21) |
| Any tub baths |
1 |
70 |
1.4% |
0.13 (0.02–1.09)‡ |
|
Smoking |
|
|
|
|
| Current |
2 |
12 |
14.3% |
3.02 (0.67–13.58) |
| Former (>100 cigarettes) |
3 |
57 |
5.0% |
1.07 (0.22–5.08) |
|
Comorbid condition |
|
|
|
|
| Asthma |
0 |
16 |
0% |
0.48 (0.03–7.10) |
| Chronic lung disease |
0 |
9 |
0% |
1.02 (0.07–18.76) |
| Chronic kidney disease |
0 |
11 |
0% |
0.74 (0.04–10.46) |
| Diabetes mellitus |
1 |
51 |
1.9% |
0.45 (0.03–1.93) |
| Heart disease |
1 |
35 |
2.8% |
0.42 (0.05–3.27) |
| Immunocompromised§ | 2 | 13 | 13.3% | 3.33 (0.71– 15.70) |
* Relative risk (RR) compares attack rates for persons with and without the exposure or risk factor. RRs were estimated by adding 0.5 to cells with zero values (asthma, and chronic lung or kidney disease).
† Overall attack rate based on all residents (n = 171), including non-respondents.
‡ P < 0. 05.
§ Immunosuppressive therapy, human immunodeficiency virus (HIV) infection, or organ transplant.