Skip to main content

Table 2 Legionnaires’ disease attack rates and relative risks among residents of an apartment complex for seniors (n = 143 respondents)

From: Legionnaires’ disease case-finding algorithm, attack rates, and risk factors during a residential outbreak among older adults: an environmental and cohort study

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)
  1. * 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).
  2.  Overall attack rate based on all residents (n = 171), including non-respondents.
  3.  P < 0. 05.
  4. § Immunosuppressive therapy, human immunodeficiency virus (HIV) infection, or organ transplant.