a1 Institut de Veille Sanitaire, Saint Maurice, France
a2 European Programme for Intervention Epidemiology Training (EPIET), Saint-Maurice, France
Legionnaires' disease (LD) is an aetiology of community-acquired bacterial pneumonia in adults, with a high case-fatality ratio (CFR). We conducted a matched case-control study to identify risk factors for sporadic, community-acquired LD. Cases of sporadic, community-acquired and biologically confirmed LD, in metropolitan France from 1 September 2002 to 31 September 2004, were matched with a control subject according to age, sex, underlying illness and location of residence within 5 km. We performed a conditional logistic regression on various host-related factors and exposures. Analysis was done on 546 matched pairs. The CFR was 3·5%. Age ranged from 18–93 years (mean 57 years), with a 3·6 male:female sex ratio. Cases were more likely to have smoked with the documentation of a dose-effect relation, to have travelled with a stay in a hotel (OR 6·1, 95% CI 2·6–14·2), or to have used a wash-hand basin for personal hygiene (OR 3·5, 95% CI 1·6–7·7) than controls. Tobacco and travel have been previously described as risk factors for LD, but this is the first time that such a dose-effect for tobacco has been documented among sporadic cases. These findings will provide helpful knowledge about LD and help practitioners in identifying patients at high risk.
(Accepted December 11 2007)
(Online publication January 23 2008)
This paper was presented in part at the 20th Annual Ewgli Meeting, Rome, 18–20 May 2005.