Risk factors for Campylobacter enteritis in Switzerland.

From February to December 1991, 167 sporadic cases of Campylobacter enteritis in Switzerland and 282 controls were enrolled in a case-control study using self-administered questionnaires. In the multivariate matched analysis, travel abroad was identified as the most important risk factor for an infection with Campylobacter (adjusted odds ratio [OR] = 21.2, 95% confidence interval [CI]7.6-56.2). Having foreign citizenship also increased the risk (OR = 6.7, 95% CI 1.3-34.5). Among food items consumed within five days before onset of illness, consumption of poultry liver was shown to be a risk factor (OR = 5.7, 95% CI 1.4-22.8), while the consumption of curd or cottage cheese lowered the risk (OR = 0.5, 95% CI 0.3-0.9). The unmatched analysis confirmed travel abroad and the consumption of poultry liver as risk factors and the consumption of curd or cottage cheese as being protective, and, in addition, identified the consumption of poultry as a risk factor (OR = 2.0, 95% CI 1.1-3.3). The study showed the feasibility of using self-administered questionnaires for this type of analysis. The method is logistically simple and reduces the cost of case-control studies.