[MORBUS: the Sentinel Practice Network. Report on a study in South Oldenbury].

There has been considerable public concern that emissions from intensive livestock farming may have hazardous effects on human health, particularly on the respiratory system. From October 1991 to September 1992, data on consultations of asthmatic children (up to 8 years) were obtained by a network of 25 GP and paediatric practices in South Oldenburg, a region with one of the highest livestock densities in Germany. Comparable data from a similar network of 75 practices in 3 adjacent regions (Brunswick, Hanover, Verden) with average livestock density served as a reference. In South Oldenberg, 2084 consultations of 542 asthmatic children were observed, with asthma being the reason for visit in 734 of the contacts (36%). The boy-girl ratio was 2.1:1 among index patients and 1.9:1 among consultations. Consultation rate was 25.2 contacts by asthmatic children per 1,000 total consultations of children up to 8 years in South Oldenburg, compared to 17.8 per 1,000 in Hanover, 15.7 per 1,000 in Brunswick and 13.6 per 1,000 in Verden. Consultations due to asthma scored 11.2/1,000 in South Oldenburg, 10.8/1,000 in Hanover, 7.2/1,000 in Brunswick and 6.5/1,000 in Verden. Asthmatic patients in South Oldenburg were younger (mean age 38 vs. 42 months) than those observed in the reference regions. There were no regional patterns in sex ratio, severity of asthma, respiratory allergies or atopic dermatitis. As this is an ecological study design, inferences concerning the cause of the observed regional differences can only be weak. We therefore propose a case-control study in order to obtain exposure and health data on an individual level.