CANCER RISK IN ASTHMATIC SUBJECTS SELECTED FROM HOSPITAL DISCHARGE REGISTRY

We wanted to study cancer risk in asthmatic subjects. With the use of central health registries, a cohort of 64,346 patients, treated hospit al with an asthma diagnosis, was followed with respect to cancer devel opment. The observed numbers of different types of cancer were compare d with the expected numbers estimated from population data, with consi deration taken to patient age, sex, survival, and the year of diagnosi s. In general, a marked reduction of cancer incidence (2 out of 3 of t he expected numbers) was found, with the exception of two cancer types : cancer of the respiratory tract and cancer of endocrine glands. A mo re noticeable reduction in cancer risk was seen for multiple myeloma, malignant melanoma, mammary cancer, uterine body cancer, and stomach c ancer. The causes of this ''protective effect'' are not indicated by t he present analysis, and need further study.