IS MYCOPLASMA-PNEUMONIA ASSOCIATED WITH CHILDHOOD ACUTE LYMPHOBLASTIC-LEUKEMIA

Acute lymphoblastic leukemia (ALL) in the childhood peak may be a rare response to delayed first exposure to one or more common infectious a gent(s). Mycoplasma Pneumonia has the appropriate socioeconomic correl ates and clinical symptoms and the hypothesis that delayed first expos ure to it may contribute to ALL is considered. Counts of positive repo rts of M Pneumonia from disease surveillance data for England and Wale s (United Kindom) for 1975-92 have been taken as proxies for community burden of infection. Variation by months of birth (cohort) and diagno sis (period) of incidence of ALL in children born and diagnosed 1975-9 2 are compared with predictions. When periods were classified by mean M. Pneumonia count rate in the nine preceding months, standardized mor bidity ratios (SMR) for the highest and lowest 20 percent were 108 and 89 (rate ratio ERR] = 1.2, 95 percent confidence interval [CI] = 1.1- 1.4). SMRs for cohorts with highest and lowest predicted risk (i.e., l owest and highest M Pneumonia count rate around birth and during infan cy) were 110 and 97 (RR = 2.1, CI = 1.0-1.3). The trend for period was most marked in the cohorts with low opportunity for exposure when you ng. This ecologic analysis provides preliminary support for the hypoth esis.