Is Mycoplasma Pneumonia associated with childhood acute lymphoblastic leukemia?

Abstract

Acute lymphoblastic leukemia (ALL) in the childhood peak may be arare response to delayed first exposure to one or more common infectiousagent(s). Mycoplasma Pneumonia has the appropriate socioeconomic correlatesand clinical symptoms and the hypothesis that delayed first exposure to itmay contribute to ALL is considered. Counts of positive reports of MPneumonia from disease surveillance data for England and Wales (UnitedKingdom) for 1975-92 have been taken as proxies for community burden ofinfection. Variation by months of birth (cohort) and diagnosis (period) ofincidence of ALL in children born and diagnosed 1975-92 are compared withpredictions. When periods were classified by mean M Pneumonia count rate inthe nine preceding months, standardized morbidity ratios (SMR) for thehighest and lowest 20 percent were 108 and 89 (rate ratio [RR] = 1.2, 95percent confidence interval [CI] = 1.1-1.4). SMRs for cohorts with highestand lowest predicted risk (i.e., lowest and hi ghest M Pneumonia count ratearound birth and during infancy) were 110 and 97 (RR = 1.1, CI = 1.0-1.3).The trend for period was most marked in the cohorts with low opportunity forexposure when young. This ecologic analysis provides preliminary support forthe hypothesis.