The risk of cancer following hospitalization for infection in infancy: A population-based cohort study

Background: The relation between infections in infancy and subsequent cancer risk in children and young adults is controversial. Our aim was to examine this association in the Jerusalem Perinatal Study, a population-based cohort comprising all offspring from western Jerusalem and surroundings born from 1964 to 1976. Methods: Identity numbers of nonmalformed singletons with recorded data about hospital admission in the 1st year of life (n = 24,554) were linked to the Population and Cancer Registries. Person-year incidence rates were calculated for the exposed (admitted for infection) and nonexposed (not admitted for infection) groups from birth to date of cancer diagnosis, death, or December 31, 2004. We used Cox proportional hazards models to adjust for covariates associated with hospitalization. Results: The median follow-up was 36 years. Cancer developed in 283 individuals. Hospitalization for infection was not associated with overall cancer risk [risk ratio (RR), 0.88; 95% confidence interval (95% CI), 0.56-1.37]. The incidence rate for non-Hodgkin's lymphoma was higher in the exposed compared with the nonexposed group (RR, 3.46; 95% CI, 1.38-8.68), remaining unchanged after controlling for birth weight, gender, and maternal education. Leukemia risk was not significantly associated (RR, 0.44; 95% CI, 0.06-3.24) with hospitalization for infection. Conclusions: Hospital admission in the 1st year of life due to infection is associated with an increased risk of non-Hodgkin's lymphoma. This is consistent with observations that mild immunodeficiencies predispose to lymphoma. Survival of infants with subtle immune defects, who may have previously succumbed to their infection, may contribute to the increased incidence of non-Hodgkin's lymphoma observed over the last 50 years.