Childhood immunization and atopic disease into middle-age--a prospective cohort study.

The association between childhood immunizations and risk of atopic diseases is unclear. No study has examined possible associations between childhood immunizations and such diseases in middle age. The Tasmanian Longitudinal Health Study (TAHS) is a population based cohort study of respiratory disease. The TAHS participants were followed from 7 to 44 yrs of age. Immunizations during childhood were examined for any association with asthma and atopic disease at age 44 yrs. Multivariable regression models were used to estimate relative risks while adjusting for confounders. Cox regression was used to estimate the association between childhood immunizations and asthma developing after the age of 7 yrs. We found no association between any childhood immunization (Diphtheria, Tetanus, Pertussis, Polio, Smallpox) and asthma (ORs ranged from 0.87 to 1.17 p > 0.05), eczema (ORs ranged from 0.99 to 1.07 p > 0.05), food allergy (ORs ranged from 0.97 to 1.11 p > 0.05), or hay fever (ORs ranged from 1.02 to 1.05 p > 0.05) at age 44. Nor did we find any association between childhood immunizations and an increased risk of incident asthma after the age of 7 yrs (Diphtheria HR = 1.06, 95% CI 0.82, 1.36; Tetanus HR = 1.13, 95% CI 0.88, 1.44; Pertussis HR = 1.03, 95% CI 0.81, 1.30; Polio HR = 1.15, 95% CI 0.86, 1.54; Smallpox HR = 1.21, 95% CI 0.99, 1.48; DTP HR = 1.05, 95% CI 0.85, 1.30). Our analysis does not support any association between common childhood immunizations and risk of asthma and atopic disease in middle-age. Our findings should provide reassurance that in terms of life time risk of asthma and atopic disease, childhood immunization is safe.