RESUMO
BACKGROUND: After the Chernobyl accident in 1986, children of the contaminated Narodichesky region of Ukraine were obliged to participate in a yearly medical screening. They have been exposed to 137cesium (137Cs; half-life = 30 years) in contaminated soils, air, and food. OBJECTIVE: Using a "natural experiment" approach and a longitudinal prospective cohort study design, we investigated the association of soil 137Cs and spirometry measures for 415 children using 1,888 repeated measurements from 1993 to 1998. METHODS: Mean baseline village soil 137Cs measurements, which varied from 29.0 to 879 kBq/m2, were used as exposure indicators. A standardized spirometry protocol and prediction equations specific to Ukrainian children were used by the same pulmonologist in all screenings. RESULTS: Children living in villages with the highest quintile of soil 137Cs were 2.60 times more likely to have forced vital capacity (FVC) < 80% of predicted [95% confidence interval (CI), 1.07-6.34] and 5.08 times more likely to have a ratio of forced expiratory volume in 1 sec (FEV1) to FVC% < 80% (95% CI, 1.02-25.19). We found statistically significant evidence of both airway obstruction (FEV1/FVC%, peak expiratory flow, and maximum expiratory flow at 25%, 50%, and 75% of FVC) and restriction (FVC) with increasing soil 137Cs. CONCLUSIONS: These findings are unique and suggest significant airway obstruction and restriction consequences for children chronically exposed to low-dose radioactive contaminants such as those found downwind of the Chernobyl Nuclear Power Plant.