Effect of age at exposure on chromosome abnormalities in MIC-exposed Bhopal population detected 30 years post-disaster

Follow-up cytogenetic study was carried out on 145 individuals from areas stratified by Indian Council of Medical Research, for evaluation of the effect of age-at-exposure and its interaction with exposure status on chromosomal aberrations (CA) in blood-lymphocytes. CA was presented as abnormal cell (Abc), aberrations (Abn) and number of aberration/abnormal cell (Abn/Abc), and correlated with age-at-exposure (childhood: <1-10 years; young: 11-26 years; adult: >27 years). Age related increase in abnormalities (Abc, Abn, Abn/Abc) was observed in all exposure strata, except moderately exposed adult-group, which has exhibited lower Abn/Abc than similarly exposed childhood and young age-groups. Elevation of CA was also related to exposure status. Abn/Abc frequency was significantly higher in the severely exposed young and adult groups compared to the controls of the same age. Two-way ANOVA revealed significant abnormalities between the exposed groups; however, interaction of age and exposure was not statistically significant. Significant difference in group-means of Abc and Abn was also observed between adult and childhood in Tukey HSD test. Altogether, a significant interaction of age and MIC-exposure on CA could not be established due to inter-individual variation and lack of baseline information on CA. Significantly higher Abn was observed in people consuming tobacco; however, interaction of lifestyle with additional environmental/occupational exposures during last 30 years against a background exposure to MIC remained un-elucidated. Nevertheless, the study was important for demonstration of the correlation of the current status of CA in circulating lymphocytes with age and exposure status of the MIC-exposed survivors.