Cytogenetic analysis of South Asian berry pickers in British Columbia using the micronucleus assay in peripheral lymphocytes.

Micronuclei in peripheral blood lymphocytes from British Columbia seasonal farmworkers and controls were evaluated using the cytokinesis-block technique. The farmworkers harvested berry crops and were likely occupationally exposed to pesticides. Subjects were 39 female subjects of South Asian descent; 18 farmworkers employed during 1993 and 21 age-matched controls. The mean age was 55.9 years. Micronuceli were also scored for the presence of kinetochores. No significant difference was found between the frequency of micronucleated binucleates in the farmworkers group (19.20/1000 binucleates), and the control group (21.76/1000 binucleates). However, among the farmworkers employed in 1993, there was a positive, but not statistically significant, association between micronucleated cell frequency and weeks worked: 16.44/1000 binucleates in those working less than 20 weeks; 23.78/1000 binucleates in those working 20 to 23 weeks; and 25.43/1000 binucleates in those working more than 23 weeks. In those who had ever been employed as farmworkers, there was an elevated frequency of micronucleated cells in the group with the longest history of employment as a farmworker (25.28/1000 binucleates) compared to those with the shortest employment history (16.48/1000 binucleates). This trend remained evident after adjusting for age, red blood cell folate, meat consumption, coffee consumption and recent vaccination. A positive association between the consumption of meat and micronucleus frequency was also observed. Non-meat eaters were likely life-long vegetarians. Micronuclei in farmworkers had a lower frequency of kinetochore positive micronuclei than controls. This study indicates that South Asian berry pickers in British Columbia may be at risk for genetic damage. More studies in other ethnic groups and in males are needed to generalize the findings of this study. More direct measures of exposure are needed to elucidate the sources of genotoxicity.