3. Results
This study involved 128 individuals (men), 71 of whom reported
working in jobs with exposure to coal and 57 of whom reported
working at different jobs (unexposed group). No significant differences in average age were detected between the unexposed
(41.51 ± 15.04 years) and exposed groups (42.75 ± 8.45 years)
(P = 0.273–Student’s t-test). The mean exposure time (i.e., time
of experience in the coal industry) for the exposed group was
12.63 ± 7.87 years. All individuals in this study were required to
be non-smokers to eliminate confounding factors.
The comet assay and MN test parameters analyzed are presented
in Table 1. Based on the comet assay results, the exposed group
had significantly increased DI and DF compared with unexposed
individuals (P = 0.002 and P < 0.001, respectively; Mann–Whitney
U-test). Significant differences were observed between the exposed
and unexposed groups based on the MN and nucleoplasmic bridge
frequencies (P < 0.001, Mann–Whitney U-test).
Unexposed individuals had higher frequencies in the number of
cells in class 0 (P = 0.0009), and the exposed group had an increased
number of cells in classes 1, 2 and 3 (P = 0.0016, P = 0.042 and
P = 0.0087, respectively). Fig. 1 shows the distribution of damage
classes in each group.
No correlation was found between age or exposure time and
the different parameters of the comet assay and MN test (data not
shown).
The exposed individuals exhibited lower average levels of TBARS
and CAT, while the mean SOD levels were higher in this group (both
P < 0.001–Mann–Whitney U-test; Table 2).
A hematocrit analysis demonstrated the differences between
the exposed and unexposed groups (P = 0.0119), with the exposed
individuals exhibiting higher hematocrit levels (43.84 ± 4.72) than
the unexposed individuals (41.37 ± 3.89)