Table II.
BPDE-induced chromatid breaks per cell by age, sex, race, smoking history, cryopreservation duration and seeding count of cells in study subjects
| Variables | n | Number of chromatid breaks per cell | P-value |
| Geometric mean (95% CI)a | |||
| Age (years)b | 0.546 | ||
| <57.5 | 139 | 0.23 (0.21–0.26) | |
| ≥57.5 | 139 | 0.22 (0.20–0.25) | |
| Gender | 0.026 | ||
| Female | 147 | 0.25 (0.22–0.28) | |
| Male | 131 | 0.21 (0.19–0.23) | |
| Race | 0.824 | ||
| Non-Hispanic white | 207 | 0.23 (0.21–0.25) | |
| Hispanic | 53 | 0.24 (0.20–0.28) | |
| Others | 18 | 0.18 (0.14–0.24) | |
| Current smoking status | 0.012 | ||
| Current | 127 | 0.25 (0.23–0.28) | |
| Former | 151 | 0.21 (0.19–0.23) | |
| Pack-years (pack × year)b | 0.400 | ||
| <35 | 139 | 0.22 (0.20–0.25) | |
| ≥35 | 139 | 0.24 (0.21–0.26) | |
| Cryopreservation duration (days)b | 0.258 | ||
| <383 | 139 | 0.24 (0.22–0.27) | |
| ≥383 | 139 | 0.22 (0.20–0.24) | |
| Seeding count (×106 per culture)b | <0.001 | ||
| <1.6 | 136 | 0.27 (0.24–0.30) | |
| ≥1.6 | 142 | 0.19 (0.17–0.22) |
CI, confidence interval.
a
Least squares means (95% CI) were calculated based on natural log-transformed number of chromatid breaks per cell with adjustment for gender, current smoking status and seeding count and then were converted to their exponential form, i.e. geometric mean (95% CI).
b
Categorized by median of selected variables among 278 study subjects.