Table II.
mtDNA copy number by characteristics of OPL patients and control subjects
| Variables | OPL patients | Controls | P a | ||
|---|---|---|---|---|---|
| n | mtDNA copy number, mean (SD) | n | mtDNA copy number, mean (SD) | ||
| Overall | 143 | 1.36 (0.74) | 357 | 1.11 (0.32) | <0.001 |
| Sex | |||||
| Male | 87 | 1.43 (0.87) | 215 | 1.10 (0.33) | <0.001 |
| Female | 56 | 1.26 (0.47) | 142 | 1.13 (0.29) | 0.019 |
| P a | 0.203 | 0.312 | |||
| Ageb | |||||
| ≤59 | 72 | 1.41 (0.89) | 186 | 1.09 (0.27) | <0.001 |
| >59 | 71 | 1.32 (0.57) | 171 | 1.14 (0.36) | 0.004 |
| P a | 0.446 | 0.133 | |||
| Race | |||||
| Caucasians | 126 | 1.33 (0.70) | 323 | 1.11 (0.32) | <0.001 |
| Others | 17 | 1.60 (1.02) | 34 | 1.10 (0.31) | 0.012 |
| P a | 0.172 | 0.846 | |||
| Smoking status | |||||
| Never | 60 | 1.40 (0.81) | 182 | 1.09 (0.27) | <0.001 |
| Ever | 83 | 1.34 (0.69) | 175 | 1.13 (0.35) | 0.002 |
| P a | 0.628 | 0.216 | |||
| Pack-years in ever smokersc | |||||
| <20 | 20 | 1.51 (1.00) | 92 | 1.10 (0.38) | 0.003 |
| ≥20 | 44 | 1.27 (0.54) | 83 | 1.17 (0.32) | 0.179 |
| P a | 0.218 | 0.251 | |||
| Alcohol consumptiond | |||||
| Never | 53 | 1.36 (0.56) | 249 | 1.11 (0.30) | <0.001 |
| Ever | 85 | 1.33 (0.76) | 108 | 1.12 (0.35) | 0.011 |
| P a | 0.792 | 0.892 | |||
aAll P values were determined by the Student’s t-test.
bThe median age in the control group was 59 years.
cPack-years were not available for 19 ever smokers.
dIn the OPL group, five patients did not answer the alcohol consumption question.