Table 2. Mean mtDNA copy number by selected known risk factors between melanoma cases and healthy controls.
| Cases (n = 500) | Controls (n = 500) | P value* | |
|---|---|---|---|
| Overall | 1.15 | 0.99 | <0.001 |
| Age (y) | |||
| ≤60 | 1.26 | 1.06 | 0.009 |
| >60 | 1.05 | 0.91 | 0.015 |
| P value # | 0.005 | 0.007 | |
| Sex | |||
| Male | 1.13 | 0.99 | 0.080 |
| Female | 1.17 | 0.98 | 0.034 |
| P value # | 0.534 | 0.672 | |
| Hair color | |||
| Black or brown | 1.14 | 0.99 | 0.056 |
| Blond or red | 1.16 | 0.99 | 0.025 |
| P value # | 0.782 | 0.923 | |
| Eye color | |||
| Not blue | 1.15 | 0.99 | 0.035 |
| Blue | 1.15 | 0.99 | 0.040 |
| P value # | 0.834 | 0.912 | |
| Skin color | |||
| Dark brown | 1.13 | 0.98 | 0.027 |
| Fair | 1.16 | 1.00 | 0.036 |
| P value # | 0.547 | 0.641 | |
| Tanning ability after prolonged sun exposure | |||
| Average or deep | 1.15 | 0.99 | 0.032 |
| Light or none | 1.15 | 0.99 | 0.072 |
| P value # | 0.924 | 0.956 | |
| Lifetime sunburns with blistering | |||
| 0 | 1.14 | 0.98 | 0.033 |
| ≥1 | 1.15 | 1.01 | 0.041 |
| P value # | 0.825 | 0.762 | |
| Freckling in the sun as a child | |||
| No | 1.15 | 0.98 | 0.048 |
| Yes | 1.15 | 1.00 | 0.046 |
| P value # | 0.843 | 0.826 | |
| Family history of skin cancer | |||
| No | 1.13 | 0.95 | 0.026 |
| Yes | 1.20 | 1.07 | 0.034 |
| P value # | 0.012 | 0.024 | |
*The P value comparing mean mtDNA copy number between cases and controls.
#The P value comparing mean mtDNA copy number between groups defined by selected characteristics.