Table 3.

Association between relative mtDNA copy number and colorectal cancer risk

All casesIncident casesbPrevalent casesb
mtDNA levelaNo. of controlsNORc (95% CI)NORc (95% CI)NORc (95% CI)
1st quartile2191301.81 (1.13–2.89)613.51 (1.60–7.68)691.32 (0.77–2.26)
2nd quartile219591.00221.00371.00
3rd quartile219741.40 (0.86–2.29)271.58 (0.69–3.62)471.20 (0.68–2.11)
4th quartile2171593.40 (2.15–5.36)584.66 (2.15–10.11)1013.37 (2.02–5.62)
P value for curvilinearity<0.0001<0.0001<0.0001
  • aQuartile levels are based on gender-specific cutoff values: men ≤ 0.36, 0.37–0.47, 0.48–0.62, >0.62; women ≤ 0.40, 0.41–0.54, 0.55–0.71, >0.71.

  • bBlood samples were collected 28.9 (SD = 26.4) months before cancer diagnosis for incident cases and 13.1 (SD = 12.5) months after cancer diagnosis for prevalent cancer cases.

  • cAdjusted for age at sample collection, gender, BMI, smoking status, alcohol drinking, weekly moderate or vigorous physical activity, history of diabetes, and batch number for mtDNA copy number assay.