Table 3. Risk of PCa as estimated by mtDNA copy number in subgroups of cases and controls with selected characteristics.

Variable	Cases, No.a		Controls, No.a		OR (95%CI)b	P value
	High	Low	High	Low
Age, years
<70	65	26	45	46	2.39 (1.28–4.47)	0.006
≥70	60	42	52	51	1.45 (0.83–2.53)	0.194
BMI, kg/m2
<25	76	48	69	69	1.54 (0.97–2.64)	0.063
≥25	49	20	28	28	2.42 (1.14–5.16)	0.022
Smoking status
Never	61	32	46	50	1.98 (1.09–3.61)	0.026
Ever	64	36	51	47	1.61 (0.90–2.87)	0.110
Daily dietary fat intakec
Low/moderate	89	44	77	79	2.01 (1.24–3.25)	0.005
High	36	24	20	18	1.19 (0.51–2.80)	0.685

Abbreviations: PCa  =  prostate cancer; mtDNA  =  mitochondrial DNA; OR  =  odds ratio; CI  =  confidence intervals; BMI  =  body mass index.

^aCases and controls were dichotomized based on the median mtDNA copy number in controls.

^bAnalyses were performed using unconditional models adjusted for age, BMI, daily dietary fat intake, smoking status and family history of PCa where appropriate.

^cThe three categories of low, moderate and high are defined in Table 1.