Table 4.

Risk of renal cell carcinoma as estimated by mtDNA content^*

mtDNA copy number	Case patients, No. (%)	Control subjects, No. (%)	Adjusted OR† (CI)
By median‡
≥1.219	102 (39)	138 (49)	1.0 (reference)
<1.219	158 (61)	143 (51)	1.53 (1.07 to 2.19)
By spline modeling cutoff points
≥1.216	102 (39)	143 (51)	1.0 (reference)
0.814–1.215	123 (47)	125 (44)	1.43 (0.98 to 2.07)
<0.814	35 (14)	13 (5)	4.15 (2.03 to 8.48)
			P for trend <.001

^*mtDNA = mitochondrial DNA; OR = odds ratio; CI = confidence interval.

^†Odds ratios were adjusted by age, sex, smoking status, hypertension history, and body mass index. The trend in odds ratios was tested by use of the test for linear trend. All statistical tests were two-sided.

^‡Median is based on levels in control subjects.