Table 1.

Baseline characteristics of case and control subjects, ATBC study

Cases(n = 203)Controls(n = 656)
MtDNA copy number, mediana130.4100.0–161.8122.2100.0–147.10.04
Age, y5854–615854–620.78
Height, cm174170–179173169–1780.14
BMI (units)26.223.9–28.225.723.7–28.50.57
Smoking history
 Total cigarettes smoked/d2015–251815–250.88
 Years of smoking3731–423631–420.08
 Pack-years of smoking3524–453423–440.13
Medical history (%)7.4
 Diabetes mellitus24.40.09
 Peptic ulcers75.417.10.70
Primary school education or less (%)42.477.90.45
Living in city (%)7.447.70.18
Daily dietary intakec
 Energy, kcal2,6882,236–3,1702,5852,164–3,1360.25
 Total fat, gc123114.3–133122113–1320.28
 Saturated fat, gc5345–645243–600.07
 Carbohydrate, gc264236–288269246–2890.10
 Protein, gc9487–10094.186–1010.79
 Folate, μgc337275–402328269–3920.37
 Alcohol, g9.22.42–26.810.72.5–24.00.96
Physical activity (%)
 Occupational activity0.91
  Not working43.845
 Leisure activity0.49
  Light or moderate5355.3
  Exercising to keep fit6.98.7
Serum levels–baselinec
 Baseline AT, μg/L11.99.7–13.811.810.0–13.60.65
 Baseline BC, μg/L162110.0–270190122.0–2810.17
 Retinol, μg/L574479.0–664574496.0–6680.53
 AT, μg/Ld17.214.9–20.817.615.2–20.10.98
 BC, μg/Ld3,0161,386–4,81731172,124–3,9070.87
 Retinol, μg/L596494–674584503–6830.72
Randomization group (%)
 Alpha-Tocopherol (AT)24.625.60.87
 Beta-Carotene (BC)21.724.9
 AT and BC26.124.2
  • aUnits of measurement = number of copies of mtDNA per cell.

  • bP values for categorical variables were based on the χ2 test or Fisher's exact test; P values for continuous variables were based on Wilcoxon's rank-sum test.

  • cAdjusted by total energy intake. Number of controls = 609.

  • dNumber of controls = 642; Postintervention serum measures limited to subjects in the intervention arm only.