Table 3.

Spearman correlation coefficients of biomarkers with cigarettes per day and other biomarkers

Age (y)Cigarettes/dTotal NNALTotal 1-HOPTotal cotinineCO
Age (y)10.1240.149−0.0020.1310.046
0.01430.00560.96680.01380.4013
Cigarettes/d10.4780.1260.4260.631
<0.00010.0168<0.0001<0.0001
Total NNAL10.1830.6190.586
0.0006<0.0001<0.0001
Total 1-HOP10.2200.182
<0.00010.0011
Total cotinine10.535
<0.0001
CO1
  • NOTE: Each cell contains two values: (a) Spearman correlation coefficient; (b) P value of testing if the correlation is significant.