Table 5

Correlation of FeNO with observed smoking variables and eCO ppm

ParametersFeNO (ppb)
R valueP value
Smoking duration (years)−0.138<0.001*
No of cigarettes/days−0.1320.014†
Brinkman Index−0.243<0.001*
eCO ppm−0.281<0.001*
  • (Spearman correlation)

  • *p<0.001.

  • †*p<0.05.

  • eCO, exhaled breath carbon monoxide; FeNO, fractional exhaled nitric oxide.