Table 4.

Factors associated with NCV by linear regression analysis.

β unstandardized coefficients, SE: standard error, NCV: nailfold capillary blood velocity, NCV_5min: nailfold capillary blood velocity after 5 minutes of cigarette smoking, NCV_30min: nailfold capillary blood velocity after 30 minutes of cigarette smoking, ECO_5min: concentration of expiratory CO after 5 minutes of cigarette smoking detected by micro smokerlyzer, ECO_30min: concentration of expiratory CO after 30 minutes cigarette smoking detected by micro smokerlyzer, PD: average pack of the daily smoking, SY: total smoking years, PY: total pack-year calculated by PD × SY.