Park Su San, Lee Ju Yul, Cho Sung-Il
School of Public Health and Institute of Health and Environment, Seoul National University, Korea.
J Prev Med Public Health. 2007 Jul;40(4):297-304. doi: 10.3961/jpmph.2007.40.4.297.
We investigated the validity of the dipstick method (Mossman Associates Inc. USA) and the expired CO method to distinguish between smokers and nonsmokers. We also elucidated the related factors of the two methods.
This study included 244 smokers and 50 ex-smokers, recruited from smoking cessation clinics at 4 local public health centers, who had quit for over 4 weeks. We calculated the sensitivity, specificity and Kappa coefficient of each method for validity. We obtained ROC curve, predictive value and agreement to determine the cutoff of expired air CO method. Finally, we elucidated the related factors and compared their effect powers using the standardized regression coefficient.
The dipstick method showed a sensitivity of 92.6%, specificity of 96.0% and Kappa coefficient of 0.79. The best cutoff value to distinguish smokers was 5-6 ppm. At 5 ppm, the expired CO method showed a sensitivity of 94.3%, specificity of 82.0% and Kappa coefficient of 0.73. And at 6 ppm, sensitivity, specificity and Kappa coefficient were 88.5%, 86.0% and 0.64, respectively. Therefore, the dipstick method had higher sensitivity and specificity than the expired CO method. The dipstick and expired CO methods were significantly increased with increasing smoking amount. With longer time since the last smoking, expired CO showed a rapid decrease after 4 hours, whereas the dipstick method showed relatively stable levels for more than 4 hours.
The dipstick and expired CO methods were both good indicators for assessing smoking status. However, the former showed higher sensitivity and specificity and stable levels over longer hours after smoking, compared to the expired CO method.
我们研究了试纸法（美国莫斯曼联合公司）和呼出一氧化碳（CO）法区分吸烟者和非吸烟者的有效性。我们还阐明了这两种方法的相关因素。
本研究纳入了从4个当地公共卫生中心的戒烟诊所招募的244名吸烟者和50名已戒烟者，他们已戒烟超过4周。我们计算了每种方法有效性的敏感性、特异性和kappa系数。我们获得了ROC曲线、预测值和一致性以确定呼出气体CO法的临界值。最后，我们阐明了相关因素，并使用标准化回归系数比较了它们的效应大小。
试纸法的敏感性为92.6%，特异性为96.0%，kappa系数为0.79。区分吸烟者的最佳临界值为5 - 6 ppm。在5 ppm时，呼出CO法的敏感性为94.3%，特异性为82.0%，kappa系数为0.73。在6 ppm时，敏感性、特异性和kappa系数分别为88.5%、86.0%和0.64。因此，试纸法比呼出CO法具有更高的敏感性和特异性。试纸法和呼出CO法均随吸烟量增加而显著升高。自上次吸烟后时间越长，呼出CO在4小时后迅速下降，而试纸法在4小时以上显示相对稳定的水平。
试纸法和呼出CO法都是评估吸烟状态的良好指标。然而，与呼出CO法相比，前者显示出更高的敏感性和特异性，且在吸烟后较长时间内水平稳定。
