Subject Characteristics at Baseline and Year 3.

<p>ECG = electrocardiogram cpd = cigarettes per day.</p>*<p>Carbon monoxide levels for the current smokers at year 3 was 19.1(11.0) ppm.</p>**<p>Cigarettes per day for the current smokers at year 3 was 13.5 (8.2) cpd.</p>