Table 3

Changes in saliva cotinine concentrations between the first and second samples*

Hospitality workers
Government employeesSmokefree workplacesSmoking only in designated areasNo smoking restrictionsAll workers in smokefree workplacesAll workers in workplaces that allow smoking
Change in cotinine concentration (second—first sample result)†ABCDE (=A+B)F (=C+D)
*The average times between samples were 7.6 and 8.4 hours for hospitality workers in smoking and non-smoking premises, respectively, and 7.2 hours for government employees.
†Setting results less than the limit of detection (0.2 ng/g) at half that value.
‡Subjects with cotinine increases only.
§Subjects with a decrease in cotinine concentration taken as having no change. Assumes that a decrease is the result of clearance of work unrelated ETS exposure.
Mean pre-shift (ng/g)0.120.371.121.600.161.30
Mean post-shift (ng/g)
Number with decrease8 (16%)3 (30%)6 (30%)1 (8%)11 (18%)7 (22%)
Number with no change36 (72%)5 (50%)6 (30%)1 (8%)41 (68%)7 (22%)
Number with increase6 (12%)2 (20%)8 (40%)10 (83%)8 (13%)18 (56%)
    Median (ng/g)‡
    Mean (ng/g)‡
    Range (ng/g)‡0.08–0.30.05–0.130.1–3.60.2–70.05–0.30.1–7.0
Overall mean cotinine increase (ng/g)§
Total number in group50 (100%)10 (100%)20 (100%)12 (100%)60(100%)32(100%)