Table 3.
Adjusted and weighted geometric mean of serum cotinine levels (ng/mL) by secondhand smoke (SHS) exposure source and smoking intensity among adult current smokers in the USA, 1999–2012
| No SHS exposure at home or work (n=2174) | SHS exposure at work only (n=428) | SHS exposure at home only (n=1590) | SHS exposure at home and work (n=355) | |
|---|---|---|---|---|
| Overall (all smoking intensity levels combined) Smoking intensity | 93.3 (87.1–100.0) | 106.0 (92.5–121.5) | 123.2*(114.1–133.1) | 130.2* (116.8–145.2) |
| Light smokers† | 52.0 (47.2–57.4) | 62.7 (51.3–76.5) | 67.2* (57.9–78.0) | 74.4* (58.2–95.2) |
| Moderate/heavy smokers† | 219.4 (204.9–235.1) | 220.9 (193.1–252.6) | 255.2*(236.1–275.8) | 250.5* (223.0–281.3) |
Adjusted for covariates used in multivariable linear regression models, stratified by smoking intensity, from table 2.
*
Pairwise t test yields significant difference in adjusted and weighted geometric mean cotinine level compared with those with no SHS exposure at home or work (p<0.05) for the same smoking intensity level.
†
Light smokers smoked 1–9 cigarettes per day on average over the previous 5 days, moderate/heavy smokers smoked 10+ cigarettes per day on average over the previous 5 days.