Table 1 Distribution of respondent characteristics in the incidence and prevalence series.
| Characteristic | Referent series for the incidence analysis (n = 823 person‐surveys) | Prevalence series (n = 1673 person‐surveys) | ||||
|---|---|---|---|---|---|---|
| Mean (median) | SD | % | Mean (median) | SD | % | |
| Age (years) | 14.6 | 1.5 | 14.8 | 1.4 | ||
| Depression symptoms score | 2.2 | 0.7 | 2.3 | 0.8 | ||
| Average cigarette consumption in the past 3 months (cig/month) | 54.6 (9.0) | 119.7 | 159.5 (67.0) | 219.6 | ||
| Average cigarette consumption in the past 3–6 months (cig/month) | 32.2 (1.5) | 92.9 | 133.7 (32.5) | 211.0 | ||
| Time since the onset of cigarette use (years) | 1.1 (1.0) | 1.1 | 1.6 (1.5) | 1.2 | ||
| Male sex | 34 | 29 | ||||
| Slowest CYP2A6 activity status | 3 | 5 | ||||
| Positive TD status 6 months ago | 24 | |||||
McGill University Study on the Natural History of Nicotine Dependence (NDIT Study), Montreal, Quebec, 1999–2004.
SD, standard deviation; TD, tobacco dependence.