Selected characteristics (%) of the study samples across six countries
| Australia (n = 403) | Hong Kong (n = 336) | Netherlands (n = 351) | South Africa (n = 291) | United Kingdom (n = 164) | United States (n = 241) | |
|---|---|---|---|---|---|---|
| Current smoker | 20.4 | 3.0 | 14.8 | 19.6 | 22.8 | 21.3 |
| Former smoker | 12.7 | 3.0 | 11.3 | 8.2 | 17.3 | 11.1 |
| Age (years) | ||||||
| ⩽18 | 38.3 | 16.7 | 14.0 | 8.7 | 20.9 | 24.9 |
| 19–20 | 42.0 | 62.2 | 34.8 | 22.9 | 38.7 | 62.2 |
| 21–22 | 8.8 | 19.0 | 23.9 | 18.8 | 11.0 | 10.0 |
| 23–29 | 7.3 | 1.8 | 24.8 | 38.5 | 10.4 | 2.9 |
| ⩾30 | 3.8 | 0.3 | 2.6 | 11.1 | 19.0 | 0.0 |
| Men1-150 | 22.7 | 40.0 | 19.7 | 47.9 | 24.5 | 38.6 |
| Family income1-150 | ||||||
| Lower | 2.8 | 11.0 | 1.7 | 27.0 | 5.5 | 2.5 |
| Lower-middle | 15.0 | 38.2 | 4.6 | 22.5 | 12.3 | 11.3 |
| Middle | 46.6 | 40.0 | 33.7 | 35.1 | 49.1 | 40.0 |
| Upper-middle | 30.1 | 10.4 | 50.7 | 13.7 | 27.0 | 42.2 |
| Upper | 5.5 | 0.3 | 9.2 | 1.8 | 6.1 | 4.2 |
| Parent(s) smoked1-150 | ||||||
| % Yes | 51.1 | 47.6 | 63.0 | 49.0 | 46.0 | 57.3 |
| No of friends who smoke1-150 | ||||||
| 0 | 11.7 | 26.2 | 12.0 | 9.3 | 6.1 | 6.7 |
| 1–2 | 26.9 | 47.3 | 33.3 | 22.8 | 29.4 | 30.8 |
| 3–4 | 22.4 | 16.1 | 23.9 | 16.2 | 18.4 | 19.2 |
| 5–6 | 15.9 | 4.5 | 13.7 | 8.3 | 14.7 | 15.8 |
| ⩾7 | 23.1 | 6.0 | 17.1 | 43.4 | 31.3 | 27.5 |
↵1-150 p<0.001.