Time using e-cigarettes (in months), prevalence of using e-cigarettes with nicotine, number of cartridges with nicotine per week and number of milligrams of nicotine that cartridges contain among current e-cigarette users according to sociodemographics and smoking habits in Barcelona, Spain (2015)
| n* | Time using e-cigarette in months | Used e-cigarettes with nicotine | n† | Number of cartridges with nicotine per week | Milligrams of nicotine of the cartridges | ||||||
| Median (IQR) | P value | % | P value | OR (95% CI) | Median (IQR) | P value | Median (IQR) | P value | |||
| Overall | 600 | 6 (3–12) | – | 56.0 | – | – | 336 | 2 (1–3) | – | 10 (6–13) | – |
| Sex | 0.011‡ | 0.001§ | 0.211‡ | 0.454‡ | |||||||
| Male | 219 | 7 (4–15) | 65.3 | 1.79 (1.26 to 2.53) | 143 | 2 (1–4) | 11 (6–13) | ||||
| Female | 381 | 6 (3–12) | 50.7 | 1 | 193 | 1 (1–3) | 10 (6–13) | ||||
| Age (years) | <0.001¶ | 0.001¶ | 0.262¶ | ||||||||
| <25 | 140 | 4 (2–7.75) | 40.7 | <0.001** | 1 | 57 | 1 (1–2) | 11 (6–13) | |||
| 25–44 | 299 | 8 (3.5–12) | 58.9 | 2.10 (1.39 to 3.17) | 176 | 2 (1–4) | 10 (6–13) | ||||
| 45–64 | 153 | 8 (5.33–14.5) | 63.4 | 2.41 (1.50 to 3.88) | 97 | 2 (1–3) | 10 (6–12) | ||||
| ≥65 | 8 | 12 (7.88–22.53) | 75.0 | 4.06 (0.78 to 21.12) | 6 | 2 (0.875–9) | 8.5 (6–13) | ||||
| Education level | <0.001¶ | 0.919§ | 0.302¶ | 0.995¶ | |||||||
| Primary or less | 55 | 7 (2–18) | 58.2 | 1.39 (0.75 to 2.58) | 32 | 2 (1–8) | 8 (6–13) | ||||
| Secondary | 291 | 6 (3–12) | 55.3 | 1.22 (0.85 to 1.76) | 161 | 1 (1–3) | 10 (6–13) | ||||
| University or more | 254 | 8 (4–13) | 56.3 | 1 | 143 | 2 (1–3) | 10 (6–12) | ||||
| Smoking status (current) | 0.023‡ | <0.001§ | 0.095‡ | 0.103‡ | |||||||
| Smoker | 391 | 6 (3–12) | 63.7 | 2.46 (1.73 to 3.50) | 249 | 2 (1–3) | 11 (6–13) | ||||
| Non-smoker | 209 | 7 (4–14) | 41.6 | 1 | 87 | 2 (1–6) | 8 (6–12) | ||||
| Number of cigarettes smoked currently | 0.099¶ | 0.001§ | 0.435¶ | 0.458¶ | |||||||
| <10 | 226 | 6 (3–12) | 57.1 | 1 | 129 | 2 (1–3) | 10 (6–13) | ||||
| 10–19 | 143 | 6 (3–12) | 69.9 | 1.73 (1.10 to 2.71) | 100 | 1 (1–2.75) | 11 (7–13) | ||||
| ≥20 | 22 | 12 (3–19) | 90.9 | 6.76 (1.53 to 29.92) | 20 | 1 (1–4.5) | 11 (6–13) | ||||
| Smoking status (before) | 0.004‡ | <0.001§ | 0.236† | 0.070† | |||||||
| Smoker | 521 | 6 (3–12) | 62.0 | 7.08 (3.77 to 13.29) | 323 | 2 (1–3) | 10 (6–13) | ||||
| Non-smoker | 79 | 6 (2–9) | 16.5 | 1 | 13 | 2 (1–5.5) | 13 (7.5–16) | ||||
| Number of cigarettes smoked before | <0.001¶ | <0.001§ | 0.012¶ | 0.366¶ | |||||||
| <10 | 78 | 6 (3–12) | 41.0 | 1 | 32 | 1.5 (1–3) | 12 (6–13) | ||||
| 10–19 | 272 | 6 (3–12) | 56.6 | 1.74 (1.04 to 2.93) | 154 | 1 (1–3) | 10 (6–13) | ||||
| ≥20 | 171 | 12 (6–18) | 80.1 | 5.17 (2.83 to 9.41) | 137 | 2 (1–5) | 10 (6–12) | ||||
| Nicotine dependence†† before e-cigarette initiation | 0.120‡ | 0.102§ | 0.762‡ | 0.801‡ | |||||||
| Low | 499 | 6 (3–12) | 62.7 | 2.38 (0.98 to 5.78) | 312 | 2 (1–3) | 10 (6–13) | ||||
| Medium/high | 22 | 12 (6–12.5) | 45.5 | 1 | 10 | 2 (1–4.25) | 10 (8–12) | ||||
OR (adjusted for sex, age and education level).
*All samples.
†E-cigarette users who used liquids with nicotine (n=336).
‡Mann-Whitney U test.
§χ2 test.
¶Kruskal-Wallis test.
**Fisher’s exact test.
††Measured with the Heavy Smoking Index (low: 0–2; medium: 3–4; high: 5–6).