| Boys | Girls | ||
---|---|---|---|---|
 | N = 2646 | N = 2551 | ||
 | Mean | 95% CI | Mean | 95% CI |
Age (years, mean) | 15.1 | (15.0–15.1) | 15.1 | (15.0–15.1) |
Regular alcohol consumption (%)a | 29.0 | (26.7–31.3) | 16.5 | (14.7–18.4) |
Current smoking (%) | 22.3 | (20.4–24.1) | 22.8 | (21.1–24.5) |
Physical activity (hours per week, mean) | 8.2 | (7.8–8.5) | 5.3 | (5.0–5.5) |
Vitamin supplement use (%)b | 6.6 | (5.6–7.7) | 4.8 | (3.8–5.7) |
Mineral supplement use (%)b | 3.0 | (2.3–3.6) | 1.5 | (1.0–2.0) |
BMI (kg/m2) | 21.2 | (21.0–21.4) | 21.5 | (21.3–21.7) |