Table 1.

Sociodemographic characteristics for ALSPAC, CSEW and STS/ATS samples

Sociodemographic	ALSPAC n = 3389 % (95% CI)	CSEW n = 1165 %	RD% (95% CI) P value	Smoking Toolkit Study and Alcohol Toolkit Study n = 950 %	RD% (95% CI) P value
Female	51.8 (49.9–53.7)	53 (50.0–55.9)	−1.2 (−4.5–2.2) P = 0.556	47.4 (44.1–50.6)	4.4 (0.8–8.0) P = 0.008
Not in education, employment or training (NEET)	8.4 (7.4–9.6)	4 (3.0–5.3)	4.4 (2.9–5.9) P ≤ 0.001	–	–
Parents' lower socioeconomic status	4.2 (3.4–5.3)	–	–	8.7 (7.0–10.7)	−4.5 (−6.4–2.6) P ≤ 0.001

ALSPAC = Avon Longitudinal Study of Parents and Children; CSEW = Crime Survey for England and Wales; RD% = risk difference % (ALSPAC as comparator); STS/ATS = Smoking and Alcohol Toolkit Studies.