Parent-completed SDQs were available on 4,610 (58 %) children. Mothers who reported consuming ≥4 drinks were less likely than other mothers to provide SDQs (52 vs. 60 %; χ 2 = 40.08, p < 0.001). Other maternal correlates of non-response included younger age, higher parity, smoking and use of cannabis, depression, being unmarried, rented tenure, and lower level of education (Online Supplementary Table 1). Teacher-completed SDQs were available on 4,274 (54 %) and KS2 data on 6,939 (87 %) children. Their availability (Online Supplementary Tables 2 and 3) was not associated with drinking status, but other correlates of non-availability included use of cannabis, being unmarried and rented tenure (both SDQ and KS2), and lower parity and higher level of maternal education (KS2 only).
