their offspring were mean age 15.5 years) and three time points for the offspring (at birth, childhood and adolescence.2 We investigated the association between a genetic risk score for smoking (ever vs never) and maternal education in ALSPAC, and in the ARIES sub-sample. The results are shown in Table 3, and indicated that the genetic risk score for smoking and maternal education are associated in ARIES, but not in the full sample. Table 3Associations between a genetic risk score for smoking and maternal education, in ALSPAC and ARIESAssociation between genetic risk score and ever smoking in ALSPACNOR (95% CI)PSmoking genetic risk score 172911.07 (1.02 to 1.12)0.003Association with being in the ARIES sub-studyNOR (95% CI)PSmoking (ever vs never)132490.59 (0.52 to 0.68)<0.001Smoking genetic risk scorea78371.00 (0.93 to 1.07)0.92Maternal educationb124931.86 (1.58 to 2.19)<0.001Association between smoking/smoking genetic risk score and maternal education in ALSPAC and ARIESALSPACNOR (95% CI)PSmoking (ever vs never)121180.45 (0.40 to 0.50)<0.001Smoking genetic risk scorea70461.01 (0.95 to 1.08)0.74ARIESNOR (95% CI)PSmoking (ever vs never)9860.61 (0.44 to 0.84)0.003Smoking genetic risk scorea7911.20 (1.02 to 1.41)0.03aGenetic risk score including variants reaching P < 0.05 for association with ever vs never smoking in the Tobacco and Genetics Consortium GWAS (see Supplementary Material, available at IJE online). Associations
