Table 1.

Instrumental variable analysis of the association between academic achievement and the risk for alcohol use disorder (AUD)

Variable	AA (crude) HR [95% CI]	Instrumental variable HR [95% CI]	Instrumental variable controlling for parental educational and risk for AUD HR [95% CI]	MZ twins expected from co-relative design HR [95% CI]
AUD	2.14 [2.11, 2.17]	1.52 [1.28, 1.80]	1.43 [1.20, 1.69]	1.44 [1.35, 1.52]
AUD—males	2.27 [2.23, 2.30]	1.45 [1.18, 1.77]	1.36 [1.12, 1.66]	1.66 [1.49, 1.84]
AUD—females	2.00 [1.94, 2.03]	1.81 [1.32, 2.45]	1.67 [1.23, 2.28]	1.30 [1.12, 1.51]

Notes: AA = academic achievement; HR = hazard ratio; CI = confidence interval; MZ = monozygotic.