Table 3.

Bivariate twin model results split by sex and sample

		Netherlands		Finland		Minnesota
		Male	Female	Male	Female	Male	Female
RSI	A	0.83 [0.01, 0.85]	0.66 [0.42, 0.82]	0.07 [-0.14, 0.84]	0.68 [0.01, 0.77]	0.60 [-0.70, 1.00]	0.45 [0.13, 0.54]
	C	-0.01 [-0.02, 0.69]	0.15 [0.01, 0.39]	0.68 [-0.01, 0.77]	0.18 [-0.11, 0.70]	0.17 [-0.25, 0.51]	0.31 [-0.01, 0.61]
	E	0.18 [0.12, 0.24]	0.19 [0.16, 0.24]	0.25 [0.17, 0.42]	0.14 [0.11, 0.22]	0.23 [0.16, 0.33]	0.23 [0.16, 0.33]
CI	A	0.26 [0.01, 0.81]	0.52 [0.01, 0.78]	0.70 [-0.08, 0.77]	0.41 [-0.01, 0.49]	0.54 [0.17, 0.63]	-0.06 [-0.37, 0.89]
	C	0.47 [0.11, 0.57]	0.20 [-0.10, 0.59]	0.04 [-0.19, 0.78]	0.40 [-0.02, 0.60]	0.29 [-1.00, 0.64]	0.75 [0.48, 0.83]
	E	0.28 [0.22, 0.34]	0.27 [0.22, 0.35]	0.26 [0.16, 0.38]	0.19 [0.10, 0.27]	0.16 [0.02, 0.26]	0.31 [0.24, 0.45]
Cor.	Phen.	0.58 [0.54, 0.62]	0.58 [0.55, 0.61]	0.51 [0.45, 0.56]	0.51 [0.46, 0.56]	0.70 [0.57, 0.76]	0.69 [0.64, 0.75]
	A	1.00 [0.89, 1.00]	0.55 [0.51, 0.61]	1.00 [-1.00, 1.00]	0.69 [-0.21, 1.00]	0.70 [-1.00, 0.75]	NA
	C	NA	0.85 [-1.00, 1.00]	1.00 [-1.00, 1.00]	0.31 [-1.00, 1.00]	1.00 [-1.00, 1.00]	0.81 [-1.00, 1.00]
	E	0.44 [0.22, 0.56]	0.48 [0.34, 0.69]	0.48 [-0.24, 0.70]	0.36 [0.04, 0.47]	0.41 [0.10, 0.98]	0.67 [0.42, 1.00]

Note A refers to additive genetic component; C refers to shared environmental component, and E refers to unique environmental component; Cor. refers to the correlation between substances; Phen. refers to the phenotypic correlation. NA indicates a correlation that cannot be estimated due to one or more negative point estimates, - indicates bound did not converge. The first number refers to the point estimate and the number in brackets is the 95% confidence interval around that point estimate. RSI refers to regular smoking initiation; CI refers to cannabis initiation