. Author manuscript; available in PMC: 2022 Jan 1.

Published in final edited form as: Behav Genet. 2020 Nov 4;51(1):82–96. doi: 10.1007/s10519-020-10026-8

Table 2:

Product-moment, polychoric & tetrachoric correlations for measures of BMI and ITOB by zygosity and sex: twin (within-trait cross-twin) correlations (2a), phenotypic (cross-trait within-twin) correlations (2b) and cross-trait cross-twin correlations (2c)

	MZ	DZ		MZf	DZf	MZm	DZm	Dzo
BMI	0.64	0.41	BMI	0.81	0.38	0.73	0.30	0.31
BMIo	0.59	0.43	BMIo	0.79	0.37	0.73	0.32	0.32
BMIb	0.70	0.48	BMIb	0.84	0.47	0.75	0.37	0.34
ITOB	0.51	0.34	ITOB	0.61	0.36	0.59	0.27	0.24
ITOBo	0.64	0.40	ITOBo	0.76	0.45	0.68	0.32	0.28
ITOBb	0.68	0.49	ITOBb	0.73	0.61	0.79	0.42	0.31

	total	female	male		same-sex	female	male
BMI-ITOB	0.10	0.03	0.08	BMI-ITOB	0.11	0.02	0.09
BMIo-ITOBo	0.11	0.01	0.07	BMIo-ITOBo	0.14	0.00	0.10
BMIb-ITOBb	0.10	0.01	0.05	BMIb-ITOBb	0.10	−0.02	0.08

	MZ	DZ		MZf	DZf	MZm	DZm	Dzo
BMI-ITOB	0.03	0.09	BMI-ITOB	0.04	0.02	0.13	0.04	0.09
BMIo-ITOBo	0.02	0.11	BMIo-ITOBo	0.05	−0.02	0.15	0.04	0.07
BMIb-ITOBb	−0.02	0.10	BMIb-ITOBb	0.03	−0.04	0.15	0.06	0.07

MZ: monozygotic twins; DZ: dizygotic twins; m: male; f: female; o: opposite sex twins