Table 2.

Proband-wise Concordance and Phenotypic Correlation in MZ and DZ Twin Pairs, and Estimated Genetic (A) and Environmental Effects (C and E) of the Best Fitting Model of Different DED Outcome Variables

DED Outcome Variable	Distribution Used for Twin Modeling	No. of Complete Twin Pairs, MZ/DZ	Probandwise Concordance, %		Correlation (95% CI)		Additive Genetic Effects, A (95% CI)	Environmental Effects (95% CI)
			MZ	DZ	MZ	DZ		Common, C	Unique, E
DED symptoms in preceding 3 mos	Dichotomous	838/622	34.1	26.7	0.30 (0.17 to 0.42)	0.13 (−0.02 to 0.28)	0.29 (0.18 to 0.40)	–	0.71 (0.60 to 0.82)
DED diagnosis and current use of artificial tears	Dichotomous	716/516	32.5	16.1	0.44 (0.27 to 0.58)	0.12 (−0.11 to 0.33)	0.41 (0.26 to 0.56)	–	0.59 (0.44 to 0.74)
Interblink interval, s	Ordinal, quartiles	108/175	–	–	0.30 (0.09 to 0.48)	0.06 (−0.13 to 0.24)	0.25 (0.07 to 0.42)	–	0.75 (0.58 to 0.93)
Tear osmolarity, mOsm/L	Normal	99/145	–	–	0.39 (0.23 to 0.53)	0.22 (0.04 to 0.38)	0.40 (0.25 to 0.53)	–	0.60 (0.47 to 0.75)
Schirmer-1 value, mm/5 min	Ordinal, quartiles	103/157	–	–	0.56 (0.39 to 0.69)	0.35 (0.17 to 0.50)	0.58 (0.43 to 0.70)	–	0.42 (0.30 to 0.57)
TBUT, s	Normal	104/162	–	–	0.33 (0.17 to 0.50)	0.27 (0.12 to 0.41)	–	0.30 (0.18 to 0.40)	0.71 (0.60 to 0.82)
Blepharitis signs	Dichotomous	83/164	88.2	83.0	0.75 (0.52 to 0.90)	0.51 (0.26 to 0.71)	0.78 (0.59 to 0.90)	–	0.22 (0.10 to 0.41)