Table 3.

Paired t tests of ARC mean in LEP discordant pairs

Discordant pairs	Mean ARC		Difference, one-tailed p
	stronger twin	weaker twin
All twins (n = 42)	0.169	−0.112	0.022
DZ (n = 28)	0.209	−0.125	0.040
MZ (n = 14)	0.089	−0.089	0.174

ARC = Age related-change in CANTAB performance over 10 years; LEP = LEP at baseline adjusted for birthweight, height and household income.