Table 3.

Odds ratios 100g increase in birth weight for twin-pairs discordant for ASD and ASD-like traits on the A-TAC using conditional logistic regression.

		ASD	Restricted/ Repetitive	Language	Social
Overall	No. discordant pairs*	78	375	309	78
	OR 100g increase in BW (95% CI)	0.87‡ (0.78, 0.96)	0.95† (0.90, 0.99)	0.90‡ (0.85, 0.95)	0.91† (0.82, 1.00)
MZ	No. discordant pairs*	20	108	106	25
	OR 100g increase in BW (95% CI)	0.86† (0.76, 0.97)	0.93 (0.85, 1.03)	0.85‡ (0.77, 0.95)	0.88 (0.73, 1.06)
DZ	No. discordant pairs*	44	214	161	44
	OR 100g increase in BW (95% CI)	0.86† (0.74, 1.00)	0.94 (0.88, 1.01)	0.91† (0.85, 0.98)	0.91 (0.78, 1.05)
Males	No. discordant pairs	58	239	201	53
	OR 100g increase in BW (95% CI)	0.89† (0.80, 0.99)	0.94† (0.89, 0.99)	0.92‡ (0.87, 0.98)	0.94 (0.84, 1.05)
Females	No. discordant pairs*	20	136	108	25
	OR 100g increase in BW (95% CI)	0.72† (0.51, 1.00)	0.96 (0.89, 1.05)	0.85‡ (0.76, 0.95)	0.84 (0.69, 1.02)

BW=Birth Weight; OR=Odds Ratio; CI=Confidence Interval;

^*Discordant for ASD (or component feature) measured by A-TAC cut-off scores;

^†p≤0.05;

^‡p≤ 0.01