Table 4.

Regression parameters (βs & 95% confidence intervals) for models examining the effects of sex and birth weight on symptoms of hyperactivity

	Model 1	Model 2	Model 3	Model 4	Model 5	Model 6
	Familial	Tobacco	Parental Age	Medical Problems	Ext Comorbidity	Int Comorbidity
Sex	-.22 (-.29, -.15)	-.26 (-.32, -.20)	-.23 (-.30, -.16)	-.24 (-.31, -.17)	-.15 (-.20, -.09)	-.23 (-.29, -.16)
Linear birth weight	-.33 (-.52, -.14)	-.27 (-.46, -.09)	-.37 (-.56, -.18)	-.34 (-.53, -.14)	-.14 (-.30, .02)	-.27 (-.46, -.08)
Linear interaction	.18 (-.11, .37)	.12 (-.07, .30)	.20 (.01, .40)	.20 (0, .39)	.02 (-.13 .17)	.11 (-.07, .30)
Quadratic birth weight	.20 (.04, .36)	.08 (.02, .14)	.12 (.05, .18)	.19 (.02, .35)	.09 (.03, .15)	.10 (.04, .16)
Quadratic interaction	-.10 (-.26, .05)	---	---	---	---	---

Note: bold font indicates p<.05; All models included child age, ethnicity, and family income as covariates; Model 1 was the primary analysis and included parental ADHD diagnosis as a covariate; Model 2 included prenatal tobacco exposure as a covariate; Model 3 included maternal and paternal age at birth as a covariate; Model 4 included prenatal, labor and delivery, and perinatal medical problems as covariates; Model 5 included child symptoms of ODD and CD as covariates; Model 6 included child diagnoses of depression, anxiety, and learning disorder as covariates; The quadratic interaction was not included in models 2-5 as this term was not significant in the primary analysis.