Table A1.

The VIF values of the multicollinearity test of linear regression model with confounding variables.

Variables	VIF Values
ETS/ Packs of cigarettes per week	1.06
Child’s gender (male = 1)	1.10
Age of child in months	1.57
Low birth weight (yes = 1)	1.08
Mother’s age in years	1.15
Education attainment of the mother	1.09
If mother is the primary caregiver of the child	1.19
Family income in the last year	1.12
Mean VIF	1.50

Notes: VIF, variance inflation factor.