Table 6.

Effect of the exposure on the difference in healthy snack ratio and the targeted determinants between T0 (baseline) and T1 (post-intervention), as compared with the control group, among 14–16-year-old adolescents, ‘Snack Track School’ app intervention, Flanders, Belgium, January–April 2016

	Unadjusted effects†		Adjusted effects‡
	DID	se	DID	se
Healthy snack ratio
Exposure§
Did not use the app	−0·28	2·48	−3·33	2·66
Low users	−3·21	2·64	−3·35	2·74
High users	−3·42	2·50	−3·80	2·54
Awareness
Exposure§
Did not use the app	−0·01	0·08	−0·03	0·09
Low users	0·10	0·08	0·15	0·09
High users	−0·01	0·04	0·01	0·08
Intention
Exposure§
Did not use the app	−0·21*	0·10	−0·16	0·11
Low users	−0·16	0·10	−0·08	0·11
High users	−0·10	0·10	−0·11	0·10
Attitude taste
Exposure§
Did not use the app	−0·06	0·10	0·08	0·11
Low users	0·01	0·11	0·10	0·12
High users	0·16	0·10	0·12	0·11
Attitude health
Exposure§
Did not use the app	−0·16*	0·07	−0·10	0·08
Low users	−0·26**	0·08	−0·24**	0·08
High users	−0·05	0·07	−0·07	0·07
Self-efficacy
Exposure§
Did not use the app	−0·10	0·08	−0·09	0·09
Low users	−0·12	0·09	−0·10	0·09
High users	0·04	0·08	0·03	0·08
Habit
Exposure§
Did not use the app	−0·02	0·08	0·05	0·08
Low users	−0·13	0·08	−0·08	0·08
High users	0·02	0·08	0·02	0·08
Knowledge about the healthiness of snacks
Exposure§
Did not use the app	1·44	0·67*	1·66*	0·71
Low users	1·46	0·71*	1·55*	0·72
High users	1·02	0·67	1·01	0·67

DID, difference-in-difference.

*P<0·05, **P<0·01.

^†Crude multilevel models without covariates.

^‡Multilevel models adjusted for age, BMI Z-score, sex and education type.

^§Reference group=control group.