A theory-based intervention delivered by an online social media platform to promote oral health among Iranian adolescents: a cluster randomized controlled trial

Figures & data

Figure 1. The Health Action Process Approach model (Schwarzer, 2008).

Table 1. Baseline characteristics by group.

		Group
	Control (n = 278)	Adolescent intervention (n = 253)	Adolescent + Mother intervention (n = 260)
Age, years; M±SD	15.38 ± 1.29	15.18 ± 1.04	15.34 ± 1.58
Mother’s education (years); M±SD	6.27 ± 2.66	5.89 ± 2.55	5.97 ± 2.88
Monthly Household income in U.S. Dollar a; M±SD	553.01 ± 201.15	570.19 ± 261.25	541.22 ± 253.63
Sex; n (%)
Male	159 (57.2%)	152 (60.1%)	148 (56.9%)
Female	119 (42.8%)	101 (39.9%)	112 (43.1%)
Number of classes	10	10	10
Average number of students in the classes	26	24	25

Note. SD = standard deviation;

^a4500 Rials = 1 U.S. Dollar, January 2018.

Table 2. Descriptive statistics for outcome measures by time and group.

		Baseline	Reliability	Month 1	Reliability	Month 6	Reliability
Outcome measure	Group	M (SD)	α	M (SD)	α	M (SD)	α
Outcome expectancies	Control	3.21 (1.12)	0.88	3.18 (1.02)	0.89	3.12 (0.97)	0.80
	Adolescent	3.22 (1.18)		4.19 (1.12)		4.21 (1.05)
	Adolescent +	Mother3.17 (0.98)		4.24 (1.09)		4.19 (1.03)
Risk perception	Control	4.88 (0.97)	0.79	4.83 (1.02)	0.81	4.78 (1.07)	0.85
	Adolescent	4.85 (1.0)		5.15 (0.81)		5.13 (0.82)
	Adolescent +	Mother4.91 (1.10)		5.17 (1.07)		5.18 (1.01)
Self-efficacy	Control	2.70 (0.67)	0.83	2.73 (0.93)	0.88	2.71 (0.96)	0.78
	Adolescent	2.66 (0.90)		3.03 (1.01)		3.04 (1.0)
	Adolescent +	Mother2.71 (0.73)		3.12 (1.03)		3.16 (1.03)
Intention	Control	2.92 (0.65)	0.89	2.94 (0.69)	0.90	2.89 (0.73)	0.83
	Adolescent	2.99 (0.87)		3.39 (1.02)		3.41 (1.0)
	Adolescent +	Mother2.95 (0.75)		3.56 (0.99)		3.58 (1.06)
Action planning	Control	1.91 (0.56)	0.90	1.84 (0.42)	0.82	1.79 (0.45)	0.93
	Adolescent	1.94 (0.68)		2.55 (0.98)		2.53 (0.71)
	Adolescent +	Mother1.92 (0.53)		2.65 (0.96)		2.68 (0.79)
Coping planning	Control	2.02 (0.40)	0.94	2.00 (0.64)	0.82	1.98 (0.58)	0.86
	Adolescent	2.06 (0.66)		2.62 (0.83)		2.61 (0.57)
	Adolescent +	Mother2.04 (0.57)		2.76 (0.94)		2.78 (0.68)
Self-Monitoring	Control	1.97 (0.59)	0.84	1.84 (0.56)	0.88	1.82 (0.49)	0.81
	Adolescent	1.93 (0.61)		2.61 (0.74)		2.64 (0.68)
	Adolescent +	Mother1.90 (0.57)		2.77 (0.60)		2.94 (0.73)
Perceived social support	Control	4.37 (1.25)	0.90	4.26 (1.16)	0.82	4.21 (1.03)	0.87
	Adolescent	4.39 (1.28)		4.41 (1.10)		4.39 (1.30)
	Adolescent +	Mother4.32 (1.21)		5.01 (1.24)		5.06 (1.13)
OHRQoL	Control	79.86 (18.60)	0.83	79.12 (19.01)	0.88	81.22 (18.45)	0.91
	Adolescent	78.19 (20.29)		81.27 (20.76)		90.36 (17.72)
	Adolescent +	Mother78.39 (21.54)		80.61 (18.22)		91.72 (20.05)
Tooth brushing	Control	12.11 (3.44)	NA	12.04 (3.48)	NA	11.93 (3.57)	NA
	Adolescent	12.32 (3.73)		14.90 (4.39)		14.92 (4.27)
	Adolescent+	Mother12.30 (3.16)		16.03 (4.29)		16.06 (4.59)
Dental plaque	Control	2.82 (0.84)	NA	2.86 (0.93)	NA	2.88 (0.95)	NA
	Adolescent	2.80 (0.67)		2.55 (0.56)		2.53 (0.51)
	Adolescent +	Mother2.71 (0.82)		2.14 (0.69)		2.12 (0.73)
Community Periodontal Index (CPI)	Control	1.72 (0.39)	NA	1.71 (0.43)	NA	1.70 (0.49)	NA
	Adolescent	1.70 (0.55)		1.69 (0.59)		1.60 (0.62)
	Adolescent +	Mother1.68 (0.65)		1.63 (0.73)		1.33 (0.92)

Note. SD = standard deviation.

Figure 2. Flowchart of the participants throughout the trial.

Table 3. Three-level linear mixed models predicting the effects of the intervention on tooth brushing (TB), dental plaque (DP), Parent Social Support (PSS), Outcome Expectancies (OE), Risk Perceptions (RP) and Self-monitoring (SM).

	TB		DP		PSS		OE		RP		SM
Variable	Β (SE)	p-value	Β (SE)	p-value	Β (SE)	p-value	Β (SE)	p-value	Β (SE)	p-value	Β (SE)	p-value
Group (Ref: Control)
Adolescent	1.12 (1.85)	0.51	−0.07 (0.34)	0.83	0.04 (0.02)	0.046	0.02 (0.14)	0.886	0.07 (0.17)	0.680	0.01 (0.01)	0.32
M + A	0.42 (1.84)	0.819	−0.11 (0.33)	0.739	0.14 (0.20)	0.438	0.08 (0.13)	0.538	0.14 (0.16)	0.381	0.03 (0.01)	0.003
Time (Ref: Baseline)
One month	2.57 (0.21)	P < 0.001	0.04 (0.05)	0.423	0.08 (0.04)	0.045	0.97 (0.06)	P < 0.001	0.30 (0.04)	P < 0.001	0.07 (0.05)	0.16
Six months	2.60 (0.22)	P < 0.001	−0.06 (0.05)	0.230	0.14 (0.04)	P < 0.001	0.99 (0.06)	P < 0.001	0.28 (0.06)	P < 0.001	0.18 (0.05)	P < 0.001
Group × Time
Adolescent vs. Control at one month	2.64 (0.29)	P < 0.001	−0.29 (0.07)	P < 0.001	0.12 (0.08)	0.133	1.01 (0.08)	P < 0.001	0.35 (0.05)	P < 0.001	0.74 (0.05)	P < 0.001
M + A vs. Control at one month	3.74 (0.28)	P < 0.001	−0.60 (0.05)	P < 0.001	0.74 (0.06)	P < 0.001	0.44 (0.09)	P < 0.001	0.31 (0.05)	P < 0.001	0.88 (0.09)	P < 0.001
M + A vs. Adolescents at one month	1.10 (0.30)	P < 0.001	−0.32 (0.09)	P < 0.001	0.62 (0.07)	P < 0.001	−1.01 (0.69)	0.144	0.04 (0.04)	0.317	0.19 (0.07)	0.007
Adolescent vs. Control at six months	2.78 (0.29)	P < 0.001	−0.33 (0.06)	P < 0.001	0.15 (0.09)	0.094	1.09 (0.09)	P < 0.001	0.39 (0.04)	P < 0.001	0.92 (0.08)	P < 0.001
M + A vs. Control at six months	3.90 (0.27)	P < 0.001	−0.64 (0.08)	P < 0.001	0.85 (0.05)	P < 0.001	1.13 (0.07)	P < 0.001	0.38 (0.05)	P < 0.001	1.21 (0.07)	P < 0.001
M + A vs. Adolescents at six months	1.12 (0.28)	P < 0.001	−0.31 (0.08)	P < 0.001	0.70 (0.06)	P < 0.001	0.10 (0.09)	0.267	−0.01 (0.05)	0.841	0.33 (0.05)	P < 0.001
Age	−0.02 (0.15)	0.894	−0.03 (0.03)	0.317	0.05 (0.03)	0.094	0.02 (0.03)	0.505	0.02 (0.02)	0.317	0.03 (0.06)	0.62
Female (Ref: Male)	−0.46 (0.51)	0.744	−0.26 (0.11)	0.018	−0.14 (0.11)	0.203	−0.04 (0.11)	0.716	0.04 (0.09)	0.657	0.04 (0.03)	0.18
Mother’s level of education	0.07 (0.05)	0.161	0.07 (0.11)	0.524	0.03 (0.01)	0.003	0.01 (0.01)	0.317	0.01 (0.008)	0.211	0.13 (0.07)	0.063
Intercept	8.56 (2.67)	0.001	3.22 (0.54)	P < 0.001	4.98 (0.51)	P < 0.001	3.42 (0.47)	P < 0.001	5.18 (0.41)	P < 0.001	2.42 (0.35)	P < 0.001
${\widehat{\mathbf{\sigma }}}_{\mathbf{st}}^2$ (student)	29.36 (1.57	P < 0.001	1.31 (0.07)	P < 0.001	1.40 (0.07)	P < 0.001	1.09 (0.06)	P < 0.001	0.84 (0.04)	P < 0.001	0.41 (0.01)	P < 0.001
${\widehat{\mathit{\sigma }}}_{\mathit{sc}}^2$ (school)	5.54 (0.20)	P < 0.001	0.34 (0.01)	P < 0.001	0.23 (0.008)	P < 0.001	0.49 (0.02)	P < 0.001	0.15 (0.005)	P < 0.001	0.35 (0.03)	P < 0.001

Note. p-values < 0.05 are in bold, M + A = Mother and adolescent intervention.

Table 4. Three-level Linear Mixed Models Predicting the Effects of the Intervention on Self-Efficacy (SE), Intention (INT), Action Planning (AP), Coping Planning (CP), community periodontal index (CPI), and oral health related quality of life (OHRQOL).

	SE		INT		AP		CP		CPI		OHRQOL
Variable	Β (SE)	p	Β (SE)	p	Β (SE)	p	Β (SE)	p	Β (SE)	p	Β (SE)	p
Group (Ref: Control)
Adolescents	0.02 (0.17)	0.906	0.05 (0.20)	0.802	0.07 (0.12)	0.560	0.06 (0.23)	0.794	0.05 (0.11)	0.650	0.94 (1.86)	0.613
M + A	0.04 (0.16)	0.802	0.02 (0.20)	0.920	0.09 (0.11)	0.413	0.20 (.26)	0.441	−0.01 (0.11)	0.928	1.36 (1.82)	0.635
Time (Ref: Baseline)
One month	0.37 (0.04)	P < 0.001	0.02 (0.04)	0.045	0.07 (0.05)	0.161	0.02 (0.05)	0.689	−0.03 (0.03)	0.317	0.74 (0.90)	0.411
Six months	0.38 (0.05)	P < 0.001	0.03 (0.05)	0.548	0.12(0.05)	0.016	0.04 (0.05)	0.424	−0.07 (0.02)	P < 0.001	1.35 (0.90)	0.134
Group × Time
Adolescents vs. Control at one month	0.34 (0.06)	P < 0.001	0.39 (0.06)	P < 0.001	0.67 (0.07)	P < 0.001	0.58 (0.08)	P < 0.001	−0.02 (0.04)	0.617	2.82 (1.33)	0.034
M + A vs. Control at one month	0.48 (0.05)	P < 0.001	0.60 (0.07)	P < 0.001	0.80 (0.06)	P < 0.001	0.76 (0.07)	P < 0.001	−0.07 (0.04)	0.080	2.87 (1.30)	0.027
M + A vs. Adolescents at one month	0.14 (0.06)	0.020	0.20 (0.06)	3.33	0.13 (0.06)	0.031	0.18 (0.08)	0.024	0.05 (0.03)	0.094	0.06 (1.27)	0.962
Adolescents vs. Control at six months	0.36 (0.06)	P < 0.001	0.44 (0.06)	P < 0.001	0.70 (0.06)	P < 0.001	0.59 (0.07)	P < 0.001	−0.05 (0.04)	0.211	9.82 (1.53)	P < 0.001
M + A vs. Control at six months	0.43 (0.06)	P < 0.001	0.66 (0.08)	P < 0.001	0.87 (0.07)	P < 0.001	0.80 (0.06)	P < 0.001	0.34 (0.03)	P < 0.001	11.98 (1.20)	P < 0.001
M + A vs. Adolescents at six months	0.08 (0.05)	0.110	0.22 (0.07)	0.002	0.17 (0 07)	0.016	0.20 (0.07)	0.004	−0.29 (0.03)	P < 0.001	2.16 (1.03)	0.036
Age	0.01 (0.02)	0.617	0.02 (0.02)	0.317	0.02 (0.05)	0.689	0.01 (0.02)	0.617	−0.01 (0.02)	0.617	−0.73 (0.45)	0.105
Female (Ref: Male)	0.08 (0.09)	0.373	0.34 (0.11)	0.002	0.44 (0.10)	P < 0.001	0.36 (0.20)	0.071	−0.21 (0.09)	0.02	0.27 (1.52)	0.859
Mother’s level of education	0.01 (0.01)	0.317	0.003 (0.006)	0.617	0.01 (0.01)	0.317	0.01 (0.01)	0.317	−0.004 (0.004)	0.317	0.12 (0.14)	0.391
Intercept	2.50 (0.38)	P < 0.001	2.43 (0.35)	P < 0.001	1.86 (0.34)	P < 0.001	1.91 (0.35)	P < 0.001	2.06 (0.25)	P < 0.001	90.08 (7.10)	P < 0.001
${\widehat{\mathbf{\sigma }}}_{\mathbf{st}}^2$ (student)	0.70 (0.04)	P < 0.001	0.44 (0.03)	P < 0.001	0.39 (0.02)	P < 0.001	0.25 (0.02)	P < 0.001	0.21 (0.01)	P < 0.001	221.06 (13.36)	P < 0.001
${\widehat{\mathit{\sigma }}}_{\mathit{sc}}^2$ (school)	0.24 (0.01)	P < 0.001	0.24 (0.009)	P < 0.001	0.31 (0.01)	P < 0.001	0.40 (0.02)	P < 0.001	0.09 (0.003)	P < 0.001	121.48 (4.27)	P < 0.001

Note. p-values< 0.05 are in bold, M + A = Mother and adolescent intervention.

Schwarzer, R. (2008). Modeling health behavior change: How to predict and modify the adoption and maintenance of health behaviors. Applied Psychology, 57, 1–29. doi:10.1111/j.1464-0597.2007.00325.x

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