Table 1.

Characteristics of the twenty-five studies included in final analysis

Study	Study design	Quality of evidence	Number of participants
Khani et al. [4], 2019	Quasi-experimental	2	300
Irwin et al. [5], 2007	Prospective cohort	2	1214
Brinker et al. [6], 2018	RCT	1	1260
Geller et al. [7], 2005	Prospective cohort	2	344
Sümen et al. [8], 2015	Quasi-experimental	2	567
Hughes et al. [9], 1993	RCT	1	543
Swindler et al. [10], 2007	Prospective cohort	2	517
Jia et al. [11], 2020	RCT	1	271
Tuong et al. [12], 2015	RCT	1	50
Wu et al. [13], 2019	Controlled trial	2	1573
Hawkes et al. [14], 2012	RCT	1	400
Miljković et al. [15], 2014	RCT	1	5360
Kamell et al. [16], 2011	Prospective cohort	2	1260
Kouzes et al. [17], 2017	Prospective cohort	2	100*
Kristjánsson et al. [18], 2003	Controlled trial	2	184
Aarestrup et al. [19], 2014	RCT	1	2323
Brinker et al. [20], 2017	Cross-sectional	4	205
Cassel et al. [21], 2018	Prospective cohort	2	208
Loescher et al. [22], 2019	Prospective cohort	2	220
Katz et al. [23], 1991	RCT	1	251
Davis et al. [24], 2015	Prospective cohort	2	1284
White et al. [25], 2019	RCT	1	382
White et al. [26], 2010	RCT	1	80
Lowe et al. [27], 1999	RCT	1	3400
Kamin et al. [28], 1993	Prospective cohort	2	387

Quality of evidence scale based on the JAMA Dermatology modified Oxford Centre for Evidence-based Medicine for ratings of individual studies [29]. Evidence is ranked as follows: (1—RCT), (2—Well-designed controlled trial without randomization; prospective comparative cohort trial), (3—Case-control studies; retrospective cohort study), (4—Case series with or without intervention; cross-sectional study), (5—Opinion of respected authorities; case reports)

RCT randomized control trial

*Only high school students included in count