Table 1.

Characteristics of included studies.

Study authors (year)	Purpose of intervention	Mode of intervention	Diseases or conditions	Participant’s age (years)
Abbate et al (2017) [20]	Treatment	Online	Smoking	18+
Adam et al (2016) [21]	Prevention	In-person	Weight gain and diet	23-40
Alley et al (2016) [22]	Prevention	Online	Physical activity	18+
Bracken et al (2019) [23]	Prevention	In-person	Type 2 diabetes	50-74
Buckingham et al (2017) [24]	Prevention	In-person	HIV	18+
Burrell et al (2012) [25]	Prevention	In-person	HIV	18+
Cowie et al (2018) [26]	Treatment	In-person	Alzheimer disease	60+
Frandsen et al (2014) [27]	Treatment	In-person	Smoking	18+
Frandsen et al (2016) [9]	Treatment	In-person	Smoking	18+
Guthrie et al (2019) [28]	Treatment	In-person	Postmenopausal vulvovaginal symptoms	45-70
Heffner et al (2013) [29]	Treatment	Online	Smoking	18+
Huesch et al (2018) [30]	Treatment	In-person	Bipolar disorder	18+
Ince et al (2014) [31]	Treatment	Online	Depressive symptoms	18+
Jones et al (2012) [32]	Prevention	In-person	Physical activity	16-18a
Jones et al (2017) [33]	Prevention	Online	HIV	18-29
Juraschek et al (2018) [34]	Prevention	Both	Cancer survivors	18+
Kayrouz et al (2016) [10]	Treatment	Online	Anxiety, depression	18-70
Kendall et al (2018) [35]	Treatment	In-person	Chronic dizziness, chronic neck pain	65-85
Kira et al (2016) [36]	Prevention	In-person	Smoking	16+
Kuhn et al (2017) [37]	Treatment	Online	PTSDb	18+
Nash et al (2017) [38]	Treatment	In-person	Hypertension	18-69
Partridge et al (2015) [39]	Prevention	Both	Weight gain	18-35
Rabin et al (2013) [40]	Prevention	Online	Physical activity	18-39
Raviotta et al (2016) [41]	Prevention	Both	HPVc	18-25
Rounds et al (2019) [42]	Treatment	Both	Obesity	18-65
Sanchez et al (2018a) [43]	Treatment	In-person	ARHLd	18+
Sanchez et al (2018b) [43]	Treatment	In-person	ARHL	50-89
Shere et al (2014) [44]	Treatment	In-person	Pregnancy	18-45
Usadi et al (2015a) [45]	Treatment	In-person	Infertility	18-40
Usadi et al (2015b) [45]	Treatment	In-person	Infertility	18-40
Volkova et al (2017) [46]	Prevention	Online	Healthy food purchase	18+
Waltman et al (2019) [47]	Prevention	In-person	Bone loss	19+
Watson et al (2018) [48]	Treatment	Online	Smoking	18+

^aParticipants were 11th-grade students. Age range is estimated.

^bPTSD: posttraumatic stress disorder.

^cHPV: human papillomavirus.

^dARHL: age-related hearing loss.