Table 4.

Study characteristics

Criterion	Category	No. of studies	And references
Country	United States	11	[7,9,65-72,74]
	United Kingdom	2	[6,8]
	Germany	1	[73]
Ethnic majority	White and ‘Caucasian’	5	[7,8,69,71,72]
	African-American	2	[65,67]
	Hispanic-American	2	[66,68]
	Not reported	5	[6,9,70,73,74]
Health condition	Type 1 diabetes	1	[70]
	Dental malocclusion	1	[9]
	Leukemia (remission)	1	[69]
	Nocturnal enuresis	1	[6]
	Asthma	7	[7,8,65-68,73]
	Cystic fibrosis	1	[74]
	Encopresis	1	[71]
	Sickle cell disease	1	[65]
	Recurrent headache (non-malignant)	1	[72]
Sample size	Reported sample size calculation	3	[6,7,71]
	No sample size calculation; total participants n < 120	6	[8,65,69,70,72,74]
	No sample size calculation; total participants n ≥ 120	5	[9,66-68,73]
Intervention	< 6 months	7	[6,9,65,69,71,72,74]
length	≥ 6 months	7	[7,8,66-68,70,73]
Follow-up	None	10	[7-9,65-67,69-71,74]
(post- intervention)	< 6 months	1	[72]
	≥ 6 months	3	[6,68,73]
Quality assessment ratings	0	0
	½	0
	1	1	[9]
	1½	1	[74]
	2	5	[6,7,67,70,73]
	2½	3	[65,66,71]
	3	3	[68,69,72]
	3½	1	[8]
	4	0