Table 2 Characteristics of included studies (N=600)
Characteristics | All studies (1982–2020) | Early Group (1982–2006) | Middle Group (2011–2013) | Late Group (2018–2020) | ||||
|---|---|---|---|---|---|---|---|---|
N = 600 | N = 200 | N = 200 | N = 200 | |||||
N | Percent (%) | N | Percent (%) | N | Percent (%) | N | Percent (%) | |
Location | ||||||||
 North America | 399 | 66.5 | 151 | 75.5 | 138 | 69.0 | 110 | 55.0 |
 Europe | 122 | 20.3 | 26 | 13 | 32 | 16.0 | 64 | 32.0 |
 Australia | 43 | 7.2 | 16 | 8 | 19 | 9.5 | 8 | 4.0 |
 Asia | 25 | 4.2 | 4 | 2 | 8 | 4.0 | 13 | 6.5 |
 South America | 7 | 1.2 | 2 | 1 | 1 | 0.5 | 4 | 2.0 |
 Africa | 4 | 0.7 | 1 | 0.5 | 2 | 1.0 | 1 | 0.5 |
Design | ||||||||
 Randomized controlled trial (RCT) | 299 | 49.8 | 108 | 54.0 | 90 | 45.0 | 101 | 50.5 |
 Non-randomized, single group | 223 | 37.2 | 66 | 33.0 | 85 | 42.5 | 72 | 36.0 |
 Non-randomized, multi-intervention | 45 | 7.5 | 15 | 7.5 | 15 | 7.5 | 15 | 7.5 |
 Randomized, multi-intervention | 33 | 5.5 | 11 | 5.5 | 10 | 5.0 | 12 | 6.0 |
Number of arms | ||||||||
 1 | 235 | 39.2 | 74 | 37.0 | 86 | 43.0 | 75 | 37.5 |
 2 | 326 | 54.3 | 109 | 54.5 | 106 | 53.0 | 111 | 55.5 |
 3 | 29 | 4.8 | 13 | 6.5 | 6 | 3.0 | 10 | 5.0 |
 4 | 9 | 1.5 | 14 | 7.0 | 2 | 1.0 | 3 | 1.5 |
 5 | 1 | 0.2 | 0 | 0.0 | 0 | 0.0 | 1 | 0.5 |
Number of measurement timepoints | ||||||||
 1 | 5 | 0.8 | 2 | 1.0 | 0 | 0.0 | 3 | 1.5 |
 2 | 428 | 71.3 | 154 | 77.0 | 143 | 71.5 | 131 | 65.5 |
 3 | 148 | 24.7 | 38 | 19.0 | 49 | 24.5 | 61 | 30.5 |
 4 | 19 | 3.2 | 6 | 3.0 | 8 | 4.0 | 5 | 2.5 |
Treatment length | ||||||||
 6 weeks or less | 140 | 23.3 | 45 | 22.5 | 45 | 22.5 | 50 | 25.0 |
 7–12 weeks | 236 | 39.3 | 73 | 36.5 | 75 | 37.5 | 88 | 44.0 |
 13–26 weeks | 150 | 25.0 | 46 | 23.0 | 59 | 29.5 | 45 | 22.5 |
 27–52 weeks | 55 | 9.2 | 25 | 12.5 | 17 | 8.5 | 13 | 6.5 |
 53 weeks or more | 19 | 3.2 | 11 | 5.5 | 4 | 2.0 | 4 | 2.0 |
Baseline sample size | ||||||||
 1–24 | 124 | 20.7 | 45 | 22.5 | 34 | 17.0 | 44 | 22.0 |
 25–49 | 183 | 30.5 | 57 | 28.5 | 57 | 28.5 | 69 | 34.5 |
 50–99 | 165 | 27.5 | 44 | 22.0 | 65 | 32.5 | 56 | 28.0 |
 100 or more | 128 | 21.3 | 54 | 27.0 | 44 | 22.0 | 31 | 15.5 |
Age of participants | ||||||||
 Youth (0–18 years) | 173 | 28.3 | 46 | 23.0 | 69 | 34.5 | 58 | 29.0 |
 Adult (18+ years) | 427 | 71.7 | 154 | 77.0 | 131 | 65.5 | 142 | 71.0 |
Sex of participants | ||||||||
 Women only | 139 | 23.2 | 63 | 31.5 | 41 | 20.5 | 35 | 17.5 |
 Men only | 27 | 4.5 | 7 | 3.5 | 10 | 5.0 | 10 | 5.5 |
 Both | 434 | 72.3 | 130 | 65.0 | 149 | 74.5 | 155 | 77.5 |
Intervention setting | ||||||||
 Clinic | 154 | 25.7 | 64 | 32 | 50 | 25 | 40 | 20 |
 Community | 122 | 20.3 | 50 | 25 | 36 | 18 | 36 | 18 |
 Remote | 99 | 16.5 | 18 | 9 | 37 | 18.5 | 44 | 22 |
 K-12 school | 96 | 16 | 26 | 13 | 37 | 18.5 | 33 | 16.5 |
 Home | 54 | 9 | 18 | 9 | 21 | 10.5 | 15 | 7.5 |
 Workplace | 32 | 5.3 | 6 | 3 | 12 | 6 | 14 | 7 |
 University | 17 | 2.8 | 6 | 3 | 4 | 2 | 7 | 3.5 |
 Care Facility (e.g., nursing home) | 15 | 2.5 | 9 | 4.5 | 1 | 0.5 | 5 | 2.5 |
 Church | 10 | 1.7 | 3 | 1.5 | 2 | 1 | 5 | 2.5 |
 Prison | 1 | 0.2 | 0 | 0 | 0 | 0 | 1 | 0.5 |
Target behaviora | ||||||||
 Physical activity | 465 | 77.5 | 139 | 69.5 | 165 | 82.5 | 161 | 80.5 |
 Nutrition | 347 | 57.8 | 125 | 62.5 | 119 | 59.5 | 103 | 51.5 |
 Mental health | 57 | 9.5 | 21 | 10.5 | 13 | 6.5 | 23 | 11.5 |
 Sleep | 37 | 6.2 | 7 | 3.5 | 7 | 3.5 | 23 | 11.5 |
 Screen time | 23 | 3.8 | 5 | 2.5 | 7 | 3.5 | 11 | 5.5 |
 Tobacco | 22 | 3.7 | 13 | 6.5 | 6 | 3 | 3 | 1.5 |
 Alcohol | 7 | 1.2 | 3 | 1.5 | 3 | 1.5 | 1 | 0.5 |
 STIs | 4 | 0.7 | 1 | 0.5 | 0 | 0 | 3 | 1.5 |
Fundinga | ||||||||
 Any funding | 402 | 67 | 112 | 56 | 134 | 67 | 156 | 78 |
 NIH (USA) | 142 | 35.3 | 40 | 35.7 | 48 | 35.8 | 54 | 34.6 |
 NHMRC (Australia) | 13 | 3.2 | 1 | 0.8 | 5 | 3.7 | 7 | 4.5 |
 NIHR (Europe) | 11 | 2.7 | 0 | 0 | 0 | 0 | 11 | 7.1 |
 MRC (UK) | 8 | 2.0 | 0 | 0 | 4 | 2.9 | 4 | 2.6 |
 CIHR (Canada) | 7 | 1.7 | 3 | 2.7 | 1 | 0.7 | 3 | 1.9 |
 Other government | 78 | 19.4 | 22 | 19.6 | 31 | 23.1 | 25 | 16.0 |
 Foundation/Center | 118 | 29.4 | 40 | 35.7 | 39 | 29.1 | 39 | 25 |
 University/Institution | 55 | 13.7 | 15 | 13.4 | 15 | 11.1 | 25 | 16 |
 Early career awards | 33 | 8.2 | 6 | 5.4 | 10 | 7.5 | 17 | 10.9 |
 Doctoral | 19 | 4.5 | 4 | 3.6 | 8 | 5.9 | 7 | 4.5 |
 Private/Corporation | 17 | 4.2 | 10 | 8.9 | 2 | 1.5 | 5 | 3.2 |
 Post-doctoral | 15 | 3.7 | 5 | 4.5 | 4 | 2.9 | 6 | 3.8 |