Table 2.
Summary of the evidence for WM, PA and diet
| Behavior/Technology Focus | Type of review/ synthesis | No. reviews | Quality of reviews | Design/quality of included studies c | Size & overlap of evidence base | Findings and overall conclusions |
|---|---|---|---|---|---|---|
| Effects on weight-related outcomes | ||||||
| Mobile | Narrative | 4 | One high, | One RCTs only; Two RCTs and quasi-experimentsOne Any study design | 27 studies | Significant positive effects (e.g. between 1.5 and 4.5kg weight loss) reported in at least 3/4 of studies of SMS/app-based interventions included in each review. One high quality review of RCTs, of which majority at low risk of bias, concluded that there is strong evidence for effectiveness. |
| three low | Two assessed quality and majority judged high quality | CCA = 15%, high | ||||
| Meta-analysis | 3 | One high, | Two RCTs only; One RCTs and quasi-experiments | 24 studies | Significant, moderate-sized pooled effects (1.09-2.17kg weight loss) reported across all reviews, though most studies of SMS interventions. Larger effects from more modern technologies and an app reported in one high quality review, but RCTs included in this review were rated as low to moderate quality. | |
| two low | All assessed study quality: 1 found low-moderate quality; 2 rated about half of studies as high quality | CCA = 15%, high | ||||
| All | 7 | Two high, five low | Three RCTs only; Three RCTs and quasi-experiments; One Any design; Five assessed study quality with variable findings | 43 studies CCA = 10%, high | Strong evidence of effectiveness: Two high quality reviews of RCTs of variable methodological quality suggest positive effects, but findings mainly relate to SMS-based interventions; so need further high quality research on modern mobile technologies, such as mobile apps. | |
| Web 2.0 | Narrative | 1 | Low | RCTs only | 20 studies | Only one study isolated effects of social media, in others embedded in larger interventions, so difficult to draw any conclusions. |
| Study quality assessed as moderate-high quality | ||||||
| Meta-analysis | 2 a | One high, | Both RCTs only | 34 studies | In one review, significant positive pooled effects on BMI, but not on other weight-related outcomes. In other, only 2 of 22 studies showed significant effects on primary weight-related outcomes with 0.1 median effect size overall and non-significant pooled effects on weight | |
| one low | Both assessed study quality: one rated all studies as unclear or high risk of bias; one rated half of studies as high quality | CCA = 0%, no overlap | ||||
| All | 3 | Two low, | All RCTs only | 45 studies | Lack of evidence on effectiveness: Positive effects in one review on some BMI but not on weight and other anthropometric measures in this or another review; mixed findings may reflect failure to isolate social media components in many studies and active comparison groups. | |
| one high | Two of three assessed study quality, with mixed findings | CCA=10%, high | ||||
| Effects on PA | ||||||
| Mobile | Narrative | 5 | All low | Two RCTs and quasi-experiments; Three Any design One assessed study quality as moderate-high | 43 studies CCA=12%, high | Only one review of mostly SMS interventions found significant positive effects amongst the majority of included studies, in another isolating RCTs less than half showed significant effects. |
| Meta-analysis | 2 b | Both low | One RCTs only; | 21 studies | One review reported significant, moderate-sized pooled effect ( g = 0.54) from a range of study designs examining SMS and app-based interventions. The second review reported generally positive effects from 5 studies, but did not report pooled estimates of the effects. | |
| One any design Both assessed study quality and rated more than half of included studies as high quality | CCA = 10%, moderate | |||||
| All | 6 | All low | One RCTs only; Two RCTs and quasi-experiments; | 43 studies | Weak evidence of effectiveness: Although most reviews reported some positive findings, the low quality of all these reviews, range of study designs included and lack of study quality assessment precludes any definitive conclusions about effects on PA | |
| Four any design Three of seven assessed study quality, and rated this as moderate-high for most studies | CCA=14%, high | |||||
| Web 2.0 | Meta-analysis | 3 a | All high | RCTs only | 33 studies | Lack of evidence on effectiveness: Reviews do not report effective results or use definitions for including studies that are not conclusive. One review reported no significant pooled effects, another reported significant pooled effects on fitness and PA, but this and the remaining review of only one RCT included other ‘remote’ interventions (e.g. telephone calls) preventing conclusions about social media, and highlighting the need for clearer definitions of Web 2.0 interventions. |
| All assessed study quality: two rated most studies as low risk of bias; one rated all studies as unclear or high risk of bias | CCA = 2%, slight | |||||
| Effects on diet | ||||||
| Mobile | Meta-analysis | 1 b | Low | RCTs only | 12 studies | Weak evidence of effectiveness: Generally positive findings from small numbers of primary research studies (max 3) examining effects on fruit and vegetable and calorie intake, plus marginal effects in one study on sugar and fat intake. More review evidence of good quality is needed to establish effects on dietary behaviors. |
| Study quality assessment found half of studies at low risk of bias | ||||||
| Web 2.0 | Meta-analysis | 1 a | High | RCTs only | Five studies | Weak evidence of effectiveness: Significant, small decrease in fat consumption across five studies. More evidence from studies of good quality is needed to ascertain the effects of the technologies on dietary outcomes. |
| All studies were rated as unclear or high risk of bias | ||||||
a The meta-analysis by Williams et al. (ID = 44) was used to inform the results on weight-related, PA and diet outcomes.
b The meta-analysis by Lyzwinski (ID = 30) was used to inform the results on weight-related, PA and diet outcomes.
c Study design of included studies: ‘RCTs only’, systematic reviews that included only randomized controlled trials; ‘RCTs & Quasi-experiments’, systematic reviews that included pseudo-randomized, quasi-experiments, as defined by the authors themselves; ‘Any design’, systematic reviews that included primary research studies of any type of design, including case control, before-after, pilot trials, RCTs, uncontrolled CT.