Seventeen studies (n=811) were included in the review. The design of the individual studies was not reported clearly.
The quality scores ranged from 14 to 26 (mean 18.4, standard deviation 3.12). The attrition rates (13 studies) ranged from 10 to 45% (mean 23.23, standard deviation 11.6).
Parental participation (5 studies).
Two studies, including one of African American females, found no significant differences in weight loss between interventions delivered to adolescents with and without their parents. One study found a significant difference in the percentage of overweight adolescents in favour of separate interventions for adolescents and parents (1 year follow-up 20.5%), compared with a joint intervention (1 year follow-up 5.5%). Another study found that after 15 months, relative weight loss was significantly improved in a SHAPEDOWN intervention group involving parental participation, compared with a no intervention control group. Another study that assessed the SHAPEDOWN intervention, but only included individuals with IDDM, found no statistically significant difference in weight loss between those receiving the intervention and those receiving standard care for IDDM.
Exercise interventions (5 studies).
One study reported increased cardiovascular fitness and visceral adiposity for a lifestyle education and physical training programme conducted after school in comparison with lifestyle education alone. However, increasing the intensity of the exercise did not result in any benefit in terms of the percentage body fat. Similarly, another study failed to find any significant differences in BMI between exercise programmes of differing intensities. Two school-based studies both reported significant benefits of exercise interventions compared with no intervention control groups: one in terms of body weight and the other in terms of the percentage of overweight individuals. One study reported no significant differences in weight loss or percentage body fat for those receiving an exercise, diet and lifestyle programme, compared with those receiving the diet and lifestyle programme alone or those receiving no intervention.
Dietary interventions (2 studies).
One study reported no significant difference in weight loss between groups receiving behavioural change education with and without dietary restrictions. Another study reported that individuals following a low carbohydrate diet as opposed to a low fat diet achieved significantly greater weight loss after 12 weeks.
Monetary rewards (2 studies).
One study found that greater weight loss was achieved with more frequent monetary incentives. However, another study by the same authors reported that similar levels of weight loss were achieved when monetary incentives were removed.
Telephone and mail-based interventions (1 study).
No significant differences in BMI were reported between adolescents receiving a telephone- or mail-based intervention, compared with those receiving the same intervention but clinic based.
Medication (2 studies).
One study reported that adolescents taking metformin had a significantly reduced BMI (1.3% reduction) compared with those receiving placebo (2.3% increase). In another study, adolescents receiving sibutramine combined with a behavioural, diet and exercise regimen achieved a 4.5% greater reduction in BMI than adolescents just receiving the behavioural, diet and exercise regimen and placebo.
Attenders versus non-attenders (1 study).
One behavioural intervention study found that increased attendance was not associated with significant changes in weight loss.