Mihas 2010.

Methods	Study design: RCT. Study grouping: parallel. Allocation ratio in RCTs: 1:1. Analyses methods for RCTs: available‐case analysis; end values. Description of randomisation: from 286 finally eligible students, 218 were assigned randomly using a computerised random number generator to participate in the study in 2 groups of 109 students (intervention group and control group). How were missing data handled? Over 12 months, 11 participants lost in intervention group and 16 in control group. Data analysed based on participants having full data at end of follow‐up (98/109 randomised in intervention group; 93/109 randomised in control group). Number of study contacts: 3. Period of follow‐up (from when duration of active intervention period ended): 14 months. Periods of recruitment: NR. Intervention took place between September 2007 and January 2008. Sample size justification adequately described? Was based on previously reported intervention changes in energy intake among children. To detect standardised differences > 5% in dietary intake (main dependent variable) between study groups before and after intervention, achieving 90% statistical power at a probability level < 0.05, 87 participants should be recruited in each study group. To counter potential low response and dropouts, the authors increased this number by 25% to 109 for each study group. Sampling method: 342 adolescents of 5 high schools located in Vyronas district were initially eligible. 309/342 students voluntarily were interested in participating in study. Study objective: to evaluate short‐term (15‐day) and long‐term (12‐month) effects of a 12‐week school‐based health and nutrition interventional programme regarding energy and nutrient intake, dietary changes and BMI. Study population: students aged 12‐13 years (7th grade).
Participants	Baseline characteristics (reported for 2 groups and overall) Lower fat intake (≤ 30%TE) Age (mean in years): 13.1 (SD 0.8). Sex: 51% girls. Ethnicity: NR. Education: NR. Income: NR. Pubertal stage: NR. Parental BMI: NR. Child total energy (kJ): 8503.3 (SD 1419.3). Child total fat (%TE): 35.4 (SD 4.7). Child saturated fat (%TE): 12.4 (SD 2). Child total protein (%TE): 15.3 (SD 1.4). Child total CHO (%TE): 49.7 (SD 6.2). Child physical activity (hours/week): sports activities 3.3 (SD 3.6); playing or walking 2.5 (SD 1.6). Child physical inactivity or screen time or both (hours/day): TV/computer/video games 2.5 (SD 1. 7). Child CVD risk (excluding fatness): regular smoker 3.1%. Child body fatness (kg/m2): BMI 24 (SD 3.1). Usual or modified fat intake Age (mean in years): 13.3 (SD 0.9). Sex: 50.5% girls. Ethnicity: NR. Education: NR. Income: NR. Pubertal stage: NR. Parental BMI: NR. Child total energy (kJ): 8583.7 (SD 1522.4). Child total fat (%TE): 36.2 (SD 5.2). Child saturated fat intake (%TE): 12.8 (SD 2.3). Child total protein (%TE): 14.9 (SD 1.8). Child total CHO (%TE): 48.4 (SD 6.8). Child physical activity (hours/week): sports activities 3.0 (SD 3.1); playing or walking 2.7 (SD 2.0). Child physical inactivity or screen time or both (hours/week): TV/computer/video games 2.4 (SD 1.4). Child CVD risk (excluding fatness): regular smoker 4.3%. Child body fatness (kg/m2): BMI 24.3 (SD 3.3). Overall Age: P = 0.106. Sex: P = 0.947. Ethnicity: NR. Education: NR. Income: NR. Pubertal stage: NR. Parental BMI: NR. Child total energy: NR. Child total fat: NR. Child total protein: NR. Child total CHO: NR. Child physical activity: sports activities P = 0.539; playing/walking P = 0.445. Child physical inactivity or screen time or both: TV/computer/video games P = 0.659. Child CVD risk (excluding fatness): regular smoker P = 0.649. Child body fatness: BMI P = 0.518. Included criteria: children aged 12‐13 years at high schools located in Vyronas district, Athens, Greece. Excluded criteria: organic cause for high or low weight, received any medication that might interfere with growth or weight control, or were on specific diets. Pretreatment: no significant differences in age, gender, BMI, overweight/obesity, smoking, screen time, weekly hours of sport activities, weekly hours of playing or walking, and weekly hours of hobbies between groups before the nutrition intervention. Brief description of participants: 12‐ to 13‐year‐old adolescents from Greece; CVD risk: very few children were regular smokers. Total number completed RCT: 98 in intervention group; 93 in control group. Total number randomised: 218.
Interventions	Intervention characteristics Lower fat intake (≤ 30%TE) Energy prescription: NR. Total fat prescription: 30%TE. SFA, PUFA, MUFA prescription: SFA 10%TE; increased PUFA:SFA ratio. Total protein prescription: NR. Total CHO prescription: increased intake of complex CHO and fibre, decreased consumption of refined sugar. Other diet prescription details: cholesterol <300 mg/day; sodium <2 g/day. Method number of dietary assessments: self‐administered 7‐days semi‐quantitative FFQ: 3 assessments (baseline, 15 days and 12 months after end of intervention). Other components prescribed: dental health hygiene and dietary consumption attitudes. Duration of intervention: 12 weeks. Implementation: conducted by class home economics teacher supervised by health visitor or family doctor; incorporated 12 hours of classroom material during 12‐week period. 2 meetings conducted with parents (given screening results of children; presentations given on the prevention of the development of chronic diseases). Multicomponent workbooks covering mainly dietary issues, dental health hygiene and consumption attitudes were produced for each student. Cues and reinforcing messages using posters and displays in classroom. Usual or modified fat intake Energy prescription: NR. Total fat prescription: NR. SFA, PUFA, MUFA prescription: NR. Total protein prescription: NR. Total CHO prescription: NR. Other diet prescription details: NR. Method number of dietary assessments: self‐administered 7‐days semi‐quantitative FFQ: 3 assessments (baseline, 15 days and 12 months after end of intervention). Other components prescribed: NR. Duration of intervention: NR. Implementation: no health education intervention and no parental educational sessions took place.
Outcomes	BMI BMI (kg/m2) (adjusted for age and gender). Energy intake Energy intake (kJ). Fat intake %TE. Saturated fat intake %TE. Protein intake %TE. CHO intake %TE.
Identification	Sponsorship source: Ministry of Education and the National Foundation for the Youth. Country: Greece. Setting: high schools, Vyronas district, Athens. Comments: NA. Author's name: Constantinos Mihas. Institution: Department of Internal Medicine, General Hospital of Kimi 'G. Papanikolaou,' Kimi, Evia, 34003 Greece. Email: gas521@yahoo.co.uk. Declaration of interests: yes; conflicts of Interest: none declared. Study ID: Vyronas 2009. Type of record: journal article.
Notes
Risk of bias
Bias	Authors' judgement	Support for judgement
Random sequence generation (selection bias)	Low risk	Computerised random number generator used; baseline characteristics similar between groups.
Allocation concealment (selection bias)	Unclear risk	NR.
Blinding of participants and personnel (performance bias) All outcomes	Low risk	Authors stated blinding not feasible, but primary outcome not likely to be influenced by lack of blinding.
Blinding of outcome assessment (detection bias) All outcomes	Low risk	Authors stated that blinding was not feasible, but assessment of primary outcome not likely influenced by lack of blinding.
Incomplete outcome data (attrition bias) All outcomes	Low risk	Similar in both groups, paper mentioned loss of 5 participants during trial (due to health problems, lack of interest and move to other schools). Of 109 allocated in each group, 10 in intervention group and 12 in the control group were not analysed (reasons unclear). 10% (22/213) lost over 17 months.
Selective reporting (reporting bias)	Low risk	Protocol not available, but prespecified outcomes in methods reported in results section.
Other bias	Unclear risk	Limited information on control group diet prescription, unable to judge if prescribed diets being compared differed in components other than total fat.