Table 1 Description of the six studies
StudyDesignSettingPopulationInterventionControlOutcome measuresFollow-upQuality assessmentDirection and size of the effectsDifferential effect by socioeconomic status
Reynolds et al. 200011Randomised controlled trialElementary schools, Birmingham, USA28 schools; 1698 4th grade students, mean age 8.7 years; 50% female; 83% European-American; 16% African-American;1% other7-week intervention; (High 5); Group 1: immediate intervention (classroom component, parent component, food service component); Group 2: delayed interventionDelayed interventionDiet and psychosocial variables1, 2 yearsMedium risk of biasIntervention students consumed more fruit and vegetables after 1 year (mean, 95% CI) 3.96 servings (3.51 to 4.44) than controls 2.28 (1.92 to 2.66) (p<0.0001) and 2 years follow-up intervention 3.20 (2.89 to 3.52) versus control 2.21 (1.94 to 2.49) (p<0.0001)Intervention resulted in increases in fruit and vegetable consumption that was greater in higher income (mean difference after 1 year 2.4 portions per day, p<0.0001) than in lower income children (mean difference 1.3 portions per day, p<0.0003)
Friel et al. 199912Comparative quasi-experimental studyPrimary schools, IrelandEight primary schools, 821 Irish school children aged 8–10 years10-week intervention (NEAPS) aiming to build awareness of healthy eating and regular exerciseControl schoolsChildren’s knowledge, behaviours and preferences of healthy foodstuffs3 monthsHigh risk of biasIntervention children’s consumption of fruit and vegetables increased and salty food decreasedThe NEAPS programme was less effective in pupils in disadvantaged areas (f = 5.606, p<0.018)
Reinaerts et al. 200713Controlled clinical trialPrimary schools, the Netherlands12 primary schools, approx. 939 children aged 4–12 years9-month intervention aimed to (1) increase children daily fruit and vegetable consumption or (2) create supportive environments. Group (1) free fruit and vegetable distribution; Group (2) multicomponent programmeDelayed interventionFruit, vegetables and fruit juice consumption12 monthsHigh risk of biasFruit and vegetable consumption increased in groups 1 and 2In the free fruit and vegetable group (group 1), 24-h fruit juice and vegetable consumption increased more in “non-native” children (beta coefficient  = 1.30, p<0.01) than in ‘native’ children (beta coefficient  = 0.24, p<0.05)
Winkleby et al. 199714Cluster randomised controlled trialCommunity education classes, USA24 community classes; 242 adults with low literacy6-week intervention (SNAP) targeting low fat eating followed by 12-week maintenance phase; Group 1 SNAP intervention; Group 2 general nutrition (GN) interventionControl (GN) classesNutrition knowledge, nutrition attitudes, % calories from fat30 weeksLow risk of bias60% of SNAP groups met the goal of consuming 30% of dietary energy from fat at follow-up compared with 34% of GN groupThe group with better educated participants (Group 2) achieved 34% of dietary goals compared with group 3 who had the highest non-US-born and non-English speakers, which achieved 60% of dietary goals
Calfas et al. 200215Randomised controlled trialPrimary care providers, San Diego, USA10 providers, 173 adults, mean age 37.5 years (SD 8.4); 69% female; 71.7% Caucasian, 11.6% Asian-American/Pacific Islander, 8.1% Hispanic, 4.0% African-American, 1.7% multiracial, 2.9% other4-month intervention (PACE+ for adults); computerised assessment and goal setting; then randomised to four groups: Group1 mail only; Group 2 infrequent phone and mail; Group 3 frequent phone and mail; Group 4 controlNo interventionSelf-report of: five target behaviours (moderate and vigorous physical activity, stage of change, dietary fat, fruit/vegetable intake, overeating behaviours)4 monthsLow risk of biasNo difference between groups; those who set dietary goals had reduced pre–post dietary fat consumption (−1.05 versus −0.07 servings per day, p<0.002) and increased fruit and vegetable consumption (+1.66 versus +0.34 servings per day, p<0.001) compared with those who did notGreater attrition among the ethnic minority participants than among the Caucasian participants (p<0.04)
Kristal et al. 199916Randomised controlled trialHealth care clinics, Atlanta, Birmingham, Miami, USAThree clinical centres, 1702 participants, mean age 60.2 years (SD 6.6), 100% women, 60% white, 9% Hispanic, 31% black12-month intervention; Group 1: dietary intervention (aiming to reduce fat intake to 20% energy, increase fruit and vegetables and reduce saturated fat)Control groupTotal dietary fat; fat-related dietary habits; food purchasing patterns6 monthsMedium risk of biasDifference in consumption of added fat between the intervention and control group was −8.9 g/day in blacks and −12.0/day in whites (p<0.05)Intervention effects were significantly larger among blacks compared with whites for poultry and fish but smaller for added fat, dairy food and baked goods