27. Supplementary feeding versus no supplementary feeding (control, placebo, standard care, dietary advice), outcome: school attendance, cognition tests and educational attainment.
| Review | Target group | Intervention | Outcome | Corresponding risk with intervention (95% CI) | Number of participants (studies) |
| Cognitive tests | |||||
| Kristjansson 2007 | School children (aged 5–19 years) | Balanced | Full scale IQ (total) (adjusted ICC = 0.15) | MD 3.90 (–2.88 to 10.68)a,b | 231 (1) |
| Full scale IQ (separated) (cluster size as in analysis) (adjusted ICC = 0.15) | MD 3.80 (0.51 to 7.10)a,c,d | 231 (1) | |||
| Performance IQ (total) (adjusted ICC = 0.15) | MD 5.00 (–2.60 to 12.6)a,b | 231 (1) | |||
| Performance IQ (separated) (cluster size as in analysis) (adjusted ICC = 0.15) | MD 5.74 (1.73 to 9.74)a,c,e | 231 (1) | |||
| Verbal IQ (total) (adjusted ICC = 0.15) | MD 3.10 (–2.99 to 9.19)a,b | 231 (1) | |||
| Verbal IQ (separated) (cluster size as in analysis) (adjusted ICC = 0.15) | MD 3.35 (–0.21 to 6.92)a,c | 231 (1) | |||
| Kristjansson 2015a | Disadvantaged infants and young children (aged 3 months to 5 years) | Supplement food | Cognitive ability | SMD 0.58 (0.17 to 0.98)f,g | 99 (1) |
| High energy | Change on Bailey Scale of Mental Development (BSMD) | SMD –0.40 (–0.79 to –0.00)h | 113 (1) | ||
| Ota 2015 | Pregnant women | Balanced | Child's Bailey mental score (1 year) | MD –0.74 (–1.95 to 0.47) | 411 (1) |
| Child's IQ (5 years) | MD 0.00 (–4.98 to 4.98) | 153 (1) | |||
| High protein | Child's Bailey mental score (1 year) | MD 0.32 (–0.91 to 1.55) | 396 (1) | ||
| Educational attainment | |||||
| Kristjansson 2007 | School children (aged 5–19 years) | Balanced | Maths change overall (ICC = 0.15) | SMD 0.31 (0.09 to 0.53)a,i | 337 (2) |
| Change in reading (ICC = 0.15) | MD 0.09 (–0.11 to 0.29)a | 106 (1) | |||
| Change in spelling (ICC = 0.15) | MD 0.24 (0.01 to 0.47)a,h | 106 (1) | |||
| School attendance | |||||
| Kristjansson 2007 | School children (aged 5–19 years) | Balanced | Change in attendance (ICC = 0.15) | MD 4.95 (–3.56 to 13.46)a | 108 (1) |
| End of study attendance (ICC = 0.15) | MD –0.23 (–17.93 to 17.47)a | 72 (1) | |||
| CI: confidence interval; ICC: intracluster correlations; IQ: intelligence quotient; MD: mean difference. | |||||
aAll comparisons: low‐ and middle‐income country (LMIC) controlled before‐and‐after studies (CBAs). bSensitivity analyses made very little difference to either the point estimate or the significance. cFour subgroups of one study (Agarwal 1989). dChildren who were given school lunches had an end‐of‐study full‐scale intelligence quotient (IQ) that was 3.8 points higher than children who were not given school lunch. Sensitivity analyses with intracluster correlation (ICCs) at 0.10 and 0.20 still significant. eChildren who were given school lunches had an end‐of‐study performance IQ that was 5.74 points higher than children who were not given school lunch. Sensitivity analyses with ICCs at 0.10 and 0.20 both significant. fTrial compared results for time point 4 children (supplemented with stimulation from 42 to 84 months of age) to those of time point 2 children (supplemented from 63 to 84 months of age) at 63 months. gLMIC randomised controlled trial (RCT). hChange in spelling achievement significantly greater for children who received school meals (breakfast). Sensitivity analysis with an ICC of 0.10 showed much the same results, however, the sensitivity analysis with an ICC of 0.20 was non‐significant. iChange in maths achievement significantly greater for children who received school meals (lunch and breakfast); results of an analysis with Agarwal 1989 broken down into four nutritional subgroups were similar (standardised mean difference 0.44, 95% confidence interval 0.22 to 0.67). Sensitivity analyses for ICCs of 0.10 and 0.20 made little difference.
Additional comments:
- An ICC of 0.15 was used for maths, reading, spelling, attendance and intelligence outcomes, with ICCs of 0.10 and 0.20 used for sensitivity analyses (Kristjansson 2007).
- Kristjansson 2015a narratively reported one additional cluster‐RCT in an LMIC (Pollitt 2000). The study found no main effects of supplementation on the Bailey Scales of Mental Development but reported positive effects in a contrast over time for the younger cohort but not for the older cohort (P < 0.05; 53 children).
- Kristjansson 2015a narratively reported long‐term follow‐up of cognitive development. Grantham‐McGregor 1997 followed up 97% (127 children) of the original cohort of stunted children (Grantham‐McGregor 1991; 129 children) after four years and tested them on a battery of cognitive and perceptual tests. A multiple regression found effects on perceptual motor tasks, but not on general cognition or memory. Interestingly, stimulation had a significant effect on later perceptual‐motor skills for all children (P < 0.05), but supplementation only had a significant effect for children whose mothers had higher scores on a test of verbal intelligence (P < 0.05). Grantham‐McGregor 2007 also found that supplemented children had higher mean scores than the control group on 14 out of 15 cognitive tests (P = 0.02). Pollitt 1997 performed a seven‐year follow‐up of Husaini 1991. They found no differences between the intervention (125 children) and control (106 children) groups on the Peabody Picture Vocabulary Test, emotionality, and maths. They found small (15‐second difference), positive effects of supplementation on working memory performance, although these are unlikely to be clinically significant.