Table 1
Characteristics and results of studies
| First author, location, and study type | n | Study period | Definition of human milk (HM) intake | Statistical analysis and outcome | Confounding factors | Major problems* |
|---|---|---|---|---|---|---|
| *No precalculation of sample size in any study. | ||||||
| †T, total number in study; I, number in intervention group; C, number in control group. | ||||||
| ‡OR, odds ratio. | ||||||
| §CI, 95% confidence interval. | ||||||
| ¶RR, relative risk. | ||||||
| **All control infants were exclusively fed formula milk (FM), except in Narayanan et al19 where the control group was given pasteurised HM + formula milk. | ||||||
| El Mohandes,20 USA, cohort | T 173† I 59 C 114 | 0–38 days | HM only as enteral nutrient ⩾1 week or as 40% of enteral calorie intake + FM | Survival analysis using time to infection: lower incidence of sepsis in HM group; OR = 0.38‡, CI = 0.05–0.95§, p = 0.04 | None mentioned or controlled | Flawed definition of HM feeding No exclusively HM fed group Infection severity not assessed |
| Schanler,21 USA, cohort | T 108 I 62 C 46 | 0–9 weeks | >50 ml/kg/day HM averaging through hospital stay + FM | Logistic regression: lower proportion of sepsis episodes in HM group; OR = 0.46, CI = 0.24–0.87, p = 0.016 | Controlled: antenatal steroid exposure Not controlled: maternal education, maternal contact and holding, milk intakes | No subgroup analysis of exclusive HM fed group Severity of infection not assessed Important confounders not controlled |
| Furman,22 USA, cohort | T 119 I 79 C 40 | 0–6 weeks | Graded doses 1–24, 25–49, ⩾50 ml/kg HM through week 4 + FM | Poisson regression analysis: lower number of sepsis episodes in ⩾50 ml/kg HM group; RR = 0.27, CI = 0.08–0.95, p<0.05 | Controlled: birth weight, gender, ethnicity Not controlled: dexamethasone | No exclusive HM fed group Severity of infection not assessed Important confounder not controlled |
| Hylander,23 USA, cohort | T 212 I 123 C 89 | Hospital stay | Any amount of HM+FM Duration unknown | Logistic regression on selected group of measured variables: lower odds of infection in HM groups; OR = 0.46, CI = 0.24–0.87, p = 0.016 | Controlled: maternal sociodemographic factors, birth weight, 5 minute Apgar, days of mechanical ventilation | Flawed definition of HM feeding No exclusive HM fed group Severity of infection not assessed, duration of feeding unknown |
| Blaymore-Bier,25 Australia, cohort | T 39 I 24 C 15 | 1, 3, 7, 12 months | Any amount of HM+FM up to 1 year | ANCOVA: lesser days of URTI symptoms at: 1 month, p = 0.02, and 7 months, p = 0.006 | Controlled: socioeconomic status | Small numbers with only 5 infants exclusively HM fed Bias in detecting outcome |
| Contreras-Lemus,24 Mexico, cohort | T 118 I 59 C 59 | Hospital stay | Preterm HM only Duration unknown | χ2 Lower incidence of diarrhoea; RR¶ = 9, and urinary infection; RR5 in HM group, p<0.01 | None mentioned or accounted for | No details of diagnosis of outcome measures. Duration of feeding unknown |
| Narayanan,17 India, RCT | T 70 I 32 C 38 | Hospital stay | EBM (mother’s own or mature donor) + FM Duration unknown | χ2 test Lower infection rate in HM group (n = 9), FM (n = 24), p<0.01 | None mentioned or accounted for | Small numbers with only 5 infants <1500 g Flawed definition of HM feeding, duration unknown Lack of exclusive HM fed group |
| Narayanan,18 India, RCT | T 66 I 33 C 33 | Hospital stay | Colostrum 10 ml TDS (mother’s own or mature donor) + FM Duration unknown | χ2 test Lower infection rate in HM group (n = 7), FM (n = 18), p<0.01 | None mentioned or accounted for | Small numbers with only 5 infants <1500 g Flawed definition of HM feeding, duration unknown Lack of exclusive HM fed group |
| Narayanan,19 India, RCT Narayanan | T 226 I 169 | Hospital stay | Raw or pasteurised EHM (mother’s own or mature donor) Duration unknown | χ2 test Greater infection rate pasteurised HM + FM group 33.3%, raw HM group: 10.5%, p<0.05 | None mentioned or accounted for | Inadequate numbers with only 20 infants <1500 g No exclusively formula fed group** Duration of HM feeding unknown |
