Infants are at high risk of undernutrition – high requirements for growth, frequent infections affecting appetite and increasing requirements, inefficient metabolism, dependence on adults for food!
There are various ways of defining or looking for undernutrition:
- Wasting – ie low BMI or weight for height. Pushed by WHO as way of identifying most vulnerable, but in affluent societies seems to mostly identify tall children
- Stunting – low height for age, indicating chronic poor growth. But in affluent societies, more likely to be constitutional or organic disease? Social gradients in height in UK persisted until 1990s, but socially deprived short children had shorter parents and were smaller at birth, so not all nutritional.
- Low weight centile – usually just selects out low birth weight babies.
- Falling through weight centiles (“growth faltering”) selects for relatively large infants regressing to mean.
“Failure to thrive” has gone out of fashion. “Thrive” seems to suggest something more than growth, but really we are just talking weight and height. “Failure” suggests not only that there is a definite problem, but also that it’s somebody’s fault! Variability in definition and use.
The main issue here is poor sensitivity and specificity for a genuine problem. 27% of Danish cohort infants met one or more of 7 different growth criteria in at least one of the two age groups (2–6 and 6–11 months of life). The concurrence among the criteria was generally poor, with most children identified by only one criterion. Positive predictive values of different criteria ranged from 1% to 58%. Most single criteria identified either less than half the cases of significant undernutrition (found in 3%) or included far too many, thus having a low positive predictive value. [Olsen, Arch Dis Child 2007;92:109-114 doi:10.1136/adc.2005.080333 ]
Things get even less consistent in older kids, where you can have low fat but apparently normal growth except at the extreme end of range.
Combination of weight faltering and low BMI is perhaps best. These kids subsequently have growth and body composition patterns suggestive of previous undernutrition. Overall, about 2/3 of kids with either weight faltering or low BMI probably adequate nutrition but variant growth pattern. Weight faltering kids are relatively short at follow up, but not more so than parents, so probably “catching down”. [Proceedings of the Nutrition Society. 71(4):545-55, 2012 Nov. PMID: 22954067]
Undernutrition is NOT associated with deprivation in UK, presumably as welfare focuses on families with young children. In the Gateshead Millennium Baby Study, both the highest and the lowest levels of deprivation were associated with weight faltering; this was independent of the type of milk feeding. No relation was found with maternal educational status.
Abuse and neglect are a factor in only a minority of cases.
Some evidence of differences in maternal feeding behaviour and appetite, eating behaviour. In Gateshead study maternal eating restraint (“I need to control how much I eat”) was unrelated to weight gain. Response to food refusal seems important.
In Gateshead study, infants of mothers with high depression symptom scores (EPDS >12) had significantly slower weight gain and increased rates of weight faltering up to 4 months (relative risk 2.5), especially if they came from deprived families, but by 12 months they were no different from the remainder of the cohort. [Arch Dis Child 2006;91:312-317 doi:10.1136/adc.2005.077750]
Either low appetite or actually not undernourished in strict sense!
Being faddy was only weakly associated with poor growth, and simply eating a limited variety was unrelated to growth [cf high eating restriction scores]. High milk consumption was associated with lower appetite but not with poor growth.[ Pediatrics. 120(4):e1069-75, 2007 Oct. UI: 17908727]
See Fussy eating
In Newcastle, There was a significant positive relationship between weight gain in infancy and picture vocabulary at age 10, adjusted for economic deprivation, gestational age and birthweight, but not with any of the other outcomes. There was a statistically significant association between birthweight and all four outcomes, where best outcome is at or just above average birthweight. In this population, the association between early growth and cognitive outcomes is stronger for growth before birth, postnatal weight gain having a relatively minor impact.[ Paediatr Perinat Epidemiol. 2007 Jan;21(1):57-64.]
Being able to see what happens in the house at mealtimes is the most useful thing! Interventions that include home visits work best. So Health Visitor is key.
Speech and Language, Dietician advice may be appropriate in some cases.
Identifying children with underlying medical problem important, even if these are a minority. Similarly those with social concerns. But proportionate response to symptoms and signs important, rather than long lists of investigations.
Although tempting, high energy oral supplements eg Pedisure suppress appetite for normal food. In series of 48 kids referred to a tertiary feeding clinic who were taking predominantly supplements (half neurodevelopmentally abnormal), most were successfully weaned off and had improved feeding behaviour a year later. Average weight Z score unchanged, 17% had significant catch up growth. [Archives of Disease in Childhood. 100(11):1024-7, 2015 Nov. UI: 25809349]