Neurodevelopmental, cognitive, behavioural and mental health impairments following childhood malnutrition: a systematic review

ABSTRACT Background Severe childhood malnutrition impairs growth and development short-term, but current understanding of long-term outcomes is limited. We aimed to identify studies assessing neurodevelopmental, cognitive, behavioural and mental health outcomes following childhood malnutrition. Methods We systematically searched MEDLINE, EMBASE, Global Health and PsychINFO for studies assessing these outcomes in those exposed to childhood malnutrition in low- and middle-income settings. We included studies assessing undernutrition measured by low mid-upper arm circumference, weight-for-height, weight-for-age or nutritional oedema. We used guidelines for synthesis of results without meta-analysis to analyse three outcome areas: neurodevelopment, cognition/academic achievement, behaviour/mental health. Results We identified 30 studies, including some long-term cohorts reporting outcomes through to adulthood. There is strong evidence that malnutrition in childhood negatively impacts neurodevelopment based on high-quality studies using validated neurodevelopmental assessment tools. There is also strong evidence that malnutrition impairs academic achievement with agreement across seven studies investigating this outcome. 8 of 11 studies showed association between childhood malnutrition and impaired cognition. This moderate evidence is limited by some studies failing to measure important confounders such as socioeconomic status. 5 of 7 studies found a difference in behavioural assessment scores in those exposed to childhood malnutrition compared to controls but this moderate evidence is similarly limited by unmeasured confounders. Mental health impacts were difficult to ascertain due to few studies with mixed results. Conclusions Childhood malnutrition is associated with impaired neurodevelopment, academic achievement, cognition and behavioural problems but evidence regarding possible mental health impacts is inconclusive. Future research should explore the interplay of childhood and later-life adversities on these outcomes. Whilst evidence on improving nutritional and clinical therapies to reduce long-term risks is also needed, preventing and eliminating child malnutrition is likely to be the best way of preventing long-term neurocognitive harms. PROSPERO registration number CRD42021260498 KEY QUESTIONS What is already known? – High mortality risk and impaired growth are well-recognised short-term risks of childhood malnutrition – Whilst there is increasing appreciation of longer-term risks for survivors, notably adult cardiometabolic non-communicable disease, other longer-term risks have been poorly described. What are the new findings? – There is strong evidence that malnutrition impairs neurodevelopment and academic achievement in childhood which has significant implications for future wellbeing and prospects of those affected – Childhood malnutrition is associated with impaired cognition and behavioural problems with evidence of effects through to adolescence and adulthood but the effect of nutritional treatment and interplay with childhood adversity, co-existing illness such as HIV and environmental factors in influencing these outcomes is unclear What do the new findings imply? – Study findings imply that there are likely to be long-term effects of childhood malnutrition on cognition and wellbeing lasting through adolescence and adulthood – Long-term needs of malnutrition survivors need to be carefully considered in treatment programmes. Further research is needed on the effects of nutritional therapy, adversity and environmental factors to tailor future interventions, particularly with regards to mental health which has been little researched