The acceleration of infant growth is thought to increase the later susceptibility to insulin resistance and non-insulin-dependent diabetes in animals; slow growth resulting from undernutrition is therefore thought to have a beneficial effect. To test this proposal in humans, Atul Singhal, Alan Lucas and colleagues from the Institute of Child Health, London, UK, assessed fasting concentrations of a marker for insulin resistance-32-33 split proinsulin-in 216 adolescents born prematurely in the 1980s who had previously participated in randomised intervention trials of infant nutrition. Comparison was also possible with 61 adolescents who had not been born prematurely who received 'normal' nutrition in the first few weeks after birth.
Fasting proinsulin concentration-and therefore a possible tendency to diabetes-was 20% lower in adolescents who had been given a relatively low nutrient diet early in infancy compared to both preterm infants given a high nutrient diet and healthy children born at full term.
Alan Lucas comments: "Whether our results can be generalised to full-term infants requires further research. We recognise that preterm infants are different to those born at term in many respects-most notably that they have medical problems related to prematurity itself. Nevertheless, even if our findings are not generalisable they could still apply to the 6% of the population born preterm."
Atul Singhal and Alan Lucas conclude: "We have shown for the first time in human beings the importance of a lower nutrient intake and slower growth early in postnatal life in favourably programming a key health outcome. Our observations are irrespective of size at birth and in fact suggest that associations between low birthweight for gestation and later cardiovascular risk factors could reflect factors acting early in infancy rather than antenatally. Our findings, therefore, could partly explain what up to now has been regarded as the fetal origins of adult disease.
Because postnatal factors may be more amenable to intervention, the distinction between antenatal and postnatal programming of risk factors for cardiovascular disease, as well as being of scientific importance, probably has important public-health implications. Our data lend support to the benefit of relative undernutrition associated with colostrum and breastfeeding very early in infancy in reducing the risk of cardiovascular disease. If confirmed in infants not born prematurely, our findings would suggest that public-health interventions that aim to reduce the risk of coronary heart disease by the promotion of weight gain in infancy, could even be deleterious. Consequently, present recommendations for infant feeding need to be reappraised as new data emerge."
Contact: Medical Research Council (MRC) Press Office, 20 Park Crescent, London W1B 1AL, UK;
T) 44-207-637-6011;
E) Johannes.steyn@headoffice.mrc.ac.uk
Stephen Cox, Chief Press Officer, Great Ormond Street Hospital for Children NHS Trust and the Institute of Child Health, 3rd Floor, Ormond House, 26-27 Boswell St, London WC1N 3JZ, UK;
T) 44-207-829-8671;
f) 44-207-829-7912;
E) CoxS@gosh.nhs.uk
Journal
The Lancet