Development of age-dependent micronutrient centile charts and their utility in children with chronic gastrointestinal conditions at risk of deficiencies: A proof-of-concept study.

BACKGROUND & AIMS: Interpretation of blood micronutrient levels requires age-appropriate reference intervals. This study developed age-dependent micronutrient centiles for healthy children (HC) and explored their utility in sick children. METHODS: 244 blood samples were collected from normal HC who underwent tests for acute illness. Age-dependent, centile charts were fitted for zinc, copper, magnesium and selenium in plasma and erythrocytes (RBC), and for vitamins B1, B2 and B6 in RBC. For 34 children with Crohn's disease (CrD) and 55 with coeliac disease (CoeD), Z-scores for the levels of these micronutrients were computed, using the new charts. Associations were explored between plasma and RBC micronutrient Z-scores, and in CrD with CRP and serum albumin. RESULTS: In HC, plasma zinc and selenium increased and plasma copper, magnesium and RBC vitamins B1, B2 and B6 decreased with age. In HC and in CrD, plasma and RBC Z-scores for copper, selenium and magnesium (all p < 0.001) were positively correlated, but not for zinc. In CrD, albumin was related with plasma zinc (rho = 0.62; p < 0.001) and selenium Z-scores (rho = 0.65; p < 0.001) and plasma copper Z-score with CRP (rho = 0.45; p = 0.02). A higher proportion of CrD children had low levels for B2 (21% vs 0%; p = 0.01) and B6 (18% vs 0%; p = 0.02) using the new centile charts than the local laboratory references. CONCLUSION: Age-dependent micronutrient centile charts enable tracking of micronutrient status, Z-score calculation and may prevent misdiagnosis and inappropriate treatment of deficiencies. In systemic inflammatory conditions, RBC measurements of certain micronutrients may be more reliable to use than measurements in plasma.

Development and validation of a novel paediatric weight estimation equation in multinational cohorts of sick children.

AIM: In sick children who are unable to be weighed estimation of weight is often required, but the routinely used equations lack accuracy and precision. This study aimed to develop a novel equation (Children's European Estimator of Weight-CEEW) using measurements of mid-upper arm circumference (MUAC) and other predictors in multinational groups of sick children in Europe. METHODS: Weight estimation equations were developed in 2086 children from the UK, Greece and the Netherlands, using a combination of demographics, MUAC and height measurements. The final CEEW equations were compared against the performance of the European Resuscitation Council (ERC), Advanced Paediatric Life Support (APLS) and the Cattermole equations. RESULTS: Two final CEEW equations were developed, incorporating measurements of age, gender and MUAC, with (CEEW1) or without (CEEW2) the inclusion of height. Both equations presented very high coefficients of determination (R2>96.5%), minimal mean prediction error and narrower limits of agreement than the comparator equations. 88% (CEEW1) and 77% (CEEW2) of weight estimates fell within 15% of measured body weight. These figures compared with less than 57%, 57% and 37% for the ERC, APLS and Cattermole equations respectively. CONCLUSION: The CEEW equations performed substantially better than other routinely used equations for weight estimation. An electronic application for mobile use is presented.