Urinary creatinine and hydroxyproline in relation to childhood malnutrition.

I . Urinary excretions of creatinine (Cre) and hydroxyproline (OHPr) were measured in two groups of children: (a) 24 h collections in male and ‘spot’ samples in female marasmic infants throughout the course of treatment, and (b) ‘spot’ samples in underprivileged preschool children at home. Results were related to certain somatic measurements and in some instances to some dietary factors. 2. Analysis of 24 h samples taken at intervals throughout 120 d of treatment showed a steady rise towards normal levels from very low initial values of OHPr. There was no correlation with age or body-weight on admission, nor of OHPr excretion through recovery with increase in height. Excretion of Cre also increased during recovery but the trend was more erratic. There was no relation to initial weight deficit or age but mean Cre excretion through recovery did correlate with rate of increase in weight. Values of Cre excretion at different stages of recovery expressed in terms of weight or height differed somewhat from those reported by others. The possible significance of these findings is discussed. 3. High correlations of the OHPr index according to Whitehead (1965) determined on 6 h and 24 h collections provided evidence for the representative nature of ‘spot’ samples. 4. Partial correlation analysis of body-weight and urine volume in relation to Cre excretion (mg/z4 h) showed that the former (r = 0.719) had a greater influence than the latter (7 = 0.485). 5. In a subgroup of eleven marasmic infants aged 3-5 months multiple linear regression analyses of OHPr and Cre excretion on somatic and dietary factors revealed no consistent correlations. 6. Periods of lowered OHPr and Cre excretion were frequent but in only half of the instances were they related to intercurrent infection. 7. A high correlation was found between changes in excretion of OHPr and of Cre throughout recovery. 8. An appraisal was made of the OHPr index according to Whitehead (1965). On the basis of the considerable influence that age was shown to have on this index during the preschool period an OHPr index (age-adjusted) was suggested for use. 9. The OHPr index (age-adjusted) determined on ‘spot ’ samples from underprivileged preschool children at home and from marasmic infants during recovery was shown to be closely correlated with a modified ‘index of thriving’ based on somatic measurements. 10. The value of Cre and OHPr determinations in the study of severely malnourished children during recovery and in the detection of mild undernutrition is discussed in the light of these experimental results.