Body Composition of Children with Myelomeningocele, Determined by ⁴⁰K, Urinary Creatinine and Anthropometric Measures

Abstract

Objective: The purpose of this study was to develop a method to prevent obesity in myelomeningocele (MM) children by determining the effects of growth, calories and physical activity on body composition and to apply this data to clinical practice, specifically, to correlate lean body mass (LBM) with calorie needs and to correlate body fatness with anthropometry measures.

Methods: The body compositions of 14 children (four males and ten females) with MM were estimated from potassium content (⁴⁰K), urinary creatinine and anthropometry measurements at the beginning and end of a six-month period. Three subjects who did not have MM were also evaluated as controls. Dietary and physical activity and dietary-goals estimates were taken from records kept by the patients after initial discussion of physical activity and dietary goals with the families.

Results: The study showed potassium content (⁴⁰K), or LBM, in children with MM to be approximately 50% of the potassium content (⁴⁰K) of children without MM. The percentage of LBM correlated with physical activity, but not with the location of neurological lesion. Lean body mass and creatinine excretion also were significantly correlated, indicating that creatinine excretion is a good measure of lean body tissue in these children. Thorax and abdominal skinfolds, as well as total circumferential measurements (waist being highest), showed significant correlations with the percent of body fat. The caloric intake requirement to maintain the growth of a child with MM was found to be approximately 50% of the recommended daily allowance (RDA) for a child without MM of the same age. Changes in LBM were observed in children with MM who increased physical activity over a six-month interval and were greater than in those who reduced calories alone, however not significantly, presumably due to the short duration of the study.

Conclusion: To prevent obesity, physical activity should begin in infancy; this will increase LBM and thereby calorie needs. Skinfolds and circumferences (abdominal and thorax skinfolds and waist circumference) which significantly correlated with body fat should be used clinically. Calorie needs according to LBM should be reduced to 50% of the RDA or approximately nine cal/cm height for maintenance or seven cal/cm height for weight loss in MM children after age six (possibly at three to four years of age if nonambulatory).

• body potassium (⁴⁰K)
• creatinine excretion
• anthropometric measures
• myelomeningocele
• lean body mass

The authors wish to thank Professor Richard Bozian, M.D., Professor James Stevens, Ph.D., Vanessa Laffert and Carolyn Kelley for their assistance with this manuscript.

Notes

This project was supported in part by Grant No. MCJ-399156-09-0 awarded by the Maternal and Child Health Bureau (Title V, Social Security Act), Health Resources and Service Administration, Public Health Service, Department of Health and Human Services.

Presented in part at the 123rd Annual Meeting of the American Association on Mental Retardation, May 26, 1999, New Orleans, Louisiana.