Serum Osteocalcin Regulation in Protein-Energy Malnourished Children

Abstract

To evaluate bone turnover changes occurring during proteinenergy malnutrition, serum osteocalcin, a marker of bone formation, has been studied in healthy control, stunted, and severely malnourished (kwashiorkor and marasmus) Senegalese children. Serum osteocalcin levels were dramatically reduced in stunted, kwashiorkor, and marasmic childrencompared with control children. In addition serum osteocalcin levels of control children living in Senegal were lower (-46%) than those of African children living in France. Interestingly, serum osteocalcin level was not related to its major known regulator s (la,25-dihydroxycholecalciferol, 25-hydroxycholecalciferol, and PTH) nor to stunting,but was related to serum transthyretin and thyroid hormones concentrations. These data suggest that serum osteocalcin level is related to protein-energy status and that bone formation was affected in apparently healthy and in malnourished PEM is a great probl em which concerns about half the world' s children. However, contrary to other aspects of PEM , bone metabolism has received little attention. Most of the studies on bone are from the last decades and were hindered by the lack of appropriate tools for investigation of bone turno ver. Previous studies based on radiography or ash weights have suggested an increase of bone resorption (1), whereas recently, Branca et al. (2), using urinary pyridinoline and deox ypyridinoline concentrations, have dem onstrated that bone resorption is decre ased in PEM. Thanks to the availability of new specific biochemical mark ers, such as osteocalcin, it was found relevant to reevalute with more insight the other side of bone turnover, i.e. bone formation.Osteocalcin is the most abundant noncollagenous bone protein and is produced by osteoblast (3). Most of the newly synthesized osteocalcin remains bound to bone hydroxyapatite, but a small fraction of the protein is released into the blood (3, 4) and serum osteocalcin appears to be an useful marker of Senegalese children.Serum osteocalcin could be a potent tool in the study of the alterations of bone formation in malnutrition. (Pediatr Res 37: 606-610, 1995) Abbreviations 1,25(OH)2D, la,25-dihydroxycholecalciferol 25(OH)D, 25-hydroxycholecalciferol CD, control children living in Dakar CP, control children living in Paris iPTH, immunoreactive PTH K, kwashiorkor children M, marasmic children MS, moderately stunted children PEM , protein-energy malnutrition SS, severely stunted children bon e formation (4). To further clarify possibl e effects of PEM on bone form ation , serum osteocalcin concentrations were determi ned in groups of children from Senegal (West Africa) with various forms of malnutrition in relation to mark ers of the protein energy and the inflammation status. In addition, the main regulators of osteocalcin synthesis, i.e. 1,25(OH)2D and parath yroid and thyroid hormones, were measured to investigate the regulation of serum osteocalcin concentration in PEM . METHODSOur criteria for inclusion in the study were based on age and anthropome...

Low mineral density of a weight‐bearing bone among adult women in a high fertility population

“…Indian pre-schoolers aged 3 – 5 accustomed to low calcium intake (~ 200 mg/day) but with adequate protein and calorie intake maintain positive calcium balance (Begum and Pereira 1969; also see Prentice and Bates 1993). Further suggesting a link between macro-nutrient intake and bone mineral status, among Senegalese children 9 – 24 months old, severe protein-energy malnutrition is associated with reduced serum osteocalcin, a marker of bone formation (Ndiaye et al 1995). Tsimane rarely experience such severe malnutrition as occurs in kwashiorkor or marasmus, but low energetic surplus may interact with high immune activation to reduce BMD, despite high physical activity levels and compensatory mechanisms that regulate mineral balance.…”

Biochemical Measurements of Bone Turnover in Children and Adolescents

“…Bone turnover is reduced in malnourished children [103,104]. Low body weight is accompanied by a low body surface and a low muscular mass resulting in a low urinary creatinine which artificially increases values of urinary creatinine-corrected resorption markers.…”

“…However, comparability of data cannot be assumed as they were obtained in different laboratories. Black children in Senegal have lower OC than black children in France [103]. Bone markers are also influenced by nutritional status [104].…”

Experience of famine and bone health in post-menopausal women

“…4 Low protein intake can reduce intestinal calcium absorption as the result of secondary hyperparathyroidism. 19 In addition, bone re-modelling is reduced, as evidenced by a low serum osteocalcin level which is a bone formation marker, in malnourished children 20 and patients with anorexia nervosa. 21 People are usually poorly educated in the region with famine.…”