Seasonal variations in vitamin D in relation to growth in short prepubertal children before and during first year growth hormone treatment

• Published in: Journal of endocrinological investigation 2015-12, Vol.38 (12), p.1309-1317
• Main Authors: Andersson, B., Swolin-Eide, D., Kriström, B., Gelander, L., Magnusson, P., Albertsson-Wikland, K.
• Format: Article
• Language: English
• Subjects: 25-Hydroxyvitamin D; Child; Endocrinology; Female; Growth Disorders - blood; Growth Disorders - drug therapy; Growth hormone; Growth Hormone - administration & dosage; Growth Hormone - pharmacology; Growth response; Humans; Male; Medicine; Medicine & Public Health; Metabolic Diseases; Original Article; Outcome Assessment (Health Care); Pediatrics; Pediatrik; Seasons; Vitamin D - analogs & derivatives; Vitamin D - blood
• ISSN: 1720-8386; 0391-4097; 1720-8386
• DOI: 10.1007/s40618-015-0360-1

Purpose This study investigated the relationship between seasonal variations in 25-hydroxyvitamin D (25(OH)D) levels and growth in prepubertal children during both the pretreatment year and the first year of GH treatment. Methods The study included 249 short prepubertal children with a broad range of GH secretion, GH max during a 24 h profile median 23; range 1–127 mU/L, 191 boys (mean age ± SD, 8.6 ± 2.6 years), 58 girls (7.5 ± 1.9 years) receiving GH treatment (mean 43 µg/kg/day; range 17–99 µg/kg/day). Serum 25(OH)D was measured using an automated IDS-iSYS immunoassay. Results 25(OH)D levels showed seasonal variation, and decreased significantly during GH treatment. 25(OH)D levels at start and first year reduction in 25(OH)D, correlated (−) with the first year growth response during treatment. The degree of GH secretion capacity within our study population of mainly non-GH deficient children and 25(OH)D sufficient (67 ± 29 nmol/L) had no influence on 25(OH)D levels. Growth during GH treatment were independent of seasonal variations in 25(OH)D. Multiple regression analysis showed that 25(OH)D levels at treatment start, together with auxological data and IGF-binding protein-3 SDS , explained 61 % of the variation in first year gain in height SDS . Conclusion 25(OH)D levels were associated with first year growth response to GH and may be a useful contribution to future growth prediction models.