title: Varying role of vitamin D deficiency in the etiology of rickets in young children vs. adolescents in northern India.
abstract: The relative importance of calcium vs. vitamin D deficiency in the etiology of nutritional rickets in the tropics may be different in children compared with adolescents. We studied calcium intake, sun exposure, serum alkaline phosphatase, and 25 hydroxyvitamin D in 24 children and 16 adolescents with rickets/osteomalacia. The values were compared with those obtained in control subjects (34 children and 19 adolescents). We found that young children with rickets had lower calcium intake compared with controls (285 +/- 113 vs. 404 +/- 149 mg/day, p < 0.01), but similar sun exposure (55 +/- 28 vs. 56 +/- 23 min x m2/day) and 25 hydroxyvitamin D (49 +/- 38 vs. 61 +/- 36 nmol/l). Sixteen of 24 children with rickets had 25 hydroxyvitamin D above the rachitic range (> 25 nmol/l), in contrast to one of 16 adolescents. Adolescent patients had low calcium intake vs. controls (305 +/- 196 vs. 762 +/- 183 mg, p < 0.001), and lower sunshine exposure (16 +/- 15 vs. 27 +/- 17 min x m2/day, p < 0.01) and serum 25 hydroxyvitamin D (12.6 +/- 7.1 vs. 46 +/- 45.4 nmol/l, p < 0.001). The odds ratio for developing rickets with a daily calcium intake below 300 mg was 4.8 (95 per cent CI, 1.9 - 12.4, p = 0.001). Subjects with rickets were randomized to receive 1 g calcium daily, with or without vitamin D. Children showed complete healing in 3 months, whether they received calcium alone or with vitamin D. Adolescents showed no response to calcium alone, but had complete healing with calcium and vitamin D in 3-9 months (mean 5.3 months). Thus deficient calcium intake is universal among children and adolescents with rickets/osteomalacia. Inadequate sun exposure and vitamin D deficiency are important in the etiology of adolescent osteomalacia.
authors.affiliation: Department of Endocrinology, Sanjay Gandhi Postgraduate Institute of Medical Sciences, Lucknow, India.
authors.forename: K
authors.initials: K
authors.lastname: Balasubramanian
authors.forename: J
authors.initials: J
authors.lastname: Rajeswari
authors.lastname: Gulab
authors.forename: Y C
authors.initials: YC
authors.lastname: Govil
authors.forename: A K
authors.initials: AK
authors.lastname: Agarwal
authors.forename: A
authors.initials: A
authors.lastname: Kumar
authors.forename: V
authors.initials: V
authors.lastname: Bhatia
mesh_terms: D000293:Adolescent; D000469:Alkaline Phosphatase / Q000097:blood; D002118:Calcium / Q000627:therapeutic use; D002648:Child; D002675:Child, Preschool; D003196:Computer Graphics; D005260:Female; D006801:Humans; D007223:Infant; D008297:Male; D010018:Osteomalacia / Q000175:diagnosis / Q000188:drug therapy / Q000209:etiology*; D011859:Radiography; D012279:Rickets / Q000175:diagnosis / Q000188:drug therapy / Q000209:etiology; D018709:Statistics, Nonparametric; D016896:Treatment Outcome; D014807:Vitamin D / Q000627:therapeutic use; D014808:Vitamin D Deficiency / Q000150:complications* / Q000175:diagnosis / Q000188:drug therapy; D014953:Wrist / Q000000981:diagnostic imaging
chemical_list: D014807:Vitamin D; D000469:Alkaline Phosphatase; D002118:Calcium