Osteopenia and vitamin D deficiency in children with sickle cell disease.
OBJECTIVE
To assess the prevalence in children with sickle cell disease of low bone mineral density (BMD), a feature found in up to 82% of adults but not well known in children.


METHODS
In 53 children (45 SS, 4 SC, 4 Sbeta-thalassemia) with a mean age of 12.8 +/- 2.4 years, we assessed height; weight; sexual maturation; number of hospitalizations, painful crises, and transfusions in the last 3 years; calcium intake; steady-state hemoglobin and leukocyte count; calcaemia, phosphataemia, and calciuria/creatinuria; serum 25-(OH)D and PTH concentrations; and osteocalcin, urinary deoxypyridinoline, and the C-terminal component of pro-collagen type I. BMD was assessed using dual X-ray absorptiometry.


RESULTS
Mean lumbar spine Z-score was -1.1 +/- 1.3 (-3.9 to +1.8). The Z score was significantly lower in girls than in boys in the prepubertal subgroup (-1.74 +/- 0.27 vs. -0.53 +/- 0.31) (P = 0.0169), but not in the pubertal group (-1.15 +/- 0.41 vs. -1.33 +/- 0.70). BMD was not associated with any of the disease-severity markers in girls but was unexpectedly associated with fewer vaso-occlusive crises and hospitalizations in boys. BMD did not correlate with hemoglobin or leukocyte counts. Vitamin D deficiency [25-(OH)D < 12 ng/mL] was found in 76% of patients and secondary hyperparathyroidism (PTH > 46 pg/mL) in 38%. BMD was not related to calcium intake, vitamin D status, osteocalcin, or bone resorption markers.


CONCLUSIONS
A slight BMD decrease was found in SCD children, starting before puberty and being more marked in females. The decrease was unrelated to disease severity, vitamin D deficiency, or bone hyperresorption, suggesting abnormal bone formation as the underlying mechanism.
Chapelon
E
E
Pediatrie Generale, Hopital Jean Verdier, Paris, France.
Garabedian
M
M
Brousse
V
V
Souberbielle
J C
JC
Bresson
J L
JL
de Montalembert
M
M
D000293:Adolescent; D000755:Anemia, Sickle Cell / Q000097:blood / Q000150:complications* / Q000628:therapy; D000886:Anthropometry; D015415:Biomarkers; D015519:Bone Density; D001851:Bone Diseases, Metabolic / Q000097:blood / Q000453:epidemiology* / Q000209:etiology; D001862:Bone Resorption / Q000652:urine; D002118:Calcium / Q000378:metabolism; D002136:Calcium, Dietary / Q000032:analysis; D002648:Child; D005260:Female; D006760:Hospitalization / Q000706:statistics & numerical data; D006801:Humans; D008159:Lumbar Vertebrae / Q000737:chemistry; D008297:Male; D015675:Osteocalcin / Q000097:blood; D010012:Osteogenesis / Q000502:physiology; D010281:Parathyroid Hormone / Q000097:blood; D015995:Prevalence; D011627:Puberty; D014808:Vitamin D Deficiency / Q000097:blood / Q000453:epidemiology* / Q000209:etiology
D015415:Biomarkers; D002136:Calcium, Dietary; D010281:Parathyroid Hormone; D015675:Osteocalcin; D002118:Calcium