Body composition and bone mineral density in children with premature adrenarche and the association of LRP5 gene polymorphisms with bone mineral density.
BACKGROUND
Precocious increase in adrenal androgen production is the hallmark of premature adrenarche (PA). Adrenal androgens have anabolic properties.


OBJECTIVE
The objective of the study was to test whether body composition and bone mineral density (BMD) are altered in PA and study whether genetic variation in low-density lipoprotein receptor-related protein 5 (LRP5) affects BMD in PA.


METHODS
This was a cross-sectional study.


METHODS
The study was conducted at a university hospital.


METHODS
The study included 126 prepubertal children (64 with PA, 10 boys; 62 non-PA controls, 10 boys). Femoral neck and lumbar spine areal and calculated volumetric BMD (dual energy X-ray absorptiometry), body composition (bioimpedance), serum 25-hydroxyvitamin D, and markers of bone turnover and calcium homeostasis were compared between the PA and control groups. Single-nucleotide polymorphisms of LRP5 were determined and associated with BMD.


RESULTS
Children with PA had higher femoral neck and lumbar spine BMD(areal) than the controls (Z-score 0.56 vs. -0.09, P < 0.001, and 0.20 vs. -0.31, P = 0.009, respectively). However, the mean BMDs did not differ significantly between the groups when adjusted for height or bone size. BMD(areal) correlated strongly with height sd score in both groups. Among the PA children, LRP5 single-nucleotide polymorphism E644E minor variant was associated with lower and F549F minor variant with higher BMD. Total body fat mass, fat percent, serum PTH, and alkaline phosphatase concentrations were higher and 25-hydroxyvitamin D lower in the PA group.


CONCLUSIONS
Prepubertal children with PA had higher BMD(areal) compared with healthy controls. This was mainly explained by their increased height. LRP5 polymorphisms may contribute to bone mass accrual in prepubertal PA children.
Departments of Pediatrics, University of Kuopio and Kuopio University Hospital, FI-70211 Kuopio, Finland. pauliina.utriainen@uku.fi
Pauliina
P
Utriainen
Jarmo
J
Jääskeläinen
Anne
A
Saarinen
Esko
E
Vanninen
Outi
O
Mäkitie
Raimo
R
Voutilainen
D050499:Adrenarche / Q000235:genetics*; D001823:Body Composition; D015519:Bone Density / Q000235:genetics*; D002648:Child; D003430:Cross-Sectional Studies; D005260:Female; D005272:Femur Neck / Q000033:anatomy & histology; D005387:Finland; D006801:Humans; D026502:LDL-Receptor Related Proteins / Q000235:genetics*; D060492:Low Density Lipoprotein Receptor-Related Protein-5; D008297:Male; D010902:Pituitary Gland / Q000254:growth & development*; D011110:Polymorphism, Genetic; D012016:Reference Values; D013131:Spine / Q000033:anatomy & histology
D026502:LDL-Receptor Related Proteins; C555482:LRP5 protein, human; D060492:Low Density Lipoprotein Receptor-Related Protein-5