Structural and functional state of bone tissue in children during the second growth spurt

Abstract

The period of intensive growth of children is accompanied by active processes of modeling and remodeling of bone tissue. The formation of bone tissue depends on many factors, but first of all it is an adequate supply of essential nutrients to the child, which primarily include calcium, phosphorus, magnesium and vitamin D. Depending on the level of mineralization of bone tissue in children during intensive growth will depend on whether the bone tissue reaches the peak of bone mass accumulation. Adequate mineralization of bone tissue is the key to bone health in the future, which will be realized in reducing the number of low-energy fractures and, accordingly - in improving the quality of life in the elderly.

Purpose - to establish the peculiarities of the state of bone tissue in children during the growth spurt, depending on the status of vitamin D and indicators of mineral metabolism.

Materials and methods. 205 children aged 9-17 years were examined, which were divided into groups depending on the presence of growth spurt (GS) and its intensity. The examination included analysis of anamnesis data, assessment of physical and sexual development levels, ultrasound and X-ray (DXA) densitometry, determination of levels of total and ionized calcium, phosphorus, magnesium and vitamin D.

Results. Ultrasound densitometry showed a decrease in bone mineral density (BMD) in 24 children (48.0%) (Z-score -1.8±0.56) I group; 28 children (60.87%) (Z-score -1.96±0.27) group II and 43 children (39.45%) (Z-score -1.68±0.72) group III. 32 children were examined with DXA, 18 of them (56.25%) were diagnosed with decreased BMD. In children of group I who had reduced BMD, the average level of vitamin 25-(OH)-D was 39.04±11.84 nmol/l, while in children with normal BMD - 42.43±6.3 nmol/l. In children of group II BMD in which it was reduced, the average level of 25- (OH)-D was 45.68±5.48 nmol/l; at normal BMD - 45,47±4,69 nmol/l. Children of group III with reduced BMD had an average level of 25-(OH)-D 36.73±8.94 nmol/l; with a normal BMD - 42.91±9.1 nmol/l. The average indicators of calcium supply in the groups are as follows: in children of group I - the level of total calcium was 2.22±0.15 mmol/l, ionized calcium - 1.12±0.28 mmol\l; in children of group II - the level of total calcium 2.13±0.11 mmol/l, the level of ionized calcium 0.99±0.10 mmol/l; in children of group III - the level of total calcium 2.26±0.18 mmol/l, the level of ionized calcium 1.12±0.10 mmol/l. The average levels of magnesium were as follows: Group I - 0.96±0.44 mmol/l; Group II - 0.89±0.11 mmol/l; Group III - 0.85±0.19 mmol/l. When determining the average levels of phosphorus, the following data were obtained: Group I - 1.47±0.22 mmol/l; Group II - 1.5±0.23 mmol/l; Group III - 1.49±0.23 mmol l.

Conclusions. Decreased bone mineral density in children during growth spurt is due to deficiency or deficiency of vitamin D and low supply of macronutrients - calcium, phosphorus, magnesium. However, the most significant factor in reducing BMD is the lag in the processes of bone mass accumulation against the background of intensive linear skeletal growth.

The research was carried out in accordance with the principles of the Helsinki declaration. The study protocol was approved by the Local ethics committee of the participating institution. The informed consent of the patient was obtained for conducting the studies.

No conflict of interest was declared by the authors.