Bone Mineralization In Children Research Articles

Growth and Bone Mineralization in Children With Cellac Disease (Cd). Effect of Calcium and Vitamin D Supplementation 10

Growth and Bone Mineralization in Children With Cellac Disease (Cd). Effect of Calcium and Vitamin D Supplementation 10

Bone density in children and adolescents with cystic fibrosis

OBJECTIVE: To assess bone mineralization in children and adolescents with cystic fibrosis. DESIGN: A cross-sectional, observational study of bone mineral density (BMD) in the lumbar vertebrae and the proximal femur of 62 patients aged 4.9 to 17.8 years (mean, 10.7 years). The age-normalized BMD findings ( z scores) were correlated with multiple variables, including measures of pulmonary disease, nutritional status and growth, genotype, calcium intake, and serum 25-hydroxyvitamin D and 1,25-dihydroxyvitamin D levels. RESULTS: The mean BMD zscore was –1.03 ± 0.14 (±SE) in the lumbar vertebrae and –0.71 ± 0.17 in the proximal femur. The BMD in this age range declined relative to normal values at a rapid rate of roughly 1 SD every 6 to 8 years. The BMD z scores correlated well with multiple measures of disease severity, particularly weight and forced expiratory volume in 1 second. CONCLUSIONS: Significant osteoporosis in adults with CF results at least in part from a failure to accumulate bone mineral at a normal rate during skeletal growth and development. The cause of this is likely multifactorial. With increasing longevity, the skeletal consequences of CF become an important consideration. (J P EDIATR 1996;128:28-34)

Decreased bone mineralization in children with phenylketonuria under treatment.

Children with phenylketonuria (PKU) obtain a great deal of their protein and mineral intakes from synthetic elemental formulae devoid of phenylalanine. To assess the effect of such diets and/or the disease on bone mineralization, children with PKU were compared to normal children for many parameters of mineral homeostasis and bone mineralization. A total of 11 children with PKU of mean age 10.9 +/- 4.2 years were compared to a large group of normal control children mean age 11.4 +/- 4.2, and an age and sex matched subset (n = 11). Children with PKU had lower serum calcium (9.1 +/- 0.9 vs 10.4 +/- 1.9 mg/dl P < 0.01) amd magnesium (1.67 +/- 1.4 vs 2.07 +/- 0.16 mg/ dl, P < 0.001) but normal values for phosphorus, zinc, and copper. The percentage tubular reabsorption of phosphorus was increased in PKU (93 +/- 3% vs 88 +/- 6%, P < 0.05) suggesting a lower phosphorus intake and/or absorption. Serum 25-hydroxyvitamin D, parathyroid hormone and 1,25 dihydroxyvitamin D were similar in PKU and control children. Serum albumin and lean body mass by dual energy X-ray absorption were not different suggesting that protein intake was adequate. In the 11 pairs, a decreased bone mineral density was seen for the lumbar spine (0.61 +/- 0.15 vs 0.72 +/- 0.24 P < 0.05), and lower extremities (1.56 +/- 0.30 vs 1.87 +/- 0.56 P < 0.05) by paired t-test. Compared to the total controls and the paired controls, decreases were seen in markers of bone formation; bone alkaline phosphatase, (72 +/- 30 vs 126 +/- 43 P < 0.001), osteocalcin (10.7 +/- 3.4 vs 13.1 +/- 2.0 P < 0.05) and procollagen type I carboxyterminal propeptide. No differences were seen in the bone resorption markers tartrate resistant acid phosphatase and urine Ca/Cr. The changes noted could not be related after age correction to serum phenylalanine levels, protein intake, or mineral intakes. It is unclear whether deficits in bone mineralization relate to the disease process itself or its treatment.

Vitamin D metabolism and bone mineralization in children with juvenile rheumatoid arthritis

To examine bone mineralization and bone mineral content in a cross-sectional population of children with juvenile rheumatoid arthritis (JRA). Bone mineral content was measured by single-photon absorptiometry in 44 children with JRA and 37 control children. Serum concentrations of minerals, vitamin D, parathyroid hormone, osteocalcin, bone alkaline phosphatase, and tartrate-resistant acid phosphatase, and urinary concentrations of minerals, were determined. Bone mineral content was decreased in children with JRA. Significantly lower concentrations of osteocalcin (7.4 +/- 3.4 vs 12.5 +/- 2.5 micrograms/L) and bone alkaline phosphatase (78.8 +/- 36.4 vs 123.0 +/- 46.0 IU/L) suggested reduced bone formation; lower levels of tartrate-resistant acid phosphatase (10.3 +/- 4.1 vs 14.4 +/- 5.8 IU/L) and a lower urinary calcium/creatinine ratio (0.07 +/- 0.06 vs 0.12 +/- 0.09) suggested decreased bone resorption. The serum calcium concentration was significantly lower (9.3 +/- 1.0 vs 10.0 +/- 0.4 mg/dl), as was the parathyroid hormone concentration (19.8 +/- 8.6 vs 26.7 +/- 9.3 ng/L); 1,25-dihydroxyvitamin D values (30.1 +/- 10.5 vs 30.4 +/- 9.3 pg/ml) were normal. These data suggest that decreased mineralization in JRA is related to low bone turnover; parathyroid hormone and 1,25-dihydroxyvitamin D levels may be inappropriately normal for the decreased serum calcium concentration in children with JRA.

Bone mineralization in children and adolescents with a milk allergy

To evaluate the correlation between dietary calcium intake and mineralization of the immature skeleton 55 children and adolescents aged 5–14 years (mean, 9.5 years) with a positive radioallergosorbent test (RAST) for serum antibodies to cow's milk protein were evaluated. Bone mineral density (BMD) in the lumbar spine and proximal femurs were measured by dual energy X-ray absorptiometry. BMD at each site for each subject was converted to an age-adjusted Z score based on our own series of 95 normal pediatric controls. Calcium intake was determined using a detailed food frequency questionnaire administered by a nutritionist during a 30–40-min interview. Dietary adjustments to the condition varied and resulted in a wide range of calcium intakes. Calcium supplements were taken by 22% of the subjects and were included in the determination of daily calcium intake. The group of 55 subjects was divided into quartiles based on calcium intake (mean ± S.E mg calcium/day): Group 1, 409 ± 21, Group 2, 663 ± 16, Group 3, 950 ± 32, Group 4, 1437 ± 124. Bone density Z scores in the proximal femur serially increased across the calcium intake groups (mean ± S.E.): Group 1, −0.16 ± 0.31; Group 2, 0.05 ± 0.33; Group 3, 0.44 ± 0.24; Group 4, 0.79 ± 0.41 ( P = 0.03). A similar pattern was found with lumbar spine BMD Z scores: Group 1, −0.16 ± 0.27; Group 2,0.10 ± 0.21; Group 3,0.18 ± 0.20; Group 4,0.30 ± 0.25 ( P = 0.05). These data add further to the evidence that dietary calcium intake is important for optimal mineralization of the growing skeleton.

Effect of gluten-free diet on bone mineral content in growing patients with celiac disease

Osteoporosis is a complication of celiac disease in adulthood, but little is known about the influence of the disease on bone mineralization in children. In the present study we evaluated radial bone mineral content (BMC) in celiac children and adolescents at diagnosis and after they consumed a gluten-free diet (GFD). The BMC values of 33 celiac patients at diagnosis were significantly lower than those of 255 control subjects (P < 0.001). There was no difference between diabetic and non-diabetic celiac patients. In 14 patients the BMC increased significantly (P < 0.05, ANCOVA) after 1.28 y of GFD. In these patients the mean annual BMC increment was 0.07 g/cm, significantly greater (P < 0.05) than the increment of normal growing children (0.05 g.cm-1.y-1). Our data indicate that although osteoporosis complicates celiac disease during childhood and adolescence, GFD alone is able to remarkably improve bone mineralization.

Dietary Calcium and Bone Mineral Status of Children and Adolescents

We studied 164 healthy, white children aged 2 to 16 years; there were 88 boys and 76 girls. By the method of single photon absorptiometry, we found that age, height, and weight correlated positively with bone mineral content of the radius bone. In the children's diet, most of those aged 2 to 11 years met the recommended dietary allowance (800 mg daily) for calcium. Children older than 11 years had low dietary calcium intake; only 15% met the recommended dietary allowance for calcium (1200 mg daily). Dietary calcium intake was associated with bone mineral status. Children ingesting more than 1000 mg of calcium daily had higher bone mineral content than those ingesting less. Almost all serum determinations of calcium, phosphate, magnesium, alkaline phosphatase, parathyroid hormone, 25-hydroxyvitamin D, and 1,25-dihydroxyvitamin D were within normal limits and had no correlation with children's bone mineral status.

DIETARY NEEDS IN BONE MINERALIZATION OF CHILDREN

There has been very little data about the dietary factors which may affect children's bone mineral status. We prospectively studied 88 white healthy children aged 3 to 16 years (mean age 8.7 years). There were 46 boys and 42 girls in our study. During a 3 month study, weight and height were recorded, and at least two 24-48 hour dietary histories were averaged for intakes of calcium, phosphate, magnesium, sodium, protein, and total calories. Bone mineral status was measured by photon absorptiometry on the child's distal non-dominant radius. Blood was drawn for serum calcium, phosphorus, magnesium, alkaline phosphatase, and 25-OH vitamin D. We found that the child's age (r=0.84, p<0.001), weight (r=0.86, p<0.001), and height (r=0.84, p<0.001) were correlated to bone mineral status. Dietary calcium intakes were correlated to the children's bone mineral status (r=0.31, p<0.01). Children ingesting more than 1000 mg calcium daily had higher bone mineral status (8%) than those ingesting less (t test, p<0.03). Dietary protein (r=0.25, p<0.03) was also associated to bone mineral status; children ingesting more than 50 g protein had higher bone mineral status (12%) than those taking less (p<0.01). We found no significant relation between bone mineral status and dietary phosphate, magnesium, sodium, and total calories. All serum determinations were within normal ranges for children and none correlated with the child's dietary intakes or bone mineral status. In summary, our study has shown that age, weight, height, calcium and protein intakes have important effects on children's bone mineral status.