Asymptomatic hypercalciuria: prevalence and metabolic characteristics.

Hypercalciuria is of continuing interest as a risk factor for kidney stones in children. We screened 592 healthy Turkish children (308 boys, 284 girls, aged 3 month-16 years) for hypercalciuria by measurement of urinary calcium/creatinine (UCa/Cr) ratio in the second-morning urine samples. Hypercalciuria was noted in 17 children (2.9%), 9 of them were boy and 8 of them were girl. Oral calcium-loading test could only be done in 7 children who were diagnosed as having hypercalciuria, and it revealed absorptive hypercalciuria in 2 cases and renal hypercalciuria in no cases. The frequency of a family history of urolithiasis in asymptomatic hypercalciuric children was 50%. Median UCa/Cr ratios and urinary magnesium/creatinine (UMg/Cr) ratios were 0.11 and 0.10 and the 97th percentiles were 0.32 and 0.23 respectively. The UCa/Cr ratio in second-morning urine samples was correlated with the UMg/Cr ratio (r = 0.44) and was independent of age and sex.

Calcium, magnesium and phosphorus concentrations in human milk and in sera of nursing mothers and their infants during 26 weeks of lactation.

Longitudinal calcium, magnesium and phosphorus concentrations were measured in milk and sera of 20 nursing mothers and their infants during a period of 26 weeks. Within this period, progressive increase in serum calcium, magnesium and total protein concentrations were observed in breast-fed infants, in association with decreasing phosphorus content of breastmilk. Maternal serum calcium, magnesium and total protein concentrations also increased during this period. It is speculated that a decrease in serum phosphorus in breast-fed infants can cause rickets. It is also speculated that the physiological rise in serum calcium concentrations in maternal serum may be related to the physiological increase in serum total protein.