Zeni S, de Portela M L, del Carmen Morasso M, Río M E
Arch Latinoam Nutr. 1984 Mar;34(1):35-45.
The calcium/creatinine ratio (Ca/Creat.) as an indicator of calcium nutritional status was evaluated in "basal urine" from 24 children comprised within the ages of three to 36 months during a 60-day period. The children were divided in normal or undernourished, according to Waterlow's classification. Children under 12 months of age were fed ad libitum with one of two commercial milk formulas, assigned according exclusively to the pediatric criterium. Children older than 12 months received milk besides the habitual hospital diet. In all cases the food intake was controlled and the calcium intake calculated. At the end of the study, basal urine was collected and calcium and creatinine determined. The results revealed that: a) In the normal children the Ca/Creat. ratio gradually decreased with age tending to a low value of 0.2 at the age of 36 months. The relationship between the Ca/Creat. ratio and the calcium intake showed a change in the slope when the requirements were met according to RNC (60 mg/kg/day); b) In undernourished children, the Ca/Creat. ratio was nearly constant whatever their age or calcium intake. The trend to approach the value of 0.2 for calcium intake (about 250 mg/kg/day), however, and the absence of the inflexion point, would suggest that the requirements of these children are far higher than the NRC recommendation, and that the change of the slope would be found for intakes over those obtained in our study. According to these findings, we conclude that the Ca/Creat. ratio in basal urine does not reflect calcium intake, but would depend on the bone calcium turnover. Consequently, it would be a simple and useful indicator of calcium nutritional status.
在60天的时间里，对24名年龄在3至36个月之间儿童的“基础尿”中的钙/肌酐比值（Ca/Creat.）作为钙营养状况指标进行了评估。根据沃特洛分类法，将这些儿童分为正常或营养不良两类。12个月以下的儿童随意喂食两种市售配方奶粉中的一种，完全按照儿科标准分配。12个月以上的儿童除常规医院饮食外还饮用牛奶。在所有情况下，食物摄入量均受到控制并计算钙摄入量。研究结束时，收集基础尿并测定钙和肌酐。结果显示：a）在正常儿童中，Ca/Creat.比值随年龄逐渐降低，在36个月时趋于低至0.2的值。当根据推荐营养素摄入量（RNC，60毫克/千克/天）满足需求时，Ca/Creat.比值与钙摄入量之间的关系显示斜率发生变化；b）在营养不良的儿童中，无论其年龄或钙摄入量如何，Ca/Creat.比值几乎恒定。然而，钙摄入量趋于接近0.2的值（约250毫克/千克/天）且不存在拐点，这表明这些儿童的需求远高于美国国家研究委员会的建议，并且在摄入量超过我们研究中所获得的摄入量时会发现斜率变化。根据这些发现，我们得出结论，基础尿中的Ca/Creat.比值不能反映钙摄入量，而是取决于骨钙周转率。因此，它将是钙营养状况的一个简单而有用的指标。
