Heaney R P, Davies K M, Recker R R, Packard P T
Creighton University, Center for Hard-Tissue Research, Omaha, NE 68178.
J Nutr. 1990 Aug;120(8):869-75. doi: 10.1093/jn/120.8.869.
Consistency of intake over time for calcium, phosphorus, protein and energy, as estimated from diet diaries, was studied prospectively in two groups of women. One group provided short-term data (n = 165), and the other, data spanning intervals of up to 20 y (n = 164). Although group average intakes changed little, there was a great deal of individual variation. Even at intervals as short as 6 m, current intake estimates accounted for only about 40% of the variance of intakes at an earlier time. Over longer intervals, the predictive value of one estimate in respect to a second deteriorated even further. Thus, across 5 y, less than 25% of the variance of all four nutrient intakes could be accounted for by current intake. The 95% confidence interval for an estimate of earlier intake based upon a later measurement was more than +/- 700 mg for calcium, the least consistent nutrient. The other three nutrients showed nearly identical interstudy consistency, with uncertainties relative to their respective means being about half as large as for calcium. These data show that accurate longitudinal estimates of intake require continuous, prospective monitoring and that current intake is not a good estimator of past intake for most nutrients, especially for calcium.
通过饮食日记估算，对两组女性的钙、磷、蛋白质和能量摄入量随时间的一致性进行了前瞻性研究。一组提供短期数据（n = 165），另一组提供长达20年时间段的数据（n = 164）。尽管两组的平均摄入量变化不大，但个体差异很大。即使在短短6个月的时间间隔内，当前摄入量估计值也仅占早期摄入量方差的约40%。在更长的时间间隔内，一次估计相对于另一次估计的预测价值进一步恶化。因此，在5年期间，所有四种营养素摄入量的方差中，不到25%可由当前摄入量解释。对于一致性最差的营养素钙，基于后期测量对早期摄入量进行估计的95%置信区间超过±700毫克。其他三种营养素在不同研究间的一致性几乎相同，相对于各自均值的不确定性约为钙的一半。这些数据表明，准确的摄入量纵向估计需要持续的前瞻性监测，并且对于大多数营养素，尤其是钙，当前摄入量并非过去摄入量的良好估计指标。
