et al.(1999) and Abrams et al. (1999), a calcium intake of 800 mg/day could be expected to achieve the levels of calcium needed for bone accretion. Again, the assumption that another approximately 30 percent is needed to cover about 97.5 percent of the population—through derivation as mean estimates and the assumption of normal distribution—results in a calculated and rounded RDA value for calcium of 1,000 mg/day.
Again, as with younger children, there are relatively few studies available and most have small sample sizes. While the studies included some ethnic/racial diversity, they focused on girls. These limitations cannot be remedied at this time. However, the data are sufficiently robust to support an estimation of an average requirement of 800 mg/day calcium.
As reviewed in Chapter 4, data from a recent study (Vatanparast et al., 2010) have provided bone calcium accretion levels for children and adolescents ranging from 92 to 210 mg/day. Average bone calcium accretion was included in the factorial method, and the intake levels can be estimated as shown in Table 5-2.
While the committee was aware of data suggesting that calcium retention may vary by gender among children, these differences between girls and boys and between the 9- to 13- and 14- to 18-year age groups are relatively small quantitatively, and the limited nature of the data do not allow further specification of these differences to the extent they are real. Given the application of DRI values in real world settings such as school meal planning, recommending that boys receive a small amount more calcium than girls is not practicable, but it is also not warranted given the limited nature of the data suggesting this possibility. Additionally, there is wide variability in the onset of puberty and the pubertal growth spurt, and it is reasonable to conclude that increases in calcium intake may be needed early in puberty at times when children may be only 9 or 10 years old. Thus, for reference values for both boys and girls in the 9- to 13- and 14- to 18-year life stages, the differences in calcium intake to achieve mean bone calcium accretion as elucidated by Vatanparast et al. (2010) have been interpolated between 9- to 18-year old girls (1,037) and boys (1,224). This interpolation yields an estimated mean need for calcium for boys and girls of 1,100 mg/day with rounding, a value approximately at the midpoint between the two groups. Again, assuming a normal distribution, this estimate to achieve a mean calcium accretion represents the median and, thus, an EAR. The EAR is therefore set at 1,100 mg for both boys and girls for both life stages encompassed by the 9 through 18 year age range. In order to cover 97.5 percent of the population, an estimated RDA value for calcium of 1,300 mg/day is established.