of 20 percent net calcium retention in children based on the data from 4 through 8 year olds (Matkovic, 1991; Matkovic and Heaney, 1992), it is reasonable to set the AI for calcium at 500 mg (12.5 mmol)/day intake to achieve the 100 mg (2.5 mmol)/day retention. For this age group, there is a substantial need for further investigation using both balance techniques and bone densitometry to more precisely estimate calcium needs.

AI for Children

1 through 3 years

500 mg (12.5 mmol)/day

 

4 through 8 years

800 mg (20.0 mmol)/day

Utilizing the 1994 CSFII data, adjusted for day-to-day variation (Nusser et al., 1996), the median calcium intake is 766 (19.2 mmol)/day for children aged 1 through 3 years (see Appendix D). Their AI of 500 mg (12.5 mmol)/day will fall between the tenth percentile (468 mg [11.7 mmol]/day) and the twenty-fifth percentile of calcium intake (599 mg [15 mmol]/day). For children aged 4 through 8 years, the median calcium intake is 808 mg (20.2 mmol)/day, which is very close to the AI of 800 mg (20 mmol)/day for this age group.

Special Considerations

Chronic Illness. Many chronic illnesses that affect children are associated with abnormalities of calcium metabolism and bone mineralization. Among the most significant of these are juvenile rheumatologic conditions (Reed et al., 1990), renal disease (Stapleton, 1994), liver failure (Bucuvalas et al., 1990), and endocrine disturbances, including insulin-dependent diabetes mellitus (Favus and Christakos, 1996). The value of adjustments in calcium intake for children with these conditions is beyond the scope of this report.

Ages 9 through 13 and 14 through 18 Years
Sexual Maturity

From 9 through 18 years of age, calcium retention increases to a peak and then declines. The peak calcium accretion rate typically occurs at mean age 13 years for girls and 14.5 years for boys (Martin et al., 1997). After menarche, calcium retention in girls declines rapidly (Weaver et al., 1995) as does bone formation and bone resorption (Abrams et al., 1996b; Wastney et al., 1996). Even though bone formation and resorption decrease exponentially after me-



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