er that the 19- through 30-year age group since calcium absorption is known to fall with advancing age.

Utilizing the 1994 CSFII data, adjusted for day-to-day variation (Nusser et al., 1996), the median intake for men aged 51 through 70 years is 708 mg (17.7 mmol)/day (see Appendix D). Their AI of 1,200 mg (30 mmol)/day falls between the ninetieth percentile of intake, 1,122 mg (28.1 mmol)/day, and the ninety-fifth percentile of calcium intake, 1,268 mg (31.7 mmol)/day. For women in this age range, the median calcium intake is 571 mg (14.3 mmol)/day. Their AI markedly exceeds the ninetieth percentile of calcium intake, 891 mg (22.3 mmol)/day.

Estrogen Loss and Osteoporosis. Although diminished estrogen at menopause causes accelerated bone loss, estrogen deficiency-related bone loss cannot be prevented by increasing calcium intake (see earlier section “Factors Affecting the Calcium Requirement”). Estrogen does to some extent influence calcium absorption, but available evidence is not sufficient to support different AIs for women in this age range depending on their menopausal status or their use of hormone replacement therapy.

Calcium Retention. Few men over age 70 have participated in balance studies. In the studies in which they have been included, it is not possible to separate their data from those of the younger men studied. Among women, there are too few balance data at high calcium intakes to identify a plateau intake value. To the extent that the age-related decline in calcium absorption efficiency is not offset by increased renal conservation of calcium, the intake requirement for men and women would be expected to increase with advancing age.

Fracture Rates. Several intervention studies have revealed a linkage between calcium intake and the clinically important outcome, frac-