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The EARs and RDAs relied primarily upon calcium balance studies for persons 1 to 50 years of age. The effect of menopause on bone resulted in specifying different EARs and RDAs for women and men 51 to 70 years of age. After the age of 70 years, the effects of aging on bone loss resulted in EARs and RDAs that are the same for men and women. The AIs for infants are based on the calcium content of human milk. There is no evidence that calcium requirements are different for pregnant and lactating females compared with their non-pregnant or non-lactating counterparts.

The ULs for calcium for adults are based on data related to the incidence of kidney stones, largely from work conducted with postmenopausal women who use calcium supplements. Newer data from a feeding study provided evidence of intake levels among infants not associated with elevated calcium excretion, and allowed derivation of a UL for infants. The UL for children and adolescents 9 to 18 years of age gives consideration to the pubertal growth spurt and increases the UL as compared with that for children 1 to 8 years of age.

Dietary Reference Intakes for Vitamin D

DRI values for vitamin D (Table S-2) were established as EARs and RDAs for all life stage groups except infants up to 12 months of age for which an AI was specified. These reference values assume minimal sun exposure.

Measures of serum 25OHD level serve as a reflection of total vitamin D exposure—from food, supplements, and synthesis. Although serum 25OHD level cannot be considered a validated health outcome surrogate, it allowed comparison of intake or exposure with health outcomes. Newer data also allowed the simulation of a requirement distribution based on serum 25OHD concentrations. A level of 40 nmol/L (16 ng/mL) was consistent with the intended nature of an average requirement, in that it reflects the desired level for a population median—it meets the needs of approximately half the population. Moreover, benefit for most in the population is associated with serum 25OHD levels of approximately 50 nmol/L (20 ng/mL), making this level a reasonable estimate for a value akin to “coverage” for nearly all the population. Available data were used to link specified serum levels of 25OHD with total intakes of vitamin D under conditions of minimal sun exposure in order to estimate DRIs.

For children and adolescents 1 to 18 years of age, EARs and RDAs are specified on the basis of serum 25OHD concentrations of 40 and 50 nmol/L (16 and 20 ng/mL), respectively. Likewise this approach was used for young adults and adults from 19 through 50 years of age and was supported by data on osteomalacia. The EAR for persons older than 50 years of age is the same as that for younger adults, as the simulated requirement

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