70 years of age reflects a diverse set of physiological conditions—notably premenopausal, perimenopausal, and postmenopausal—with respect to the condition of bone health, and cannot be reliably characterized as a homogeneous single group for the purpose of deriving EARs and RDAs for calcium. Some may benefit from increased calcium, and some may not. Further, there is considerable variability in the age of onset of menopause, and so assumptions about the proportion of this age group that may or may not benefit cannot be made. Therefore, to ensure public health protection and to err on the side of caution, preference is given to covering the apparent benefit for BMD with higher intakes of calcium for postmenopausal women within this group. The EAR for women 51 through 70 years is set at 1,000 mg calcium per day. The addition of 200 mg/day to the estimates provided by Hunt and Johnson (2007) gives a reasonable margin of safety for lessening bone loss to the extent that is possible and is reasonably consistent with data from the existing intervention trials. Further, the value of 1,000 mg/day is still within the 95 percent prediction interval offered by Hunt and Johnson (2007) for a value that encompasses a wider range of persons than younger menopausal women. Although this does result in a different DRI for women than for men in the 51 through 70 year age group, the physiological differences and apparent response to increased calcium intake evidenced from randomized trials warrants this difference.
As there is no reason to assume that requirements for this life stage are not normally distributed, the approximate 20 to 30 percent addition to achieve the level needed to cover 97.5 percent of the population results in an estimated RDA of 1,200 mg/day. The level errs in the direction of a lower value given concerns about an upper level of intake (see Chapter 6).
This reference value for women 51 to 70 years of age is notably uncertain and reflects a decision to provide public health protection in the face of inconsistent data. It also identifies menopausal women between the ages of 51 and 70 years as the basis for the reference value, rather than nonmenopausal women, on the assumption that during this life stage many and eventually all will become menopausal. The value cannot be more certain until such time as there is information on calcium balance specifically for women experiencing the early stages of menopause, as well as well-controlled trials that more clearly elucidate dose–response measures for menopausal younger women relative to calcium intake and bone health.
Bone loss and the resulting osteoporotic fractures are the predominant bone health concern for persons >70 years of age. Although measures to ascertain fracture risk are often self-reported and can be challenging to