TABLE 4-9 Retrospective or Cross-Sectional Studies Concerning Lactation-Induced Bone Loss

Major Findings

Women who lactated more than 2 years had similar risk of fracture as women who never lactated.

Higher radius BMC with lactation (45 to 55 years of age and postmenopausal); no effect of total body Ca.

No increased risk of fracture with history of lactation (>65 years of age).

Higher BMD associated with history of lactation in perimenopausal women 40 to 54 years of age.

No association between hip fracture in women >45 years of age and lactation history.

Higher BMD in women 35 to 65 years of age who lactated compared to no lactation.

BMD at ultradistal radius 7% lower in 40 lactating women at 5.6 months pp compared to 40 controls. No difference at distal or midradius; BMD regained 4 to 6 months pw in 19 women studied.

No association between BMD at 26 to 37 years of age and lactation history. Ca intake not associated with bone measurements.

45 to 74 year olds with hip fractures compared to controls. Cases lactated for less months than nontrauma controls (N = 81) and trauma controls (N = 83).

Lower BMC associated with greater months of lactation.

BMD at any site not associated with lactation. Higher BMD of hip associated with long-term lactation (age-stratified random sample of all adult women inRochester, MN).

No association between radiograph measurements at 30 to 44 years of age and size of families. Ca intake not associated with bone measurements.

Lower BMC in women 30 to 35 years of age in those who had long-term versus short-term lactation.

BMC in postmenopausal women (44 to 80 years of age) not associated with months of lactation.

which calcium supplementation of lactating mothers of more than one infant was evaluated.

Lactating Adolescents. A study in lactating adolescents found that 15 mothers consuming 900 mg (22.5 mmol)/day calcium had a significant decrease in BMC of the distal radius over the first 16 weeks postpartum. No change was observed in 21 mothers who were consuming 1,850 mg (46.3 mmol)/day of calcium (Chan et al., 1982b). Although the results of these studies are intriguing, several concerns about the findings have been expressed, including not finding bone loss in the adult women, a higher rate of bone loss than that seen in any pathological condition, and bone mass mea-

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