TABLE 4.

Changes in maternal bone mineral status at the hip at 13 and 52 wk postpartum¹

	Percentage change from 2 wk2
	13 wk		52 wk		P3
	Calcium group (n = 25)	Placebo group (n = 27)	Calcium group (n = 39)	Placebo group (n = 37)	Time	Group	Overall calcium effect4
Total hip
BMC	−4.0 ± 1.25	−6.2 ± 1.56	−7.0 ± 1.66	−8.3 ± 1.56	≤0.001	0.005	−10.7 (−18.1, −3.4)
BA	−0.7 ± 1.1	−2.0 ± 1.0	−1.3 ± 1.1	−1.9 ± 1.1	0.08	0.05	−3.8 (−7.6, 0.0)
BMD	−3.3 ± 0.97	−4.2 ± 0.86	−5.8 ± 0.968	−6.4 ± 0.969	≤0.001	0.01	−6.9 (−12.1, −1.7)
SA-BMC	−3.1 ± 0.97	−3.7 ± 0.86	−5.5 ± 0.968	−6.0 ± 0.869	≤0.001	0.05	−6.0 (−12.0, 0.0)
Femoral shaft
BMC	−2.6 ± 1.5	−5.6 ± 1.46	−5.2 ± 1.57	−7.0 ± 1.46	≤0.001	0.003	−9.3 (−15.3, −3.3)
BA	0.3 ± 1.0	−1.7 ± 1.0	0.0 ± 1.0	−1.0 ± 1.0	0.6	0.3	−1.6 (−4.7, 1.5)
BMD	−2.9 ± 0.87	−3.9 ± 0.86	−5.2 ± 0.868	−6.0 ± 0.869	≤0.001	0.01	−7.7 (−13.4, −1.9)
SA-BMC	−2.9 ± 0.87	−3.6 ± 0.86	−5.2 ± 0.868	−5.8 ± 0.869	≤0.001	0.02	−7.3 (−13.3, −1.3)
Trochanter
BMC	−6.1 ± 2.9	−6.9 ± 2.75	−10.4 ± 2.97	−10.3 ± 2.87	≤0.001	0.02	−15.2 (−27.7, −2.7)
BA	−2.0 ± 2.5	−2.1 ± 2.4	−3.6 ± 2.5	−2.4 ± 2.4	0.2	0.05	−7.7 (−15.6, 0.2)
BMD	−4.1 ± 1.37	−4.8 ± 1.36	−6.8 ± 1.36	−7.9 ± 1.369	≤0.001	0.02	−7.5 (−13.7, −1.3)
SA-BMC	−4.1 ± 1.47	−4.7 ± 1.37	−6.7 ± 1.46	−7.8 ± 1.369	≤0.001	0.02	−7.1 (−13.1, −1.1)
Femoral neck
BMC	−5.1 ± 2.05	−6.9 ± 1.97	−8.8 ± 2.06	−8.9 ± 2.06	≤0.001	0.07	−8.5 (−17.7, 0.7)
BA	−1.0 ± 1.7	−2.6 ± 1.6	−1.1 ± 1.7	−2.8 ± 1.6	0.2	0.6	−2.1 (−9.1, 4.9)
BMD	−4.2 ± 1.17	−4.3 ± 1.16	−7.6 ± 1.169	−6.1 ± 1.16	≤0.001	0.02	−6.4 (−11.6, −1.2)
SA-BMC	−4.2 ± 1.27	−4.2 ± 1.16	−7.6 ± 1.269	−6.1 ± 1.16	≤0.001	0.02	−6.0 (−11.4, −0.6)

¹Hip scans were conducted by dual-energy X-ray absorptiometry. BMC, bone mineral content; BA, bone area; BMD, bone mineral density; SA-BMC, size-adjusted BMC derived by including BA and body weight in the hierarchical ANCOVA model. Body weight was not a significant independent variable of bone mineral status at the hip and was removed from the models presented.

²All values are means ± SEs from hierarchical ANOVA and ANCOVA models with continuous variables in natural logarithms that involve subjects nested by group, time, and time × group interaction terms.

³P values for each component from the model without the interaction term. The time × group interaction term was not significant at any site in the hip.

⁴Overall magnitude of group differences expressed as mean (95% CI) percentage differences obtained from hierarchical models without interaction terms and representing the average calcium effect over all 3 time points.

^5–7Significance of differences from 2 to 13 and 52 wk within each group: ⁵P ≤ 0.05, ⁶P ≤ 0.001, ⁷P ≤ 0.01.

^8,9Significance of differences from 13 to 52 wk within each group: ⁸P ≤ 0.01, ⁹P ≤ 0.05.