Table 5.
Comparison of bone density variables among women with a history of lactation to women who have never breast fed where months of breast-feeding were assessed as a continuous variable.
| Never breast fed (n = 35) |
Lactation history (n = 97) |
P value | |
|---|---|---|---|
| Maternal age mean ± SD (years) | 25.3 ± 4.1 | 31.5 ± 5.7 | 0.000 |
| Height mean ± SD | 163.8 ± 6.0 | 162.0 ± 6.4 | NS |
| Prepregnancy weight mean ± SD | 63.9 ± 16.0 | 64.0 ± 11.8 | NS |
| Prepregnancy BMI mean ± SD | 23.7 ± 5.0 | 24.3 ± 4.1 | NS |
| Current weight mean ± SD | 72.1 ± 16.6 | 71.8 ± 13.1 | NS |
| Current BMI mean ± SD | 26.8 ± 5.2 | 27.3 ± 4.4 | NS |
| Weight gain mean ± SD | 8.2 ± 5.4 | 8.4 ± 8.0 | NS |
| Gravidity mean ± SD | 1.49 ± 1.1 | 4.97 ± 2.6 | 0.000 |
| Parity mean ± SD | 1.37 ± 0.84 | 4.85 ± 2.4 | 0.000 |
| Months lactation mean ± SD | 0 | 36.9 ± 31.6 | 0.000 |
| Months pregnancy + lactation mean ± SD |
11.4 ± 7.1 | 77.7 ± 49.6 | 0.000 |
| FN-BMD mean ± SD | 0.807 ± 0.10 | 0.791 ± 0.11 | 0.014 |
| FN T-scores mean ± SD | [−0.383] ± 0.87 | [−0.528] ± 0.99 | 0.013 |
| FN Z-scores mean ± SD | [−0.357] ± 0.87 | [−0.401] ± 0.98 | 0.045 |
| LS-BMD mean ± SD | 0.963 ± 0.11 | 0.891 ± 0.39 | NS |
| LS T-scores mean ± SD | [−0.757] ± 1.06 | [−0.731] ± 1.04 | NS |
| LS Z-scores mean ± SD | [−0.649] ± 1.01 | [−0.608] ± 1.06 | NS |
*SD: standard deviation; NS: not significant; BMI: body mass index; FN: femoral neck; BMD: bone mineral density; LS: lumbar spine.