López J M, González G, Reyes V, Campino C, Díaz S
Departmento de Endocrinología, Metabolismo y Nutrición. Escuela de Medicina, P Universidad Católica de Chile.
Osteoporos Int. 1996;6(2):153-9. doi: 10.1007/BF01623940.
To investigate the changes in maternal bone density and turnover associated with lactation we ran a longitudinal study in fully breastfeeding women (age 26.3 +/- 4.1 years, mean +/- SD) at the first (stage I, n = 30) and sixth (stage II, n = 25) months postpartum and 6 months after weaning (stage III, n = 20), and in a contemporary control group of non-nursing women. At each time point bone density, serum calcium, phosphorus, alkaline phosphatases, parathyroid hormone (PTH), osteocalcin, follicle stimulating hormone (FSH), estradiol (E2), prolactin (PRL) urinary hydroxyproline and creatinine (OH-P/Cr) were measured in both groups. The daily calcium intake of nursing women (1479 +/- 590 mg/day at stage I) was higher than in non-nursing women (536 +/- 231 mg/day at stage I). Biochemical markers of bone turnover were higher (p < 0.05) in nursing than in non-nursing women at stages I and II, while in stage III only OH-P/Cr was elevated. The lumbar spine (L2-4) bone mineral density was similar in the two groups at the beginning of the study (1.148 +/- 0.111 g/cm2 in nursing women vs 1.211 +/- 0.102 g/cm2 in non-nursing women; p = 0.06), but it was lower in nursing women at stage II (1.144 +/- 0.110 g/cm2 vs 1.216 +/- 0.095 g/cm2 respectively; p < 0.05). Right femoral neck bone density decreased by 3% between stages I and II in nursing women but did not differ from values in non-nursing women (0.947 +/- 0.110 vs 0.973 +/- 0.108 in stage I and 0.918 +/- 0.114 vs 0.975 +/- 0.098 in stage II respectively; p < 0.05, ANOVA). After weaning, lumbar spine and femoral neck bone density increased by 6% and 8% respectively (p < 0.05, ANOVA). No correlation was found between changes in bone turnover markers or bone density and parity, frequency and duration of nursing episodes, body weight, body mass index, and plasma PRL, E2 and PTH levels. We conclude that in nursing women with a daily calcium intake at the recommended dietary allowance ( > 1200 mg/day), full breastfeeding extending over 6 months is characterized by increased maternal bone turnover and a transient bone loss which normalizes after weaning.
为了研究与哺乳相关的母体骨密度和骨转换变化，我们对完全母乳喂养的女性（年龄26.3±4.1岁，均值±标准差）进行了一项纵向研究，这些女性在产后第1个月（第一阶段，n = 30）、第6个月（第二阶段，n = 25）以及断奶后6个月（第三阶段，n = 20）接受观察，同时设立了一个非哺乳女性的当代对照组。在每个时间点，对两组女性均测量骨密度、血清钙、磷、碱性磷酸酶、甲状旁腺激素（PTH）、骨钙素、促卵泡激素（FSH）、雌二醇（E2）、催乳素（PRL）、尿羟脯氨酸和肌酐（OH-P/Cr）。哺乳女性的每日钙摄入量（第一阶段为1479±590毫克/天）高于非哺乳女性（第一阶段为536±231毫克/天）。在第一阶段和第二阶段，哺乳女性的骨转换生化标志物高于非哺乳女性（p < 0.05），而在第三阶段只有OH-P/Cr升高。在研究开始时，两组女性的腰椎（L2 - 4）骨矿物质密度相似（哺乳女性为1.148±0.111克/平方厘米，非哺乳女性为1.211±0.102克/平方厘米；p = 0.06），但在第二阶段，哺乳女性的骨密度较低（分别为1.144±0.110克/平方厘米和1.216±0.095克/平方厘米；p < 0.05）。在哺乳女性中，右股骨颈骨密度在第一阶段和第二阶段之间下降了3%，但与非哺乳女性的值无差异（第一阶段分别为0.947±0.110和0.973±0.108，第二阶段分别为0.918±0.114和0.975±0.098；p < 0.05，方差分析）。断奶后，腰椎和股骨颈骨密度分别增加了6%和8%（p < 0.05，方差分析）。未发现骨转换标志物或骨密度的变化与产次、哺乳次数和持续时间、体重、体重指数以及血浆PRL、E2和PTH水平之间存在相关性。我们得出结论，对于每日钙摄入量达到推荐膳食摄入量（> 1200毫克/天）的哺乳女性，持续6个月以上的完全母乳喂养的特点是母体骨转换增加和短暂的骨质流失，断奶后骨质流失恢复正常。
