Bone mass is recovered from lactation to postweaning in adolescent mothers with low calcium intakes

Bezerra, Flávia Fioruci; Mendonça, Laura Maria Carvalho de; Lobato, Erika C.; O’Brien, Kimberly; Donangelo, Carmen M.

doi:10.1093/ajcn/80.5.1322

Cited by 68 publications

(69 citation statements)

References 19 publications

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“…Such low Ca intake has also been reported in other studies performed in developing and developed countries (18,19,27) . Other investigators have shown that nulliparous adolescents present a higher net daily Ca retention compared with adult women because they absorb more Ca from their diet, in spite of excreting more Ca in urine and faeces, and of having a higher bone turnover (28)(29)(30) .…”

Section: Discussionsupporting

confidence: 83%

Changes in bone mineral density of adolescent mothers during the 12-month postpartum period

Malpeli¹,

Mansur²,

Santiago³

et al. 2009

Public Health Nutr.

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Objective: Bone mineral density (BMD) loss has been described in adult women in the 12-month postpartum period. However, little is known about the precise BMD pattern in adolescent mothers. The present study aimed to evaluate BMD in Argentinean adolescent mothers followed up during the 12-month postpartum period. Design: Analytical, prospective clinical trial. BMD and body composition were determined by dual-energy X-ray absorptiometry; bone mineral content (BMC) and BMD were measured in the lumbar spine (L2-L4), femoral neck (FN), femur trochanter (TR), total hip (TH) and total body. Changes in BMD and BMC were analysed using ANOVA for pairwise comparisons. Other comparisons were performed with the paired-sample t test and Wilcoxon test; Pearson's correlation coefficient was used to analyse the relationship among continuous variables. Setting: La Plata, Argentina. Subjects: Adolescent mothers (n 35; 17 years old or less) were recruited within 15 d after delivery. Studies and follow-up were performed at 15 d and 3, 6 and 12 months postpartum. Results: BMD and BMC losses at 3 and 6 months and recovery at 12 months fitted a quadratic curve (ANOVA) at the three sites studied (FN, TH, TR), in total-body BMD (P 5 0?000) and BMC (P 5 0?038). At hip sites, BMD loss occurred at 3 months (FN, P 5 0?000; TR, P 5 0?000; TH, P 5 0?000) and 6 months (FN, P 5 0?000; TR, P 5 0?000; TH, P 5 0?000) compared with basal values. Percentage BMD loss immediately after delivery up to 6 months was about 5 %. Conclusions: Adolescents showed significant BMD and BMC losses at 6 months postpartum, with an almost total recovery at 12 months in all sites studied.

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Section: Discussionsupporting

confidence: 83%

Changes in bone mineral density of adolescent mothers during the 12-month postpartum period

Malpeli¹,

Mansur²,

Santiago³

et al. 2009

Public Health Nutr.

View full text Add to dashboard Cite

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“…However, a study of adolescents recovering from lactation found that there was a substantial increment in bone mass despite a habitual intake of Ͻ500 mg calcium/day (78). Randomization to a 1 g calcium supplement conferred a small benefit in bone mass gain during 6 mo of recovery (452), which confirms that calcium intake can have a positive impact on bone mass accrual during this interval.…”

Section: Human Datamentioning

confidence: 94%

Maternal Mineral and Bone Metabolism During Pregnancy, Lactation, and Post-Weaning Recovery

Kovacs

2016

Physiological Reviews

370

524

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During pregnancy and lactation, female physiology adapts to meet the added nutritional demands of fetuses and neonates. An average full-term fetus contains ϳ30 g calcium, 20 g phosphorus, and 0.8 g magnesium. About 80% of mineral is accreted during the third trimester; calcium transfers at 300-350 mg/day during the final 6 wk. The neonate requires 200 mg calcium daily from milk during the first 6 mo, and 120 mg calcium from milk during the second 6 mo (additional calcium comes from solid foods). Calcium transfers can be more than double and triple these values, respectively, in women who nurse twins and triplets. About 25% of dietary calcium is normally absorbed in healthy adults. Average maternal calcium intakes in American and Canadian women are insufficient to meet the fetal and neonatal calcium requirements if normal efficiency of intestinal calcium absorption is relied upon. However, several adaptations are invoked to meet the fetal and neonatal demands for mineral without requiring increased intakes by the mother. During pregnancy the efficiency of intestinal calcium absorption doubles, whereas during lactation the maternal skeleton is resorbed to provide calcium for milk. This review addresses our current knowledge regarding maternal adaptations in mineral and skeletal homeostasis that occur during pregnancy, lactation, and post-weaning recovery. Also considered are the impacts that these adaptations have on biochemical and hormonal parameters of mineral homeostasis, the consequences for long-term skeletal health, and the presentation and management of disorders of mineral and bone metabolism.

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“…During pregnancy with higher physiological PRL concentrations in the range of 75-100 ng/ml, PRL was found to increase both the rates of bone formation and the resorption, i.e., inducing a state of high bone turnover, thus resulting in minimal or undetectable changes in the densitometric parameters [13,21]. In long-term lactation with an increased loss of calcium in milk, higher PRL levels in the range of 200-300 ng/ ml could induce significant bone loss, which was totally reversible after the cessation of lactation [20,28,29]. Prolonged pathological hyperprolactinemia, on the other hand, was accompanied by persistent bone loss with low BMD and BMC and increased risks of osteoporosis and fracture [22][23][24].…”

Section: Discussionmentioning

confidence: 95%

High Physiological Prolactin Induced by Pituitary Transplantation Decreases BMD and BMC in the Femoral Metaphysis, but Not in the Diaphysis of Adult Female Rats

2008

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High physiological prolactin (PRL) stimulated intestinal calcium absorption and renal calcium uptake in mammals. Previous histomorphometric study revealed a significant increase in bone turnover in the trabecular part of the PRL-exposed long (cortical) bone; however, whole-bone densitometric analysis was unable to demonstrate such effect. We therefore studied differential changes in bone mineral density (BMD) and contents (BMC) of the femoral diaphysis and metaphysis in adult female rats exposed to high PRL induced by anterior pituitary (AP) transplantation. The estrogen-dependent effects of PRL on the femur were also investigated. We found that chronic exposure to PRL had no effect on BMD or BMC of the femoral diaphysis, which represented the cortical part of the long bone. It is interesting that 7 weeks after an AP transplantation, BMD and BMC of the femoral metaphysis were significantly decreased by 8% and 14%, respectively. Ovariectomy (Ovx) for 2, 5, and 7 weeks also decreased BMD and BMC in the femoral metaphysis, but not in the diaphysis. However, the AP transplantation plus Ovx (AP+Ovx) produced no additive effects. Nevertheless, 2.5 µg/kg 17β-estradiol (E2) supplementation abolished the osteopenic effects of both Ovx and AP+Ovx on the femur. As for the L5-6 vertebrae, BMD and BMC were not affected by PRL exposure, but were significantly decreased by Ovx and AP+Ovx, and such decreases were completely prevented by E2 supplementation. It could be concluded that high physiological PRL induced a significant osteopenia in the trabecular part, i.e., the metaphysis, of the femora of adult female rats in an estrogen-dependent manner. Since PRL had no detectable effect on the vertebrae, the effects of PRL on bone appeared to be site-specific.Key words: diaphysis, femur, metaphysis, prolactin, vertebrae.Prolactin (PRL), as a calcium-regulating hormone, has been reported to stimulate intestinal calcium absorption, enhance renal calcium reabsorption, and induce high bone turnover in nonmated female rats [1][2][3]. By regulating calcium mobilization in these target organs during pregnancy and lactation, the high physiological PRL of 75-300 ng/ ml increases calcium availability for fetal growth and milk production [4]. Moreover, the basal PRL level of 7-10 ng/ ml was required for the maintenance of normal bone turnover and duodenal calcium absorption in rats [5,6].It has been shown that PRL acted directly on the intestinal absorptive cells to enhance calcium absorption [3]. In bone, osteoblasts but not osteoclasts strongly expressed functional PRL receptors (PRLR), indicating that bone was also a target of PRL [7]. However, the direct effect of PRL on osteoblasts to enhance bone turnover was complicated by its indirect actions through hyperprolactinemiainduced hypogonadism, which in turn induced chronic estrogen deficiency [8,9]. Moreover, the PRL-enhanced calcium absorption may indirectly contribute to the increase in bone calcium deposition, as previously suggested by the 45 Ca kinetic and histomorphometri...

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Bone mass is recovered from lactation to postweaning in adolescent mothers with low calcium intakes

Cited by 68 publications

References 19 publications

Changes in bone mineral density of adolescent mothers during the 12-month postpartum period

Changes in bone mineral density of adolescent mothers during the 12-month postpartum period

Maternal Mineral and Bone Metabolism During Pregnancy, Lactation, and Post-Weaning Recovery

High Physiological Prolactin Induced by Pituitary Transplantation Decreases BMD and BMC in the Femoral Metaphysis, but Not in the Diaphysis of Adult Female Rats

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