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. 2023 Oct;113(4):426-436.
doi: 10.1007/s00223-023-01125-9. Epub 2023 Aug 28.

Bone Mineral Density During and After Lactation: A Comparison of African American and Caucasian Women

Marilyn Augustine  1 , Robert Boudreau  2 , Jane A Cauley  2 , Deborah Majchel  3 , Nayana Nagaraj  4 , Lauren S Roe  2 , Poonam Sood  5 , Andrew F Stewart  6 , Mara J Horwitz  7
Affiliations

Bone Mineral Density During and After Lactation: A Comparison of African American and Caucasian Women

Marilyn Augustine et al. Calcif Tissue Int. 2023 Oct.

Abstract

During lactation, changes in maternal calcium metabolism are necessary to provide adequate calcium for newborn skeletal development. The calcium in milk is derived from the maternal skeleton through a process thought to be mediated by the actions of parathyroid hormone-related protein (PTHrP) in combination with decreased circulating estrogen concentrations. After weaning, bone lost during lactation is rapidly regained. Most studies of bone metabolism in lactating women have been performed in Caucasian subjects. There are well-documented differences between African American (AA) and Caucasian (C) bone metabolism, including higher bone mineral density (BMD), lower risk of fracture, lower 25-hydroxyvitamin D (25(OH) D), and higher PTH in AA compared to C. In this prospective paired cohort study, BMD and markers of bone turnover were compared in self-identified AA and C mothers during lactation and after weaning. BMD decreased in both AA and C women during lactation, with similar decreases at the lumbar spine (LS) and greater bone loss in the C group at the femoral neck (FN) and total hip (TH), demonstrating that AA are not resistant to PTHrP during lactation. BMD recovery compared to the 2 week postpartum baseline was observed 6 months after weaning, though the C group did not have complete recovery at the FN. Increases in markers of bone formation and resorption during lactation were similar in AA and C. C-terminal telopeptide (CTX) decreased to 30% below post-pregnancy baseline in both groups 6 months after weaning, while procollagen type 1 N-terminal (P1NP) returned to baseline in the AA group and fell to below baseline in the C group. Further investigation is required to determine impacts on long term bone health for women who do not fully recover BMD before a subsequent pregnancy.

Keywords: Biochemical markers of bone turnover; DXA; Lactation; Parathyroid hormone; Race/ethnicity(other); Systems biology.

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Conflict of interest statement

Marilyn Augustine, Robert Boudreau, Jane A. Cauley, Deborah Majchel, Nayana Nagaraj, Lauren S. Roe, Poonam Sood, Andrew F. Stewart and Mara J Horwitz have no conflict of interest.

Figures

Fig. 1
Fig. 1
Enrollment flowsheet
Fig. 2
Fig. 2
Percent change in BMD from baseline (unadjusted). Box plots show median, interquartile range, max and min values with outlying data points plotted. p-values on the figure are for change from baseline
Fig. 3
Fig. 3
Box plots show median, interquartile range, max and min values with outlying data points plotted. p-values on the figure are for change from baseline
See this image and copyright information in PMC

References

    1. Laskey MA, Prentice A, Shaw J, Zachou T, Ceesay SM, Vasquez-Velasquez L, Fraser DR. Breast-milk calcium concentrations during prolonged lactation in British and rural Gambian mothers. Acta Paediatr Scand. 1990;79:507–512. doi: 10.1111/j.1651-2227.1990.tb11504.x. - DOI - PubMed
    1. Kovacs CS. Calcium and bone metabolism in pregnancy and lactation. J Clin Endocrinol Metab. 2001;86:2344–2348. doi: 10.1210/jcem.86.6.7575. - DOI - PubMed
    1. (2011) Institute of Medicine (US) Committee to review dietary reference intakes for vitamin D and calcium. In: Ross AC, Taylor CL, Yaktine AL et al (ed) 5, Dietary reference intakes for adequacy: calcium and vitamin D. National Academies Press (US), Washington (DC) - PubMed
    1. Sowers M, Corton G, Shapiro B, Jannausch ML, Crutchfield M, Smith ML, Randolph JF, Hollis B. Changes in bone density with lactation. JAMA. 1993;269:3130–3135. doi: 10.1001/jama.1993.03500240074029. - DOI - PubMed
    1. Teerapornpuntakit J, Chanprapaph P, Karoonuthaisiri N, Charoenphandhu N. Site-specific onset of low bone density and correlation of bone turnover markers in exclusive breastfeeding mothers. Breastfeed Med. 2017;12:331–337. doi: 10.1089/bfm.2016.0204. - DOI - PubMed

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