Prenatal but not continued postpartum vitamin D supplementation reduces maternal bone resorption as measured by C-terminal telopeptide of type 1 collagen without effects on other biomarkers of bone metabolism

Christine Krupa; Huma Qamar; Karen M O'Callaghan; Akpevwe Onoyovwi; Abdullah Al Mahmud; Tahmeed Ahmed; Alison D Gernand; Daniel E Roth

doi:10.1016/j.endmts.2023.100154

Prenatal but not continued postpartum vitamin D supplementation reduces maternal bone resorption as measured by C-terminal telopeptide of type 1 collagen without effects on other biomarkers of bone metabolism

Endocr Metab Sci. 2024 Mar 31:14:None. doi: 10.1016/j.endmts.2023.100154.

Authors

Christine Krupa¹, Huma Qamar¹, Karen M O'Callaghan^{1

2}, Akpevwe Onoyovwi¹, Abdullah Al Mahmud³, Tahmeed Ahmed³, Alison D Gernand⁴, Daniel E Roth^{1

5

6}

Affiliations

¹ Centre for Global Child Health, Hospital for Sick Children, Toronto, Canada.
² Department of Nutritional Sciences, King's College London, United Kingdom.
³ Nutrition and Clinical Services Division, International Centre for Diarrhoeal Disease Research, Bangladesh, Dhaka, Bangladesh.
⁴ Department of Nutritional Sciences, The Pennsylvania State University, PA, United States.
⁵ Department of Nutritional Sciences, University of Toronto, Toronto, Canada.
⁶ Department of Paediatrics, Hospital for Sick Children and University of Toronto, Toronto, Canada.

Abstract

Vitamin D is a key regulator of bone mineral homeostasis and may modulate maternal bone health during pregnancy and postpartum. Using previously-collected data from the Maternal Vitamin D for Infant Growth (MDIG) trial in Dhaka, Bangladesh, we aimed to investigate the effects of prenatal and postpartum vitamin D₃ supplementation on circulating biomarkers of bone formation and resorption at delivery and 6 months postpartum. MDIG trial participants were randomized to receive a prenatal;postpartum regimen of placebo or vitamin D₃ (IU/week) as either 0;0 (Group A), 4200;0 (B), 16,800;0 (C), 28,000;0 (D) or 28,000;28,000 (E) from 17 to 24 weeks' gestation to 6 months postpartum. As this sub-study was not pre-planned, the study sample included MDIG participants who had data for at least 1 biomarker of interest at delivery or 6 months postpartum, with a corresponding baseline measurement (n = 690; 53 % of 1300 enrolled trial participants). Biomarkers related to bone turnover were measured in maternal venous blood samples collected at enrolment, delivery, and 6 months postpartum: osteoprotegerin (OPG), osteocalcin (OC), receptor activator nuclear factor kappa-B ligand (RANKL), fibroblast growth factor 23 (FGF23), procollagen type 1 N-terminal propeptide, (P1NP) and carboxy terminal telopeptide of type 1 collagen (CTx). Supplementation effects were expressed as percent differences between each vitamin D group and placebo with 95 % confidence intervals (95 % CI). Of 690 participants, 64 % had 25-hydroxyvitamin D concentrations (25OHD) <30 nmol/L and 94 % had 25OHD < 50 nmol/L at trial enrolment. At delivery, mean CTx concentrations were 27 % lower in group E versus placebo (95 % CI: -38, -13; P < 0.001), adjusting for enrolment concentrations. However, at 6 months postpartum, CTx concentrations were not statistically different in group E versus placebo (14 %; 95 % CI: -5.3, 37; P = 0.168), adjusting for delivery CTx concentrations. Effects on other biomarkers at delivery or postpartum were not statistically significant. In conclusion, prenatal high-dose vitamin D supplementation reduced bone resorption during pregnancy, albeit by only one biomarker, and without evidence of a sustained effect in the postpartum period. However, further evidence is needed to substantiate potential maternal bone health benefits of vitamin D in the postpartum period.

Keywords: Bone turnover; Carboxy terminal telopeptide of type 1 collagen; Postpartum; Pregnancy; Vitamin D.