MRC Nutrition and Bone Health Research Group, University of Cambridge, Cambridge, UK.
MRC Lifecourse Epidemiology Unit, University of Southampton, Southampton General Hospital, Southampton, UK.
J Bone Miner Res. 2021 Jul;36(7):1269-1280. doi: 10.1002/jbmr.4295. Epub 2021 May 7.
In pregnancy, changes in maternal calcium (Ca) economy occur to satisfy fetal Ca demand. It is unclear whether maternal mineral reserves facilitate these requirements and no data exist from sub-Saharan Africa. The aim was to determine skeletal changes with peripheral quantitative computed tomography (pQCT) and bone biochemistry between early second and third trimesters. Pregnant rural Gambians aged 18 to 45 years (n = 467) participating in a trial of antenatal nutritional supplements (ISRCTN49285450) had pQCT scans and blood collections at mean (SD) 14 (3) and 31 (1) weeks' gestation. Outcomes were pQCT: radius/tibia 4% total volumetric bone mineral density (vBMD), trabecular vBMD, total cross-sectional area (CSA), 33%/38% radius/tibia cortical vBMD, bone mineral content (BMC), total CSA; biochemistry: collagen type 1 cross-linked β-C-telopeptide (β-CTX), type 1 procollagen N-terminal (P1NP), parathyroid hormone (PTH), and 1,25(OH) D. Independent t tests tested whether pooled or within-group changes differed from 0. Multiple regression was performed adjusting for age. Data for change are expressed as mean (confidence interval [CI] 2.5, 97.5%). Radius trabecular vBMD, cortical vBMD, and BMC increased by 1.15 (0.55, 1.75)%, 0.41 (0.24, 0.58)%, and 0.47 (0.25, 0.69)%. Tibia total and trabecular vBMD increased by 0.34 (0.15, 0.54)% and 0.46 (0.17, 0.74)%, while tibia cortical vBMD, BMC, and cortical CSA increased by 0.35 (0.26, 0.44)%, 0.55 (0.41, 0.68)% and 0.20 (0.09, 0.31)%, respectively. CTX, PTH, and 1,25(OH) D increased by 23.0 (15.09, 29.29)%, 13.2 (8.44, 19.34)%, and 21.0 (17.67, 24.29)%, while P1NP decreased by 32.4 (-37.19, -28.17)%. No evidence of mobilization was observed in the peripheral skeleton. Resorption, although higher in late versus early gestation, was lower throughout pregnancy compared with non-pregnant non-lactating (NPNL) in the same community. Formation was lower in late pregnancy than in early, and below NPNL levels. This suggests a shift in the ratio of resorption to formation. Despite some evidence of change in bone metabolism, in this population, with habitually low Ca intakes, the peripheral skeleton was not mobilized as a Ca source for the fetus. © 2021 crown copyright . Journal of Bone and Mineral Research published by Wiley Periodicals LLC on behalf of American Society for Bone and Mineral Research (ASBMR). The article published with the permission of the Controller of HMSO and the Queen's Printer of Scotland..
在妊娠期间，母体钙（Ca）代谢会发生变化，以满足胎儿对 Ca 的需求。目前尚不清楚母体矿物质储备是否有助于满足这些需求，而且来自撒哈拉以南非洲的数据尚不存在。本研究旨在通过外周定量计算机断层扫描（pQCT）和骨生物化学检测，确定妊娠中期至晚期的骨骼变化。参与产前营养补充剂试验（ISRCTN49285450）的年龄在 18 至 45 岁的农村冈比亚孕妇（n=467），在妊娠 14（3）周和 31（1）周时分别进行 pQCT 扫描和血液采集。检测指标为 pQCT：桡骨/胫骨 4%总体积骨矿物质密度（vBMD）、小梁 vBMD、总横截面积（CSA）、桡骨/胫骨皮质 vBMD 33%/38%、骨矿物质含量（BMC）、总 CSA；骨生化指标：Ⅰ型胶原交联 β-C-端肽（β-CTX）、Ⅰ型前胶原 N 端肽（P1NP）、甲状旁腺激素（PTH）和 1,25（OH）2D。采用独立 t 检验检验各组或总体变化是否与 0 有差异。采用多元回归分析，调整年龄因素。变化数据以均值（2.5%至 97.5%置信区间 [CI]）表示。桡骨小梁 vBMD、皮质 vBMD 和 BMC 分别增加了 1.15%（0.55%，1.75%）、0.41%（0.24%，0.58%）和 0.47%（0.25%，0.69%）。胫骨总 vBMD 和小梁 vBMD 分别增加了 0.34%（0.15%，0.54%）和 0.46%（0.17%，0.74%），而胫骨皮质 vBMD、BMC 和皮质 CSA 分别增加了 0.35%（0.26%，0.44%）、0.55%（0.41%，0.68%）和 0.20%（0.09%，0.31%）。CTX、PTH 和 1,25（OH）2D 分别增加了 23.0%（15.09%，29.29%）、13.2%（8.44%，19.34%）和 21.0%（17.67%，24.29%），而 P1NP 则降低了 32.4%（-37.19%，-28.17%）。在周围骨骼中未观察到动员的证据。尽管妊娠晚期的吸收率高于妊娠早期，但与同一社区的非妊娠非哺乳期（NPNL）相比，整个孕期的吸收率均较低。与妊娠早期相比，妊娠晚期的形成率较低，且低于 NPNL 水平。这表明吸收率与形成率之间的比值发生了变化。尽管有证据表明骨代谢发生了变化，但在钙摄入量较低的人群中，外周骨骼并未作为胎儿的钙源而被动员。版权所有©2021 英国皇家化学学会。《骨与矿物质研究杂志》由 Wiley 期刊出版公司代表美国骨与矿物质研究协会（ASBMR）出版。经英国王室文书局和苏格兰女王印玺局许可后发表。
