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Guide
Secondary analysis of this double-blind randomized clinical trial found no benefit of vitamin D supplementation at higher doses in infants with 25(OH)D concentrations below 50 nmol/L at birth. See below for details.
Vitamin D status at birth reflects maternal-fetal transfer of 25-hydroxyvitamin D (25[OH]D). The recommended intake of vitamin D during pregnancy and lactation is 600 IU per day. When the concentration of 25(OH)D in pregnant women is less than 50 nmol/L, the risk of vitamin D insufficiency (25[OH]D<50 nmol/L) or deficiency (25[OH]D<30 nmol/L) is higher at birth. As a result, public health policy in North America recommends that all breastfed infants begin vitamin D supplementation (400 IU daily) shortly after birth. However, the dose of vitamin D supplementation required for infants with 25(OH)D3 concentrations below 50 nmol/L at birth is currently unknown.
Recently, a research team from McGill University in Canada conducted a secondary analysis of a double-blind randomized clinical trial to determine whether infants with a 25(OH)D concentration of less than 50 nmol/L at birth need a higher dose (1000 IU vs. 400 IU per day) to promote bone mass gain throughout infancy. The study was published in JAMA Pediatr. (Impact Factor: 26.796).
Study design
This double-blind randomized clinical trial was conducted between March 2016 and March 2019 at a center in Greater Montreal, Quebec, Canada, and recruited 139 healthy full-term singleton infants from 866 infants who were screened for vitamin D status at birth. Data analysis was conducted from June 2021 to November 2022.
Capillary blood was collected 24 to 36 hours after birth to measure total serum 25(OH)D concentrations. Infants with concentrations of less than 25(OH)D 50 nmol/L were randomized to receive oral vitamin D3 supplements of 1000 IU or 400 IU per day during the period of 1 to 12 months. Infants with 25(OH)D concentrations ≥ 50 nmol/L were used as the reference group.
Primary outcomes: The investigators pre-planned measurements at 1, 3, 6, and 12 months, including whole-body bone mineral content, lumbar bone mineral content, and bone mineral density using dual-energy x-ray absorptiometry, and serum 25(OH)D3 using liquid chromatography tandem mass spectrometry.
outcome
Of the 139 included infants, 81 (58.3%) were males with a median gestational age (IQR) of 39.6 (38.9-40.6) weeks at birth. There were a total of 49 infants in the 1000IU group, 49 infants in the 400IU daily group, and 41 infants in the reference group.
➤ There was no difference in mean (SD) whole-body bone mineral content between experimental groups over time (1000 IU/d group, 173.09 [2.36]g; 400 IU/d group, 165.94 [66.08]g). Similarly, no differences were observed in lumbar bone mineral content or density.
➤与400IU/d组（3个月,77.4[23.3]nmol/L;6个月,85.1[18.6]nmol/L;12个月,82.3[14.3]nmol/L）相比，1000IU/d组（3个月,115.2[35.3]nmol/L;6个月,121.6[34.4]nmol/L;12个月,99.6[28.8]nmol/L）在3-12月龄血清25（OH）D3水平显著升高。
conclusion
In this study, higher doses of vitamin D supplementation in infants with 25(OH)D concentrations below 50 nmol/L at birth had no benefit on bone mass in infancy. The study supports a standard dose of 400 IU of vitamin D per day for breastfed infants in Montreal.
参考文献：[1]Gharibeh N, Razaghi M, CA V, et al. Effect of Vitamin D Supplementation on Bone Mass in Infants With 25-Hydroxyvitamin D Concentrations Less Than 50 nmol/L: A Prespecified Secondary Analysis of a Randomized Clinical Trial[J]. JAMA Pediatr, 2023 Apr 1; 177(4):353-362.