Safety Aspects of a Randomized Clinical Trial of Maternal and Infant Vitamin D Supplementation by Feeding Type Through 7 Months Postpartum

Oral Contraceptive Pills Increase Circulating 25-Hydroxy-Vitamin D Concentrations in Women Who Are Lactating

OBJECTIVE

 This article aims to determine the association between maternal 25-hydroxy-vitamin D [25(OH)D] status and intake of hormonal oral contraceptive pills (OCPs) in women who are lactating.

STUDY DESIGN

 Women who were exclusively breastfeeding participated in a randomized controlled trial assessing vitamin D supplementation at 400, 2,400, or 6,400 international unit (IU)/d from 1 month through 7 months postpartum. This observational, secondary analysis assessed whether OCPs were associated with maternal 25(OH)D concentrations in women who are lactating. Multivariate regression models were used to predict 25(OH)D concentrations and create parameter estimates for each variable.

RESULTS

 In a bivariate analysis, the use of OCPs at 4 months was associated with increased serum 25(OH)D (p = 0.02). OCPs' use at 7 months was associated with a higher trend in 25(OH)D, but this finding was not statistically significant (p = 0.1). In a multivariate regression model at 4 months, independent positive predictors of 25(OH)D concentrations were the use of OCPs (p = 0.03) and treatment with vitamin D at 6,400 IU/d (p ≤ 0.0001). Negative predictors were Black (p = 0.001) and Hispanic (p = 0.0001) race and ethnicity, and body mass index (BMI) greater than 30 (p = 0.0002). The same pattern occurred at 7 months, with more southern latitude as a positive independent predictor (p = 0.04) of 25(OH)D concentration.

CONCLUSION

 The use of OCPs was associated with greater 25(OH)D in women who are lactating. Additionally, treatment with vitamin D at 6,400 IU/d and southern latitude was associated with greater 25(OH)D in women who are lactating. Black and Hispanic race and ethnicity, and BMI greater than 30, were independently associated with lower 25(OH)D in women who are lactating.

KEY POINTS

· The association of OCP with serum 25(OH)D concentrations during postpartum lactation is unknown.. · OCPs' use was associated with higher 25(OH)D concentrations in postpartum women who are lactating.. · Treatment with vitamin D and southern latitude was associated with greater 25(OH)D in women who are lactating.. · Black and Hispanic, and BMI > 30 were associated with lower 25(OH)D in women who are lactating.. · Practitioners can counsel women who are lactating on OCPs' use and the positive effects on their 25(OH)D status..

Impact of Maternal Vitamin D Supplementation during Breastfeeding on Infant Serum Vitamin D Levels: A Narrative Review of the Recent Evidence

Vitamin D supplementation for breastfed infants is recommended due to low levels of vitamin D in human milk and the high prevalence of vitamin D deficiency. The relationship between maternal vitamin D supplementation while breastfeeding and infant serum vitamin D levels is beginning to be described. A literature review was conducted that investigated the impact of maternal supplementation, with at least 4000 IU of vitamin D, on infant serum vitamin D levels. Inclusion criteria were publication between 2016-2022, primary research, exclusively breastfed infants, and mothers taking vitamin D supplements while breastfeeding. Exclusion criteria were publication prior to 2016, review articles, results that did not include infant serum vitamin D levels, and research using participants already included in this review. Over 90% of infants whose mothers took vitamin D supplements while breastfeeding had adequate serum vitamin D levels. The final mean serum vitamin D of all infant participants whose mothers consumed vitamin D supplementation was 66.7 nmol/L, while mean serum vitamin D in those whose mothers did not consume supplements was 33.5 nmol/L. Consumption of vitamin D supplements by lactating women exclusively breastfeeding their infants can lead to adequate serum vitamin D levels in their infants.

Comparison of Infant Bone Mineral Content and Density After Infant Daily Oral Vit D 400 IU Supplementation Versus Nursing Mother Oral 6,400 IU Supplementation: A Randomized Controlled Lactation Study

Background: Vitamin D (vitD) plays a major role in maintenance of bone mineral homeostasis. It is unknown if bone mineral content (BMC) and bone mineral density (BMD) differ between infants who receive direct vitD supplementation and those who receive vitD indirectly via their mother's breast milk, while she received a high dose of vitD. It is hypothesized that there would be no differences in BMC or BMD by treatment group. Design/Methods: Randomized, double-blind trial to compare BMD and BMC of infants who received direct vitD (400 IU vitD₃/day) in addition to their mother receiving standard dosage (400 IU vitD₃/day) versus infants whose mothers were their only source of vitD and were given high-dose supplementation (6,400 IU vitD₃/day). Participants were exclusively breastfeeding mothers and their infant consuming only human milk. Infant BMC and BMD were measured by dual-energy X-ray absorptiometry (DXA) scans of the infant's total body using Hologic Discovery A Densitometer and analyzed using Hologic Infant software at 1, 4, and 7 months of age. Results: Infant BMC and BMD did not differ significantly at 1, 4, or 7 months of age between direct and indirect supplementation arms. The mean difference in BMC from 1 to 7 months was 1.624 and 1.464 g for the 400 and 6,400 IU groups, respectively, (p = 0.5); the mean difference in BMD over this same period was 0.042 and 0.032 g/cm² for the 400 and 6,400 IU groups, respectively (p = 0.2). Although some differences among races were observed, this did not reflect changes in bone growth between the treatment arms. Conclusion: High-dose vitD supplementation of mothers during lactation provided an efficacious alternative to direct supplementation of infants, as evidenced by noninferior infant BMD and BMC. Clinical Trial Registration number: NCT00412074.

Evaluating Vitamin D Status in Infants Less than Seven Months; What Are the Preferred Biochemical Measurements?

Background: To ensure the safety of higher dose vitamin D supplementation in pregnant and lactating mothers, and urinary calcium/creatinine (UCa/Cr) ratios, serum calcium, and serum 25(OH)D concentrations are closely monitored. To achieve optimal maternal and infant vitamin D status, while avoiding hypercalcemia, safety measures assessing vitD supplementation must be reliable. Whether or not this holds true for infants before 7 months of age, remains unknown. Objective: Analyze the association among UCa/Cr ratio, serum calcium, intact serum parathyroid hormone (iPTH), 25(OH)D, and 25(OH)D/iPTH ratio in infants to determine whether evidence supports the use of these parameters as valuable measures of hypervitaminosis D or toxicity in infants. Methods: A series of analyses were performed on the cohort of infants who participated in the National Institute of Child Health and Human Development lactation vitD supplementation trial to determine the association among UCa/Cr ratio, serum calcium, iPTH, 25(OH)D, and 25(OH)D/iPTH ratio. Results: Upon multivariate analysis, serum calcium was significantly associated with 25(OH)D (p = 0.0441), iPTH (p = 0.0017), and 25(OH)D/iPTH ratio (p = 0.0001). Infant UCa/Cr did not associate with 25(OH)D but did associate with iPTH (p = 0.0008) and 25(OH)D/iPTH ratio (p = 0.0001). The correlation between UCa/Cr and 25(OH)D/iPTH ratios was significantly stronger than the association between UCa/Cr ratio and iPTH. Serum calcium more strongly correlated with 25(OH)D/iPTH ratio versus 25(OH)D and iPTH. Conclusion: In this healthy cohort of infants 1 to 7 months old, UCa/Cr and serum calcium are more valid indicators of 25(OH)D/iPTH ratio than either 25(OH)D or iPTH alone. Moreover, serum calcium (and not UCa/Cr) is a valid indicator of infant total circulating 25(OH)D and should be measured if vitamin D toxicity is a concern. Clinical Trial Registration number: FDA IND Number: 66,346; ClinicalTrials.gov Number: NCT00412074.

Maternal Vitamin D Status Correlates to Leukocyte Antigenic Responses in Breastfeeding Infants

It is unknown if vitamin D (vitD) sufficiency in breastfeeding mothers can lead to physiological outcomes for their children that are discernible from infant vitD sufficiency per se. In a 3-month, randomized vitD supplementation study of mothers and their exclusively breastfeeding infants, the effects of maternal vitD sufficiency were determined on infant plasma concentrations of 25-hydroxyvitamin D (i.e., vitD status) and 11 cytokines. An inverse correlation was seen between maternal vitD status and infant plasma TNF concentration (r = −0.27; p < 0.05). Infant whole blood was also subjected to in vitro antigenic stimulation. TNF, IFNγ, IL-4, IL-13, and TGFβ1 responses by infant leukocytes were significantly higher if mothers were vitD sufficient but were not as closely correlated to infants’ own vitD status. Conversely, IL-10 and IL-12 responses after antigenic challenge were more correlated to infant vitD status. These data are consistent with vitD-mediated changes in breast milk composition providing immunological signaling to breastfeeding infants and indicate differential physiological effects of direct-infant versus maternal vitD supplementation. Thus, consistent with many previous studies that focused on the importance of vitD sufficiency during pregnancy, maintenance of maternal sufficiency likely continues to affect the health of breastfed infants.

An Update on Vitamin D Deficiency in the twenty-first century: nature and nurture

PURPOSE OF REVIEW

Here, we review the most up-to-date understanding of the pathogenesis, prevention and treatment of vitamin D deficient rickets in children. This will include recent advances in the genetic determinants of abnormal vitamin D metabolism, with the intention of aiding clinicians with establishing the diagnosis and implementing treatment plans for children presenting with vitamin D deficiency rickets.

RECENT FINDINGS

Vitamin D deficiency rickets is a frequently encountered, but entirely preventable, disorder of bone mineral metabolism. Risk factors for developing vitamin D deficiency rickets include inadequate exposure to sunlight, exclusive breast feeding without vitamin D supplementation and inadequate intake of vitamin D, calcium or phosphorus. Other factors that may influence the development of vitamin D deficiency and/or rickets include genetic alterations or medications that alter vitamin D metabolism.

SUMMARY

Vitamin D levels in individuals are influenced by environmental factors, as well as genetic factors. A thorough understanding of these factors is critical for the evaluation and treatment of a child presenting with rickets. There remains a great need for additional research to determine ideal vitamin D status across diverse populations, and to better understand how vitamin D status affects overall health.