Maternal and infant vitamin D status during lactation: Is latitude important?

Abstract

Background: The effect of latitude on maternal and infant vitamin D status during lactation ispresumed to be strongly associated with higher rates of deficiency in those living at higher latitudes, yet with lifestyle changes, this conclusion may no longer be correct. Objective: To ascertain if higher latitude adversely affects the vitamin D status of lactating women and their fully breastfeeding infants. Study Design/Methods: Fully breastfeeding women and their infants were eligible for participation in this study as part of a larger prospective vitamin D supplementation trial. Women were recruited from two sites of differing latitude: Charleston, SC at 32˚N and Rochester, NY at latitude 43˚N. Maternal and infant baseline vitamin D status, intact parathyroid hormone (IPTH), serum calcium and phosphorus as a function of site/latitude were measured. The primary outcome was maternal and infant total circulating 25(OH)D at baseline by center/latitude, and the secondary outcome was the percent of women and infants who had achieved a baseline concentration of at least 20 ng/mL, meeting the Institute of Medicine's definition of sufficiency at 4 to 6 weeks postpartum. Statistical analysis was performed using SAS version 9.3. Results: Higher latitude adversely affected vitamin D status only in lactating Caucasian women. African American and Hispanic women and infants living in Rochester compared to Charleston had improved vitamin D status, an effect that was no longer significant when controlling for socioeconomic factors and season. Overall, there was a significant vitamin D deficiency at baseline in lactating mothers, and a far greater deficiency in their infants. Maternal baseline 25(OH)D concentration remained positively associated with being Caucasian, BMI and summer months. Breastfeeding infant vitamin D status mirrored maternal status and remained positively associated with being Caucasian and summer months. Those infants who had been on a vitamin D supplement at the time of enrollment in the study had markedly improved vitamin D status compared to those infants not on supplement, but represented a significant minority of the cohort. Conclusions: There was a significant vitamin D deficiency among a cohort of women and their infants living at two diverse latitudes-Charleston, SC and Rochester, NY. Given the higher rate of vitamin D deficiency among African American and Hispanic women and their infants living at a lower latitude, conclusions about vitamin D status based on latitude alone may be faulty.

Correlation of serum levels of Vitamin D3 with serum parathormone in nursing mothers and infants 1-6 months’ age from South Punjab, Pakistan

“…This was concordant with the study by Wagner CL et al showing moderate positive correlation (r – 0.42 – 0.65, p-value < 0.0001) between lactating mother-infant VD 3 levels. 19 It was also concordant with the study results by Husain et al who showed a moderate positive relation between VD 3 levels of mother and infant pair (Pearson coefficient = 0.516, P < 0.001). 20 This positive relation between Infant & maternal VD 3 concentrations (r s =0.41, P=0.001) was also highlighted by Salameh et al 21 …”

“…Maternal serum calcium in our study was comparable to the levels in a study by Wagner et al (8.98 ± 0.7 vs. 9.4 ± 0.4). 19 Similarly, maternal phosphorus in our study was comparable to the mothers recruited from Charleston, SC (4.19 ± 0.97 vs. 4.14 ± 0.62) but it was higher compared to mothers recruited from Rochester, NY (3.8 ± 0.60). A moderate positive correlation (r s – 0.55, p-value < 0.001) between the maternal and infant VD 3 was observed.…”

“… 24 Study by Wagner et al also highlighted the inverse relationship between VD 3 & PTH levels in lactating mothers (r = - 0.32) as well as in infants (r = -0.35). 19 So, the evidence for inverse relationship between VD 3 & PTH is not conclusive in either way.…”

Maternal Versus Infant Vitamin D Supplementation During Lactation: A Randomized Controlled Trial

“…Baseline characteristics of the lactating mother and infant cohort have been published previously. 21 Our study was designed to test the primary hypothesis that the lactating woman requires substantially more dietary vitamin D than the amount received from maternal supplementation with 400 IU/day. 1,11 We based our maternal supplementation dosing on previous studies: for every 1000 IU per day vitamin D 3 , milk antirachitic activity would increase by ∼80 IU/L in a way that would sustain the nursing infant.…”

Vitamin D supplementation during pregnancy: Updated meta-analysis on maternal outcomes

“…1 ). We excluded 27 studies, mainly because the comparisons were among different doses of vitamin D without a placebo or control group [7 [15] , [24] , [35] , [40] , [45] , [51] , [55] , [57] , [58] , [29] , [64] , [65] , [68] . Also, four trials were not randomised [2] , [12] , [14] , [33] and three were done in pregnant women with chronic conditions [3] , [4] , [20] .…”