Parity and vitamin D metabolites

Pooled estimate of vitamin D deficiency among pregnant women in India: a systematic review and meta-analysis

BACKGROUND

Vitamin D deficiency among pregnant women is a public health concern globally. In India, individual studies report high prevalence. However, lack of national data masks the true burden. This work determined the pooled prevalence of vitamin D deficiency among pregnant women in India through a systematic review of literature and meta-analysis.

METHODS

Three different search engines yielded 15 eligible articles. Study quality was assessed by 10 different criteria and summary of study quality was categorized as per Cochrane standards. Meta-analysis was performed to estimate pooled prevalence of vitamin D deficiency among healthy pregnant women and heterogeneity among selected studies. A sample of n = 4088 was used to study the pooled prevalence among pregnant women.

RESULTS

The random effects combined estimate was 32.35% (95% CI, (12.58-117.48). High heterogeneity (tau² = 0.39, I² = 100%) and high risk of bias was observed among the selected studies. The test for overall effect was observed to be z = 2.54(P = 0.01).

CONCLUSION

Pooled estimate > 30% emphasizes the need for screening through antenatal care services and initiate preventive measures to address the deficiency.

Severe vitamin D deficiency among pregnant women and their newborns in Turkey

OBJECTIVES

Vitamin D deficiency is an important health problem in pregnant women and their infants in sunny countries. Low socio-economic status (LSES), covered dressing style, pregnancies in winter season and having dark skin are the major risk factors for vitamin D deficiency. The present study evaluated serum 25-hydroxyvitamin D3 [25(OH)D3] concentrations in pregnant women and in their newborns and determined the risk factors in LSES cities in Turkey.

METHODS

Ninety-seven pregnant women and their newborns were included in the study between December 2012 and February 2013. All of the pregnant women had irregular follow-up or had received no antenatal care, were pregnant during summer, had presented to the hospital after 37 weeks of gestation (WG) and had received no vitamin D supplementation. A detailed history was obtained, which included mothers' age, number of births and dressing sytle. Maternal and cord blood samples were taken to measure 25(OH)D3 levels.

RESULTS

All of the pregnant women were predominantly LSES, had covered dressing style and none of them had received vit D3 supplementation during pregnancy. The mean serum 25(OH)D3 level and mean cord blood level of of 97 mothers were 4.97 ± 3.27 ng/ml and 4.29 ± 2.44 ng/ml, respectively. There was a strong positive correlation between maternal serum and umbilical cord 25(OH)D3 levels (r: 0.735, p < 0.05). Ninety-five mothers had serum 25(OH)D3 below 20 ng/ml and all cord blood serum 25(OH)D3 levels were below 20 ng/ml. Level of 25(OH)D3 was not correlated with mother age, WG or newborn weight. Serum 25(OH)D3 concentrations in primigravida and multigravida were 3.71 ± 1.88 and 5.2 ± 3.4 ng/ml, respectively, with a significant difference between them (p < 0.05).

CONCLUSION

Severe vitamin D deficiency is common in reproductive women and their newborns in LSES cities of Turkey. Covered dressing style, not receiving any vitamin D supplementation and primigravida women are at greatest risk. Vitamin D supplementation campaigns which should cover pregnant women and the newborn to prevent maternal and perinatal vitamin D deficiency should be implemented especially in risk areas.

Racial variation in vitamin D cord blood concentration in white and black male neonates

AIM

The aim of this study is to evaluate racial variation in umbilical cord blood concentration of vitamin D and to explore its correlation with markers of the insulin-like growth factor axis (IGFs) and sex steroid hormones in white and black male neonates.

METHODS

In 2004-2005, venous umbilical cord blood samples were collected from 75 black and 38 white male neonates, along with maternal and birth characteristics from two hospitals in Maryland, United States. 25-Hydroxyvitamin D [25(OH)D] and 1,25-dihydroxyvitamin D [1,25(OH)(2)D] were measured by radioimmunoassay and testosterone, estradiol, and sex hormone-binding globulin (SHBG) by immunoassay and IGF-1, IGF-2, and IGF-binding protein-3 by ELISA. Crude and multivariable-adjusted geometric mean concentrations were computed.

RESULTS

Mean 25(OH)D levels were lower in black than in white neonates (11.44; 95 % CI 10.10-12.95 ng/mL vs. 18.24; 95 % CI 15.32-21.72 ng/mL; p < 0.0001). Black neonates were at higher risk of suboptimal vitamin D levels [25(OH)D < 20 ng/mL] than whites (84 vs. 63 %). 25(OH)D concentrations varied by season in whites but not in blacks and were significantly inversely correlated with mother's parity (number of live births) in blacks but not in whites. Mean concentration of 1,25(OH)(2)D did not differ by race. 25(OH)D and 1,25(OH)(2)D did not correlate with IGFs, sex steroid hormones, and SHBG.

CONCLUSIONS

Suboptimal vitamin D levels were prevalent especially in blacks and influenced by mother's parity and by season. The observed vitamin D differences between black and white neonates warrant further evaluation of the etiology of the disparity in chronic diseases in adulthood.

First trimester serum 25-hydroxyvitamin D status and factors related to lower levels in gravids living in the Spanish Mediterranean coast

OBJECTIVE

To assess first trimester serum 25-hydroxyvitamin D [25(OH)D] status and factors related to deficient levels in pregnant Spanish women.

METHODS

This cross-sectional study was carried out among 502 gravids (11 to 14 weeks) living in the Spanish Mediterranean sea coast (near Almería at latitude 36° N, longitude 2° W) to whom serum 25(OH)D levels were measured by electrochemiluminescence immunoassay. Logistic and multiple linear regression analysis were performed to assess the influence of ethnicity, immigration status, season of the year at blood sampling, body mass index (BMI), parity and smoking habit over 25(OH)D levels.

RESULTS

The median (interquartile range, IQR) serum 25(OH)D levels for the entire sample was 27.4 ng/mL (IQR = 20.9-32.8). Only 35.9% of participants had adequate serum 25(OH)D levels (≥30 ng/mL) whereas in 41.4% and 22.7% these levels were found to be insufficient (20-29.9 ng/mL) and deficient (<20 ng/mL), respectively. Vitamin D status was found to be significantly lower in Arab women as compared to Caucasian women. 25(OH)D levels were positively correlated with gestational age at sampling and inversely with BMI values (univariate analysis). Logistic regression analysis determined that non-Caucasian ethnicity, season at sampling (autumn/winter), and nulliparity were factors related to deficient 25(OH)D levels. Multiple linear regression found a similar model yet also including maternal weight inversely correlating with 25(OH)D levels.

CONCLUSION

Despite living in one of the sunniest, warmest, and driest climates of Europe, gravids displayed a high prevalence of first trimester insufficient/deficient serum 25(OH)D levels related to season at sampling, nulliparity, maternal weight, and non-Caucasian ethnicity.

Maternal vitamin D status throughout and after pregnancy

Prospective longitudinal study of vitamin D status and its risk factors in 75 pregnant women from early pregnancy until 6 months postpartum, by serial measurement of serum 25 (OH) vitamin D levels. The serum levels at booking were not significantly different between nationalities (p = 0.06), parity (p = 0.2), education levels (p = 0.4), dress code (p > 0.5), consumption of vitamin D fortified milk (p = 0.2) or, fatty fish (p = 0.5), sun-exposed body surface area (p = 0.3), weekly time exposed to the sun (p = 0.08) or the sun exposure index (p = 0.2). Vitamin D status progressively worsened as the proportion with adequate serum levels fell from 31% at the antenatal visit, to 23% after birth and 17%, 6 months later (p = 0.02). While 80% of mothers who were exclusively breast-feeding had low vitamin D levels 6 months after delivery, this occurred in only 67% of those partially breast-feeding (p = 0.6).