Vitamin D supplementation, cord 25-hydroxyvitamin D and birth weight: Findings from the Odense Child Cohort

• Published in: Clinical nutrition (Edinburgh, Scotland) Vol. 36; no. 6; pp. 1621 - 1627
• Main Authors: Lykkedegn, Sine, Beck-Nielsen, Signe Sparre, Sorensen, Grith Lykke, Andersen, Louise Bjoerkholt, Fruekilde, Palle Bach Nielsen, Nielsen, Jan, Kyhl, Henriette Boye, Joergensen, Jan Stener, Husby, Steffen, Christesen, Henrik Thybo
• Format: Journal Article
• Language: English
• Published: England Elsevier Ltd 01-12-2017
• Subjects: Adolescent; Adult; Birth Weight; Body Mass Index; Denmark - epidemiology; Dietary Supplements; Female; Fetal Blood - chemistry; Gastroenterology and Hepatology; Humans; Male; Maternal Nutritional Physiological Phenomena; Prevalence; Prospective Studies; Risk Factors; Seasons; Supplementation; Treatment Outcome; Vitamin D; Vitamin D - administration & dosage; Vitamin D - blood; Vitamin D Deficiency - blood; Vitamin D Deficiency - epidemiology; Young Adult; 25-hydroxyvitamin D; small for gestational age; PW; SGA; PW/BW; placental/birth weight ratio; Vitamin D; BW; 25(OH)D; Birth weight; GA; Supplementation; gestational age; placental weight
• ISSN: 0261-5614; 1532-1983
• DOI: 10.1016/j.clnu.2016.10.008

Summary Background & aims Hypovitaminosis D, defined as serum 25-hydroxyvitamin D (s-25(OH)D) <50 nmol/L, is frequent in pregnant women and neonates worldwide and has been associated with both low birth weight (BW) and placental weight (PW) as well as reduced placental development. We aimed to assess the prevalence and the risk factors of cord vitamin D deficiency (s-25(OH)D <25 nmol/L) and insufficiency (s-25(OH)D 25–50 nmol/L) and to evaluate the association between cord s-25(OH)D levels and neonatal outcomes (BW, PW and PW/BW ratio). Methods Women enrolled in Odense Child Cohort, a Danish observational prospective population-based cohort, who gave birth to singletons and donated a blood sample for s-25(OH)D measurements were included (n = 2082). Results The prevalence of cord vitamin D deficiency was 16.7% and 41.0% for insufficiency. White skin, winter season at birth, maternal supplementation dose of <15 μg/day, non-western ethnicity and high body mass index (BMI) were identified as independent risk factors of both vitamin D deficiency and insufficiency. Adherence to the recommended vitamin D supplementation dose (10 μg/day) was reported by 87% (primipara 91% vs. multipara 81%, p < 0.0001). An U-shaped relationship between cord s-25(OH)D and BW was visualized by spline regression (p = 0.003). After adjustment, cord s-25(OH)D was positively associated with BW ( β  = 1.522, p = 0.026), PW ( β  = 0.927, p < 0.001) and PW/BW ratio ( β  = 0.018, p < 0.001), largely driven by positive associations for cord s-25(OH)D >60 nmol/L. Conclusion Cord hypovitaminosis D was present in 57.7%. Multipara was identified as a novel risk factor of non-adherence to vitamin D supplementation recommendations; and a maternal supplementation dose <15 μg/day as a novel, independent risk factor of cord hypovitaminosis D. Higher BW, PW, and PW/BW ratio were associated to higher cord s-25(OH)D levels with a suggested cut-off at 60 nmol/L. More studies are encouraged to elucidate the impact of cord s-25(OH)D levels on offspring health and to establish optimal cut-offs for these outcomes.