Abstract
Objective
Obtaining adequate vitamin D during pregnancy is important for the health of mother and child. Low circulating 25-hydroxyvitamin D (25OHD) concentrations, a measure of vitamin D status, have been reported in pregnant women in several countries; yet, there are few studies of pregnant Canadian women. We measured 25OHD concentrations in a multi-ethnic group of pregnant women living in Vancouver (49°N) and explored the determinants of 25OHD.
Methods
336 pregnant women (16-47 y) between 20 and 35 weeks gestation provided a blood sample and completed questionnaires.
Results
Mean 25OHD was 67 (95% CI 64-69) nmol/L. Only 1% of women had a 25OHD concentration indicative of severe deficiency (<25 nmol/L). However, 24% and 65% of women were vitamin D insufficient based on cut-offs of 50 and 75 nmol/L, respectively. In multivariate analysis, mean 25OHD concentrations were 12 nmol/L higher in the summer compared to in winter. Women of European (White) ethnicity had a 9-13 nmol/L higher mean 25OHD concentration than women from other ethnic groups. Almost 80% of women took vitamin D-containing supplements containing ≥400 IU/d. However, 24% and 65% of these women had 25OHD <50 and <75 nmol/L, respectively.
Conclusion
Vitamin D insufficiency was not uncommon in this group of pregnant women. Season and ethnicity were determinants of 25OHD but the magnitude of their effect was not large. Most women took vitamin D-containing supplements but this did not provide much protection against insufficiency. Consideration should be given to increasing the amount of vitamin D in prenatal supplements.
Key words: Vitamin D, nutrition and metabolism, pregnancy, Vancouver
Résumé
Objectif
Des apports suffisants en vitamine D durant la grossesse sont importants pour la santé de la mère et de l’enfant. Dans plusieurs pays, on rapporte de faibles concentrations en 25-hydroxy-vitamine D (25OHD), une mesure du statut en vitamine D, dans le sang des femmes enceintes, mais il y a eu peu d’études sur le sujet auprès des Canadiennes enceintes. Nous avons mesuré les concentrations en 25OHD au sein d’un groupe multiethnique de femmes enceintes vivant à Vancouver (49 °N) et exploré les déterminants de la concentration en 25OHD.
Méthode
En tout, 336 femmes enceintes (de 16 à 47 ans) entre la 20e et la 35e semaine de gestation ont fourni un échantillon de sang et rempli des questionnaires.
Résultats
La concentration moyenne en 25OHD était de 67 nmol/L (IC de 95 % = 64-69). Seulement 1 % des femmes avaient une concentration en 25OHD indiquant un grave déficit (<25 nmol/L). Cependant, 24 % et 65 % des femmes, respectivement, étaient carencées en vitamine D selon que l’on place le point de coupure à 50 ou à 75 nmol/L. Dans une analyse multivariée, les concentrations moyennes en 25OHD étaient de 12 nmol/L de plus l’été que l’hiver. Les femmes d’origine ethnique européenne (blanche) avaient une concentration moyenne en 25OHD de 9 à 13 nmol/L de plus que les femmes d’autres groupes ethniques. Près de 80 % des femmes prenaient des suppléments contenant ≥400 UI/jour de vitamine D. Cependant, 24 % et 65 % de ces femmes, respectivement, avaient des concentrations en 25OHD de <50 et de <75 nmol/L.
Conclusion
Les carences en vitamine D n’étaient pas rares dans ce groupe de femmes enceintes. La saison et l’ethnicité étaient des déterminants des concentrations en 25OHD, mais l’ampleur de leur effet n’était pas importante. La plupart des femmes prenaient des suppléments contenant de la vitamine D, mais cela ne les protégeait pas beaucoup contre les carences. Il faudrait songer à accroître la quantité de vitamine D dans les suppléments nutritifs prénatals.
Mots clés: vitamine D, nutrition, métabolisme, grossesse, Vancouver
Footnotes
Conflict of Interest: None to declare.
References
- 1.Bodnar L, Catov JM, Simhan HN, Holick MF, Powers RW, Roberts JM. Maternal vitamin D deficiency increases the risk of preeclampsia. J Clin Endocrinol Metab. 2007;92(9):3517–22. doi: 10.1210/jc.2007-0718. [DOI] [PMC free article] [PubMed] [Google Scholar]
- 2.Von Dadelszen P, Magee L. What matters in preeclampsia are the associated adverse outcomes: The view from Canada. Curr Opin Obstet Gynecol. 2008;20(2):110–15. doi: 10.1097/GCO.0b013e3282f733a2. [DOI] [PubMed] [Google Scholar]
- 3.Ward L, Gaboury I, Ladhani M, Zlotkin S. Vitamin D-deficiency rickets among children in Canada. CMAJ. 2007;177(2):161–66. doi: 10.1503/cmaj.061377. [DOI] [PMC free article] [PubMed] [Google Scholar]
- 4.Zipitis CS, Akobeng AK. Vitamin D supplementation in early childhood and risk of type 1 diabetes: A systematic review and meta-analysis. Arch Dis Child. 2008;93(6):512–17. doi: 10.1136/adc.2007.128579. [DOI] [PubMed] [Google Scholar]
- 5.Erkkola M, Kaila M, Nwaru BI, Kronberg-Kippila C, Ahonen S, Nevalainen J, et al. Maternal vitamin D intake during pregnancy is inversely associated with asthma and allergic rhinitis in 5-year-old children. Clin Exp Allergy. 2009;39(6):875–82. doi: 10.1111/j.1365-2222.2009.03234.x. [DOI] [PubMed] [Google Scholar]
- 6.Javaid MK, Crozier SR, Harvey NC, Gale CR, Dennison EM, Boucher BJ, et al. Maternal vitamin D status during pregnancy and childhood bone mass at age 9 years: A longitudinal study. Lancet. 2006;376(9504):36–43. doi: 10.1016/S0140-6736(06)67922-1. [DOI] [PubMed] [Google Scholar]
- 7.Heaney RP. Functional indices of vitamin D status and ramifications of vitamin D deficiency. Am J Clin Nutr. 2004;80(6Suppl):1706S–1709S. doi: 10.1093/ajcn/80.6.1706S. [DOI] [PubMed] [Google Scholar]
- 8.Bouillon R, Carmeliet G, Daci E, Segaert S, Verstuyf A. Vitamin D metabolism and action. Osteoporos Int. 1998;8(Suppl2):S13–S19. doi: 10.1007/PL00022727. [DOI] [PubMed] [Google Scholar]
- 9.FoodNutrition Board, Institute of Medicine. Committee to review dietary reference intakes for vitamin D and calcium. Washington, DC: National Academy Press; 2010. [Google Scholar]
- 10.First Nations, InuitMétis Health Committee. Vitamin D supplementation: Recommendations for Canadian mothers and infants. Paediatr Child Health. 2007;12(7):583–89. doi: 10.1093/pch/12.7.583. [DOI] [PMC free article] [PubMed] [Google Scholar]
- 11.Bodnar LM, Simhan HN, Powers RW, Frank MP, Cooperstein E, Roberts JM. High prevalence of vitamin D insufficiency in black and white pregnant women residing in the northern United States and their neonates. J Nutr. 2007;137:447–52. doi: 10.1093/jn/137.2.447. [DOI] [PMC free article] [PubMed] [Google Scholar]
- 12.Grover SR, Morley R. Vitamin D deficiency in veiled or dark-skinned pregnant women. Med J Aust. 2001;175(5):251–52. doi: 10.5694/j.1326-5377.2001.tb143558.x. [DOI] [PubMed] [Google Scholar]
- 13.Neimanis IM, Paterson JM, Bain E. Preventing neural tube defects. Survey of preconceptional use of folic acid. Can Fam Phys. 1999;45:1717–22. [PMC free article] [PubMed] [Google Scholar]
- 14.Wu H, Gozdzik A, Barta JL, Wagner D, Cole DE, Vieth R, et al. The development and evaluation of a food frequency questionnaire used in assessing vitamin D intake in a sample of healthy young Canadian adults of diverse ancestry. Nutr Res. 2009;29(4):255–61. doi: 10.1016/j.nutres.2009.03.006. [DOI] [PubMed] [Google Scholar]
- 15.Westerhof W. CIE Colourimetry. In: Serup J, Jemec G, editors. In Vivo Examination of the Skin: A Handbook of Non-Invasive Methods. Boca Raton, FL: CRC Press; 1995. [Google Scholar]
- 16.Piérard GE. EEMCO guidance for the assessment of skin colour. J Eur Acad Dermatol Venereol. 1998;10(1):1–11. doi: 10.1016/s0926-9959(97)00183-9. [DOI] [PubMed] [Google Scholar]
- 17.Rockell JE, Skeaff CM, Williams SM, Green TJ. Association between quantitative measures of skin colour and plasma 25-hydroxyvitamin D. Osteoporos Int. 2008;19(11):1639–42. doi: 10.1007/s00198-008-0620-4. [DOI] [PubMed] [Google Scholar]
- 18.DiaSorin. New LIAISON® 25-OH Vitamin D TOTAL. 2007. [Google Scholar]
- 19.Vitamin D External Quality Assessment Scheme. Available at: https://doi.org/www.deqas.org (Accessed June 8, 2010).
- 20.Mulligan ML, Felton SK, Riek AE, Bernal-Mizrachi C. Implications of vitamin D deficiency in pregnancy and lactation. Am J Obstet Gynecol. 2009;202(5):429e1–9. doi: 10.1016/j.ajog.2009.09.002. [DOI] [PMC free article] [PubMed] [Google Scholar]
- 21.Bischoff-Ferrari HA, Giovannucci E, Willett WC, Dietrich T, Dawson-Hughes B. Estimation of optimal serum concentrations of 25-hydroxyvitamin D for multiple health outcomes. Am J Clin Nutr. 2006;84(1):18–28. doi: 10.1093/ajcn/84.1.18. [DOI] [PubMed] [Google Scholar]
- 22.Langlois K, Greene-Finestone L, Little J, Hidiroglou N, Whiting S. Vitamin D status of Canadians as measured in the 2007 to 2009 Canadian Health Measures Survey. Health Rep. 2010;21(1):47–55. [PubMed] [Google Scholar]
- 23.Waiters B, Godel JC, Basu Tapan K. Perinatal vitamin D and calcium status of northern Canadian mothers and their newborn infants. J Am Coll Nutr. 1999;18(2):122–26. doi: 10.1080/07315724.1999.10718839. [DOI] [PubMed] [Google Scholar]
- 24.Sloka S, Stokes J, Randell E, Newhook LA. Seasonal variation of maternal serum vitamin D in Newfoundland and Labrador. J Obstet Gynaecol Can. 2009;31(4):313–21. doi: 10.1016/S1701-2163(16)34148-2. [DOI] [PubMed] [Google Scholar]
- 25.Holick MF. The cutaneous photosynthesis of previtamin D3: A unique photoendocrine system. J Invest Dermatol. 1981;77(1):51–58. doi: 10.1111/1523-1747.ep12479237. [DOI] [PubMed] [Google Scholar]
- 26.Ginde AA, Sullivan AF, Mansbach J C, Jr CA. Vitamin D insufficiency in pregnant and nonpregnant women of childbearing age in the United States. Am J Obstet Gynecol. 2010;202(5):436. doi: 10.1016/j.ajog.2009.11.036. [DOI] [PMC free article] [PubMed] [Google Scholar]
- 27.O’Riardan MN, Kiely M, Higgins JR, Cashman KD. Prevalence of suboptimal vitamin D status during pregnancy. Ir Med J. 2008;101(8):240–43. [PubMed] [Google Scholar]
- 28.Matsuoka LY, Wortsmann J, Haddad JG, Kolm P, Hollis BW. Racial pigmentation and the cutaneous synthesis of vitamin D. Arch Dermatol. 1991;127(4):536–38. doi: 10.1001/archderm.1991.04510010104011. [DOI] [PubMed] [Google Scholar]
- 29.Rockell JE, Green TJ, Skeaff CM. Season and ethnicity are determinants of serum 25-Hydroxyvitamin D concentrations in New Zealand children aged 5–14 y. J Nutr. 2005;135(11):2602–8. doi: 10.1093/jn/135.11.2602. [DOI] [PubMed] [Google Scholar]
- 30.Taylor S, Westerhof W, Im S, Lim J. Noninvasive techniques for the evaluation of skin colour. J Am Acad Dermatol. 2006;54(5):S282–90. doi: 10.1016/j.jaad.2005.12.041. [DOI] [PubMed] [Google Scholar]
- 31.Gozdzik A, Barta JL, Wu H, Wagner D, Cole DE, Vieth R, et al. Low wintertime vitamin D levels in a sample of healthy young adults of diverse ancestry living in the Toronto area: Associations with vitamin D intake and skin pigmentation. BMC Public Health. 2008;8:336–65. doi: 10.1186/1471-2458-8-336. [DOI] [PMC free article] [PubMed] [Google Scholar]
- 32.Heaney RP, Davies KM, Chen TC, Holick MF, Barger-Lux MJ. Human serum 25-hydroxycholecalciferol response to extended oral dosing with cholecalciferol. Am J Clin Nutr. 2003;77(1):204–10. doi: 10.1093/ajcn/77.1.204. [DOI] [PubMed] [Google Scholar]
- 33.Bodnar LM, Catov JM, Roberts JM, Simhan HN. Prepregnancy obesity predicts poor vitamin D status in mothers and their neonates. J Nutr. 2007;137(11):2437–42. doi: 10.1093/jn/137.11.2437. [DOI] [PMC free article] [PubMed] [Google Scholar]
- 34.Statistics Canada. Health Statistics Division. 2007. [Google Scholar]
- 35.Fleischman AR, Rosen JF, Cole J, Smith CM, DeLuca HF. Maternal and fetal serum 1,25-dihydroxyvitamin D levels at term. J Pediatr. 1980;97(4):640–42. doi: 10.1016/S0022-3476(80)80030-8. [DOI] [PubMed] [Google Scholar]
- 36.Hollis BW. Circulating 25-hydroxyvitamin D levels indicative of vitamin D sufficiency: Implications for establishing a new effective dietary intake recommendation for vitamin D. J Nutr. 2005;135(2):317–22. doi: 10.1093/jn/135.2.317. [DOI] [PubMed] [Google Scholar]
- 37.Holick MF. Sunlight and vitamin D for bone health and prevention of autoimmune diseases, cancers, and cardiovascular disease. Am J Clin Nutr. 2004;80(6Suppl):1678S–88S. doi: 10.1093/ajcn/80.6.1678S. [DOI] [PubMed] [Google Scholar]