Vitamin D levels in pregnant women in the city of Burgos (Spain)
Javier Pi1, Iria Flavia Vallina2, Felisa Alonso2, Javier Lozano3, Estefania Santos1, Celia Guerrero4, Beatriz Caton2 & Eva Tutor2
Introduction: Vitamin D deficiency is very common in the population, including pregnant women. There are few studies in Spain to explain their causes, so we started one in the city of Burgos, Spain (latitude 42.2° N) in April 2009 to study vitamin D status, factors that can influence and their relationship with gestational diabetes. We present preliminary data from the study on vitamin D levels.
Aims: Study in pregnancy: i) vitamin levels, and ii) its variation throughout the pregnancy and its possible relationship with several variables: anthropometric, racial, nutritional, lifestyle and seasonal.
Subjecs/methods: i) Measurement of serum vitamin D levels (25-hydroxyvitamin D (25OHD) (Modular Analytics E170, Roche) setting the following categories (ng/ml): normal (N): ≥30; insufficiency (I): 2029.9; deficiency (D): 1019.9; severe deficiency (SD): <10 (grouped into N, I, D (D & SD) for analysis) in pregnant women in the first and third trimester of pregnancy during gynecological control. ii) Questionnaire to collect the above mentioned variables in the first trimester.
Results: i) Sample: 612 women tested with a mean age of 32.1±4.4 years, BMI (kg/m2) 23.6±3.5, 57.3% multiparous, 84.9% non-smokers, 90.8% caucasian, 4% tanning bed users, 78% sunscreen users, 2.6% veil users, 78% urban residents, 39% >3 h of exercise/week, 17% >3 servings of dairy products/day, 11% >3 servings of fish/week. ii) Mean serum 25OHD concentration by the time of pregnancy: first trimester (n=340): 23.5±7.0 ng/ml; third trimester (n=244): 26.6±8.3 ng/ml. iii) serum 25OHD according to season and trimester: first trimester: spring: 20.5±5.1 ng/ml, summer: 26.7±7.1 ng/ml; autumn: 28.5±7.5 ng/ml; third trimester: summer: 28.8±9.5 ng/ml; autumn: 25.8±7.7 ng/ml. iv) vitamin D categories by trimester and season: first trimester: N: 14.4%, I: 54.1%, D: 31.5% (spring: N: 2.8%, I: 51.7%, D: 45.5%, summer: N: 25.2%, I: 60.3%, D: 14.5%, autumn: N: 36.7%, I: 43.3%, D: 20.0%. third trimester: N: 29,1%, I: 49.2% D 21.7% (summer: N: 43.5% I: 43.5% D: 13.0%, autumn: N: 25.9% I: 50.7%, D: 23.4%. v) Relationship between serum 25OHD and variables considered: We only found significant differences in serum 25OHD levels between first and third trimester of gestation (P<0.001).
Conclusions: Based on this preliminary data we can conclude: i) vitamin D levels in this group of pregnant women are very low and neither group studied reached normal values. ii) There is a significant differences in 25OHD levels between the first and third trimester. iii) There is no relationship between vitamin D levels and other variables analyzed iv) These results may reconsider whether the degree of normality proposed are adequate or if the protocols of nutritional supplementation to pregnant women are inadequate, given the high proportion of insufficient and deficient values founded in a group of women otherwise completely healthy.