Summary

The major source of vitamin D is cutaneous exposure to solar vitamin D effective UV radiation, in addition to dietary sources like fatty fish, fortified dairy products and supplements. During the past decade, there has been numerous reports worldwide on high prevalence of vitamin D deficiency and insufficiency, especially among pregnant and lactating women and women of childbearing age. Individual vitamin D levels vary with season. People living at northern latitudes may be at increased risk of having insufficient levels of vitamin D, as the ultraviolet irradiation during winter months is too low to enable the photosynthesis of vitamin D in the skin. This may, however, be compensated by high intake of fatty fish, cod liver oil and supplements. During pregnancy, the fetus depends solely on the vitamin D levels of the mother. Vitamin D deficiency during pregnancy has been investigated for its relation to adverse health outcomes for both the mother and the child, e.g. gestational diabetes mellitus, pre-eclampsia, caesarean section, preterm delivery, low birth weight, low birth length, and small for gestational age. Research published on these topics are from both observational studies and intervention studies, but results have so far been inconclusive. There has also been studies investigating prenatal vitamin D status and its effect on fetal brain development, cognitive function, psychological function, and neurological disease but results here are also inconclusive. As stated in the recent review on the impact of vitamin D on pregnancy related disorders and offspring health by von Websky et al.: “more observational studies and interventional randomized controlled trails are needed to be able to draw final conclusions on the impact on vitamin D on pregnancy-related disorders and offspring health”. The accepted biomarker for vitamin D is plasma 25-hydroxyvitamin D (25OHD), which is the major circulating form of vitamin D. In large cohorts, like The Norwegian Mother, Father and Child Cohort Study, plasma 25OHD have been measured in mid-pregnancy only for a small subset of the mothers due to the cost of laboratory analyses and limited biomaterial available.

This project aim to combine three subsets of the MoBa cohort where laboratory analysis of 25OHD has already been conducted. Based on the combined data and relevant background information known in the literature to have impact on the vitamin D level, we aim to build a prediction model that may provide reliable predictions on vitamin D levels at mid-pregnancy for all mothers in the MoBa cohort. This prediction score on vitamin D may in turn enable investigations into the many research questions mentioned above.

See the full project description at Cristin for more information about results, researchers, contact information etc.

Project participants

Project leader

Pål Suren, Avdeling for barns helse og utvikling, Norwegian Institute of Public Health

Project participants

Hege Marie Bøvelstad, Avdeling for barns helse og utvikling, Norwegian Institute of Public Health
Kåre Edvardsen, Universitetet i Tromsø - Norges arktiske universitet, UiT The Arctic University of Norway
Christine Louise Parr, Avdeling for kroniske sykdommer og aldring, Norwegian Institute of Public Health