| Summary: | Abstract Vitamin D is essential for bone health, but additional positive health effects of vitamin D have been observed in recent decades. Due to the lack of solar light in northern latitudes, the risk of vitamin D deficiency is elevated, which may predispose people to several adverse health consequences. In Finland, a nationwide systematic vitamin D fortification of dairy products and fat spreads has been launched, but evidence of the effects of this public health action is scarce, especially among the population in northern Finland. Vitamin D has been suggested to be linked to reproductive disorders in women such as infertility, polycystic ovary syndrome (PCOS) and early-onset menopausal transition, but previous research results have been conflicting. The aim of the present study was to evaluate vitamin D status in the population living in northern latitudes with an increased risk for vitamin D deficiency and in women with reproductive disorders. The study population included 31- and 46-year-old participants from the prospectively collected large Northern Finland Birth Cohort 1966. The impacts of the vitamin D fortification program were investigated with vitamin D measurements before and after the start of vitamin D fortification in dairy products and fat spreads. Use of vitamin D supplementation was also observed. The aim was to assess whether a history of fertility problems, PCOS or early-onset climacteric phase in women were associated with vitamin D status. The study results showed that vitamin D status improved, and that the prevalence of vitamin D deficiency decreased after the initiation of the vitamin D fortification program. Seasonal variation in vitamin D also diminished. In women, a history of infertility and decreased fecundability associated with lower vitamin D status. However, based on the study results, PCOS did not seem to increase the risk for vitamin D inadequacy. While no association was observed between climacteric status and vitamin D, hormone replacement therapy (HRT) use had an ...
|
|---|