• Combined hormonal contraceptives and vitamin D metabolism in adolescent girls 

      Öberg, Eva Gunnel Johanna; Jorde, Rolf; Figenschau, Professor Yngve; Thorsby, Per Medbøe; Dahl, Sandra Rinne; Winther, Anne; Grimnes, Guri (Journal article; Tidsskriftartikkel; Peer reviewed, 2022-03-31)
      Objective: Combined hormonal contraceptive (CHC) use has been associated with higher total 25-hydroxyvitamin D (25(OH)D) levels. Here, we investigate the relation between CHC use and vitamin D metabolism to elucidate its clinical interpretation. <p>Methods: The cross-sectional Fit Futures 1 included 1038 adolescents. Here, a subgroup of 182 girls with available 25(OH)D, 1,25-dihydroxyvitamin D ...
    • Vitamin D Status During Adolescence and the Impact of Lifestyle Changes: 2 Years’ Follow-up From the Fit Futures Study 

      Öberg, Eva Gunnel Johanna; Jorde, Rolf; Almås, Bjørg; Nielsen, Christopher Sivert; Gerds, Thomas Alexander; Cashman, Kevin D.; Grimnes, Guri (Journal article; Tidsskriftartikkel; Peer reviewed, 2023-11-13)
      Context: Longitudinal data regarding vitamin D status in adolescence is scarce. This study presents population-based data from an Arctic adolescent population (n = 589) at 16 and 18 years. Objective: The aims of this study were to investigate changes in vitamin D status during 2 years in adolescence, and whether lifestyle changes were associated with serum 25-hydroxyvitamin D (s-25(OH)D) at follow-up. ...