Introduction: Vitamin D deficiency is a big public health concern, especially among women. For this reason, "The Five Countries Study" was set up within the OPTIFORD project. This study aims at knowing the vitamin D status in adolescent and older women in five European countries according to their different dietary and behavioral habits.
Objectives: To analyze the relative contribution of sun exposure and the diet to the vitamin D status among 47 Spanish adolescents participating in "The Five Countries Study".
Methods: Validated and standardized questionnaires (health, lifestyle, sun exposure, and frequency of food consumption), biochemical analysis (25-hydroxyvitamin D (S-25-OHD) and parathormone), and assessment of sun exposure (UV dosimeter).
Results: Serum levels of S-25-OHD were higher during the summertime than in winter (61.55±12.85 nmol/l and 45.81±9.29 nmol/l, respectively). Forty-five percent of the sample had a worsening of their vitamin status in the winter, as compared with the summer (p<0.0001). During the summer, vitamin D insufficiency (S-25-OHD≤50 nmol/l) affected 17% of the population, going up to 63% in the winter. Sixty-six percent of the sample did not reach the IR of vitamin D (5 g/day), being the fish the main dietary source of vitamin D.
Conclusions: Only 34% of the participants had an adequate vitamin D status. Both adequate sun exposure and vitamin D dietary intake are recommended in order to correct deficient and insufficient situations.