{"status":"ok","message-type":"work","message-version":"1.0.0","message":{"indexed":{"date-parts":[[2026,3,24]],"date-time":"2026-03-24T09:12:42Z","timestamp":1774343562971,"version":"3.50.1"},"reference-count":27,"publisher":"SAGE Publications","issue":"4","license":[{"start":{"date-parts":[[2016,4,1]],"date-time":"2016-04-01T00:00:00Z","timestamp":1459468800000},"content-version":"tdm","delay-in-days":0,"URL":"https:\/\/journals.sagepub.com\/page\/policies\/text-and-data-mining-license"}],"content-domain":{"domain":["journals.sagepub.com"],"crossmark-restriction":true},"short-container-title":["JRSM Open"],"published-print":{"date-parts":[[2016,4,1]]},"abstract":"<jats:sec><jats:title>Objective<\/jats:title><jats:p> To analyze the seasonal variations in calcidiol and parathyroid hormone serum levels along a natural year in a paediatric population living in a region of the north of Spain considering a normal nutrition status. <\/jats:p><\/jats:sec><jats:sec><jats:title>Design<\/jats:title><jats:p> A cross-sectional study. <\/jats:p><\/jats:sec><jats:sec><jats:title>Setting<\/jats:title><jats:p> Navarra Hospital Complex, Pamplona, Spain. <\/jats:p><\/jats:sec><jats:sec><jats:title>Participants<\/jats:title><jats:p> A total of 413 Caucasian individuals (aged 3.1 to 15.4 years): 227 school children (96 males and 131 females) and 186 adolescents (94 males and 92 females), with normal nutritional status. <\/jats:p><\/jats:sec><jats:sec><jats:title>Main outcome measures<\/jats:title><jats:p> Clinical examination (sex, age, weight, height and body mass index) and blood testing (calcium, phosphate, alkaline phosphatase, calcidiol and parathyroid hormone) during the year 2014. <\/jats:p><\/jats:sec><jats:sec><jats:title>Results<\/jats:title><jats:p> Calcidiol levels were lower during spring (25.96\u2009\u00b1\u20096.64\u2009ng\/mL) and reached its maximum level in summer (35.33\u2009\u00b1\u20097.51\u2009ng\/mL); parathyroid hormone levels were lower in summer (27.13\u2009\u00b1\u20097.89\u2009pg\/mL) and reached maximum level in autumn (34.73\u2009\u00b1\u200915.38\u2009pg\/mL). Hypovitaminosis D prevalence was 14.3% in summer and 75.3% in spring. Parathyroid hormone levels were compatible with secondary hyperparathyroidism in eight individuals (1.9%). There is a correlation ( p\u2009&lt;\u20090.01) between calcidiol and parathyroid hormone ( r\u2009=\u2009\u22120.336). Logistic regression showed significant increased risk of hypovitaminosis in females (OR:1.63) and adolescents (OR:1.77), and when blood samples taken in autumn (OR:12.22), winter (OR:8.54) and spring (OR:19.72). <\/jats:p><\/jats:sec><jats:sec><jats:title>Conclusions<\/jats:title><jats:p> There is a high prevalence of hypovitaminosis D in the paediatric population with a healthy nutrition situation in Navarre, mainly during the months of autumn and winter, and, especially, in spring time. Given the difficulties in maintaining a sufficient amount of body vitamin D content along the year, it should be considered to give vitamin supplements and\/or increase the intake of its natural dietary sources or vitamin D fortified foods. <\/jats:p><\/jats:sec>","DOI":"10.1177\/2054270416632704","type":"journal-article","created":{"date-parts":[[2016,4,2]],"date-time":"2016-04-02T01:19:50Z","timestamp":1459559990000},"update-policy":"https:\/\/doi.org\/10.1177\/sage-journals-update-policy","source":"Crossref","is-referenced-by-count":3,"title":["Seasonal variations in calcidiol and parathyroid hormone levels in healthy children and adolescents in Navarre, Spain: a cross-sectional study"],"prefix":"10.1177","volume":"7","author":[{"given":"Teodoro","family":"Dur\u00e1-Trav\u00e9","sequence":"first","affiliation":[{"name":"Department of Pediatrics, Faculty of Medicine, University of Navarra, Pamplona 31008, Spain"},{"name":"Department of Pediatrics, Navarra Hospital Complex, Pamplona, 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