Rabufetti, Andrea Milani, Gregorio P. Lava, Sebastiano A. G. Edefonti, Valeria Bianchetti, Mario G. Stettbacher, Andreas Muggli, Franco Simonetti, Giacomo 2019-11-11 Background: Poor vitamin D status is a worldwide health problem. Yet, knowledge about vitamin D status among adolescents in Southern Europe is limited. This study investigated concentrations and modulating factors of vitamin D in a healthy population of male late adolescents living in Southern Switzerland. Methods: All apparently healthy subjects attending for the medical evaluation before the compulsory military service in Southern Switzerland during 2014-2016 were eligible. Dark-skin subjects, subjects on vitamin D supplementation or managed with diseases or drugs involved in vitamin D metabolism were excluded. Anthropometric measurements (body height, weight, fat percentage, mid-upper arm and waist circumference) and blood sampling for total 25-hydroxy-vitamin D, total cholesterol and ferritin concentrations testing, were collected. Participants filled in a structured questionnaire addressing their lifestyle. Characteristics of the subjects with adequate (≥50 nmol/L–≤250 nmol/L) and insufficient (<50 nmol/L) vitamin D values were compared by Kruskal-Wallis test or χ2 test. Odds ratios for 25-hydroxy-vitamin D insufficiency were calculated by univariate and AIC-selected multiple logistic regression models. Results: A total of 1045 subjects volunteered to participate in the study. Insufficient concentrations of vitamin D were detected in 184 (17%). The season of measurement was the most significant factor associated with vitamin D levels and approximately 40% of subjects presented insucient vitamin D concentrations in winter. After model selection, body fat percentage, frequency and site of recreational physical activity, and the seasonality were significantly associated with the risk of vitamin D insufficiency. Conclusions: Among healthy male late adolescents in Southern Switzerland, about one every fourth subject presents a poor vitamin D status in non-summer seasons. Body fat percentage, frequent and outdoor recreational physical activity are modulating factors of vitamin D status in this population. application/pdf https://n2t.net/ark:/12658/srd1319190 https://susi.usi.ch/global/documents/319190 https://susi.usi.ch/documents/319190/files/Rabufetti_N_2019.pdf eng info:eu-repo/semantics/altIdentifier/doi/10.3390/nu11112727 info:eu-repo/semantics/altIdentifier/ark/12658/srd1319190 info:eu-repo/semantics/openAccess CC BY Nutrients. - 2019, vol. 11, no. 11, p. 2727 Macronutrients Sunlight Physical activity Season Body composition info:eu-repo/classification/udc/61 Vitamin D status among male late adolescents living in southern Switzerland : role of body composition and lifestyle http://purl.org/coar/resource_type/c_6501