biostudies-literatureUnknown81(2)Montiel-Ojeda D<h4>Introduction</h4>Vitamin D deficiency is associated with bone metabolism and immune disorders. Radiation's seasonal variation affects vitamin D status more at the poles. In Mexico, near the equator, there have been reports of 10-20% vitamin D deficiency in children. There is no consensus on the definition of vitamin D deficiency, different organizations consider that a vitamin D level should be above 20-30 ng/mL. This study aimed to analyze vitamin D serum concentrations in children and adolescents from Mexico City and the Metropolitan Area (MA) during different seasons.<h4>Methods</h4>Cross-sectional study in children and adolescents aged 5-20 years from Mexico City and Metropolitan Area, from autumn 2016 to winter 2017. Variables of interest such as anthropometric measurements, food Annals of nutrition & metabolism61-67https://www.ebi.ac.uk/biostudies/studies/S-EPMC12011372biostudies-literatureSeasonal Differences of 25-Hydroxyvitamin D Concentrations in Children and Adolescents from Mexico City and Metropolitan Area.PMC12011372Lopez-Gonzalez DClark PMendez Sanchez LMontiel-Ojeda DGuagnelli MAfalseSeasonal Differences of 25-Hydroxyvitamin D Concentrations in Children and Adolescents from Mexico City and Metropolitan Area.<h4>Introduction</h4>Vitamin D deficiency is associated with bone metabolism and immune disorders. Radiation's seasonal variation affects vitamin D status more at the poles. In Mexico, near the equator, there have been reports of 10-20% vitamin D deficiency in children. There is no consensus on the definition of vitamin D deficiency, different organizations consider that a vitamin D level should be above 20-30 ng/mL. This study aimed to analyze vitamin D serum concentrations in children and adolescents from Mexico City and the Metropolitan Area (MA) during different seasons.<h4>Methods</h4>Cross-sectional study in children and adolescents aged 5-20 years from Mexico City and Metropolitan Area, from autumn 2016 to winter 2017. Variables of interest such as anthropometric measurements, food 2025-01-01T00:00:00Z20252025-07-07T03:10:02.086Z2025-07-07T03:10:02.086ZS-EPMC120113723951004910.1159/000542467