Lenders Carine M, Feldman Henry A, Von Scheven Emily, Merewood Anne, Sweeney Carol, Wilson Darrell M, Lee Phillip D K, Abrams Stephanie H, Gitelman Stephen E, Wertz Marcia S, Klish William J, Taylor George A, Chen Tai C, Holick Michael F
Boston Medical Center, Boston University School of Medicine, MA, USA.
Am J Clin Nutr. 2009 Sep;90(3):459-67. doi: 10.3945/ajcn.2008.27275. Epub 2009 Jul 29.
Data on the relation between vitamin D status and body fat indexes in adolescence are lacking.
The objective was to identify factors associated with vitamin D status and deficiency in obese adolescents to further evaluate the relation of body fat indexes to vitamin D status and deficiency.
Data from 58 obese adolescents were obtained. Visceral adipose tissue (VAT) was measured by computed tomography. Dual-energy X-ray absorptiometry was used to measure total bone mineral content, bone mineral density, body fat mass (FM), and lean mass. Relative measures of body fat were calculated. Blood tests included measurements of 25-hydroxyvitamin D [25(OH)D], parathyroid hormone (PTH), osteocalcin, type I collagen C-telopeptide, hormones, and metabolic factors. Vitamin D deficiency was defined as 25(OH)D < 20 ng/mL. PTH elevation was defined as PTH > 65 ng/mL.
The mean (+/-SD) age of the adolescents was 14.9 +/- 1.4 y; 38 (66%) were female, and 8 (14%) were black. The mean (+/-SD) body mass index (in kg/m(2)) was 36 +/- 5, FM was 40.0 +/- 5.5%, and VAT was 12.4 +/- 4.3%. Seventeen of the adolescents were vitamin D deficient, but none had elevated PTH concentrations. Bone mineral content and bone mineral density were within 2 SDs of national standards. In a multivariate analysis, 25(OH)D decreased by 0.46 +/- 0.22 ng/mL per 1% increment in FM (beta +/- SE, P = 0.05), whereas PTH decreased by 0.78 +/- 0.29 pg/mL per 1% increment in VAT (P = 0.01).
To the best of our knowledge, our results show for the first time that obese adolescents with 25(OH)D deficiency, but without elevated PTH concentrations, have a bone mass within the range of national standards (+/-2 SD). The findings provide initial evidence that the distribution of fat may be associated with vitamin D status, but this relation may be dependent on metabolic factors. This study was registered at www.clinicaltrials.gov as NCT00209482, NCT00120146.
青春期维生素D状态与体脂指数之间关系的数据尚缺。
确定肥胖青少年维生素D状态及缺乏的相关因素，以进一步评估体脂指数与维生素D状态及缺乏之间的关系。
获取58名肥胖青少年的数据。通过计算机断层扫描测量内脏脂肪组织（VAT）。采用双能X线吸收法测量总骨矿物质含量、骨矿物质密度、体脂肪量（FM）和去脂体重。计算体脂的相关指标。血液检测包括测量25-羟维生素D [25(OH)D]、甲状旁腺激素（PTH）、骨钙素、I型胶原C末端肽、激素和代谢因子。维生素D缺乏定义为25(OH)D < 20 ng/mL。PTH升高定义为PTH > 65 ng/mL。
青少年的平均（±标准差）年龄为14.9 ± 1.4岁；38名（66%）为女性，8名（14%）为黑人。平均（±标准差）体重指数（kg/m²）为36 ± 5，FM为40.0 ± 5.5%，VAT为12.4 ± 4.3%。17名青少年维生素D缺乏，但无人PTH浓度升高。骨矿物质含量和骨矿物质密度在国家标准的2个标准差范围内。多因素分析中，FM每增加1%，25(OH)D降低0.46 ± 0.22 ng/mL（β ± 标准误，P = 0.05），而VAT每增加1%，PTH降低0.78 ± 0.29 pg/mL（P = 0.01）。
据我们所知，我们的结果首次表明，25(OH)D缺乏但PTH浓度未升高的肥胖青少年，其骨量在国家标准范围内（±2个标准差）。这些发现提供了初步证据，表明脂肪分布可能与维生素D状态有关，但这种关系可能取决于代谢因素。本研究在www.clinicaltrials.gov注册，注册号为NCT00209482、NCT00120146。
