Division of Clinical Epidemiology and Aging Research, German Cancer Research Center (DKFZ), 69120 Heidelberg, Germany.
Medical Faculty Heidelberg, Heidelberg University, 69120 Heidelberg, Germany.
Nutrients. 2021 Nov 9;13(11):3982. doi: 10.3390/nu13113982.
serum 25-hydroxyvitamin D (25(OH)D) ("total 25 OH(D)") is the most commonly used indicator of vitamin D status. However, 25(OH)D is mostly bound to the vitamin D binding protein (VDBP) or albumin in blood, and it has been suggested that the remaining bioavailable or free 25(OH)D may be more relevant for vitamin D associated health outcomes. We aimed to explore distributions and determinants of VDBP, total, bioavailable, complementary "non-bioavailable", and free 25(OH)D in a large cohort of older adults in Germany.
total 25(OH)D, VDBP, and albumin concentrations were measured in blood samples of 5899 men and women aged 50-75 years and used to calculate bioavailable (and complementary "non-bioavailable") and free 25(OH)D concentrations. Linear regression models were used to evaluate associations of potential determinants of the various vitamin D biomarkers.
mean concentrations of VDBP, total, non-bioavailable, bioavailable, and free 25(OH)D were 323.6 µg/mL, 49.8 nmol/L, 43.4 nmol/L, 2.5 ng/mL, and 5.7 pg/mL, respectively. Seasonal variations were observed for all markers, with peak values in spring for VDBP and in summer for total, non-bioavailable, bioavailable, and free 25(OH)D. Consistent inverse associations were seen with age and body mass index for all markers, but divergent associations were seen with C-reactive protein. Strong variations by VDBP genotypes were seen for bioavailable and free 25(OH)D, and, in opposite direction for non-bioavailable 25(OH)D.
commonalities and differences in determinants of various markers of vitamin D status were observed, which may help to enable a better understanding of their potential role for various vitamin D related health outcomes.
血清 25-羟维生素 D（25（OH）D）（“总 25 羟维生素（D）”）是最常用的维生素 D 状态指标。然而，25（OH）D 主要与维生素 D 结合蛋白（VDBP）或血液中的白蛋白结合，并且有人提出，剩余的生物可利用或游离 25（OH）D 可能与维生素 D 相关的健康结果更相关。我们旨在探索德国一个大型老年人群中 VDBP、总、生物可利用、互补“非生物利用”和游离 25（OH）D 的分布和决定因素。
测量了 5899 名 50-75 岁男性和女性的血液样本中的总 25（OH）D、VDBP 和白蛋白浓度，并用于计算生物可利用（和互补“非生物利用”）和游离 25（OH）D 浓度。线性回归模型用于评估各种维生素 D 生物标志物的潜在决定因素的关联。
VDBP、总、非生物利用、生物利用和游离 25（OH）D 的平均浓度分别为 323.6 µg/mL、49.8 nmol/L、43.4 nmol/L、2.5 ng/mL 和 5.7 pg/mL。所有标志物均观察到季节性变化，VDBP 的峰值在春季，总、非生物利用、生物利用和游离 25（OH）D 的峰值在夏季。所有标志物与年龄和体重指数呈一致的负相关，但与 C 反应蛋白呈相反的关联。VDBP 基因型对生物利用和游离 25（OH）D 的变化很大，而对非生物利用 25（OH）D 的变化则相反。
观察到各种维生素 D 状态标志物的决定因素的异同，这可能有助于更好地理解它们对各种维生素 D 相关健康结果的潜在作用。
