Research Centre for Prevention and Health, Glostrup University Hospital, DK-2600 Glostrup, Denmark.
Bone. 2012 Mar;50(3):605-10. doi: 10.1016/j.bone.2011.12.016. Epub 2011 Dec 30.
Danish legislation regarding food fortification has been very restrictive and vitamin D deficiency is thought to be common in Denmark due to inadequate dietary intakes and the fact that in Denmark (latitude 56°N) vitamin D is only synthesized in the skin after exposure to solar radiation during summertime (April-September). The purpose of this study was to evaluate the vitamin D status of a general adult population in Denmark and, in addition, associations between vitamin D status and distinct lifestyle factors were studied.
A random sample of 6784 persons from a general population aged 30-60 years participated in a health examination in 1999-2001. Serum samples from all participants were stored and levels of 25-hydroxyvitamin D (25(OH)D) were measured by HPLC in 2009. The method was compared to another HPLC method. Information on dietary intake of vitamin D and other lifestyle factors were obtained by questionnaires. A total of 6146 persons defined as ethnic Danes and with successful measurements of 25(OH)D were included in the analyses.
The overall prevalence of vitamin D deficiency (25(OH)D<25 nmol/l) and insufficiency (25(OH)D<50 nmol/l) were 13.8% and 52.2%, respectively. A marked seasonal fluctuation was seen in serum levels of 25(OH)D - median values of 25(OH)D were lowest in February and highest in August. In multiple logistic regression models (n=5506), low vitamin D status was significantly associated with obesity (BMI≥30), daily smoking and a sedentary lifestyle. However, measurements of 25(OH)D were not associated with the estimated dietary intake of vitamin D. Comparison of two HPLC methods demonstrated considerable differences in accuracy.
Our results suggest that poor vitamin D status is common among adults in a Northern European country without food fortification with vitamin D. Methodological issues are, however, of great importance when using cut-off values to define poor vitamin D status. In addition, we demonstrated that low serum levels of 25(OH)D were associated with several lifestyle factors.
丹麦的食品强化法规非常严格，由于膳食摄入不足以及在丹麦（纬度 56°N）只有在夏季（4 月至 9 月）暴露在太阳辐射下才能在皮肤中合成维生素 D，因此人们认为丹麦的维生素 D 缺乏很常见。本研究的目的是评估丹麦普通成年人群的维生素 D 状况，并研究维生素 D 状况与不同生活方式因素之间的关系。
1999-2001 年，从 30-60 岁的一般人群中抽取 6784 人作为随机样本参加健康检查。所有参与者的血清样本均被储存起来，并于 2009 年通过 HPLC 测量 25-羟维生素 D（25（OH）D）水平。该方法与另一种 HPLC 方法进行了比较。通过问卷调查获得了维生素 D 及其他生活方式因素的饮食摄入量信息。在分析中，共纳入了 6146 名被定义为丹麦族裔且 25（OH）D 测量成功的人。
维生素 D 缺乏（25（OH）D<25 nmol/l）和不足（25（OH）D<50 nmol/l）的总体患病率分别为 13.8%和 52.2%。血清 25（OH）D 水平呈明显季节性波动——2 月时中位数最低，8 月时最高。在多因素逻辑回归模型（n=5506）中，低维生素 D 状态与肥胖（BMI≥30）、每日吸烟和久坐不动的生活方式显著相关。然而，25（OH）D 的测量结果与维生素 D 的估计膳食摄入量无关。两种 HPLC 方法的比较表明，准确性存在很大差异。
我们的研究结果表明，在没有维生素 D 强化食品的北欧国家，成年人的维生素 D 状态较差较为常见。然而，当使用临界值来定义维生素 D 状态较差时，方法学问题非常重要。此外，我们还证明，25（OH）D 血清水平较低与多种生活方式因素有关。
