Bonelli Patrizia, Buonocore Ruggero, Aloe Rosalia, Lippi Giuseppe
Laboratory of Clinical Chemistry and Hematology, Academic Hospital of Parma, Parma, Italy.
J Med Biochem. 2016 Apr;35(2):113-117. doi: 10.1515/jomb-2015-0014. Epub 2016 May 9.
The measurement of vitamin D is now commonplace for preventing osteoporosis and restoring an appropriate concentration that would be effective to counteract the occurrence of other human disorders. The aim of this study was to establish whether blood sampling seasonality may influence total vitamin D concentration in a general population of Italian unselected outpatients.
We performed a retrospective search in the laboratory information system of the University Hospital of Parma (Italy, temperate climate), to identify the values of total serum vitamin D (25-hydroxyvitamin D) measured in outpatients aged 18 years and older, who were referred for routine health check-up during the entire year 2014.
The study population consisted in 11,150 outpatients (median age 62 years; 8592 women and 2558 men). The concentration of vitamin D was consistently lower in samples collected in Winter than in the other three seasons. The frequency of subjects with vitamin D deficiency was approximately double in samples drawn in Winter and Spring than in Summer and Autumn. In the multivariate analysis, the concentration of total vitamin D was found to be independently associated with sex and season of blood testing, but not with the age of the patients.
According to these findings, blood sampling seasonality should be regarded as an important preanalytical factor in vitamin D assessment. It is also reasonable to suggest that the amount of total vitamin D synthesized during the summer should be high enough to maintain the levels > 50 nmol/L throughout the remaining part of the year.
目前，测量维生素D对于预防骨质疏松症以及恢复能有效对抗其他人类疾病发生的合适浓度已很常见。本研究的目的是确定采血季节是否会影响意大利未经过筛选的普通门诊患者群体中总维生素D的浓度。
我们在帕尔马大学医院（意大利，温带气候）的实验室信息系统中进行了回顾性检索，以确定2014年全年因常规健康检查前来就诊的18岁及以上门诊患者血清总维生素D（25-羟维生素D）的值。
研究人群包括11,150名门诊患者（中位年龄62岁；女性8592名，男性2558名）。冬季采集的样本中维生素D浓度始终低于其他三个季节。冬季和春季采集的样本中维生素D缺乏患者的频率约为夏季和秋季的两倍。在多变量分析中，发现总维生素D浓度与性别和采血季节独立相关，但与患者年龄无关。
根据这些发现，采血季节应被视为维生素D评估中的一个重要分析前因素。也有理由认为，夏季合成的总维生素D量应足够高，以在一年的剩余时间内维持维生素D水平>50 nmol/L。
