University of Tampere, Tampere, Finland.
Nutr Cancer. 2010;62(1):51-7. doi: 10.1080/01635580903191460.
Knowledge of the stability of serum samples stored in large biobanks is pivotal for reliable assessment of hormone-dependent disease risks. We studied the effects of sample storage time and season of serum sampling on the stability of 25-hydroxy vitamin D (25-OHD) and androstenedione in a stratified random sample of 402 women, using paired sera from the Finnish Maternity Cohort. Serum samples selected were donated between 6 and 24 yr ago. The storage time did not affect serum 25-OHD and androstenedione levels. However, there was a significant mean difference in the 25-OHD levels of sera withdrawn during winter (first sample) vs. during summer (second sample; -18.4 nmol/l, P <or= 0.001). Also at the individual level, there were significant differences in average 25-OHD levels between individuals with the paired sera taken at winter-winter compared with other alternatives (summer-winter, winter-summer, and summer-summer). The androstenedione levels showed no such differences. Long-term storage does not affect serum 25-OHD and androstenedione levels, but sampling season is an important determinant of 25-OHD levels. Stored serum samples can be used to study disease associations with both hormones. However, sampling season needs to be taken into account for 25-OHD by considering matching and stratification and, if possible, serial sampling.
大量生物库中储存的血清样本稳定性的知识对于可靠评估激素依赖性疾病风险至关重要。我们研究了血清取样时间和季节对 25-羟维生素 D（25-OHD）和雄烯二酮稳定性的影响，该研究基于芬兰母婴队列的分层随机样本中的 402 名女性的配对血清。选择的血清样本是在 6 到 24 年前捐赠的。储存时间并未影响血清 25-OHD 和雄烯二酮水平。然而，冬季（第一次采样）与夏季（第二次采样）血清中 25-OHD 水平存在显著的平均差异（-18.4 nmol/L，P <= 0.001）。同样在个体水平上，与其他季节（冬季-冬季、夏季-冬季、夏季-夏季）相比，配对血清取自冬季-冬季的个体 25-OHD 水平的平均差异具有统计学意义。雄烯二酮水平则没有这种差异。长期储存不会影响血清 25-OHD 和雄烯二酮水平，但采样季节是 25-OHD 水平的重要决定因素。储存的血清样本可用于研究两种激素与疾病的关联。但是，需要考虑季节匹配和分层，并且如果可能的话，进行连续采样，以考虑 25-OHD 采样季节。
