Younglai E V, Collins J A, Foster W G
Department of Obstetrics and Gynecology, McMaster University, Health Sciences Centre, Hamilton, Ontario, Canada.
Fertil Steril. 1998 Jul;70(1):76-80. doi: 10.1016/s0015-0282(98)00118-6.
To determine whether sperm quality has declined among Canadian men during the past 13 years and whether there are regional differences in sperm quality.
Retrospective temporal series of cross-sectional studies.
University fertility centers across Canada.
PATIENT(S): Men being investigated as part of the normal infertility work-up.
MAIN OUTCOME MEASURE(S): Sperm concentrations among all the samples were compared on an annual basis to assess any changes over 13 years from 1984 through 1996.
RESULT(S): There were regional differences and trends in both up and down directions. Linear regression analysis of the means of each center for each year showed no significant trend. However, when all the samples were analyzed by regression analysis there was a significant downward trend.
CONCLUSION(S): Linear regression analysis showed a significant downward trend in sperm concentration among 48,968 samples from Canadian men obtained from 1984 through 1996. A significant difference was seen in the mean concentrations between centers, ranging from 48.6 to 104.5 X 10(6)/mL. Secular trends in sperm density are dependent on the statistical method used for analysis.
确定在过去13年中加拿大男性的精子质量是否下降，以及精子质量是否存在地区差异。
横断面研究的回顾性时间序列。
加拿大各地的大学生育中心。
作为正常不孕症检查一部分接受调查的男性。
每年对所有样本中的精子浓度进行比较，以评估1984年至1996年这13年间的任何变化。
存在地区差异以及上升和下降趋势。对每年各中心的均值进行线性回归分析未显示出显著趋势。然而，当通过回归分析对所有样本进行分析时，存在显著的下降趋势。
线性回归分析显示，1984年至1996年从加拿大男性获取的48968个样本中，精子浓度呈显著下降趋势。各中心的平均浓度存在显著差异，范围为48.6至104.5×10⁶/mL。精子密度的长期趋势取决于用于分析的统计方法。
