CANADIAN SEMEN QUALITY - AN ANALYSIS OF SPERM DENSITY AMONG 11 ACADEMIC FERTILITY CENTERS

Objective: To determine whether sperm quality has declined among Canad ian men during the past 13 years and whether there are regional differ ences in sperm quality. Design: Retrospective temporal series of cross -sectional studies. Setting: University fertility centers across Canad a. Patient(s): Men being investigated as part of the normal infertilit y work-up. Main Outcome Measure(s): Sperm concentrations among all the samples were compared on an annual basis to assess any changes over 1 3 years from 1984 through 1996. Result(s): There were regional differe nces and trends in both up and down directions. Linear regression anal ysis of the means of each center for each year showed no significant t rend. However, when all the samples were analyzed by regression analys is there was a significant downward trend. Conclusion(s): Linear regre ssion analysis showed a significant downward trend in sperm concentrat ion among 48,968 samples from Canadian men obtained from 1984 through 1996. A significant difference was seen in the mean concentrations bet ween 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 analys is. (Fertil Steril(R) 1998;70:76-80. (C)1998 by American Society for R eproductive Medicine.).