H Fisch1, E T Goluboff. 1. Department of Urology, Squier Urologic Clinic, Columbia-Presbyterian Medical Center, New York, New York 10028, USA.
Abstract
OBJECTIVE: To determine whether geographic variations in sperm counts might bias conclusions drawn from studies of semen quality. DESIGN: Reanalysis of published data from a meta-analysis of 61 studies from 1938 to 1990 that concluded a worldwide decline in semen quality over the last 50 years. MAIN OUTCOME MEASURES: Influence of geographic location on sperm counts. RESULTS: Of 61 studies in the meta-analysis, only 20 included > or = 100 men. These 20 studies collectively comprised 91% of the total men studied. We focused our reanalysis on these 20 studies. Of the studies before 1970, all were from the United States and 80% were from New York. These studies represented locations with the highest sperm counts. In contrast, after 1970, 80% of the studies were from locations not represented earlier, including five studies from third world countries, where sperm counts were low. CONCLUSIONS: Sperm counts vary dramatically among different geographic locations.
OBJECTIVE: To determine whether geographic variations in sperm counts might bias conclusions drawn from studies of semen quality. DESIGN: Reanalysis of published data from a meta-analysis of 61 studies from 1938 to 1990 that concluded a worldwide decline in semen quality over the last 50 years. MAIN OUTCOME MEASURES: Influence of geographic location on sperm counts. RESULTS: Of 61 studies in the meta-analysis, only 20 included > or = 100 men. These 20 studies collectively comprised 91% of the total men studied. We focused our reanalysis on these 20 studies. Of the studies before 1970, all were from the United States and 80% were from New York. These studies represented locations with the highest sperm counts. In contrast, after 1970, 80% of the studies were from locations not represented earlier, including five studies from third world countries, where sperm counts were low. CONCLUSIONS: Sperm counts vary dramatically among different geographic locations.
Authors: Michael F Costello; Peter Sjoblom; Youala Haddad; Stephen J Steigrad; Edward G Bosch Journal: J Assist Reprod Genet Date: 2002-06 Impact factor: 3.412