Polybrominated diphenyl ethers in human serum and sperm quality.

Polybrominated diphenyl ethers (PBDEs) are widely used flame retardants; currently, they are identified as ubiquitous environmental contaminants. Several studies indicate that PBDEs might affect male fertility. We present the results of a pilot study on the relationship between human serum PBDEs and sperm quality. The PBDE levels in Japan are comparable to those found in European countries. Strong inverse correlations were observed between the serum concentration of 2,2',4,4',5,5'-hexabromodiphenyl ether and sperm concentration (r = -0.841, p = 0.002) and testis size (r = -0.764, p = 0.01). Extensive studies on the relationship between PBDEs and sperm quality are required.