Exposure to ethylene glycol ethers and spermatogenic disorders in man: a case-control study

A case-control study was conducted among first time patients at a clinic for reproductive disorders. The study group consisted of 1019 cases, defined as patients diagnosed infertile or subfertile on the basis of a spermiogram and 475 controls who were diagnosed as normally fertile by the same procedure. Possible exposure to ethylene glycol ethers was assessed by the presence of the urinary metabolites methoxyacetic acid (MAA) and ethoxyacetic acid (EAA) respectively for 2-methoxyethanol and 2-ethoxyethanol or their acetates. In total, EAA was detected in 39 cases and six controls, with a highly significant odds ratio of 3.11 (p = 0.004). On the other hand, MAA was only found in one case and two controls. The presence of EAA in urine proved to be strongly associated with exposure to preparations containing solvents, especially paint products, and with some groups of occupations, the most important of which were also directly or possibly connected with paint products. The absence of a significant correlation between the concentration of urinary EAA and the various measures of sperm quality could be explained by the expected latent period between exposure and observed effects. Other temporal aspects of the relation between exposure as judged from the presence of urinary EAA and diagnosis are also discussed.