Case-control study of leatherwork and male infertility

Objectives-To test the hypothesis that leatherwork is associated with male infertility mediated through the development of oligozoospermia. The basis of any association was postulated, at the outset, to be with exposure to th e solvents used in leatherwork. Methods-All new referrals with infertility presenting in Leicestershire hos pital clinics between November 1988 and September 1992 and Kettering Distri ct General Hospital from August 1990 were eligible to participate; 88.5% ag reed to be interviewed. Exposure to leatherwork and work with solvents was defined by job title. Comparisons were made with fertile controls and in an analysis within men from infertile couples with oligozoospermia as the pri mary outcome. Effects on sperm motility and deformity were investigated sec ondarily. Analyses used logistic regression for binary outcomes and multile vel modelling for continuous outcomes. Results-1906 men were interviewed. Compared with the fertile controls the m en from infertile couples were 1.10 times (95% confidence interval (95% CI) 0.46 to 2.63; p=0.99) more likely to be leatherworkers and 1.73 times (95% CI 1.26 to 2.38; p<0.001) more likely to work with solvents. Compared with other men, leatherworkers were 1.20 times (95% CI 0.43 to 3.33; p=0.73) mo re likely to present with oligozoospermia and 1.65 times (95% CI 0.37 to 7. 30; p=0.51) more likely to present with teratozoospermia. Being a leatherwo rker was associated with only a 6% reduction in sperm concentration; motili ty and deformity were similarly unaffected by this exposure. Work with solv ents did not statistically, nor clinically, increase the risk of oligozoosp ermia, teratozoospermia, or asthenozoospermia. Conclusions-There was little evidence to support the hypothesis that leathe rwork is associated with an increased risk of presenting with infertility o r oligozoospermia. There was limited evidence that leatherwork is a risk fa ctor for teratozoospermia. Workers with solvents were at an increased risk of presenting with infertility, although this was not mediated through effe cts on standard measures of semen quality; this finding merits further inve stigation.