Reproduction Abstracts

The effect of occupation and environment on semen quality is of obvious interest to doctors and their patients. The National Institute for Health and Care Excellence (NICE) suggest that men should be advised about the possible negative effects of: i) some occupations; ii) cigarette smoking; iii) alcohol consumption; iv) tight underwear; v) recreational drugs; and vi) high BMI. However, the evidence that underpins these suggestions is often quite weak, relying on small underpowered studies that inadequately control for confounding variables. By contrast, the Chemicals and Pregnancy Study UK (CHAPS-UK) was a comprehensive investigation of over 2 200 men attending 12 fertility clinics across the UK for their first semen analysis. It used a case-referent design to examine occupational and lifestyle risk factors for low motile sperm concentration (<12 million motile sperm per ml) and low sperm morphology (<4% normal forms). The results suggest that occupational risks for both low motile sperm concentration and/or low sperm morphology include exposure to paint strippers, lead and glycol ethers. By contrast modifiable and non-modifiable lifestyle factors related to low motile sperm concentrations include: i) a history of previous testicular surgery; ii) being in manual work or not working; iii) black ethnicity; iv) wearing of boxer shorts; and v) previous paternity. Lifestyle factors relating to low sperm morphology were: i) sample production in the summer; ii) cannabis use; and iii) sexual abstinence. These data challenge the general guidance given in NICE guidelines and suggest that a revision may be required.