Obesity and diabetes may be linked with male infertility

Two studies presented at the annual European Society of Human Reproduction and Embryology conference in Barcelona have contributed new research findings into male infertility by examining the relationships between obesity and diabetes, and sperm quality.

Studying the link between obesity and sperm quality, researchers from the University of Aberdeen examined the medical records of over 2,000 men who had attended the Aberdeen Fertility Clinic and grouped the men according to their body mass index (BMI). Taking into account other factors associated with infertility, such as age and social factors like smoking and alcohol intake, the researchers then analysed the correlation between BMI and sperm quality. The findings revealed that males with a high BMI tended to have a lower volume of sperm and higher number of abnormalities in their sperm than those possessing the recommended BMI. Dr A Ghiyath

Shayeb, who led the study, said: 'Our findings were quite independent of any other factors, and seem to suggest that men who are trying for a baby with their partners should first try to achieve an ideal body weight.'

In a separate study researchers at Queen's University, Belfast, analysed the DNA taken from eight males with type-1 diabetes and found genetic abnormalities in their sperm of sufficient severity to reduce its ability to fertilise an egg. 'We have shown for the first time that diabetes adversely influences male fertility at a molecular level,' said Dr Con Mallidis, who headed the study at Queen's. The findings are also applicable to type-2 diabetes, claim the researchers.

Around of a quarter of British males and females are obese and levels are on the increase. 'The bigger the problem we have with obesity, the bigger it will be with fertility,' said Dr Shayed. The number of diabetics is also rising, with the prevalence increasing from 2 per cent in 1991 to over 4 per cent in 2003. There is a strong link between obesity and type-2 diabetes. 'There is massive growth in diabetes and obesity, and concern about fertility rates, and we asked is there a connection. It is not a coincidence,' said Dr Mallidis.

Neil McClure, Professor of Obstetrics and Gynaecology at Queen's University, said that the studies revealed how male fertility can be affected by factors associated with health and fitness. 'For too long the role of general health in male fertility has been ignored,' he said, 'now, those working in this area must give greater consideration to the male and to ensuring that he is in peak physique and health to maximise the couple's chances of successful conception...' The team from Aberdeen will now look into the correlation between reduced sperm quality and infertility, in addition to studying how obesity specifically affects sperm production.