Obese men have less semen, more sperm abnormalities, and should lose weight before trying ...( This release is available in A HREF h...)

Obese men should consider losing weight if they want to have children, a scientist told the 24th annual conference of the European Society of Human Reproduction and Embryology today (Wednesday 9 July). Dr. A Ghiyath Shayeb, from the University of Aberdeen, Aberdeen, UK, said that his research had shown that men with a higher body mass index (BMI) had lower volumes of seminal fluid and a higher proportion of abnormal sperm.

Dr. Shayeb and colleagues looked at the results of seminal fluid analysis in 5316 men attending Aberdeen Fertility Centre with their partners for difficulties in conceiving. 2037 of these men had complete data on their BMIs. "We felt that it was possible that male overweight might contribute to fertility problems," he said, "particularly since it is a known risk factor for problems in conceiving among women."

The scientists divided the men into four groups according to their BMI, from being underweight to being considerably overweight. Taking into account other characteristics that could confound the analysis, such as smoking, alcohol intake, age, social deprivation, and the length of time of abstinence from sex prior to producing a semen sample for analysis, they looked for a relationship between BMI and semen quality. The analysis showed that the men in Group B, who had an optimal BMI (20-25, as classified by WHO), had higher levels of normal sperm than those in the other groups. They also had higher semen volume. There was no significant difference between the four BMI groups in sperm concentration or motility.

The researchers did not look at DNA damage in the sperm, preferring to look at the parameters of the routine semen analysis, which all men attending the fertility centre will have at least once. "Other studies have suggested an association between male obesity and incre
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