The most recent WHO guidelines for assessing sperm parameters with respect to fe
ID: 37562 • Letter: T
Question
The most recent WHO guidelines for assessing sperm parameters with respect to fertility show how certain values have changed significantly during the past 30 years.
A popular view is that human infertility has increased significantly in the past 40 years, in part to due the environmental and lifestyle factors that impact both the male and female fertility. It has been suggested that these factors have had a pronounced and negative affect on birth rates in many developed countries, including US, Europe, and Japan to below replacement values to maintain a constant level.
What specific evidence supports this view but on a local rather than worldwide basis?
Explanation / Answer
EVIDENCES FOR LIFESTYLE FACTOR
Special attention has been devoted to factors such as smoking , alcohal and obesity that are well established as health risks . Other factors like drug use, genital heat stress, psychological stress and use of cellular phones, although they have received much less attention and there effect on semen quality and male fertility is less conclusive evidence.
Smoking
Cigarette smoke is a known somatic carcinogen and cell mutagen. There is also considerable evidence that smoking adversely affect male reproductive health. The impact of cigarette smoking on male fertility been a controversial issue. Some studies did not find relation between smoking and sperm quality or sperm DNA damage while others only found effect on sperm volume. However, methodological issues especially the complexity in adjusting for confounding factors may underlie some of these negative findings. Overwhelmingly, it is now clear that smoking has a harmful effect on human male fertility. Effect of TOBACCO can be observed at both, microscopic and molecular levels. Microscopically there is an effect on the sperm concentration, motility and morphology. At the molecular level there is increased risk of sperm aneuploidy, higher levels of seminal oxidative stress alteration of sperm plasma membrane phospholipids asymmetry and sperm DNA fragmentation. Furthermore, maternal smoking during pregnancy may have an adverse and irreversible effect on semen quality in male descendants besides a higher risk of birth defects and childhood cancers in the offspring.
Alcoholism
Has been associated with reproductive health disturbances such as impotence or testicular atrophy. Spermatogenesis seems to deteriorate progressively with increasing levels of alcohol intake.Chronic alcohol consumption has a detrimental effect on male reproductive hormones and on semen quality.
Obesity
an observation in the Western world is the increased average body mass index (BMI) in the general population that has resulted in an increased prevalence of obesity is very common.some studies have associated lower WHO semen parameters with obesity. In a follow up study in couples enrolled in the Agricultural Health Study in USA, Sallm