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Pindara Private Hospital Magazine - Issue Two

Men ’s health abigger issue Obesity and infertility in men A n increasingly sedentary lifestyle and unfavourable diet in the western world are creating an epidemic of overweight and obese children and adults with associated cardiac and endocrine problems, but it seems the consequences of our overindulgence are wider reaching, with research now linking obesity in males to the higher incidence of infertility. Obesity’s effects on the cardiovascular system and type 2 diabetes are well documented and understood from a medical perspective, however, over the past 50 years, medical researchers have also noted that the increasing rate of obesity in males has been paralleled by a decline in semen quality and male reproductive potential. While the mechanisms for obesity’s effects in men are not fully understood, it is thought changing hormone profiles, sleep apnoea and even increasing scrotal temperatures are all affected by obesity and these conditions in turn are either directly or indirectly impairing semen parameters (decreased total sperm count, concentration and motility and increased DNA fragmentations index) and male fertility. In a search for an explanation, researchers have narrowed their focus on obesity’s direct and indirect effects on aromatase overactivity. Sound complicated? Well, it is complicated, but a simple explanation goes something like this: Fat or adipose tissue plays a bigger, more influential role in the body than simply making a person’s body bigger. The amount of fat and the size of the adipocytes (fat cells) have been found to cause physical and hormonal changes in obese men. How this happens is thought to be due to a negative feedback mechanism that can be tracked back to the aromatase overactivity of adipose tissue. Obese men have larger amounts of adipose tissue (fat tissue). Most obese men seeking infertility treatment present with a decreased ratio of testosterone to oestrogen. Researchers have attributed these low levels of testosterone to the overactivity of the aromatase cytochrome P450 enzyme. This enzyme is expressed in high levels in white adipose tissue – (the more fat, the more enzyme). This enzyme happens to be key to the biosynthesis of oestrogens and indeed it actually converts testosterone into oestrogens – (the more fat, the more enzyme: the more enzyme, the higher the levels of oestrogen). Elevated levels of oestrogen disrupt the normal oestrogen to testosterone ratio, and it is this decreased testosterone to oestrogen ratio that has been shown to have a deleterious impact on sperm production and male fertility. Researchers also found that white adipocytes (fat cells) secrete a number of protein hormones; and the discovery of a specific protein hormone, leptin, provided further evidence that white adipose tissue also acts as an active endocrine organ. Why is this important? Leptin is involved in normal sexual maturation and reproduction. White adipose tissue is the main site of leptin synthesis. Excessive fat accumulation results in higher circulation levels of leptin than non-obese individuals. Excess levels of leptin have a deleterious effect on sperm production and the production of androgens. The flow on effects of obesity on male fertility reach further. Obesity has a well-documented direct link to diabetes. Almost 80% of men with type 2 diabetes are obese. Resistin is an adipose-tissue-specific factor that induces insulin resistance. The more adipose tissue the more resistin is secreted. As a consequence of this insulin resistance, patients with type 2 diabetes have high circulation levels of insulin (hyperinsulinemia). This has an inhibitory effect on normal sperm production. So we see, fat is interfering with sperm production and male fertility on multiple levels; however, its effects can also be quite simple and more direct - we look again to our abundant lifestyle for clues. Toxins are a by-product of our high consumption lifestyles. Most environmental toxins are soluble in fat and therefore accumulate in fatty tissue. Morbidly obese males have been found to have excess scrotal fat; this fat is thought to have a localised effect on sperm production. How? Well, it turns out that toxins are endocrine disrupters in male fertility – if fatty tissue and therefore toxins accumulate around the scrotum and testes, the toxins can disrupt normal reproduction hormone profiles thus making obesity and environmental toxins possible co-contributors to fertility problems in obese men. Sleep apnoea is a condition that is often diagnosed in diabetic and obese men. It is due to fragmented sleep as a result of repeated episodes of upper airway obstructions and hypoxia. Patients with sleep apnoea have disrupted nightly rises in testosterone levels, which translate into lower mean levels of testosterone. It is thought this causes abnormal sperm production and impairs male reproduction potential. Similarly, patients who are overweight or obese make up to 70% of men who report erectile dysfunction and decreased libido. Many studies have found hormonal dysfunction connects obesity to erectile dysfunction. Erectile dysfunction is highly prevalent in men with both type 2 diabetes and obesity. The multifaceted relationship between obesity and male infertility involves multiple mechanisms and interrelationships. Excess body weight can impair the hormonal feedback regulation in more ways than one, and the resulting effects on semen parameters are complex and dynamic. It is possible that in every obese infertile male there is a unique combination or mechanism in play that is contributing to their fertility issues. The good news is that weight loss, gastric bypass surgery and the management of hormonal imbalance might prove useful interventions in the reversal of obesity induced infertility but this another story. Pindara Magazine 38 Autumn - Winter | 2014


Pindara Private Hospital Magazine - Issue Two
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