Overweight and obese men are more prone to infertility
The most significant contribution to the rise in obesity is thought to be the changes in behaviour and environment seen in modern society as a result of technological advances.
Updated: May 28, 2014, 05.37 PM IST
By Dr Abhishek S. Parihar
Obesity may be defined as a body mass index (BMI) of 30 or higher. It is a medical condition in which excess body fat accumulates up to the extent that the health of the individual becomes negatively affected, potentially reducing life expectancy. Most people are conscious that obesity alters one's physical appearance but are unaware that it also disrupts the delicate balance of hormones inside the body. One such health condition is infertility. While physicians have been aware of the negative impact of obesity on a woman's fertility, more recently they are discovering that the male partner's weight can also cause problems in conceiving.
Obesity is becoming increasingly common in both men and women in India and exerts significant financial pressure on health care systems. A combination of an increasingly sedentary lifestyle and unfavorable diet has resulted in increasing numbers of overweight and obese children and adults. According to the WHO, approximately 1.6 billion adults were classed as being overweight and 400 million adults were obese in 2005.2 statisticians have predicted that, by 2015, approximately 2.3 billion adults will be overweight and 700 million will be obese.
Obesity in women is known to contribute to anovulation, a reduced conception rate and an increased risk of miscarriage and prenatal complications. Furthermore, weight loss in anovulatory women restores fertility and increases the likelihood of ovulation and conception. . Male obesity has also been shown to lower sperm count, to cause significant hormonal imbalances, to increase the temperature surrounding the scrotum, and to decrease a man's overall sex drive. Obese men produce sperm which has fragmented DNA-in other words, the sperm quality is negatively affected and can both lessen fertility and increase the risk of abortion as well.
Obesity is usually caused by multiple factors and the genetic make-up of a person may be responsible for developing the condition. The most significant contribution to the rise in obesity is thought to be the changes in behaviour and environment seen in modern society as a result of technological advances. In particular, the reduction in physical activity levels is a major contributing factor in the development of the disease. Bad nutritional habits, stress, junk food and other factors contribute day after day to a dramatic explosion of obesity.
Many health conditions are associated with obesity. Well-known conditions include type 2 diabetes, coronary heart disease and sleep apnoea. It is now clear that obesity is associated with a general decline in overall fertility, with a significant relationship existing between excess body fat and problems with reproduction.
How does obesity affect male fertility?
Men who are significantly overweight can suffer alterations in sleep behaviors, sexual behaviors, hormonal profiles, scrotal temperatures and the quality of semen. Elevated temperatures within the scrotum, due to more fat tissue, harm sperm cells. Obese people often tend to reduce physical efforts and this is why a decrease in testosterone production is clearly noticed in people suffering from overweight. Obese males also suffer from higher than normal levels of estrogen because fat tissue converts male hormones such as testosterone into the female hormone estrogen. These elevated estrogen levels in men tend to suppress fertility because they prevent the synthesis of testosterone (hormones required for the development and maintenance of normal male reproductive function).
Leptin is a protein produced by fatty tissue that plays an important role in controlling food intake and energy expenditure, as well as the regulation of reproductive function. When fat stores and hence leptin levels are high, the brain acts to decrease food intake and to increase energy expenditure. Excess leptin decreases Leydig cell function (decreased intra testicular testosterone) and has a direct negative effect on sperm. Leptin therefore plays an important role in the relationship between obesity and fertility.
In addition, metabolic syndrome, a condition that can arise from obesity, is also associated with symptoms of erectile dysfunction, hence compounding the adverse effects obesity has on fertility. Nearly 80% of men with type 2 diabetes are also obese, and this insulin resistance can inhibit normal sperm development and causes DNA changes in sperm cells leading to decrease in fertility. These negative DNA changes cause lower pregnancy rates, a higher risk of miscarriage, and can lead to some serious birth defects.
Psychological factors worsen the things in obese individuals Psychological factors include a decreased sex drive and increased sexual dysfunction, which can lead to obese individuals not having sexual intercourse as frequently as non-obese people, even if they are living with a sexual partner within a relationship. Obesity can therefore affect a person's sexuality, which impacts on their overall fertility.
How does treating obesity affect fertility?
The treatment for obesity related infertility in men must include a focused approach towards treating obesity itself. Weight loss, gastric bypass surgery and the management of hormonal imbalance might prove useful interventions in the reversal of obesity-induced infertility.
Obese men showed increases in sex hormone binding globulin and testosterone after a very low-energy diet. Studies have shown that weight loss through bariatric surgery was associated with correction of the abnormal hormonal profile in obese men with an increase in SHBG and total testosterone levels and reduction in estradiol levels. Weight loss improves fertility in obese people both physiologically and psychologically. It is often the first step in fertility treatment when an obese patient seeks help from assisted reproductive technology (ART).
Recent data confirm that in infertile couples, obesity is associated with reduced male fertility. The effect of obesity on male infertility seems to be modest. However, with increasing incidence of obesity, it is expected that the number of obese men with reduced fertility will increase as well. Various hormonal changes associated with obesity are responsible for the alteration in sperm parameters and sexual dysfunction. In obese males, evidence suggests that increased estrogen as a result of aromatization in the fatty tissue may be an important mechanism for reduced androgen levels and altered sperm parameters. There is evidence that weight reduction can correct this hormonal imbalance.
(The author is an Infertility and IVF specialist; he can be contacted at email@example.com)
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