The obesity is defined as anomalous or unwarranted fat accumulation in the body which significantly affect human health and it is measured by the concept of body mass index (BMI) expressed as weight (in kilograms) of person divided by the square of height (in metres) of that person. The BMI over 30 is considered obese and BMI between 25 to 30 is considered overweight. According to World Health Organization (WHO) over 1.9 billion adults (39% of men and 40% of women) with age more than 18 years and older were overweight worldwide, of these over 650 million adults became obese in the year 2016 only. Obesity is caused by multiple factors such as inactive lifestyle, uncontrolled diet, reduction in physical activity, bad nutritional habits, stress, junk food and genetic factor.
The obesity alters physical appearance as well as disrupts the hormones balance with in the human body. The obesity is a worldwide health predicament, which encourage the various health disorders such as diabetes, coronary heart disease and sleep apnoea. The various scientific reports reported that the obesity significantly affects fertility and sperm quality in reproductive-age men. Sallmen el. al. repotted that overweight and obese men have 1.5 to 2 times lower sperm counts when compare to the normal men in reproductive age. In the present scenario, artificial reproductive technologies (ART) mainly intracytoplasmic sperm injection (ICSI) is being increasing applied in couples with declined fertility capacity. The later techniques involves injection of a single sperm straight into cytoplasm of an egg for preparation of embryos. The present review focus on how obesity affects the fertility and sperm quality in male along with treatment modalities.
Male Obesity and Infertility - A Close Association
The impact of obesity on male infertility directly leads to hormonal imbalances, increased scrotal temperatures, and indirectly leads to induction of sleep apnea, reduction of physical activity. The hormonal imbalances of obese men causes higher estrogen levels, and lower label of inhibin-B and androgen which are required in optimum concentration during sperm production in men. The obesity can elevate body temperatures, especially around the scrotum causing decreased concentration and motility of sperm, decreased sperm count and raised DNA fragmentation index. The higher BMI in man also causes decreased the sperm movement, sperm quality as a result declined sperm count.
Leptin, an adipocyte-derived hormone that perform an imperative biological task in regulating the capability of food intake, energy expenses, and regulation of reproductive function. When a person become obese, excess of fat storage is there and leptin level becomes higher as compared to its normal level. The brain of human system commands to decrease the food intake and to elevate energy expenses thus the volume of leptin decreases causing deregulation of the reproductive function such as declined intra-testicular testosterone and has a direct negative effect on sperm production and its quality.
Metabolic syndrome is a group of condition that elevate the chances of cardiac disease. This syndrome includes excess body fat and abnormal cholesterol level. This syndrome causes increased scrotal temperatures, reduced sperm concentration and motility, enhanced sperm DNA destruction and impaired spermatogenesis.
Psychological factor plays an important role in individual variability in sexual desire, activity and satisfaction. The later factor deteriorate sexual activity in obese persons, thus obese persons have decreased frequency of sex as compared to non-obese persons. Obesity can therefore influence an individual's sexual capacity, which affect on their overall fertility.
The treatment of obesity related to men infertility can be divided into four parts. The first is lifestyle and nutritional changes, second is pharmacological intervention, third is surgical treatment and last is Assisted Reproductive Technology (ART).
1. Lifestyle and nutritional changes
Lifestyle medication for loss of weight focuses on decreasing energy intake and increasing energy consumption by dietary control, augmenting physical movement using work out and behavioral actions. The dietary control is based on the principle i.e., total intake of calories (energy) should be greater than total calories (energy) consumed. The rate of weight loss is increased when the deference between the total intake of calories and total calories consumed is more. The obesity can be reduced by the choice of healthier foods i.e., increased intake of fruit, vegetables, legumes, nuts and whole grains with simultaneous controlling the energy gain from fat, carbohydrate, protein or alcohol intake.
The enhancement of physical activity through walk, exercise, yoga, swimming, cycling and running etc is crucial for the continuation of weight loss. The yoga and exercise progress the fitness, muscle strength, metabolic health, superiority of life and common wellbeing. The enhancement of physical activity can develop our muscular fitness, cardio-respiratory system, bone and functional health, blood circulation and metabolism reduce the risk of developing several ailments, like stroke, coronary heart disease, diabetes, hypertension, cancer and depression.
The weight loss medicines includes pharmacological drugs or food supplements that reduce or control body weight. The mechanism of weight loss medicines is based on reducing the appetite, altering the absorption ability to nutrients, such as fat in human body and increase the consumption of energy or accelerate burning of fat. The appetite suppressants are a drug or food supplements act on the neurochemical transmitters of the central nervous system (CNS) to reduce food intake. The appetite suppressants reduces the hunger block by absorption of certain nutrients, or increasing the consumption of calories. The examples of appetite suppressants drugs are benzphetamine, diethylpropion, mazindol and phentermine and food supplements are green tea, bitter orange, yohimbine, caffeine found in coffee, tea and dark chocolate. Appetite suppressants should only be taken with advise of doctor as a short term treatment for patients with obesity due to their side effects. The appetite suppressants are useful for control of diet and increasing the physical activity to attain significant weight loss.
Obesity increase the concentration of aromatase enzyme that is restricted in the endoplasmic reticulum of the estrogen-producing cell, responsible for estrogen biosynthesis. The aromatase enzyme transforms androgens into estrogens as a result there is an increased level of estrogen in blood responsible for decreased sperm production and testosterone production. Aromatase inhibitors such as testolactone, anastrazole and letrozole inhibit the function of aromatase enzyme thus decrease the concentration of estrogen and finally increase testosterone level in the body with increased sperm production.
The excess fat accumulation in obese man leads to infertility through elevated scrotal temperature or accumulation of surplus toxin. Scrotal lipectomy is a surgical procedure carried out to remove unwanted fat from scrotum. Around one-fifth of female patients who were previously infertile, subjected to lipectomy for elimination of extra fat were able to attain a productive pregnancy.
The weight loss surgery (Bariatric surgery) is useful for to get rid of obesity by lessening or avoiding segments of the stomach or small intestine. Bariatric surgery is used for severe obesity patient having BMI of 40 or more or in the range of 35 and 40 for persons suffering from diabetes, hypertension, hypercholesterolemia, fatty liver disease and persons who are unable to lose sufficient weight after food adjustment and pharmacological treatment. Bariatric surgery can be classified into three classes based on types of operations, first is laparoscopic adjustable gastric band, second is gastric sleeve surgery and last is gastric bypass. The first and third approaches are very helpful in the management of morbid obesity and its comorbid states. The scientific reports on bariatric surgery has disclosed that noteworthy decline in estrogen level, augmentation of testosterone level and more importantly normal level of other hormone were observed in patients, who undergone vertical banded gastroplasty.
4. Assisted reproductive techniques
Assisted reproductive treatment (ART) helps in achieving a pregnancy through management of eggs and sperm and/or embryos. The ART covers a wide spectrum of treatments such as In vitro fertilization (IVF), Intrauterine insemination (IUI) and Intracytoplasmic sperm injection (ICSI). The typical procedure of IVF comprises of collection of egg from ovaries and their fertilization with sperm under favorable conditions in laboratory. This fertilized egg or embryo is then placed in uterus. IUI comprises of placing washed and concentrated sperms within a woman's uterus (at the time when ovary release the egg) for assisting the embryo formation. ICSI involves injection of sperm directly into the cytoplasm of an egg for the formation of gamete to attain an embryo. This embryo is then placed in uterus of woman for achieving the pregnancy. This method is valuable especially in the case when sperm count in men in too low to achieve natural conception.
The obesity of men causes hormonal imbalances, increased scrotal temperatures leading to decreased concentration and motility of sperm, reduced total sperm count and elevated DNA fragmentation index thus lowering the sperm count with infertility in man. The treatment of obesity related men infertility can be achieved by lifestyle and nutritional changes, pharmacological intervention, surgical treatment and assisted reproductive technology.