Global Decline in Male Fertility
The issue of a global decline in male fertility has caused a stir since it was proposed in 1974. Although it remains contentious, recent studies have provided a considerable amount of data suggesting that semen parameters are declining over the years. Key factors potentially causing or contributing to this decrease include obesity, diet, chronic disease, environmental toxins, tobacco, marijuana, and other lifestyle considerations. Even in the face of criticism, we cannot disregard data showing a drop in sperm parameters.
Obesity and Diet
According to the World Health Organization, the global prevalence of obesity has nearly tripled between 1975 and 2016, affecting children and adolescents aged 5-19 significantly. Though related, diet may independently contribute to the decrease in sperm parameters. High-fat diets, in particular, can have substantial adverse effects on sperm number, motility, morphology, and viability. In addition, a high-fat diet has been linked to smaller testes and lower vesicle mass, and most crucially, reduced fertilization success. Recent studies have shown that the Mediterranean diet may decrease the risk of low sperm concentration and total low sperm count while being associated with higher sperm motility.
Chronic Disease and Environmental Toxins
Diabetes affects more than 400 million globally. This count has nearly quadrupled since 1980. A study in humans found that men with either type 1 or 2 diabetes mellitus had lower sperm concentration and progressive mobility than controls. Hypertension has also been connected to lower semen volume, motility, total sperm count, and motile sperm count. In addition, metabolic syndrome, defined as a combination of at least three of the following: low HDL cholesterol, high triglycerides, hyperglycemia, hypertension, and obesity, has been shown to have a relationship with sperm parameters. Several published review articles list environmental toxins like bisphenol A (BPA), cadmium, phthalates, and triclosan and suggest they have potentially harmful effects on sperm parameters.
Tobacco and Marijuana
The prevalence of smoking tobacco has afforded large-scale studies. More than 4,000 chemicals are found in most tobacco products, including heavy metals such as cadmium. The broad consensus is that tobacco smoking is linked with decreased sperm density, motility, viability, morphology, and a reduction in volume. A systematic review of 48 studies concluded that although the field is under researched, marijuana use may be associated with sperm morphological changes and decreased count, viability, motility, and concentration.
Other possible contributing factors include a sedentary lifestyle, stress, and lack of sleep. As always, MCRM Fertility strives to keep you at the forefront of new information as it becomes available. Our team is here to support you and answer any questions or concerns you may have. Read the full review here.