Male Reproductive Health: It Matters

01/02/2018 by Campion Fund

One year ago, the Campion Fund began a two- year focus on men’s reproductive health. We did this because we know that the reproductive health of men matters.  Men’s health impacts the health of their children.  Not only does the overall health of a father affect the health of the growth and development of a human embryo and fetus it affects the health of his children in adulthood.  If this is not enough reason to realize that men’s reproductive health matters, consider that the overall health of men throughout their lifetimes is tied to their reproductive health.

By studying a large group of men, scientists report an increase risk of diabetes, heart disease, hypertension, liver and renal disease later in life among men with male factor infertility. (Eisenberg ML et al. Increased risk of incident chronic medical conditions in infertile men. Analysis of United States claims data. Fertil Steril 2016: 105: 629-639.)   In the past it was stated that general health was important to an individual but reproductive health was important to humans as a species.  By demonstrating that infertility may herald later chronic disease, it becomes apparent that reproductive health is very important to an individual and not only to humankind in general. The findings of the quoted study indicate that all men who present with an infertility problem need to be undergo a complete medical evaluation to determine their general health and should receive education regarding risk factors for chronic health problems that might appear in later life.  It is not acceptable for a fertility physician to offer ICSI, (intracytoplasmic sperm injection) in IVF cycles to the forty percent of couples with male factor infertility without conducting a through medical evaluation of the man, a point made by Dr. Matt Coward at the Campion Fund NIEHS Advances in Andrology meeting October 2017.

For decades studies have indicated that sperm counts have been decreasing world-wide.  Since many of these studies had design flaws such as small numbers of enrolled men or inconsistencies in the way sperm was evaluated, or inadequately documented methods, these studies were not fully accepted by the scientific and medical communities.  Now, on November 1, 2017 a report was published in Human Reprod Update, the number one peer-reviewed journal in reproductive biology published by Oxford University Press, indicated that sperm counts of men from Europe, North America, Australia, and New Zealand declined from 1973 to 2011. The authors found a 52.4% decline in sperm concentration in semen and a 59.3% decline in total sperm counts in 42,935 men. 15% of these men had counts low enough to impair fertility. This is a carefully conducted meta-analysis of 185 studies and cannot be ignored. (Levine H, et al. Temporal trends in sperm count: a systematic review and meta-regression analysis. Human Reprod Update 2017:23:646-639). Along with these data on sperm counts there are reports of decreasing testosterone levels in men. (Travison TG et al. A population decline in serum testosterone levels in American Men. J Clin Endocrinol Metab 2007:92: 196-202; Laughlin GA et al. Low serum testosterone and mortality in older men. J Clin Endocrinol Metab 2008:93:68-75).

Do these facts matter? Yes. Testosterone levels in serum of men and decreased sperm counts are a barometer of men’s health. Do we know why this is happening?  Not really. Maternal smoking, exposure to certain chemicals and pollutants during early gestation (about 8 to 10 weeks of pregnancy) impacts the development in utero of a man’s reproductive tract) and is implicated in the reported changes of low sperm counts and lower serum testosterone levels.  Some studies suggest that stress, alcohol, drugs, pesticides, environmental toxin exposure in young boys and men may account for these facts. The number of Sertoli cells in a man’s testes is fixed and is thus an important factor in sperm counts.  Another factor is the time frame of abstinence prior to semen collection to determine sperm counts.  (This factor was accounted for in the Levine report).

Lastly, testicular cancer, the most common cancer in men aged 20-30 is increasing in incidence. It is reported to have increased 50% since 1973. Over 90% of these cancers are germ cell cancers. These cancers appear to be caused by defects that occur during the transition from germ cells to precursor sperm cells in the testes. This fact has received more public interest than the information regarding decreased sperm count or that male factor infertility as a risk factor for later chronic disease.  During the Advances in Andrology meeting mentioned previously, Dr. Blanche Capel reported that a mutation in a gene Dnd1, (dead-end homologue) a gene that is important during the transition from gem cells to sperm precursor cells, prevents germ cells from differentiating into the precursor sperm cells.  She stated that the cells with this mutation remain in the germ cell state as demonstrated by the retention of cell markers NANOG, SOX2 and NODAL The cells proliferate in this undifferentiated state leading to cancer.  This transition is also important in the process of the formation of sperm.  Thus, the mutation of Dnd1 Is also implicated in the problem of low sperm counts.

Male reproductive health does matter.  What is needed now is further excellent research as well as the recruitment of outstanding young investigators to the field. There needs to be increased funding both from the public and private sectors of society for reproductive science teaching and research. But more importantly, there need to be increased public awareness and increased heath education of men as to why they need to pay attention to their reproductive health. Without this public awareness we cannot accomplish the goal of excellent public health and wellness for men and ultimately for all women and children included.