Semen quality of young men in Switzerland: a nationwide cross‐sectional population‐based study

Abstract

Background Sperm counts have been steadily decreasing over the past five decades with regional differences in the Western world. The reasons behind these trends are complex, but numerous insights indicate that environmental and lifestyle factors are important players. Objective To evaluate semen quality and male reproductive health in Switzerland. Materials and methods A nationwide cross‐sectional study was conducted on 2523 young men coming from all regions of Switzerland, recruited during military conscription. Semen volume, sperm concentration, motility, and morphology were analyzed. Anatomy of the genital area and testicular volume was recorded. Testicular cancer incidence rates in the general population were retrieved from Swiss regional registries. Results Median sperm concentration adjusted for period of sexual abstinence was 48 million/mL. Comparing with the 5th percentile of the WHO reference values for fertile men, 17% of men had sperm concentration below 15 million/mL, 25% had less than 40% motile spermatozoa, and 43% had less than 4% normal forms. Disparities in semen quality among geographic regions, urbanization rates, and linguistic areas were limited. A larger proportion of men with poor semen quality had been exposed in utero to maternal smoking. Furthermore, testicular cancer incidence rates in the Swiss general population increased significantly between 1980 and 2014. Discussion For the first time, a systematic sampling among young men has confirmed that semen quality is affected on a national level. The median sperm concentration measured is among the lowest observed in Europe. No specific geographical differences could be identified. Further studies are needed to determine to what extent the fertility of Swiss men is compromised and to evaluate the impact of environmental and lifestyle factors. Conclusion A significant proportion of Swiss young men display suboptimal semen quality with only 38% having sperm concentration, motility, and morphology values that met WHO semen reference criteria.

Semen endocannabinoids are correlated to sperm quality in a cohort of 200 young Swiss men

“…Samples from 200 young men (age 18-22 years) were sequentially obtained from a large cohort of Swiss conscripts previously described by Rahban et al 26 and by Zufferey et al 25 Sperm samples were analysed in the context of the Swiss national study, 26 The total concentrations of BPA and BPS in urine were determined, and the presence of selected drugs (buprenorphine, paracetamol, oxycodone, fentanyl, tricyclic antidepressants, THC, cocaine, benzodiazepine, amphetamine and morphine/opiates) was screened with an immunological cassette as previously described. 25 Moreover, urinary THC-COOH (an inactive metabolite of THC), used as an indicator of cannabis consumption, was also measured by GC-MS according to a method previously reported.…”

Regional difference in semen quality of young men: a review on the implication of environmental and lifestyle factors during fetal life and adulthood

“…Red dots indicate the cities where the studies were performed and the circle around Switzerland refers to the whole country. The map was adapted from [50] and the sources of data on sperm concentration were extracted from [51][52][53][54][55]56] and as personal communications from J. Axelsson and J. Erenpreiss. Cancer data were obtained from [57].…”

“…Recently, the first study evaluating the semen quality of young men on a national level -and not only on a regional level as previously performed -was published in Switzerland [56]. A total of 2′523 volunteers representative of the male population in the country was evaluated.…”

The Early Life Influences on Male Reproductive Health

“…Another recent report, published in 2015, found that a high proportion of healthy, unselected 20-year-old Caucasian men displayed suboptimal semen quality which did not meet the lower limit of World Health Organization reference ranges for sperm concentration, motility and morphology values [15]. These findings were echoed by a further Swiss study published in 2019 where over 60% of participants displayed suboptimal median sperm concentration [12]. Sperm count is of obvious importance in fertility and reproduction, however recent studies have now demonstrated that poor sperm count is potentially associated with overall lifelong morbidity and mortality, and is effectively a 'canary in the mine' marker for lifelong health risk [14,[16][17][18].…”

“…Increasing concern exists regarding male reproductive health worldwide due to the appearance of medical reports outlining apparent adverse trends, in the context of a worldwide decline in total fertility rate (Figure 1) [9,10]. This includes an increase in the incidence of the proposed 'testicular dysgenesis syndrome' [10] which encompasses a constellation of testicular disorders including testicular cancer, [11,12] cryptorchidism and hypospadias [13]. This is in parallel with population-based evidence to suggest declining semen quality, [14] alterations in serum testosterone levels and a change in the timing of onset of male puberty [9].…”