Infertility affects approximately one in six couples worldwide. More than half the time, it is the man’s low sperm quality that is to blame. Over the last three decades, sperm quality seems to have declined for no clearly identifiable reason. Theories are running rampant without anyone having the proof to back them up.
Potential Causes
The environment, lifestyle, excess weight or obesity, smoking, alcohol consumption, and psychological stress have all been alternately offered up as potential causes, following low-quality epidemiological studies. Cellphones are not exempt from this list, due to their emission of high-frequency (800-2200 MHz) electromagnetic waves that can be absorbed by the body.
Clinical trials conducted in rats or mice suggest that these waves can affect sperm quality and lead to histological changes to the testicles, bearing in mind that the conditions met in these trials are very far from our day-to-day exposure to electromagnetic waves, mostly via our cellphones.
The same observation can be made about experiments conducted on human sperm in vitro, but changes to the latter caused by electromagnetic waves leave doubts. Observational studies are rare, carried out in small cohorts, and marred by largely conflicting results. Publication bias plays a major role, just as much as the abundance of potential confounding factors does.
Swiss Observational Study
An observational study carried out in Switzerland had the benefit of involving a large cohort of 2886 young men who were representative of the general population. The participants completed an online questionnaire describing their relationship with their cellphone in detail and in qualitative and quantitative terms.
The study was launched in 2005, before cellphone use became so widespread, and this timeline was considered when looking for a link between cellphone exposure and sperm quality. In addition, multiple adjustments were made in the multivariate analyses to account for as many potential confounding factors as possible.
The participants, aged between 18 and 22 years, were recruited during a 3-day period to assess their suitability for military service. Each year, this cohort makes up 97% of the male population in Switzerland in this age range, with the remaining 3% being excluded from the selection process due to disability or chronic illness.
Regardless of the review board’s decision, subjects wishing to take part in the study were given a detailed description of what it involved, a consent form, and two questionnaires. The first focused on the individual directly, asking questions about his health and lifestyle. The second, intended for his parents, dealt with the period before conception.
This recruitment, which took place between September 2005 and November 2018, involved the researchers contacting 106,924 men. Ultimately, only 5.3% of subjects contacted returned the completed documentation. In the end, the study involved 2886 participants (3.1%) who provided all the necessary information, especially the laboratory testing (including a sperm analysis) needed to meet the study objectives. The number of hours spent on a smartphone and how it was used were routinely considered, as was sperm quality (volume, concentration, and total sperm count, as well as sperm mobility and morphology).