Mobile phone use may affect semen quality
While various environmental and lifestyle factors have been proposed to explain the decline in semen quality observed over the last fifty years, the role of mobile phones has yet to be demonstrated.
A team from the University of Geneva (UNIGE), in collaboration with the Swiss Tropical and Public Health Institute (Swiss TPH), has published a major cross-sectional study on the subject.
It shows that frequent use of mobile phones is associated
with a lower sperm concentration and total sperm count. However, researchers
did not find any association between mobile phone use and low sperm motility
and morphology. Read the results in Fertility & Sterility.
Semen quality is determined by the assessment of
parameters such as sperm concentration, total sperm count, sperm motility and
sperm morphology. According to the values established by the World Health
Organization (WHO), a man will most probably take more than one year to
conceive a child if his sperm concentration is below 15 million per milliliter.
In addition, the percentage chance of pregnancy will decrease if the sperm
concentration is below 40 million per milliliter.
Many studies have shown that semen quality has decreased
over the last fifty years. Sperm count is reported to have dropped from an
average of 99 million sperm per millilitre to 47 million per millilitre. This
phenomenon is thought to be the result of a combination of environmental
factors (endocrine disruptors, pesticides, radiation) and lifestyle habits
(diet, alcohol, stress, smoking).
Assessing the impact of mobile phones
Is the mobile phone also to blame? After conducting the
first national study (2019) on the semen quality of young men in Switzerland, a
team from the University of Geneva (UNIGE) has published the largest
cross-sectional study on this topic. It is based on data from 2886 Swiss men
aged 18 to 22, recruited between 2005 and 2018 at six military conscription
centres.
In collaboration with the Swiss Tropical and Public Health Institute (Swiss TPH), scientists studied the association between semen parameters of 2886 men and their use of mobile phones.
''Men completed a
detailed questionnaire related to their lifestyle habits, their general health
status and more specifically the frequency at which they used their phones, as
well as where they placed it when not in use,'' explains Serge Nef, full
professor in the Department of Genetic Medicine and Development at the UNIGE Faculty
of Medicine and at the SCAHT -- Swiss Centre for Applied Human Toxicology, who
co-directed the study.
These data revealed an association between frequent use
and lower sperm concentration. The median sperm concentration was significantly
higher in the group of men who did not use their phone more than once a week
(56.5 million/mL) compared with men who used their phone more than 20 times a
day (44.5 million/mL). This difference corresponds to a 21% decrease in sperm
concentration for frequent users (>20 times/day) compared to rare users
(<1 time>
This inverse association was found to be more pronounced
in the first study period (2005-2007) and gradually decreased with time
(2008-2011 and 2012-2018). ''This trend corresponds to the transition from 2G
to 3G, and then from 3G to 4G, that has led to a reduction in the transmitting
power of phones,'' explains Martin RÖÖsli, associate professor at Swiss TPH.
''Previous studies evaluating the relationship between
the use of mobile phones and semen quality were performed on a relatively small
number of individuals, rarely considering lifestyle information, and have been
subject to selection bias, as they were recruited in fertility clinics. This
has led to inconclusive results,'' explains Rita Rahban, senior researcher and
teaching assistant in the Department of Genetic Medicine and Development in the
Faculty of Medicine at the UNIGE and at the SCAHT, first author and co-leader
of the study.
It doesn't matter where you put your phone
Data analysis also seems to show that the position of the
phone -- for example, in a trouser pocket -- was not associated with lower
semen parameters. ''However, the number of people in this cohort indicating
that they did not carry their phone close to their body was too small to draw a
really robust conclusion on this specific point,'' adds Rita Rahban.
This study, like most epidemiologic studies investigating the effects of mobile phone use on semen quality, relied on self-reported data, which is a limitation. By doing so, the frequency of use reported by the individual was assumed to be an accurate estimate of exposure to electromagnetic radiation. To address this limitation, a study funded by the Federal Office for the Environment (FOEN) was launched in 2023.
Its aim is to
directly and accurately measure exposure to electromagnetic waves, as well as
the types of use -- calls, web navigation, sending messages -- and to assess
their impact on male reproductive health and fertility potential. The data will
be collected using an application that each future participant will download to
their mobile phone. The research team is actively recruiting participants for
this study.
The aim is also to better describe the mechanism of action behind these observations. ''Do the microwaves emitted by mobile phones have a direct or indirect effect? Do they cause a significant increase in temperature in the testes? Do they affect the hormonal regulation of sperm production? This all remains to be discovered,'' concludes Rita Rahban.
