Reproductive scientists have welcomed a Swiss study that found reduced sperm quality is associated with high mobile phone use, but caution against “over-interpreting the findings”.
Declining male fertility is a growing concern. In Australia, about 1 in 20 men have low sperm counts, and a sixth of couples are affected by infertility. Similar numbers are reported globally.
This new study by a team of Geneva-based researchers took place over three sampling periods from 2005-2018, with nearly 3,000 men aged 18-22 participating.
It found high levels of mobile phone use are associated with reduced sperm concentration – a metric quantifying the number of sperm present in 1mL of semen – and total sperm count.
Men who used their phones once a week or less were found to have, on average, about 10 million more sperm/mL than those who used their phones more than 20 times each day – about a 21% difference between the study’s lowest and highest usage groups.
But the results were not uniform among the three study cohorts. The greatest disparity for high-usage participants was found in 2005-07 when 2G telecommunications technology was prevalent. Subsequent study cohorts in 2008-11 and 2012-18 corresponded with the rollout of 3G and 4G infrastructure.
This, says the study’s lead researcher Dr Rita Rahban, could explain why disparities in sperm concentration between groups improved over time.
“With the evolution from 2G to 4G, the radiation exposure might have decreased because the network is more efficient in transmitting data and therefore exposure time is reduced,” says Rahban, who is a reproductive biologist at the University of Geneva.
The study team identified the challenge of tracking the amount of electromagnetic radiation absorbed by a person as a shortcoming of its research. Mobile phone use for the study was obtained from self-reported surveys before participants provided a semen sample for analysis.
“We are conducting a new study where men can download an application on their phones that will allow us to measure more specifically electromagnetic radiation exposure depending on use and position,” says Rahban.
Sperm study cautiously welcomed by reproduction experts
Studies that find associations between variables tend to be treated cautiously by the scientific community, as they don’t show causative relationships.
This study is no different, and Rahban warns against drawing firm conclusions from the data.
However, this investigation has been well received by other reproductive science experts, owing to its large and representative sample, decade-long timescale and the quality of its conduct.
“I have been asked many times over the past decade whether there is any link between mobile phones and male fertility, however, I have been largely unconvinced by the data which has been published to date,” says Professor Allan Pacey, former chair of the British Fertility Society and andrologist at the University of Manchester, UK.
“However, today’s study is a little step forward in the debate because this is a large epidemiological study which appears to have been very well conducted. The study is not perfect, and the authors of it acknowledge that [one of the main criticisms being that mobile phone use was self-reported], but it is a study in the real world – and that is good in my opinion.
“We should be cautious about its interpretation as it only shows an association between mobile phone use and semen quality. We cannot be sure that the mobile phone is not a surrogate marker for another aspect of the men’s lifestyle or occupation.”
Pacey’s views were echoed by Professor Malcolm Sperrin, a medical physicist at the Institute of Physics and Engineering in Medicine.
“The findings certainly stimulate the need for further research,” Sperrin says.
“However, there is a vital need on the part of the ‘lay’ reader to avoid over-interpreting the findings and drawing conclusions that are difficult to justify.”
While reduced sperm concentration was observed in high-frequency phone users, neither sperm motility nor morphology were found to be worse off. Rahban also emphasised that none of the observed groups had a median value below the WHO’s infertility threshold.
“We only looked at semen quality which is an indicator of men’s potential fertility status,” Rahban says.
“In the group of men who frequently used their phones, the median sperm concentration was 44 Mio/mL which is more than 2 times higher than the reference value set by the World Health Organization for men to be considered infertile which is 15 Mio/mL.
“Therefore the risk for men to be infertile because of mobile phone use is low and no impact on sexuality was reported.”
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