Cell Phones Affect on Male Fertility is Questionable

^{doi.org/10.1093/humrep/deab001}

Background

Studies show that men in general have experienced a slow decline in sperm count and concentration. However, due to a limited number of well-designed studies, experts are still debating the various causes.

Nevertheless, certain risk factors such as high testicular heat exposure, obesity, infections, lack of sleep, occupational exposure, poor lifestyle choices and use of certain medications have all been suggested.

Recently cell phone exposure has gained attention as another potential risk factor to male fertility.

Initial animal studies revealed a possible association between cell phone radio frequency exposure and abnormal sperm parameters.

However human studies to date have proven inconsistent with no data on fecundability.

Aim

To examine the association between hours of carrying a cell phone in different locations on the male body and fecundability, with a focus on the front pants pocket as the main source of exposure.

Methodology

Two parallel prospective studies, Snart Foraeldre (SF) and Pregnancy Study Online (PRESTO), was carried out to evaluate the extent of which cell phone exposure is associated with male fertility.

Couples trying to conceive without fertility treatments were invited to participate. However female partners whose last menstrual period was more than 6 months prior to study enrolment, or couples already trying to conceive for more than 6 cycles prior, were excluded from the study.

Overall, a total of 3100 males (SF = 751, PRESTO = 2349) who satisfied the inclusion / exclusion criteria were enrolled. Semen quality was measured using the Trak home-based semen testing kit, which allows for in home measurement of sperm concentration, semen volume, and motility.

Each male self-tested two semen samples, 7 to 10 days apart, after abstaining for 2 to 7 days, during their partner’s luteal phase. Cell phone exposure was recorded via a questionnaire about average duration and exact storage locations.

Fecundability was measured by time-to-pregnancy (TTP) recorded in questionnaires given to the male respective partners. Covariates of interest was also captured to adjust for known confounders (potential bias).

Results

Preliminary analysis of completed questionnaires showed similar pregnancy rates for both groups, SF = 66% and PRESTO = 63%, and that men mostly carry their phone in the front pocket of their pants (SF = 70%, PRESTO = 62%). 

Statistical analysis of all the data however found revealed little to no association between fecundability and carrying the cell phone in the front pants pocket (FR = 0.94, 95% CI: 0.83–1.05).

Study Group	No. of pregnancies	No. of cycles	Adjusted FR	Pooled Adjusted FR
Snart Foraeldre	442	2385	0.96	–
PRESTO	1259	8059	0.93	–
	–	–	–	0.94

Similarly, no real evidence of a dose-dependent relationship was identified, between the number of hours cell phones were carried in the front pants pocket and fecundability ratios (FR), both in pooled and unpooled analysis of the 2 groups.

Hours per day	Snart Foraeldre Adjusted FR	PRESTO Adjusted FR	Pooled Adjusted FR
<1-2	0.90	0.89	0.89
3-7	0.91	1.02	1.00
≥8	1.01	0.90	0.92

Interestingly stratified analysis of couples who had been trying to conceive for the first 2 cycles did show a stronger link between hours of front pants pocket cell exposure and fecundability ratio, although the meaning of this is debatable without further studies. 

On the other hand, any front pants pocket exposure in men with body mass index < 25 significantly reduced fecundability in both study groups (FR = 0.72). This association was even more significant (combined FR = 0.68) when restricted to only men (BMI < 25) trying to conceive within the first 2 cycles.

Semen sample analysis showed males in the PRESTO group had better mean sperm concentration, sperm count, motile and total motile count, compared to the SF group. However pooled group results failed to show any significant relationship between cell phone exposure and semen parameters, whilst unpooled results were too inconsistent between the 2 groups to draw any conclusions.

Overall no significant evidence was found that cell phone use impaired semen quality or fecundability. In leaner men there was some evidence of reduced fecundability however this did not increase with longer exposure time requiring further studies.

Limitations

1. Radiofrequencies of cell phones not recorded or analysed.
2. Danish cell phones have a narrower radiofrequency band (800–900Mhz) than North American cell phones (800–2600Mhz).
3. Self reporting of cell phone exposure time in different pockets.

Funding

The study was funded by the National Institutes of Health.

Similar studies

Lewis R C, et al. (2017). Self-reported mobile phone use and semen parameters among men from a fertility clinic. https://doi.org/10.1016/j.reprotox.2016.11.008

Zhang G W, et al. (2016). Effects of cell phone use on semen parameters: Results from the MARHCS cohort study in Chongqing. https://doi.org/10.1016/j.envint.2016.02.028

Rago R, et al. (2013). The semen quality of the mobile phone users. https://doi.org/10.3275/8996

Gutschi T, et al. (2011). Impact of cell phone use on men’s semen parameters. https://doi.org/10.1111/j.1439-0272.2011.01075.x

fertilPEDIA

Low Sperm Count Overview

Low sperm count, also known as oligospermia or oligozoospermia, happens when a man has 15 million or less sperm per millilitre (mL) of…. Read more

Asthenozoospermia Overview

Asthenozoospermia, is defined as reduced or absent sperm motility (< 32%) in fresh ejaculate. It is one of the main causes of infertility in... Read more