Smartphone use may harm sperm quality

Frequent use of mobile phones has been linked to poor sperm quality, specifically lower sperm count and concentration.

In a study that recruited 2,886 men (median age 19 years, median body mass index 22.6 kg/m²) from the general Swiss population over 14 years, those who used their mobile phones more than 20 times per day had lower sperm concentration compared with those who used their mobile phones less than once per week (median, 44.5 vs 56.5 Mio/mL; p=0.04). The same pattern was observed for total sperm count (120.0 vs 127.0 Mio; p=0.008). [Fertil Steril 2023;doi:10.1016/j.fertnstert.2023.09.009]

The observed differences correspond to “a 21-percent decrease in sperm concentration and a 22-percent decrease in total sperm count for frequent (>20 times/day) [versus] rare (<once/week) mobile phone users,” according to the investigators.

Multivariable logistic regression analysis showed that mobile phone use of 5–10 times per day was associated with greater odds of having sperm concentration below the WHO reference value of 15 Mio/mL compared with use frequency of 1–5 times per day or less than once a week (adjusted odds ratio, 1.409, 95 percent confidence interval [CI], 1.02–1.90).

Semen volume, sperm motility, and morphology, however, showed no association with mobile phone use.

All participants completed a detailed questionnaire about their lifestyle habits, general health status, the frequency at which they used their phones, as well as where they placed it when not in use.

Overall, frequent phone users (>20 times/day) tended to be younger than those who used their phones <10 times per day or rarely. Men who used their phones more frequently also had higher weight and BMI and more often smoked and consumed alcohol.

Transmitting power of phones

“Mobile phones emit low-level radiofrequency electromagnetic fields (RF-EMFs; 800–2200 MHz) that can be absorbed by the human body,” the investigators said. [Fertil Steril 2008;89:124-128; Int Braz J Urol 2011;37:432-454]

Experimental studies have shown that RF-EMF exposure may impair male infertility by interrupting the germ cell cycle, increasing sperm death, and causing histological changes in the testes. [Electromagn Biol Med 2012;31:213-222; Appl Biochem Biotechnol 2011;164:546-559; Indian J Exp Biol 2014;52:890-897; Appl Biochem Biotechnol 2012;166:379-388; Toxicol Ind Health 2017;33:373-384]

In the current study, the association between mobile phone use and sperm concentration was found to be more pronounced in the first period of the study (2005 and 2007) and decreased progressively over the subsequent time periods (2008–2011 and 2012–2018). This pattern, according to the investigators, is consistent with the transition from 2G to 3G and then from 3G to 4G, which led to a substantial decrease in the output power of phones.

“In fact, given the rapid evolution of mobile phone use and technology, our study represents a snapshot of their impact during the period between 2005 and 2018,” they continued.

Meanwhile, the position of the mobile phone when not in use had no effect on semen parameters. Carrying the phones inside the trouser pockets was not associated with altered semen quality compared with carrying the phone away from the body.

“RF-EMFs from mobile phones emitting at maximum output power result in a maximum local tissue heating of 0.5 °C. The increased temperature of the testes caused by the heat generated by the handset located in the pants pocket may thus hamper spermatogenesis and sperm production,” the investigators explained. [Health Phys 2020;118:483-524]

“An association with the position of the phone on the body would thus have supported a direct effect of RF-EMF exposure on spermatogenesis and sperm function, which is not the case,” they said.

Alternatively, RF-EMF could harm sperm quality indirectly by disrupting the hypothalamic-pituitary-gonadal axis and the production of gonadotropic, luteinizing hormone, and follicle-stimulating hormones as well as the sex steroid testosterone. [Electromagn Biol Med 2012;31:213-222; Appl Biochem Biotechnol 2012;166:379-388; Environ Res 2021;202:111784; Electromagn Biol Med 2011;30:219-23]

The investigators called for additional prospective observational studies to better understand the impact of RF-EMF on male reproductive health and fertility potential, especially in light of the advent of new phone technologies in recent years.