Is prolonged/frequent use of mobile phones responsible for sperm reduction in younger men?

Question

This question has been asked previously but there has been a new study on the question which has received publicity and considerable acceptance. I am skeptical of the findings of the new study.

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Men using mobile phones at a high frequency (>20 times a day) showed a 21% reduction in sperm concentration and a 22% TSC decrease as compared to those who rarely (less than once per week) used mobile phones. Significant exposure-response trends were observed across the complete exposure range in this group of men. Moreover, these men also showed a higher risk of having a sperm concentration and TSC below the WHO reference value for fertile men. The likelihood of having a lower-than-WHO-reference sperm concentration was significantly higher in men using mobile phones 5–10 times a day than those who rarely used it in the day or week (adjusted odds ratio = 1.409).

News-Medical

In the present study, 5,605 men aged 18–22 years were surveyed across six centers in the country using questionnaires regarding their health and lifestyle as well as their parents’ preconception period. The men were also asked about the duration and frequency of mobile use (rarely, a few times per week, 1–5 times per day, 5–10 times per day, 10–20 times per day, >20 times per day) and the place where they kept the phone (in a jacket pocket, pant pocket, belt carrier, or elsewhere) when not in use.

News-Medical

The report goes on to admit of severe limitations in the process carried out to determine the thesis:

there are a few limitations to the study. It did not evaluate the daily RF-EMF absorption and relied solely on self-reported data for surveying mobile usage. Also, the characteristics of the phone, such as its brand, number of applications, network quality, use of ear accessories, and output power, were not recorded.

News-Medical

Is there any evidence, other than this recent, well-publicised evaluation (one is tempted to refer to 'click-bait') to support the claims and to really come to the conclusion that heavy mobile phone use is a major factor in sperm reduction?

There is a range of other factors, globally, which could be the cause of sperm reduction, such as drinking water pollution by pharmaceuticals. Is there a definite attempt to draw attention away from such (financially sensitive) effects and to blame mobile phone use?

Answer 1

The conclusion of the underlying paper is:

[A] lack of clear evidence for a negative association between mobile phone use and male fertility

Given the 13-year duration of this study, and how much phones have changed between 2005 (gonna just check my nokia for a SMS 20 times today?) and 2018 (gonna doomscroll twitter and check on instagram) I would not think the results as described in the linked news article are even remotely correct.

There's a strong sampling time component to their results that the authors have simply speculated wildly about in their discussion.

An 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)

When you look at the actual results provided in Table 3, there is no statistical significance for cell phone use after 2007 on their fertility metrics when the 13-year sampling cohort is stratified into smaller time intervals. The comment "the association [...] decreased progressively over the subsequent time periods" would be more accurately restated as "the association does not appear to exist after 2007".