Effect Measure

Cell phone use and sperm counts

A paper delivered at the annual meeting of the American Society for Reproductive Medicine is being reported to say that there is an apparent dose response relationship between cell phone and sperm counts, i.e., the more hours spent on the phone each day the lower sperm count levels.

Scientists in Cleveland, Mumbai and New Orleans tracked 364 men who were being evaluated for infertility, and split them into three groups based on sperm count. In the group whose sperm counts were within the normal range, those who used a cell phone more than four hours a day produced on average 66 million sperm per milliliter, 23 percent less than those in the group who didn’t use the phones at all.

The proportion of the cell-phone users’ sperm that possessed “normal forms” was 21 percent, almost half the 40 percent of normal sperm produced by men who didn’t use the phones, said the researchers, who presented their conclusions this week in New Orleans at the annual convention of the American Society for Reproductive Medicine. (Bloomberg)

Since this is a news report it isn’t clear exactly what was found, for example, is this an estimate from a regression, is this the actual difference between the high and how groups, or what, and whether there was adequate adjustment for confounding and all the other qualifiers one worries about in such observational studies.

Over the years we have frequently been asked about the health effects of cell phone towers, especially those built in close proximity to schools or residences. In general it has been our view that the non-ionizing radiation from those tower transmitters falls off so rapidly there is not much exposure to the surroundings.

On the other hand, we have always been cautious about the other transmitter — the one you hold in your hand when talking. The antenna from that transmitter, though of much lower power, is right up against your skull, so exposures are much greater than from a tower. Whether that has anything to do with the results of this study remains to be seen.

There are three possible generic explanations for the reduced sperm parameters. One is that there was some kind of sytematic error in how the data was collected produced that the results. This is called “bias” by epidemiologists, although it is not meant to indicate lack of objectivity. Systematic error is in contrast to random error, the differences produced by the luck of the draw when sampling from a population where sperm parameters vary a great deal (which is usually the case). It could have happened that by chance more of the naturally low sperm count males also used cell phones. We usually evaluate this via statistical tests. The news story had no information on what tests, if any, were done on these data. Third, it could be that using cell phones in some ways impairs sperm growth and development. This is the most interesting but least desirable outcome.

Regarding the third possibility we need to have some mechanism that could produce this outcome. The radiofrequency radiation from the cell phone handset is non-ionizing, that is, it is not the kind of radiation we think of when we talk about nuclear events or radioactive materials. It has been demonstrated, however, that non-ionizing radiation can produce subtle biological effects, whose significance is not understood. The male gonads are too far away from the transmitter for us to think there is substantial exposure, but one might posit some effect on circadian rhythms (maybe Scibling Coturnix of A Blog Around the Clock has some thoughts on this; he’s the expert and I’m just making this up) or some interference in the hypothalamic – gonadal axis, wherein the brain affects the testes via hormones. If this effect is real — and that is a very big if at this point — it is not obvious what the mechanism would be. Local heating doesn’t seem plausible.

If this does turn out to be a real effect, the cell phone companies are in big trouble. Most males will take a cavalier attitude to the remote possibility they will develop cancer in thirty years, but if you suggest, however indirectly, that their balls are going to shrivel up and drop off . . .

Comments

  1. #1 Gabe
    October 26, 2006

    How bout this: After I’m done talking on the phone I put it in MY POCKET where it sits and waits for incomming calls. That’s pretty close to my gonads. I’m surprised it isn’t mentioned in your post. :(

  2. #2 Gabe
    October 26, 2006

    And might I add: The more you use your phone, the more likely you’re going to receive incomming calls. Once your phone picks up that its receiving a call it will start transmitting, i believe, and exposure increases with each call.

  3. #3 I really shouldn't make this joke
    October 26, 2006

    Did they control for the fact that lawyers and real estate agents spend a lot of time on the phone? Because those guys are all wankers.

  4. #4 Matt Stoller
    October 26, 2006

    The test was whether people used their phones, not whether they kept their phones in their pockets. Although there’s probably correlation.

  5. #5 revere
    October 27, 2006

    There is no exposure from incoming calls. The transmitter from those calls is in the cell phone tower. It is only when you answer the call that the transmitter in the handset produces RF nonionizing radiation.

  6. #6 DCfluwatcher
    October 27, 2006

    It is my understanding that a cell phone in standby mode regularly sends out signals (perhaps in search of a local tower or an incoming call). The strength of those signals depends on several things, a key one being the ease with which it connects to a local tower or antenna (forgive my ignorance of the correct terminology). So if you have two bars on your signal stregnth indicator, your phone has to work a lot harder to get a good signal, increasing exposure. Is this not indicative of a risk in keeping phones in pockets?

  7. #7 Clin Psych
    October 27, 2006

    Geez, first antidepressants might lower your sperm count and now this? No wonder fertility clinics are going gangbusters! I remember reading a few things about plastics and infertility but they seemed speculative. In any case, decreasing sperm counts are likely explained by some combination of environmental factors that we have created in the past 50 years.

  8. #8 revere
    October 27, 2006

    DC: I’d never heard that about Standby mode. If you have a cite where I could learn more I’d appreciate it. I’m surprised they’d use that technique, although I suppose it is possible. I would think that the signal would be of very short duration, though.

    The two big issues with this in general are whether the effect is real; and if it is, what the mechanism is. I have a hard time thinking it’s direct exposure of the gonads but that’s just my guess. I know something about the subject but I no longer am directly involved.

    ClinPscyh: There is so much hormonal “static” in the environment that effects on fertility aren’t implausible but if fertility rates are decreasing (the sperm quality data has been the subject of a great deal of debate) there could be very many sources for it.

  9. #9 tardigrade
    October 27, 2006

    From the dark recesses of my mind, a phrase emerges…. the higher frequencies, say in gigahertz, the higher the energy and more ‘directional’ the signal becomes. The best phone systems have the highest amount of output and sensitivity to radio waves. When we talk on cell phones or the best home cordless phone, walls and topography matters. And also, so does distance because of the spread of the signal from the origin ~which means that with distance, the energy diminishes. If I were doing a study on this, I would try to isolate the type of phone unit (in power output), the usage in time, and the organs most likely to be impacted. I would assume sensitive tissue that has more direct contact with the high energy waves like the inner ear, and related organs as to their proximity, which means… not the gonads….. unless, we have circus acts and ventriloquism. I just have my doubts when the studies seem so…. soft in the middle……

  10. #10 DCfluwatcher
    October 27, 2006

    My quest for proof of cell phone activity in standby has been unsuccessful. However, a 2004 British popular press article about a study showing cell phone effects on sperm count had this to say:

    “Unlike previous studies, the researchers believe that phones may cause damage while in stand-by mode. Although not in use, they make regular transmissions to maintain contact with the nearest radio masts. It had been assumed such transmissions were too short to cause harm.”

    http://www.timesonline.co.uk/article/0,,2087-1159951,00.html

  11. #11 George
    October 27, 2006

    Okay, so this is a good thing … for me. Assuming there aren’t other nasty related effects..

  12. #12 Ana
    October 27, 2006

    Modern life is not good for sperm. Besides that it is a silly study.

    Where is the control group? (I only read what was posted here)

    Men who spend a lot of the time on the phone are dependent, harassed, terminally stressed out, eat poorly, are in the ‘semi’ upper classes, or struggling to get there, subject to all the myths and bad stuff – they live in towns, are subject to all kinds of pollution, don’t pay much attention to their wives, no time… and so on.

  13. #13 revere
    October 27, 2006

    tard: Yes, the tower transmssions are directional. I’ve looked at the patterns, and even given this, it isn’t plausible (to me) that the towers are a signficant exposure for most people. But the hand held transmitters are.

    DC: I’m just not familiar with the standby arguments. However I think the effects on the brain could also explain it — IF the effect on sperm is really RF related, which they may not be. We’ll have to look further. This is hard to study epidemiologically.

    Ana: this study uses “internal controls.” This is a valid and in many ways preferable way to do it. The study group is divided into three groups of varying sperm quality and then the question is asked, “how much time was spent on the phone in each group”? The hypothesis would be that the worst sperm count groups spent more time on the phone compared to the other two groups.

  14. #14 Karen
    October 28, 2006

    I can’t provide proof of the standby issue either, but living on the edge zone for cell coverage in my area, I know that my batteries discharge much faster when I’m passing through the areas with spotty coverage, so something is going on with my phone in standby. I can only think that is is trying to ping for cell connection. My phone eventually powers itself down if I’m out of a coverage zone long enough. If it wasn’t sending out some sort of signal, that wouldn’t be needed. In a covered area, the standby mode will last days.

  15. #15 g510
    October 30, 2006

    Why complain? This is a GOOD THING.

    7 bilion humans, heading toward 10, on a planet that can support 2.5 billion sustainably, will not stand. The only options are to reduce births or increase deaths. There are no other options. And this is as serious as a heart attack.

    Here we have a universally desired consumer device that indirectly has the potential to reduce births. We should be rejoicing.

    We should also ban fertility clinics. If someone’s shooting blanks, tough birdies for them, they can adopt. Even if the baby’s skin color doesn’t match theirs. People need to get over this selfish preoccupation with launching their genes into the next generation, else Ma Nature is going to whack us all but good.

    Or would you rather increase deaths instead…?

  16. #16 Anushka
    December 2, 2006

    The use of cell phones has reallly become controversial and sometimes even hampering personal communications. By the way I don’t cary mobile phones. I think there was a recent study that said it may have negative effect on brain after usage of 10-20 years. I am not sure, but the reason we don’t hear about these things very much is because the cell phones have not been around that long. But there is a study which says that CELL PHONE USE IS ASSOCIATED WITH DECLINE IN FERTILITY. It appears in today’s HULIQ at http://www.huliq.com/338/cell-phone-use-associated-with-decline-in-fertility and is from American Society for Reproductive Medicine

  17. #17 M. Randolph Kruger
    December 2, 2006

    RF of any kind causes cell resonance and some might actually stimulate certain types of cells.They will be fighting this one for a while. Hey did you hear the one about global warming being related to the RF spectrum? All of these electronic gizmos, power grids and telephone lines make the iron and nickle resonate in the earths crust and core producing heat. Now thats something that is known, metal heats up in a microwave. Loss in fertility? If I understand it, one man has the possibility of repopulating the earth with one shot. I guess we need a better definition of what a drop is.

  18. #18 revere
    December 2, 2006

    Anushka: We posted on it a while back. Use the search box and see if you can find it.

    Randy: Highly unlikely. There isn’t that much RF to do that and the earth’s mantle is already extremely hot. Lost in the noise.

  19. #19 kaled nather
    July 8, 2008

    i am finished from thseis recently that concerned the male infertility (evaluation of immunological and biochemical parameters in human seminal plasma in iraqi male patients)

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