Habits of cell phone usage and sperm quality

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Re: Habits of cell phone usage and sperm quality

#91

Post by cyphar » Fri, Feb 05, 2016, 2:07 PM UTC

maxerickson wrote: post #33

cyphar wrote: post #27

Earlier quoted context omitted.

> There could be an over-represented subgroup of the general population who are more susceptible to the cell phone radiation, but selecting from that group would not necessarily obscure the relationship between the amount of cell phone use and any resulting biological impact. That's not what he said. If you read the abstract, it says that the candidates were chosen using "questionnaires accessing demographic data and…

My point was that the selection bias proposed will not necessarily obscure a biological effect (or at least, correlation). Setting aside the legitimacy of pursuing this research, looking for effects using statistical analyses of medical records is an interesting way to direct at least a small amount of research, saying that such questions can only be asked when there is solid control of every factor is probably not a…

> My point was that the selection bias proposed will not necessarily obscure a biological effect (or at least, correlation).

I'd argue that the sample was not representative of the general population, so "it will not necessarily obscure" isn't relevant IMO because the results aren't even remotely close to being applicable to any other group of men.

> looking for effects using statistical analyses of medical records is an interesting way to direct at least a small amount of research

I agree that it's interesting. And since I can't read the paper at the moment (I'll download a copy through my university when I get a chance) I can't really comment on the statistical methods they used (I'm not even sure what they asked on the questionnaire). Statistical analysis is only useful if you take into account all of the parameter space (or at least all of the significant parameter space) otherwise you'll get a biased result.

Even then, correlation does not imply causation, so a statistical analysis would only be useful as a survey of "what could be investigated to do actual science on". People put far too much faith into statistics, and it

> saying that such questions can only be asked when there is solid control of every factor is probably not a win

Anyone can ask a question. I'm saying that the paper published should've actually been an email (or maybe just an article) sent around a faculty so they could do real research on the topic. "Asking a question" and "publishing a paper on a topic" are very different classes of activities.

Re: Habits of cell phone usage and sperm quality

#92

Post by dekhn » Sat, Feb 06, 2016, 5:09 PM UTC

snowwrestler wrote: post #66

dekhn wrote: post #56

Earlier quoted context omitted.

Like I said, a carefully designed study can eliminate many biases. I didn't claim it could eliminate hidden factors. Anyway the problem with finding something in an epi study then trying to reproduce it in a minimal environment (isolated cells exposed directly to radiation) is unlikely to uncover any complex mechanism. Cells on their own don't behave like tissue, and tissue on its own doesn't behave like an organism.

Even doing radiation tests on rats in a lab is going to have fewer confounding factors than 100 infertile human guys filling out a questionnaire. I'm not aware of any lab rat studies that found harm from cell phone radiation. And of course the basic mechanism by which radiation affects materials is pretty well understood. All this is to say: I think yummfajitas had it right. Fajitas are delicious.

There are a number of experiments where researchers have reported visible changes to sperm morphology. Here are the ones I found without looking to hard (only extracted abstract; did not read full paper from the perspective of a grad student preparing for journal club)

http://www.ncbi.nlm.nih.gov/pubmed/19578660 " However, rats exposed to RF-EMR exhibited a significantly reduced percentage of motile sperm"

http://nopr.niscair.res.in/bitstream/123456789/10343/1/IJEB%... "decrease ... in total sperm count".

http://large.stanford.edu/courses/2012/ph250/ferguson2/ "An experiment by Yan et al. in 2007 was conducted to see how cell phone radiation affected sperm quality. [10] The rats were placed in a PVC holding tube and exposed to a total of 6 hours of cell phone radiation per day for 18 weeks. After the 18 weeks were over, the rats were euthanized for tissue testing. They found that sperm motility was significantly different between the control and experimental group. [10]"

That ref is http://www.ncbi.nlm.nih.gov/pubmed/17628553, "Rats exposed to 6 hours of daily cellular phone emissions for 18 weeks exhibited a significantly higher incidence of sperm cell death than control group rats through chi-squared analysis."

http://ieeexplore.ieee.org/xpl/login.jsp?tp=&arnumber=476323... "Our findings shows a significant decrease in GPx and SOD of exposed rat sperm (p< 0.001)"

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