10-Year Cell Phone / Cancer Study Is Inconclusive 248
crimeandpunishment writes "A major international (retrospective) study into cell phones and cancer, which took 10 years and surveyed almost 13,000 people, is finally complete — and it's inconclusive. The lead researcher said, 'There are indications of a possible increase. We're not sure that it is correct. It could be due to bias, but the indications are sufficiently strong ... to be concerned.' The study, conducted by the World Health Organization and partially funded by the cellphone industry, looked at the possible link between cell phone use and two types of brain cancer. It will be published this week."
It's all relative (Score:5, Insightful)
Re:Limited study (Score:5, Insightful)
How silly.
Re:It's all relative (Score:4, Insightful)
Most people who have high cell phone usage also share other behavior. CEO use cells a lot and have high stress. Stress is a key factor in a lot of cancers. It's hard to track the roots of the problem.
Re:Limited study (Score:5, Insightful)
Not really. Sampling can give accurate results even when sampling a small percentage of the total population. If U.S. political polls select a sample size of between a few hundred and a thousand out of 300 million with only 3% error, it sounds reasonable that 13,000 would be a good sample size of a population 20 times that, giving the same margin of error.
Also remember that, assuming the sample is chosen well (it is a good cross-section of the population and not confined to one specific subgroup), the benefits of adding additional samples drops off. It is essentially logarithmic: at first, adding samples is a huge benefit: after a certain point, the incremental gain from one additional sample is only a tiny fraction of the first samples.
No answer is sort-of an answer (Score:2, Insightful)
Cell phones cause so much cancer that ... the most widespread studies cant tell whether they cause cancer at all. That is good news for cell phone users.
So each side calls success? (Score:3, Insightful)
On the other hand, cellphone companies may try to take "we're not sure that it is correct" and declare no link to cancer.
Re:"Survey"? (Score:5, Insightful)
And even if there is some correlation, people need to put it in perspective.
The last time I talked to a flat-earth-er about their fear of cell phones causing cancer, they had a drink in one hand and a cigarette in the other.
Now that, Alanis Morrissette, is irony.
Problem with surveys (Score:5, Insightful)
Oh noes...not radio! (Score:3, Insightful)
Have they done this study against other types of radio frequencies like cordless land-line phones? What about emergency services workers that carry radios on their hips until needed...are they being checked for hip-cancer? Doesn't Nike or some other shoe maker have a device that fits inside a shoe so people can listen to FM whilst jogging? Watch out for heel-cancer! The point being, why are cell-phones being singled out as possible culprits where then are so many other devices out there that use radio technology?
I think the media has way too much control over what is allowed to scare us into taking action. It seems that our efforts could be better directed toward something that actually makes sense. Let Mythbusters handle this type of shit.
Re:It's all relative (Score:4, Insightful)
cell phone radiation isn't causing some massive epidemic of brain cancer
Even if there were a high percentage of brain cancers from phone users, how would you tell the difference between cancer caused by RF wave, which has no theoretical basis or past proven medical experience/documentation, or cancer caused by weird plastics, weird dyes, lead paint, weird petrochemical outgassing from the plastic phones, which has a reasonable scientific biological basis for causing cancer, and unfortunately plenty of medical experience/documentation?
Correlation Causation...
USA Today (Score:5, Insightful)
Re:Limited study (Score:3, Insightful)
Certainly actual elections tend to fall well outside the +/- 3% accuracy claimed by many of the election-day pollsters.
Because for many of those pollsters accuracy isn't main goal; swaying people, untill the last minute, to vote for the "winners" is.
Re:Limited study (Score:4, Insightful)
Also, unless the needed data is already available somewhere, gathering more data costs more money. As someone else mentioned in a sibling post, there are diminishing returns when increasing your sample size. Eventually the cost of the data will exceed the benefit to the certainty of your results.
Re:Limited study (Score:4, Insightful)
I'm not so sure those percentages are accurate. You'll often see different polls differ by much more than that (far more often than 5% of the time or whatever the confidence level is).
Election polling is just especially difficult, since what counts is if you actually vote and who you vote for, neither of which have been determined at the time of the poll and could change. Election polling isn't simply an opinion poll, but is obviously supposed to reflect the population of people who will actually vote on election day. The polls have differing models of selecting "likely voters", and will thus have numbers that differ more than the margin of error for any single poll. In other words, taking the margin of error for a single poll and comparing it among multiple polls is invalid, since the differing polls used different means of sample selection.
Certainly actual elections tend to fall well outside the +/- 3% accuracy claimed by many of the election-day pollsters.
I guess I haven't found that to be true if you mean "tend to" is more than 50% of the time. Sure, you're going to find some that are outside of the 3% error bars, but you'd also expect that to happen, statistically speaking.
Re:Problem with surveys (Score:4, Insightful)
> I have a problem with "medical surveys" in that they a prone to make correlation-causation errors.
No they aren't. The people who conduct medical surveys such as this are invariably qualified epidemiologists who don't need to be told the difference between correlation and causation by some guy on slashdot.
Now, the media reporting of such surveys quite often conflates correlation and causation; see:
http://www.phdcomics.com/comics.php?f=1174 [phdcomics.com]
The final stage, not illustrated in the above diagram, involves some guy on slashdot conflating the actual surveys with media coverage of said surveys.
Re:Problem with surveys (Score:5, Insightful)
It's not that simple. You're ignoring statistics. You'd need a certain number of monkeys and some of them would have to be controls. If the effect is predicted to be small you may need thousands of monkeys. Animal rights groups would have a fit over this.
The monkeys would also have to experience the cellphone radiation in a similar way that humans would. The radiation would have to be emitted as if a cellphone were pressed up against their ear, and it would have to be intermittent as to simulate a human taking calls throughout the day.
Different cellphone systems run on different frequencies. If there was strong evidence to suggest that one caused cancer we couldn't necessarily assume that they all do, including future networks running on different frequencies. The same could be said about the power of the transmitter--different phones transmit at different levels of power, and future phones may be very different.
Some researchers believe that some cancers may take much longer than 10 years to show, so a thorough experiment may need to last 30 years or more. By the time good data is collected the cellphone networks would probably be using different frequencies and possibly lower power transmitters.
I'm sure there are other factors that I'm not even thinking about. Setting up a bulletproof experiment of this nature and getting solid results in a reasonable period of time is at least difficult and maybe impossible.
what? (Score:5, Insightful)
Science isn't inconclusive. There is statistically significant, or not. In this case, not.
Test another hypothesis or test again if data looks fishy.
Statistical significance (Score:5, Insightful)
To get statistical significance, you don't need to sample the entire population. Beyond a certain number for a certain confidence level, you don't get very much more.
Exactly right.
There was no statistical significance, which means that the cancers (or absence there of) were distributed over cell phone users and non-users (controls) with no preference for either group.
Normally this would be the end of it.
But by the way the reporter worded it (Inconclusive) and (to a lesser extent) the way the Researcher phrased it, indicates a clear predilection toward finding a positive correlation, which they could not do.
The takeaway is not that the study "inconclusive". The scientific takeaway is that there is yet again no evidence of correlation between cancer and cell usage.
Its over. The absence of evidence destroys this theory. Time to move on.
Re:Limited study (Score:4, Insightful)
Here are some additional details for those of you so inclined.
Consider a simple binary choice question. This is easily modelled by the binomial distribution which has well understood distributions. (Other distrbutions may be relevant but the principles remain pretty constant across them all.) The standard deviation is given by sqrt[np(1-p)] where n is the sample size and p is the probability of the observation you are interested in (the mean is np so in what follows I will be dividing by n to talk about percentages if you are taking notes). For example, are you male? If the true p is, say, 75% then you need a sample size of approximately 833 to get a 95% confidence interval (2 s.d.) of +/- 3%.
You might also note that the closer the true p is to 50%, the larger the sample size needed. If the true p is 50% you need a sample size of approximately 1100 for the same confidence interval. Furthermore, if you want to get it within 1%, the sample size goes up dramatically - to 10,000.
The population size is pretty much irrelevant. The population matters for ensuring that your sampling is truly random, but political pollsters can use the same sample sizes in Australia (pop ~20 million) as in the US (pop ~300 million) for similar accuracy. (Sampling bias is the reason that political polls can be out by so much - if you call households during work hours you are going to get a very different sample of people than if you call at dinner time.)
Re:Statistical significance (Score:5, Insightful)
I'm not so sure. Cancer is a funny thing, and "cell-phone use" is kind of a broad behavior. I have seen so many items get shifted from the "causes cancer" to "inconclusive" to "completely safe" category and then back again, that I've got something of a jaundiced eye toward "moving on" based upon one study.
Even if you remove the obvious data-cooking by the industry, there actually were studies in the 50's that showed that the connection between cigarette smoking and cancer was "inconclusive". Better-designed studies, honest studies, showed later that the connection was real. We see this back and forth with dairy products and cancer in women, with certain chemicals in insecticide, with the ground water near industrial sites, with thalidomide. Sometimes it takes a whole bunch of studies before causal relationships are exposed. Sometimes, it takes a lawyer digging up studies done by the companies themselves and then supressed.
A few days ago, there was discussion here about h. pylori and ulcers. The first studies done by the Australian researchers came up inconclusive. Twenty years later, they got the Nobel Prize for later studies that proved the connection was there. Now, nobody has to suffer with ulcers any more, and ulcer surgeries are practically unknown.
No, you don't "move on" because of one study or maybe even ten studies. Science doesn't just drop an issue because of one researcher's findings. The reason this issue with the cell phones is even being looked at is because when you've got entire populations holding microwave transceivers next to their noodles day in and day out, you want to make sure it's really safe.
Re:Statistical significance (Score:1, Insightful)
The fact it's in the microwave band means nothing and is just FUD. they don't transmit with any great strength, you'd have to duct tape one to your head and set it to transmit 24/7 for a long time to do any damage.
Re:It's all relative (Score:5, Insightful)
They did disprove it. However, the study author and the reporter really, really, really wanted to prove it so it was reported as "inconclusive".
Re:USA Today (Score:3, Insightful)
The article in USA Today has a nice little gem in it:
"The authors acknowledged possible inaccuracies in the survey from the fact that participants were asked to remember how much and on which ear they used their mobiles over the past decade. Results for some groups showed cellphone use actually appeared to lessen the risk of developing cancers, something the researchers described as "implausible.""
Now, I don't know why, but something about this statement seems kind of important.
How can something like this be "implausible". Is it only implausible because they cannot explain it?
Sounds to me like they knew what they wanted the report to say before they began the study. All they wanted was sufficient proof before hitting the 'publish' button on the report. They never found it so it is labelled "inconclusive" which really means, "we shall try again".
Re:It's all relative (Score:4, Insightful)
You should probably consider the inverse-square law.
Cell towers transmit at higher power than cell phones, but only a minuscule portion of that reaches even a person standing at the base of the tower. With a cell phone against your ear, about half of the transmitted rf energy is going through your skull.
Re:Limited study (Score:3, Insightful)