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Posts Tagged ‘Journal of the American Medical Association’

Does TV Watching Make You Sick? Not Exactly…

June 14, 2011 Leave a comment
File:Televison Hungarian ORION 1957.jpg

Beware! It might kill you! Photo Credit: Istvan Takacs

I’m a little annoyed with some headlines hitting a few news websites today:

TV Watching Raises Risk of Health problems, dying young

Excess TV time linked to early death

TV time tied to death, diabetes risk

The stories are talking about a study getting published this week in the Journal of the American Medical Association

The study is a meta-analysis of 8 studies over the past 40 years which look at the correlation between watching television and risk of diabetes and cardiovascular disease.

The study found, unsurprisingly, that increased television watching was correlated with an increased risk of type 2 diabetes and heart disease.

The pooled relative risks per 2 hours of TV viewing per day were 1.20 (95% CI, 1.14-1.27) for type 2 diabetes, 1.15 (95% CI, 1.06-1.23) for fatal or nonfatal cardiovascular disease, and 1.13 (95% CI, 1.07-1.18) for all-cause mortality.

In layman’s terms, this means that for each 2 hours of television watched per day, risk of type 2 diabetes increased by about 20%, risk of developing fatal or non-fatal heart disease increased by about 15%, and risk of dying of any cause increased by about 13%.

So does watching TV make you sick? Not exactly.

I’m not doubting the results of the study, though they should be taken with the usual grain of salt that should be taken with all epidemiological studies.

They are observational studies, not controlled studies in a lab. There are many variables which can influence the results.

That being said, the results of the study are not surprising and I have every confidence that there is truth in there.

But the media takes these types of studies, gives them a sensationalized headline and doesn’t put them in the proper context.

Watching TV does not make you sick; being lazy makes you sick. What this study is really showing is that watching TV correlates to a lazy lifestyle.

There’s nothing wrong with kicking back and watching some Star Trek reruns or even *groan* Dancing with the Stars. Just make sure you go out for a jog now and then. Or play some basketball. Or just do anything that isn’t sitting around and being lazy!

I’m sure snacking is a big factor in the results of this study as well. No doubt increased time in front of the TV leads to eating more unhealthy foods.

But if you sit in front of the tube and eat baby carrots or oatmeal, then you are probably not at a huge risk of developing heart disease or diabetes.

So if you watch a lot of TV, you’re not necessarily going to die young because TV doesn’t make you sick.

But if you eat a lot of junk food and don’t exercise, then you might die young. But then again, THAT’S not exactly news, is it?

Cell Phones, Your Brain, and the Media

February 23, 2011 72 comments

Usually, when a scientific study gets this much media attention, it has something quite impactful to report.

But when the study has nice, media-friendly buzz-words like “radiation” and “brain activity”, you get a firestorm of media coverage. Even if your study doesn’t say all that much.

The study I am referring to is called “Effects of Cell Phone Radiofrequency Signal Exposure on Brain Glucose Metabolism” which was recently published in the Journal of the American Medical Association.

The study looked at 47 healthy volunteers; a relatively small study. The researchers took these volunteers and gave them all PET scans on their brains. They had also strapped two cellphones on either side of their head. One cell phone was on, and the other was turned off.

During a 50 minute phone call, they compared the two sides of their brain to see if there was any change in glucose uptake.

What did they find?

Whole-brain metabolism did not differ between on and off conditions. In contrast, metabolism in the region closest to the antenna (orbitofrontal cortex and temporal pole) was significantly higher for on than off conditions (35.7 vs 33.3 μmol/100 g per minute; mean difference, 2.4 [95% confidence interval, 0.67-4.2]; P = .004). The increases were significantly correlated with the estimated electromagnetic field amplitudes both for absolute metabolism (R = 0.95,P < .001) and normalized metabolism (R = 0.89; P < .001). [JAMA]

So basically, whole-brain metabolism was the same whether the phone was on or off. However, in regions close to the phone’s antenna, the metabolism was “significantly higher”. It is important to point out that in this context, “significantly” means statistical significance, not a large increase. In fact, the increase was only about 7%.

Brain imaging physicist Dardo Tomasi of Brookhaven National Laboratory, who co-authored the study, said that’s several times less activity than visual brain regions show during an engaging movie. [Wired]

Ok, so now the important question: what does this mean for our health? Nora Volkow, the study’s lead author commented:

Volkow says it is too early to tell whether this is good or bad for the brain. “Much larger fluctuations in brain activity occur naturally,” says Patrick Haggard at University College London. In fact, being able to increase activity might boost the brain’s connectivity, and could even be useful therapeutically, Volkow suggests. [New Scientist]

So although the study was published as a “Preliminary Communication”, and that the study itself concludes:

This finding is of unknown clinical significance. [JAMA] (emphasis mine)

there is still a large number of news outlets which reported on the study. Why?

Well we know why already. That “unknown” word in the above quote carries a lot of baggage.

Cell phones are the new danger to health, of course. Despite there being no conclusive evidence that cell phones even have the ability to cause cancer, and the fact that even with the explosion of cell phone use in recent years, cancer rates have not increased, people are still scared of their cell phone.

This is thanks to poor media coverage, and a few crackpots out there who are determined to prove that technology is going to destroy us all.

And as a result this small, preliminary study with a result that, while interesting, is completely benign, gets extensive media coverage. Not only that, but some news sites give thinly veiled comments suggesting that the results somehow show that cell phones are dangerous, like this one:

The unusual finding, published on Tuesday in the Journal of the American Medical Association, is likely to lead to new calls for stricter regulation of radiation emissions from the ubiquitous phones. The government currently assumes the signals have no effects other than a harmless warming of tissues near where they’re held. [The Globe and Mail]

or this one:

Some studies have linked cell phone exposure to an increased risk of brain cancers, but a large study by the World Health Organization was inconclusive. [MSNBC]

Of course they used the word “inconclusive” in the above quote, when it should really read “it showed no correlation”. Scicurious points out that this is probably because “‘inconclusive’ sounds scarier”.

So nobody panic. This study does not show that cell phones are dangerous. It may show that the electric field from the antenna somehow increases metabolism of glucose, but those findings need to be corroborated by other labs. Let’s wait until their findings are duplicated on a larger scale and a mechanism by which this effect happens can be discovered before we decide what, if any, impact this study should have.