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January 30, 2012 12:59 PM Thank Goodness TV’s Not All Bad

By Aaron Carroll

As a major consumer of television and computers, I’m constantly dismayed at how every single study seems to find that their use is linked to an enormous numbers of bad things. “Screen time” makes you fat, gives you ADHD, makes you stupid, keeps you from sleeping, etc.* So it was comforting to see at least one study that shows it doesn’t kill you:

Background: Watching television and using a computer are increasingly common sedentary behaviors. Whether or not prolonged screen time increases the risk for mortality remains uncertain
Methods: Mortality for 7350 adults aged [greater than or equal to]20 years who participated in the National Health and Nutrition Examination Survey during 1999 to 2002 and were followed through 2006 was examined. Participants were asked a single question about the amount of time they spent watching television or videos or using a computer during the past 30 days.
Results: During a median follow-up of 5.8 years, 542 participants died. At baseline, 12.7% of participants reported watching television or using a computer less than one hour per day, 16.4% did so for 1 hour, 27.8% for 2 hours, 18.7% for 3 hours, 10.9% for 4 hours, and 13.5% for 5 or more hours. After extensive adjustment, the hazard ratio for all-cause mortality for the top category of exposure was 1.30 (95% confidence interval: 0.82, 2.05). No significant trend across categories of exposure was noted. The amount of screen time was also not significantly related to mortality from diseases of the circulatory system.

I will grant you I’m not unbiased here. I love TV, I love computers, and I love video games. On the whole, I think consuming amounts of technology that would stagger mere mortals has not hurt me too much; I think I’ve turned out OK. But I agree that there should be limits. Although I’m more permissive with my kids than many of my friends are with theirs, my children are not allowed to spend too much time playing video games and watching TV. They’re turning out pretty well, too.

I will also grant you that my wife and I spend an enormous amount of time with our children, and they have a number of advantages that other children might not. But that’s the point. It’s hard to determine which of these things is causal. It may be that there are other factors that are correlated with lots of TV time that may make kids or people worse off. Perhaps parents who let their kids watch enormous amounts of TV are more likely to be bad parents. Perhaps parents who let their kids watch enormous amounts of TV are working three jobs, struggling to make ends meet, and can’t play with their kids as much as they would like. Perhaps parents who let their kids watch enormous amounts of TV are depressed or sick. There are any number of scenarios where kids who have it harder are more likely to watch TV, without it being the TV that’s hurting them.

Many of the studies account for that as best they can. But the media likes to run around extrapolating a small statistically significant correlation into headlines like “TV WILL KILL YOU!” The sensationalism is pretty staggering. This leads to a publication bias, where results that are likely to shock and garner headlines are more likely to get accepted and printed.

So I’m glad to see a negative study get published. I bet you didn’t know about this study, though. It was published last week with almost no fanfare, and I doubt you will see any news stories on it. When it comes to science, I fear the media isn’t nearly as fair and balanced as many think they are.

*Full disclosure: A number of these studies have been published by friends, colleagues, and even mentors. They know how upset I am that they keep attacking the things I love, but that doesn’t seem to be stopping them.

[Cross-posted at The Incidental Economist]

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Aaron Carroll ,MD, is an associate professor of Pediatrics and the associate director of Children’s Health Services Research at Indiana University School of Medicine.

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