TV: love it or hate it, one thing you can’t deny is that it’s the best way to mindlessly vegetate after a long day of work. The cultural importance of television in all of its myriad forms is huge, which makes it strange that we have such a love/hate relationship with the glowing rectangles of comedy and drama. On the one hand, we spend ever-increasing portions of our lives watching shows on regular programmed television, or streaming it online. On the other, we have a nagging fear that our love of TV is doing something awful to our health.
And according to recent news reports, we’re right. It’s giving us cancer.
Across the world, the news has been reporting that watching TV is basically as bad as smoking. According to the Daily Mail, The Times, Jakarta Post, and dozens of other publications, watching TV has been proven to increase your risk of colorectal cancer. The Sun even went so far as to blame this all on Netflix, which was an interesting decision.
Luckily for those of us who love to binge on TV, the media got it wrong.
You probably don’t have to worry so much about Netflix and cancer after all.
The new study that has everyone blaming death and disease on the Gilmore Girls is actually a very interesting piece of science. Basically, the scientists took an existing dataset of a very large number of women, and looked at their risk of developing cancer when divided into three groups: <7 hours of TV per week, 7–14 hours of TV, 14+ hours of TV (<1, 1–2, 2+ hours per day, respectively). They found that those who watched the most TV had a statistically significant increased risk of young-onset colorectal cancer — cancer of the colon that is diagnosed before you turn 50 — when compared to those who watched very little or no TV.
Essentially, more TV means more cancer.
As far as epidemiological studies go, this was a really well-done piece of work. The researchers controlled for a lot of factors that are related to cancer — age, smoking, alcohol intake, BMI — which makes their analysis a lot better. It was also a very large group of people — more than 100,000 people for over 10 years — which also makes the study more robust.
But before you punt your TV screen-first through a window, there are a few issues with the reporting of the study that make it much less scary to your life.
TV probably isn’t giving you cancer after all.
Sometimes when you see reporting that’s probably wrong, it takes time to unpick. You have to look through complex scientific work, decode what the researchers did, and point out exactly how the journalists buggered up.
This time, it’s a bit easier.
If you read the abstract from the study, in the conclusions it says right there what the issue is:
“Independent of exercise and obesity, prolonged sedentary TV viewing time, a surrogate for a more inactive lifestyle, was associated with increased risk of young-onset CRC, particularly of the rectum.”
The thing is, even the scientists who conducted this study don’t think that TV watching itself is harmful. The issue is that watching TV stops you from doing other things that are beneficial. If you’re binging Altered Carbon, you’re less likely to be outside and exercising. If you’ve been watching reruns of Friends for the last two months, you might be eating more unhealthy snacks than, say, someone who spends most of their time at the gym.
The idea is not so much that TV itself causes harm, but that sedentary behaviour — which we know is an issue — does. TV is just a stand-in for the real issue, which is that we are spending more of our time sitting down and less of it exercising.
There were other problems with the reporting of the study. Most outlets reported the terrifying “70% increased risk” of cancer, but failed to mention that this was just a relative risk ratio. If you look at the absolute risk increase from watching TV for the highest group, it was more like a 0.008% increased risk of cancer.
The risk was also only apparent in the group that watched the most TV. For people who watched 1–2 hours a day — the majority of the people in the study — there was no increased risk of cancer at all. A more honest headline could’ve said “TV watching associated with 0.008% increased risk of cancer, but only if you watch more than 2 hours a day”.
Not as scary, but a lot more true.
The sad thing is, anyone who even read through the abstract of the study would’ve known that this wasn’t really about TV. Even the quotes used in some articles contradicted the media stories themselves.
And yet, the story became “Don’t watch TV you’ll get cancer”. Even though it was obviously wrong.
A bit sad, that.
So what does this study mean to your life? Honestly, not much at all. If you’re spending more than 14 hours a week sitting down in front of a television, it might be a good idea to go and exercise a bit more. But we all already knew that. Public health authorities have been saying it for decades. And the increased risk identified in this piece of research is so small that it means virtually nothing to the individual.
Don’t stress too much about TV.
It’s probably not giving you cancer after all.