Height & Cancer: One Doesn't Cause the Other

Written By Alaina Cyr
Image of Alaina and Lauren showing height difference

News headlines can be misleading, especially when it comes to news about health and research.

A recent headline “Tall women have higher chance of getting cancer, says study” on CBC News caught my eye. I'm 5'10". As it happens, the headline also got the attention of my colleague Lauren for a different reason. You see, Lauren is just shy of 5'2".

Should I really be alarmed? Could Lauren allow herself the luxury of relief? We sat down to talk about what the numbers really mean. Here's our conversation.

Alaina: Being a tall woman, I was naturally drawn to this headline and wondered what was behind it. So I dug in and found that, surprise surprise, the headline wasn't a good summary of what the research actually found. The newspapers framed the study in a way that created opportunity for some confusing, incorrect information to be spread around.

Lauren: Potentially frightening too. I mean, if you’re a tall person and you read that you’re at a higher risk for cancer, that’s going to be a little off-putting. As a short person, I was definitely relieved.

Alaina: One of many things to clarify here, that they don't mention until 4 paragraphs in, is that this research study actually found that height is more of a marker, something that could be used to indicate that you may have a higher chance of getting cancer. It’s not the cause of cancer.

Lauren: Exactly. Height is not the cause of taller women getting cancer. The causes of both height and cancer are something else entirely. It just seems that these things may go together to an extent, meaning there is a positive correlation.

When two factors, like height and cancer, have a positive correlation it means that when one of them increases or decreases, the other one does too. One way to understand positive correlations is by looking at ice cream sales. Ice cream sales tend to go up when there are more cases of drowning, and down when there are fewer cases of drowning. So there's a positive correlation between them. But that doesn't mean that one causes the other. There’s another factor at play that influences both ice cream sales and drownings.

Image of Alaina and Lauren sitting

Alaina: Let me guess. Hot weather?

Lauren: Yes, that’s it. When the weather is hot, more people are in the water and more people are buying ice cream. It seems similar with this study here - 2 things occurring at the same time, but not necessarily because one caused the other.

Alaina: That makes sense to me.

Lauren: This brings up why people should read about science in popular media with a bit of caution. You really have to read through the whole thing, be able to do a bit of analysis and say “What are they giving me? What kind of information am I getting in this article?” You have to think it though and realize that popular media may not be giving you the whole story. Research can be easily misunderstood or misinterpreted if you don’t put a little bit of analysis to it.

Alaina: Absolutely. When I looked at the research study itself, it was focused on a very specific population of women: post-menopausal women, from the United States, between the ages of 50 – 79. The headline says “women” in general, but you can’t really translate the results of this study to other populations.

Lauren: Yes, a lot of those types of details get lost in making a science article into a popular media article. So it’s something to always be aware of when you’re reading science in the media. Just to keep that in mind.

What you can do​:

News headlines are written to grab your attention so you'll continue to read the article. Sometimes this means cutting out or glossing over important details. Before you take a headline at face value, be sure to read through the entire article. Oftentimes the details get left for the last few paragraphs.

If you're still unclear about the message of the article, learn more about the study by reading other news articles or finding the original research paper. 

And, as always, talk to your doctor about what it means for you.