When I was out of the country a few weeks ago, the latest study proclaiming that single people are doomed followed me around. It was in the headlines of newspapers in the airports, and a story about it in another language was shown to me by a journalist at a conference where I was speaking – about the stereotyping and stigmatizing of single people that I call singlism. Ironic, in a way.
I’m talking about the study of marital status and cancer, claiming, predictably, that married cancer patients fare better than single ones: they are more likely to get diagnosed before the cancer has spread, they are more likely to receive the treatment considered definitive, and they are more likely to survive their cancer.
The researchers compared patients who were currently married to those who were not married (divorced or widowed or always-single). That last sentence right there tells you something essential about the research. This is a study from which definitive causal conclusions can never be drawn. No matter how many stories you may have read about this research suggesting that the married patients did better because they were married, none of them had any sound scientific basis for making that claim.
Most of the stories I read did not just proclaim that “married cancer patients live longer” (that exact headline is from the New York Times — I’ll critique their story in detail later); they went on to tell us why that happened. Most explanations pointed to social support and nagging (though they did not use that N word) – married patients have a spouse to make sure they get to the doctor quickly and who support them as they deal with the disease; single people, the hackneyed story goes, don’t have anyone.
Now here’s something that none of the media reports mentioned: All of the suggested explanations were just guesses. Social support was not measured. Nagging was not measured.
If you want to know more of the details of the study, read the next section. Otherwise, skip to the following section where I resume making fun of all of the bad reporting about it in the media, and most embarrassingly, in an editorial that appeared in the journal that published the original research (Journal of Clinical Oncology). The authors actually did include some of the most important caveats in their article, but what fun would it be for the media to admit that marriage may have had nothing to do with the findings?
The Details of the Research
(The original article may be either unavailable in its entirely or behind a pay wall. If you cannot access it, the best summary I found is this one from the U.S. National Library of Medicine, which even spells out the most compelling alternative explanation to the one you heard so often in the media.)
The National Cancer Institute maintains a huge database of information on the incidence, treatment, and survival from cancer. The researchers examined data from more than 700,000 people 18 and older who had been diagnosed between 2004 and 2008 with one of the 10 deadliest cancers.
Controlling for age, sex, race, education, household income, and rural vs. urban residence, the researchers found that unmarried patients who were first diagnosed were more likely to have a cancer that had spread than were the currently married patients.
Next, they looked only at those 500,000+ patients whose cancer had not spread. They determined whether the patients had gotten the treatment (either surgery and/or radiation – no information on chemotherapy was available) considered definitive for their type of cancer. They found that after adjusting for the demographic factors as well as the tumor and nodal stage, the married patients “were more likely to undergo definitive surgical and/or radiotherapeutic management” than the unmarried patients. (The authors suggested that “the most likely reason is that married patients have better adherence with prescribed treatments than unmarried patients.”)
Finally, survival rates were analyzed as of about 3 years after the diagnosis. Married patients were less likely to have died from their cancer than were the unmarried patients.
The currently married patients also fared better than the unmarried patients when they were compared to each category of unmarried people (divorced, widowed, always-single) and not just when all of those subgroups were combined.
Finally, all three of the supposed advantages of marriage were greater for the men than for the women.
Did You Notice the Problems that All of the Media Stories – and the Editorial in the Medical Journal – Missed?
The story being told about the findings of this study is that married people with cancer fared better than unmarried people because they were married, and marriage comes with benefits such as social support and encouragement to get to the doctor sooner.
The key question is: What other explanation is possible? Is there a different reason why married people might seem to fare better in the ways measured in this study?
Here’s another hint. To claim that cancer patients do better because they are married is to say that if single people would get married, they would do better, too. Another implication of that claim is that if only the divorced people had stayed married, they too would be more likely to survive cancer. Do you buy that? If not, what does that tell you about how to think about the results?
Think about your critiques. Feel free to share them in the comments section. In a few days, I will post mine in Part 2. [Here it is.]
[Note: Thanks to Alan, Jeanine, and Erin Albert for sending me links and questions about this study.]
Hospital patient image available from Shutterstock.