Tag Archives: cancer risk

When the Medical News Is Not about Weight

Debbie says:

Cancer risk news is everywhere (because cancer is so common, and so scary). Most early articles linking increased cancer risk to anything will turn out not to be true, or to be overstated, or hugely influenced by other factors. So, I wasn’t as interested in this article because of what it says as because of how it says it. The article, from that used-to-be-a-major-news-source magazine known as Time, is about links between cancer risk and height: “New research published in the journal Cancer Epidemiology, Biomarkers & Prevention found a surprising correlation between height and cancer risk among postmenopausal women; the taller the woman, the greater her risk for the disease.”

It seems to be a good enough study; it’s based on the Women’s Health Initiative data, so it’s a large pool and (as far as I can tell from a superficial article) the methodology was reasonable enough. If the article was about weight (which is constantly linked to cancer), it would end with what our own Lynne Murray calls “the faith sentence,” the capper to an article that reinforces what the writer and/or the researchers believe. In the cancer/weight articles, it is usually “proper attention to diet, weight and lifestyle management would save so many lives,” or words to that effect. In weight articles, the faith sentence is a club, used to remind you that your cancer (or whatever) is your fault and you just aren’t managing yourself properly. Here’s the American Cancer Society’s version:

While we still have much to learn about the link between weight loss and cancer risk, people who are overweight or obese should be encouraged and supported if they try to lose weight. Aside from possibly reducing cancer risk, losing weight can have many other health benefits, such as lowering the risk of other chronic diseases like heart disease and diabetes. Losing even a small amount of weight has health benefits and is a good place to start.

In the Time article, we see a very different faith sentence.

[Dr. Thomas] Rohan, [chair and professor of epidemiology and population health at Albert Einstein College of Medicine] and his colleagues say the study doesn’t imply that cancer is inevitable for every tall woman. The study found an association, not a cause-and-effect relationship. And it’s unlikely that diseases as complex as cancer can be traced to just one developmental process such as growth.

In other words, ladies, your height is not your fault, so we need an ending sentence that tells you not to worry too much, and not to assume you are doomed. If the same sentence was used as the closure for an article about the risks of fat in any area of health, it would say:

[Experts] say the study doesn’t imply that [this disease] is inevitable for every fat woman. The study found an association, not a cause-and-effect relationship. And it’s unlikely that diseases as complex as [this one] can be traced to just one developmental process such as body size. While losing weight has known health benefits, it also has associated health risks, and has been regularly demonstrated not to be reliably possible, even in very carefully controlled conditions.

The great thing about this faith sentence is that it’s true.

Women, Alcohol, and the “Faith Sentence”

Debbie says:

A couple of weeks ago, Lynne Murray blogged for us about the “faith sentence,” that little coda at the end of a journalism piece that repeats common wisdom, even if it’s completely contradictory to the facts in the article. This week’s faith sentence, from this article, is “There is no level of alcohol consumption that can be considered safe.”

Unfortunately, the entire study is available only by subscription, so we can’t quote from it directly. Perhaps more unfortunately, we can’t really blame journalists or the media for the message that’s getting out: the study’s abstract repeats the faith sentence.

I trust Sandy Szwarc at Junk Food Science, and she reports on it extensively.

The actual incidents of all cancers was 5.7% among the nondrinkers. The cancer incidents were lower among the women drinking up to 15 drinks a week: 5.2% among those consuming ≤2 drinks/week; 5.2% of those drinking 3-6 drinks/week; and 5.3% among those drinking 7-14 drinks a week.

In other words, women drinking as many as two drinks a day were associated with lower actual incidences of all cancers compared with the nondrinkers.. This is the exact opposite of what has been widely reported. Although the differences in actual cancer risks were tiny, nondrinking was associated with a 0.4% higher incidence of all cancers compared to women drinking two drinks a day.

The incidents of all cancers among the women drinking the most alcohol (15 or more alcoholic drinks a week), who made up only 5% of the cohort, was 5.8%, nearly the same as the nondrinkers. These women differed from the other groups of drinkers in other ways, such as being more likely to smoke, to exercise strenuously, have used oral contraceptives and be currently using hormone replacement therapy, have higher socioeconomic status, and lower BMIs. So considerable potential confounding factors are involved in trying to interpret this correlation.

Sandy has more to say, of course, including the salient facts that the numbers were not statistically “tenable” and that everything is based on secondary data from the Million Women Study, and the only thing it could do, even if it had produced statistically significant numbers, would be to show a correlation without a causation.

This kind of science, of course, is familiar to readers of Body Impolitic, Junk Food Science, or a legion of other sources that pay attention to science reporting. In this case, there’s another factor.

The researchers were working with the Million Women Study data, not interviewing new people, so by definition all of their subjects were women. Therefore, when the alcohol study is reported, the headlines say:

“Even Small Amounts of Alcohol Increase a Woman’s Risk of Cancer” or “Daily Drink for Middle-Aged Women Cancer Risk.”

Given the flaws in the study abstract, this is accurate reporting. The study did concentrate on women and the researchers did state that the risk is important. At the same time, listen for the implication: Drinking is fine for men. Especially in this period where there’s so much pressure to separate out the physiology, neurochemistry, and sociology of men and women, labeling something as “about women,” even if that label is factually accurate, carries a connotation of “not about men.”

Looking at various articles reporting the study, most of them simply don’t mention men. The one that does says, more than halfway through the article:

“Lead author Dr Naomi Allen from the University of Oxford said her work would help the government assess whether the limits should be changed, although the study did not look at men.”

In this case, because the study’s analysis is so thoroughly flawed, the reporting does men a favor and women a profound disservice. But it could so easily cut the other way.

Thanks to Rich Dutcher for pointing it out, and to Charlie Stross for doing a lot of the legwork.