Junkfood Science: Medical news is not medical information

February 15, 2008

Medical news is not medical information

Today provided one of the most extreme examples of medical marketing, with 2,090 news stories all appearing on precisely the same day, in media around the world, and all saying the same thing: a new study claimed to have found overweight or obesity to be associated with higher risks for cancers.

Regular JFS readers no doubt simply rolled their eyes at the desperation in another data dredge — that couldn’t report a single, solitary higher risk above random chance — claiming a link between fat and cancer.

Since reruns are boring and readers have already overdosed on fat and cancer stories, you may be most interested in what the news left out of the story.

For those needing a quick review, last fall, several major papers were released examining body fatness, diet, and lifestyles and their links to cancers. All found the same thing: nothing. The Second Expert Report by the World Cancer Research Fund and American Institute for Cancer Research reviewed 2,471 studies on 17 cancers and found no tenable associations between cancers and foods or body fatness, nor between cancer deaths and BMIs. That was followed days later by the study from scientists at the National Center for Health Statistics at the Center for Disease Control and Prevention which reviewed 40 years of actual NHANES and vital statistics data on 2.3 million Americans. It also found no viable associations between overall cancer mortality and any BMI category. Finally, there was the Million Women Study that examined relative risks for 17 cancers and mortality associated with BMI among 1.22 million women and it, too, came up with null findings.

With Prime Minister Gordon Brown promoting a Health Service constitution outlining “rights and responsibilities” and mandating healthy lifestyles and weights for people to be entitled to care under the UK’s National Health System (NHS), and the UK government’s Foresight Programme and Tackling Obesities: Future Choices Project, the obesity scares have been especially intense from across the pond.

Today, a meta-analysis looking for correlations between overweight/obesity and specific, less common cancers was published in the British journal, Lancet. It was led by Dr. Andrew Renehan from Christie Hospital NHS Foundation Trust and a member of international obesity organizations.

The authors did a literature search in Medline and Embase for internationally published papers (from 1966 to November, 2007) on certain cancers (“less common cancers” than the World Cancer Research Fund study) and the terms “obesity,” “adiposity,” “body mass index” or “body size.” They found 4,825 citations, studies of different types and durations, that included case control studies imbedded in cohort studies and control arms from clinical trials, and those using self-reported data, as well as actually measured data. They then eliminated studies that didn’t fit their criteria (those that examined cancer mortalities, rather than incidences; those that didn’t delineate specific sites, menopausal status, or break down BMI into three or more categories, etc.).

They also eliminated all of the studies that found no associations between cancers and BMI.

They ended up with 141 papers, reporting on 76 studies, for the 15 cancers they chose to examine. None of the North American population studies they used reported on galbladder, gastric, liver, esophageal or thyroid cancers. Only one cohort had different ethnicities and only two included Black Americans. They didn’t control for endless confounding factors, let alone any, such as smoking, socioeconomic status, use of hormones, medications or steroid usage, age, etc.

They only looked for correlations between higher BMIs and cancers, not correlations between lower BMIs and cancers.

Already, readers are identifying many of the common deficiencies of meta-analyses with specific goals, simply from the selectivity of studies chosen (and not chosen) that will be culled through looking for correlations.

Another interesting note is that they looked only at 282,137 cases over 41 years — a mere 0.0006% of the cancer incidences in the world, per 2002 data from the GLOBOCAN database compiled by the International Agency of Research on Cancer, the World Health Organization agency (which reports more than 10.86 million new cancer cases in one year). According to GLOBOCAN, the highest rates of cancers are not in regions of the world that are hotbeds of obesity, either. “Nearly 45 percent of the new cases were diagnosed in Asia, 26 percent in Europe, 15 percent in North America, 7 percent in Latin America, and 6 percent in Africa.” The highest cancer deaths in the world occur in Asia, followed by Eastern Europe.

Rather than split hairs, to cut to the chase, this study was a nonfinding. All of the relative risks hugged either side of 1.0 (a null finding) and none of the associations between higher BMIs and any cancer went above random chance or statistical error (RR=3.0 or 200%) for these types of data dredges.

Its data actually found what the other major studies released last fall had found: being overweight or obese is not linked to a higher overall risk for cancers.

Among men, relative risks associated with increased BMI and the cancers they examined went from a 29% lower risk to 52% higher risk; and among women, the associations went from a 43% lower relative risk to 59% higher risk. The media, of course, only told us of the higher risks, never mentioning that all of the associations were untenable, and never mentioning any of the lower risks for cancers associated with obesity.

Instead, the media and every vested interest in the war on obesity have been quick to transform nonviable correlations into causations and conclude that this study provided more evidence that being fat is bad and in need of ___ [weight loss or ‘healthy’ foods, or “public health approaches to reverse the obesity epidemic, including restricting junk food ads, taxing sugary drinks and other high-calorie, high-fat foods, lowering the cost of healthy foods and promoting physical activity in schools and workplaces...”].

The sad part of science by press release, isn’t just the harmful, agenda-driven scares lodged against those our society currently finds undesirable, but all of the medical news that goes unreported because it doesn’t come with a press release, advertisers and major advertising firms. That very same issue of Lancet also had papers, for example, examining global food insecurity, how we might better help children suffering from undernutrition in Haiti and developing countries, the problem of domestic violence against women in Nepalese, HIV testing and human rights violations, effective international interventions for undernutrition and hunger, and others.

And did you hear of the small case study by London doctors who warned of nonprescription skin-whitening creams? These products are a huge black market in parts of the world where fairer skin is associated with beauty, they said. In this issue of Lancet, they detailed the case of a 28-year old woman who had gained 28 pounds, became infertile, and developed disfiguring dark scars and bruising over her body, muscle weakness and facial hair after using a “natural” cream for years that had been found to contain a powerful steroid.

It seems, sadly, that the entire world is absorbed with appearances, and the money that can be made from looks, and too easily forgets the lives and well-being of people.

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