Body Mass Index: How Good a Measure

bmi-comparisonMother Jones posted an article questioning whether the body mass index is “a big fat scam.” It raises questions about the measure itself, the extent to which it is a predictor of health, and the politics.
See article: Click Here
In brief, the authors write:

“Doctors typically use BMI to advise their patients: If you’re below 18.5, you’re underweight; 18.5-24.9 is normal; 25-29.9 is overweight; and 30-plus is obese.

There’s just one problem: A higher BMI doesn’t necessarily mean you’re less healthy. In fact, patients with heart disease and metabolic disorders whose BMIs classify them as overweight or mildly obese survive longer than their normal and underweight peers. A 2013 meta-analysis by the National Center for Health Statistics looked at 97 studies covering nearly 3 million people and concluded that those with overweight BMIs were 6 percent less likely to die in a given year than those in the normal range. These results were even more pronounced for middle-aged and elderly people. This is known as the obesity paradox. “The World Health Organization calls BMIs of 25 to 29.9 overweight,” says Paul McAuley, an exercise researcher at Winston-Salem State University. “That is actually what is healthiest for middle-aged Americans.”

“And get this: While epidemiologists use BMI to calculate national obesity rates (nearly 35 percent for adults and 18 percent for kids), the distinctions can be arbitrary. In 1998, the National Institutes of Health lowered the overweight threshold from 27.8 to 25—branding roughly 29 million Americans as fat overnight—to match international guidelines. But critics noted that those guidelines were drafted in part by the International Obesity Task Force, whose two principal funders were companies making weight loss drugs. In his recent book Fat Politics: The Real Story Behind America’s Obesity Epidemic, political scientist Eric Oliver reports that the chairman of the NIH committee that made the decision, Columbia University professor of medicine Xavier Pi-Sunyer, was consulting for several diet drug manufacturers and Weight Watchers International.”

The measure itself is problematical. People with muscle will likely have higher BMI, but the BMI does not account for that differential.
Sometimes simple measures are not as accurate as we would like, making prediction about causality problematical. This is a great topic for those looking to explore the nexus of science, the media, public policy, and politics.

links: Washington Post article: change to BMI standard: Click here

Link to obesity meta analysis study:Click here

Taubes: Why is Nutrition So Confusing?

nutrition NY timesThe New York Times published an article by Gary Taubes that explores the challenges of scientific research when it comes to understanding nutrition.Click Here

He notes that obesity, and its related diseases like Type II diabetes, have increased dramatically since the 1960s. (Gail”s note: Leaving aside some increase is due to changing definitions, not all of the increase can be explained by that). The public discussion and research about those to issues has also increased dramatically. Taubes states, “In 1960, fewer than 1,100 articles were published on obesity or diabetes in the indexed medical literature. Last year it was more than 44,000. In total, over 600,000 articles have been published purporting to convey some meaningful information on these conditions.”

Yet, we really do not know much about causes or prevention or nutritional treatment. It is possible that our understanding about nutrition is flawed, or that our assumptions about people are flawed: that everyone’s body is the same, and what works for one person should work for everyone. Or our attachment to an beloved theory makes it hard to recognize that it does not really explain much or work: in my view, the restricted calories as the solution pretty much fails for a lot of people.

Taubes offers another possible explanation about all these articles: ” {They] are the noise generated by a dysfunctional research establishment. Because the nutrition research community has failed to establish reliable, unambiguous knowledge about the environmental triggers of obesity and diabetes, it has opened the door to a diversity of opinions on the subject, of hypotheses about cause, cure and prevention, many of which cannot be refuted by the existing evidence. Everyone has a theory. The evidence doesn’t exist to say unequivocally who’s wrong.” Continue reading »

Politics: Lies and Deception

The Congressional Budget Office released its economic outlook report that included two appendices that dealt specifically with the Affordable Health Care here

Because a number of people work full-time solely to maintain insurance coverage (either because the cost of obtaining individual insurance would be prohibitive or because they would be unable to obtain any insurance because of pre-existing conditions), the Affordable Care Act will give people some options. CBO estimates that a number of people will opt to stop working or reduce their hours because they will have access to health insurance that no longer requires them to work full-time. For some, they might opt to retire at age 62, three years before they are eligible for Medicare. For others, they might decide to leave the workplace and start their own business or go back to school  to launch a new career. For some, they will be able to drop down to a 32-hour workweek, to better meet the needs of their family.  No doubt there are many other reasons.

Krugman says this was always known and CBO puts the estimate at around 2 million in this report. He then reports the tweet by Representative Eric Cantor, the House majority leader:  “Under Obamacare, millions of hardworking Americans will lose their jobs and those who keep them will see their hours and wages reduced.”  See: Twitter account

From my perspective, outright lies do not serve the public interest. It is one thing to disagree about a public policy, but deception, distortion, spinning–whatever it is called–is still a lie.  And if a lie is the only thing you can say, then maybe it is time accept that you have no valid point and should just be quiet.

Continue reading »

Public Agrees on Obesity’s Impact, Not Government’s Role

PEW just published survey results on views about the government’s role in reducing obesity. Basically, the PEW survey found that people opined that obesity has an impact on society, but did not see much of role for government action. PEW summed it up: Yes to Calories on Menus, No to Soda Limits.

PEW writes: “Most Americans (69%) see obesity as a very serious public health problem, substantially more than the percentages viewing alcohol abuse, cigarette smoking and AIDS in the same terms. In addition, a broad majority believes that obesity is not just a problem that affects individuals: 63% say obesity has consequences for society beyond the personal impact on individuals. Just 31% say it impacts the individuals who are obese but not society more broadly.”

Read the story: Click Here
PEw obesity views











Continue reading »

Link Between Antibiotics and Obesity?

Mother Jones printed an article today by Kiera Butler and Jaeah Lee looking at the link between antibiotics and obesity.
(The Mysterious Link Between Antibiotics and Obesity:States where doctors prescribe more antibiotics also have the highest obesity rates. Why?)

The authors write: “Lately, I’ve been fascinated by a study on antibiotic prescription rates across the United States that was recently published in the New England Journal of Medicine. The researchers found a surprisingly wide variation among the states, and the rates—expressed in terms of prescriptions per 1,000 people—seemed to follow a geographical pattern: The Southeast had the highest rates, while the West’s were lower. West Virginia had the most prescriptions, and Alaska had the fewest. The rest of the country fell somewhere in between.”
Here’s a map of the findings:



Continue reading »

Health: Racial Disparities

The Harvard School of Public Health held an expert panel to discuss racial disparities.
They note: “Each speaker acknowledged that racial minorities have made significant gains over the past half-century, but said there is much more work still to do. They cited statistics providing stark evidence of continuing disparities in health, wealth, education, income, arrest and incarceration rates, foreclosure rates, and poverty. Coleman called the data “disconcerting; in some cases, alarming.”
Click here to see their report

“Health care disparities are troubling, Coleman said. One study found that doctors recommended coronary revascularization—bypass surgery that replaces blocked blood vessels with new ones—among white patients with heart disease 50% of the time, but just 23% of the time for blacks. Black women are less likely to be given a bone marrow density test than white women, even when it’s known they’ve had prior fractures. And the black infant mortality rate is 2.3 times higher than that of non-Hispanic whites.”

This Is Your Brain on Toxins–Op Ed

Today’s New York Times has an op-ed by Nicholas Kristof about the toxins in our world.
His article begins:
“Lead helps to guard your health.” That was the marketing line that the former National Lead Company used decades ago to sell lead-based household paints. Yet we now know that lead was poisoning millions of children and permanently damaging their brains. Tens of thousands of children died, and countless millions were left mentally impaired.”

He takes on the endocrine disruptors, and the politics of lobbying and regulation. He uses anecdotes and some data–but clearly, this is a big issue.  It is worth reading: Click Here

Cost of Health Insurance

An article in the NY Times’ Economix by UWE E. REINHARDT reports on the Kaiser Family Annual Survey findings on the cost of health insurance: “The survey in question is the Kaiser Family Foundation’s annual survey of employment-based health insurance, widely viewed as a gold mine for anyone seeking information on that part of the American health system. The full report is easily accessible, or readers may prefer to read just the summary or browse through the fine group of charts the foundation provides. Here is a telling chart from that pack.”

This chart, shows the costs (not controlled for inflation–i.e. current dollars) over time and doesn’t compare benefit packages–so there are some caveats here. If I was assigning a research project, I would ask students to look at the rate of inflation over this same time period and look at rates of change, to see whether the insurance premiums have tracked with inflation. Alternatively, I could ask students to to convert these to constant dollars, so that the rate of inflation is controlled and therefore can be compared.
health insurance chart










To read the NY Times post: Click Here

Do Clinical Trials Work?

pillsA NY Times article asking “Do Clinical Trials Work?” stirred up lots of questions about the challenges of using experimental designs. Read here Clinical trials (also called experimental designs) are often referred to as “the gold standard” of research. In social science, they are hard to do; when they are used, the results are often inconclusive. Somehow, I thought science might be different, but at least in terms of health research on drugs, the results are also often disappointing, according to the author Clifton Leaf. Continue reading »