Wednesday, December 1, 2010

NEJM sez 'overweight die early;' I say, Wrong.

Body-Mass Index and Mortality among 1.46 Million White Adults


Amy Berrington de Gonzalez, D.Phil., Patricia Hartge, Sc.D., James R. Cerhan, Ph.D., Alan J. Flint, Dr.P.H., Lindsay Hannan, M.S.P.H., Robert J. MacInnis, Ph.D., Steven C. Moore, Ph.D., Geoffrey S. Tobias, B.S., Hoda Anton-Culver, Ph.D., Laura Beane Freeman, Ph.D., W. Lawrence Beeson, Dr.P.H., Sandra L. Clipp, M.P.H., Dallas R. English, Ph.D., Aaron R. Folsom, M.D., D. Michal Freedman, Ph.D., Graham Giles, Ph.D., Niclas Hakansson, Ph.D., Katherine D. Henderson, Ph.D., Judith Hoffman-Bolton, Jane A. Hoppin, Sc.D., Karen L. Koenig, Ph.D., I-Min Lee, Sc.D., Martha S. Linet, M.D., Yikyung Park, Sc.D., Gaia Pocobelli, M.S., Arthur Schatzkin, M.D., Howard D. Sesso, Sc.D., Elisabete Weiderpass, Ph.D., Bradley J. Willcox, M.D., Alicja Wolk, Dr.Med.Sci., Anne Zeleniuch-Jacquotte, M.D., Walter C. Willett, M.D., Dr.P.H., and Michael J. Thun, M.D.

N Engl J Med 2010; 363:2211-2219December 2, 2010


Background

A high body-mass index (BMI, the weight in kilograms divided by the square of the height in meters) is associated with increased mortality from cardiovascular disease and certain cancers, but the precise relationship between BMI and all-cause mortality remains uncertain.

Methods

We used Cox regression to estimate hazard ratios and 95% confidence intervals for an association between BMI and all-cause mortality, adjusting for age, study, physical activity, alcohol consumption, education, and marital status in pooled data from 19 prospective studies encompassing 1.46 million white adults, 19 to 84 years of age (median, 58).

Results

The median baseline BMI was 26.2. During a median follow-up period of 10 years (range, 5 to 28), 160,087 deaths were identified. Among healthy participants who never smoked, there was a J-shaped relationship between BMI and all-cause mortality. With a BMI of 22.5 to 24.9 as the reference category, hazard ratios among women were 1.47 (95 percent confidence interval [CI], 1.33 to 1.62) for a BMI of 15.0 to 18.4; 1.14 (95% CI, 1.07 to 1.22) for a BMI of 18.5 to 19.9; 1.00 (95% CI, 0.96 to 1.04) for a BMI of 20.0 to 22.4; 1.13 (95% CI, 1.09 to 1.17) for a BMI of 25.0 to 29.9; 1.44 (95% CI, 1.38 to 1.50) for a BMI of 30.0 to 34.9; 1.88 (95% CI, 1.77 to 2.00) for a BMI of 35.0 to 39.9; and 2.51 (95% CI, 2.30 to 2.73) for a BMI of 40.0 to 49.9. In general, the hazard ratios for the men were similar. Hazard ratios for a BMI below 20.0 were attenuated with longer-term follow-up.

the media love this.

http://www.usatoday.com/yourlife/fitness/2010-12-01-overweight-death_N.htm

BMI 25 to 29.9 'overweight'
30+ obese
So, a man at average height, say 5 foot 10 inches, is 'overweight' at 174 pounds, and is 'obese' at 209.
A woman who is 'average height at 5 foot 4 inches is 'overweight' at 145 pounds, and 'obese' at 174 pounds.
You can google and find the BMI tables, but here is a website that is paying to have theirs high up on the search results:

http://www.thaipoly.com/ovw-areyou.html
Who is paying for this study? Remember: follow the money.
Iovate.
http://www.iovate.com/
They want to continue making physicians believe that being "overweight" means that you will die early, and so you should PANIC and ACT. Specifically, by taking some patented medication.
Generally, this is not true. And, no one has evidence indicating that if you take tehir patented medication, you will be an overweight person who lives longer, or will move from being oevrweight to being obese, and consequently live longer.
Please prove me wrong: post the study.
So, their lips are moving. Now, to figure out the lie.
First: we will ignore the obese people. Why? Because either you have been on steroids, or are immobilized, or you are flat out using your minutes unwisely. In any of these cases, you are an exception, or should be considered an exception. There are such great needs on this planet. If you have devoted time and money to consuming food instead of figuring out something socially redeeming to do with your time and money, that is up to you. Like we say in career counseling when attempting to help people who have the amazing fortune of being able to be undecided about work: "what if you only had one life to live?"
I do care about the plight of the obese. Just, when discussing epidemiology and pharmacology, it is a distraction. Pay me $100/hour and I will feel self-fulfilled to help you address the obesity lifestyle you have chosen.
And, anyway: who cares? The 'overweight' care. Not all. Some. But this 'some' is the bulk targeted by the profiteers. The overweight pester the docs, and crowd the gyms, and take the supplements. They hear things about body fat, or dietary fat, and flock. They perked up when the young woman in the Meridia ad said, "I'm Ready." [BTW: she is still 'overweight,' in case you were wondering.]

You who are overweight are a vast portion of the populace, and are the target - they want you to perceive yourself as 'obese,' so that you sign up for interventions that ought to be delivered to the obese. Look at the ads. A woman who looks perfect to us men is posted as a 'before,' and a well-defined body-builder with a six-pack is featured as 'after.' Will she live longer? Short answer: no. If we convince her that being 'overweight' is 'unhealthy,' or not 'fit,' then we can make money off of her. Lots of money. Because she is not 'overweight.' She is 'normal,' as God intended.

So, we will consider the 'overweight' and ignore the obese.

This study, as far as I can tell (electronic is not accessible to me yet - I will have to do something as primitive as walk over to the physical library to get details - but logic, and the space-time continuum have a stranglehold on rhetoric that is challenging to break), does not say that overweight people die earlier, but that EARLY DEATH is associated with being overweight.

Here is the key: THEY GIVE IT TO YOU IN THE ABSTRACT: TEN-YEAR FOLLOW-UP. AND MEDIAN AGE 58. People! Wake up and do the math!!!
Two questions are needed to sort this out:
1. When do people die, on average?
2. Who did they study?

That is it. Common sense defeats Goliath.

Here in the U.S., those who are sensitive to the marketing of Meridia and health club memberships have a life expectancy of 75 years, give or take.
So, the optimal way to figure out who dies early and who dies late, given a ten-year 'parameter' (self-imposed limit), would be to follow people from the age of 65 to 75, and see who dies.

for those who have made it that far, which should be a pretty representative group of the pop in general (despite inherent limits, such as the inordinate portion of Blacks who die in the womb or in early adulthood by their brothers).
That is not early death. That would be examining the differentialiation of normal death.
The odds ratios just don't fit this pattern.
If they are examining people, with a median age of 58, with a ten year follow-up ----
let me see...this will require a calculator...
http://www.metacalc.com/


OK: now we know: they examined death in a group of people from ages 58 to 68.
Life expectancy is 75.
An average.
So, the study is looking at people who...calculator needed again....
http://www.calculator.com/calcs/calc_sci.html
...are a whopping 7 years before expected death.
So, we are not looking at death, but at "early death."
THat is to say: MOST people die around the age of 75; but if you HAPPEN to be an exception, and die several years before that, we have figured out the characteristics associated with EARLY DEATH, not normal death.
Not: among those living a full life, who dies earlier.

For that, you need a group who reach some age beyond 58. Maybe 65, then follow through the age of 80. Let's get the inter-quartile range of life expectancy.

The minority (doubel-entendre intended -we epidemiologists need to be painfully aware of these disparities ) who die early are different from most of us. They have behavioral problems, or cancers, or are victims of violence or occupational hazard, or were hit by the tornado, or died from a hospital-acquired infection.

The heaving bulk of us die from heart disease, and between 70 and 80 years of age.

This study is not about the bulk of us.

That is good news: we can relax and enjoy our 'overweightness.'

All this to say: 'overweight' is a marketing tool. BMI has a loose relation with body fat. It is the body fat that will kill you; the rest of us simply believe it will kill us, but have big estimation errors in our thinking.

Look at this:

http://en.wikipedia.org/wiki/File:Correlation_between_BMI_and_Percent_Body_Fat_for_Men_in_NCHS%27_NHANES_1994_Data.PNG

It is the correlation between BMI and actual body fat. Points on or near that horizontal line are well-predicted from one to the other. The MAJORITY of dots are not wll-predicted.

Variability. What accounts for that? What accounts for data that say: my BMI may not be too bad, but my body fat is gravely indicative of my impending early death AND My BMI is bad, but I will live to be 90.

Open your Bible. Work hard, and enjoy the love of your family and community. Stay in financial control, rather than living in debt. Have kids. Have sex only in marriage. AND: eat and drink your wine, because none of us knows when we will shrug off the mortal coil.

Nothing about being 'overweight,' or supplements, or treadmills.

That is ALL from the Bible. I know, I know: "eat, drink and be merry, for tomorrow we may die" is what they made us memorize to typify the Epicurean philosophy. If your course was decent, they told, you, Epicurus NEVER actually said that, and neither did Lucretius. They did not tell you that Solomon said it.

And "mortal coil?" As with much he wrote, Shakespeare lifted that, as he lifted a gret deal, from a book he was helping translate.

The rest: heavily in Proverbs, a lot in Leviticus, and elsewhere.

You will not die early from being overweight. That contradicts established epidemiology that follows cohorts from middle-age for well beyond ten years, through the normative death expectancy range. THAT is the only way to answer the question regarding what factors will generally lead to earlier death.

Being overweight will mathematically predict your death if you are overweight because you are sedentary, or a drunkard, or have some other health condition such as something requiring steroids, or are paraplegic and inactive.

Otherwise, you are not notably at risk of early death if overweight, compared to BMI 20-25.

Relax. Don't buy their drugs or supplements. Grow old gracefully. Like Solomon says, enjoy the company of your wife, the pride your children bring, and a couple glasses of Shiraz. And stay prayed-up.
 
And what is up with all of those authors?

1 comment:

MedsVsTherapy said...

http://in.reuters.com/article/idINIndia-53567320101214

More Dada, in lieu of data.

"(Reuters) - Daily exercise over a period of 20 years helps to significantly reduce weight gain in middle age, but even that is not enough to keep away middle age bulges entirely, U.S. researchers said on Tuesday."

In other words: the concept of being overweight is --FALSELY-- so connected to the concept of being unhealthy, that Reuters plays it up as a health article, not what it actually is: a news story about personal appearance preferences - This is the same as running a story on the way that women's hair becomes less lustrous with age.

People, you will get your 70 years, 80 if you are fortunate.

You will gain some body fat.

This is 1. normal; 2. A good sign.

Why do kids heal so quickly? Why do we put on weight more easily as we age, even holding all things consistent, such as diet and exercise?

We are built to enjoy our 70 years, 80 if you are fortunate. By that time, you have figured out that all is vanity, and you have had your chance to leave an inheritance to your children's children.

Our metabolism slows down. Why? To protect us from cancer. Take your pick. Every effective youth serum gives you cancer. Our bodies heal and replicate more quickly at younger ages, so we have our time in the sun to have our children and enjoy life. After that span of time, metabolism slows down steadily.

Our cells can only replicate faithfully so many times - 14 times - the number bandied about as the number that the telomeres can split off each set of DNA in a cell as it replicates, allowing two to come form one. More than that, the telomeres do not function as well, and you get DNA mistakes, leading to unregulated cell reproduction that cannot be effectively checked by the other cells floating around that can kill off some quota of rogue-replicating cells. Cancer.

Grown old gracefully. Avoid youth serum. Recognize a beauty article even when it is masquerading as a health article.