Saturday, November 10, 2007

Middling weight wins again

Just in time for Thanksgiving comes the word we've been longing for: People who carry a little extra weight are dying at lower rates than their counterparts of "normal" size. The latest research, published in today's Journal of the American Medical Association, stirs up unresolved conflicts about the true risks of those love handles.

For years, a public health drumbeat has argued we're eating ourselves into early graves, risking cancer, heart disease and other ills. Skinny mice live longer, we're told. Losing even a few pounds will improve your health. Yet a counter-rhythm also has been gaining volume, as studies of large groups of people document that moderately chunky folks aren't actually dropping dead as anticipated. They're outliving those of normal size. Even the federal Centers for Disease Control and Prevention has flip-flopped, sharply lowering its estimates of obesity-related deaths over the past three years. Now federal officials are downplaying the death-risk angle and instead telling people that their daily lives and health care costs will improve if they weigh less.

Those who study obesity - and those who study obesity researchers - suspect two things are going on. First, the relationship between weight and health is much more nuanced and personal than can be explained with a simple weight chart or a single study. Blood pressure, cholesterol, blood sugar, family health history and even waist circumference play a role.

And second, we have such a cultural horror of fat that we're predisposed to believe even a little is bad for us. "We see our data through cultural lenses, and the cultural lens that most of us wear in contemporary American society is one in which thin is better," said Abigail Saguy, a UCLA sociology professor who is writing a book on medical and political debates about weight.

Katherine Flegal, lead author of the latest study and a senior research scientist at the National Center for Health Statistics, puts it differently. "The whole issue of weight and mortality is fairly complex. There's no simple, one-size-fits-all way to talk about this," she said. Flegal advises people to see their doctor for the best assessment of their personal health risk at any weight.

More broadly, the CDC now recommends that at all weights, people should exercise regularly and eat nutritiously to optimize health. Yet the CDC also promotes a weight range that is coming under increasing fire, from its own researchers and others.

At the crux of the debate is who is "overweight" and what the term really says about health. In 1998, in a controversial move that some argued played into the hands of the diet drug industry, the federal government toughened its guidelines, adding roughly 25 million Americans to the ranks of the dangerously hefty. Since then, the standard adopted by the National Institutes of Health says that those with a body mass index, or BMI, of 18.5 to 24.9 are "normal," with "overweight" ranging from 25 to 29.9 and "obese" starting at 30.

BMI is a ratio of weight to height, and for a woman who is 5 feet 4 inches tall, the standard says that anything between 108 and 145 pounds is normal, 146 to 174 pounds is overweight and 175-plus is obese. Yet doctors and researchers have argued about whether the data really support that description of "overweight." "Ultimately, we're going to have to do better than BMI," said Dr. Robert Lustig, who runs the pediatric obesity program at the University of California, San Francisco. A BMI between 25 and 30 actually can reflect three factors linked to improved health - muscle mass, bone density and subcutaneous fat, Lustig said. It also can capture one thing linked to bad health: visceral fat, which gathers at the abdomen and is metabolically active in dangerous ways.

Dr. Tom Hopkins, a Sacramento weight-loss specialist, shares the view that no well-documented dangers apply universally to everyone lumped into the "overweight" category. Hopkins doesn't worry about the faint hint of jowls at his jaw line, or the 205 pounds he carries on a 5-foot-11-inch frame, giving him a BMI of 28.6. "Fitness counts. Fatness doesn't," said Hopkins, who eats right and works out regularly.

The heavier people get, though, the more the ambiguities fade. By the time BMI tops 40 - for a 5-foot-4 woman that would be 233 pounds or more - much firmer links emerge with health problems.

In 2005, the same research team that conducted the newest study took a broad look at the issue, based on a large public health database. That study found unexpectedly low deaths among people who were overweight but not obese. This time, Flegal and three other researchers with the CDC and the National Cancer Institute delved deeper, seeking links between specific weight ranges and causes of death. Their conclusions:

* A little bit of pudge - BMIs of 25 to 29.9 - is correlated with lower death rates from respiratory disease, injury and a host of other ills when compared with people of normal weight.

* Merely overweight people appear to have no increased risk of death from cancer or heart disease, the two leading causes of death in America.

* A link between heart disease deaths and weight emerges only at BMIs above 30 and has been steadily weakening, possibly because of better treatments for cardiovascular disease.

* There is no link between weight and overall cancer death rates, but obese people do die more frequently from seven cancers considered weight-related, including colon, breast and pancreatic.

* The overweight and the obese, combined, have a higher risk of dying from kidney disease and diabetes.

Flegal stressed that no one really knows what is behind the statistical links between certain weights and certain fates. More study is needed. Researchers speculated that overweight people may be better equipped to withstand infections, injuries and medical procedures because they have greater nutritional reserves and often more lean body mass. For now, as the science unfolds, we're left with a broad consensus on basic health advice: Get plenty of exercise, eat your vegetables, and make sure your blood pressure, cholesterol and blood sugar levels are monitored and treated as needed. And maybe one day, the now quaint notion of pleasingly plump will give way to a trendy new concept: protectively plump.



There is a fairly reasonable argument that C-sections are overdone in some hospitals. So we have to prove that they are really frightening in order to stop women having them, apparently. The article below tries to do that by saying that C-sections are more likely to kill you than are natural deliveries. And that foremost medical propaganda organ -- the BMJ -- published it, of course. That the results might not generalize beyond Latin America is glided over. Popular summary below followed by journal abstract:

Women having a non-emergency caesarean birth have double the risk of illness or even death compared to those having a vaginal birth, according to a new study in the British Medical Journal. Researchers randomly selected 120 hospitals from eight Latin American countries. There were 97,307 births during the three-month study period -- 34 per cent were caesarean and 66 per cent vaginal. Compared to women who had a vaginal delivery, those having an elective caesarean had twice the risk of illness and mortality (including death, hysterectomy, blood transfusion and admission to intensive care) and five times the risk of needing antibiotic treatment after birth. The chances of the baby being admitted to an intensive care unit were doubled, and the risk of the baby dying in hospital was 70 per cent higher after a caesarean delivery compared to a vaginal birth. While caesarean delivery was beneficial for breech-born babies (born feet first), the authors conclude that there is no overall benefit in non-emergency caesareans, and they are likely to do harm.


Maternal and neonatal individual risks and benefits associated with caesarean delivery: multicentre prospective study

By Jose Villar et al.

Objective: To assess the risks and benefits associated with caesarean delivery compared with vaginal delivery.

Design: Prospective cohort study within the 2005 WHO global survey on maternal and perinatal health.

Setting: 410 health facilities in 24 areas in eight randomly selected Latin American countries; 123 were randomly selected and 120 participated and provided data

Participants: 106,546 deliveries reported during the three month study period, with data available for 97 095 (91% coverage).

Main outcome measures: Maternal, fetal, and neonatal morbidity and mortality associated with intrapartum or elective caesarean delivery, adjusted for clinical, demographic, pregnancy, and institutional characteristics.

Results: Women undergoing caesarean delivery had an increased risk of severe maternal morbidity compared with women undergoing vaginal delivery (odds ratio 2.0 (95% confidence interval 1.6 to 2.5) for intrapartum caesarean and 2.3 (1.7 to 3.1) for elective caesarean). The risk of antibiotic treatment after delivery for women having either type of caesarean was five times that of women having vaginal deliveries. With cephalic presentation, there was a trend towards a reduced odds ratio for fetal death with elective caesarean, after adjustment for possible confounding variables and gestational age (0.7, 0.4 to 1.0). With breech presentation, caesarean delivery had a large protective effect for fetal death. With cephalic presentation, however, independent of possible confounding variables and gestational age, intrapartum and elective caesarean increased the risk for a stay of seven or more days in neonatal intensive care (2.1 (1.8 to 2.6) and 1.9 (1.6 to 2.3), respectively) and the risk of neonatal mortality up to hospital discharge (1.7 (1.3 to 2.2) and 1.9 (1.5 to 2.6), respectively), which remained higher even after exclusion of all caesarean deliveries for fetal distress. Such increased risk was not seen for breech presentation. Lack of labour was a risk factor for a stay of seven or more days in neonatal intensive care and neonatal mortality up to hospital discharge for babies delivered by elective caesarean delivery, but rupturing of membranes may be protective.

Conclusions: Caesarean delivery independently reduces overall risk in breech presentations and risk of intrapartum fetal death in cephalic presentations but increases the risk of severe maternal and neonatal morbidity and mortality in cephalic presentations.

BMJ, published 30 October 2007


Just some problems with the "Obesity" war:

1). It tries to impose behavior change on everybody -- when most of those targeted are not obese and hence have no reason to change their behaviour. It is a form of punishing the innocent and the guilty alike. (It is also typical of Leftist thinking: Scorning the individual and capable of dealing with large groups only).

2). The longevity research all leads to the conclusion that it is people of MIDDLING weight who live longest -- not slim people. So the "epidemic" of obesity is in fact largely an "epidemic" of living longer.

3). It is total calorie intake that makes you fat -- not where you get your calories. Policies that attack only the source of the calories (e.g. "junk food") without addressing total calorie intake are hence pissing into the wind. People involuntarily deprived of their preferred calorie intake from one source are highly likely to seek and find their calories elsewhere.

4). So-called junk food is perfectly nutritious. A big Mac meal comprises meat, bread, salad and potatoes -- which is a mainstream Western diet. If that is bad then we are all in big trouble.

5). Food warriors demonize salt and fat. But we need a daily salt intake to counter salt-loss through perspiration and the research shows that people on salt-restricted diets die SOONER. And Eskimos eat huge amounts of fat with no apparent ill-effects. And the average home-cooked roast dinner has LOTS of fat. Will we ban roast dinners?

6). The foods restricted are often no more calorific than those permitted -- such as milk and fruit-juice drinks.

7). Tendency to weight is mostly genetic and is therefore not readily susceptible to voluntary behaviour change.

8). And when are we going to ban cheese? Cheese is a concentrated calorie bomb and has lots of that wicked animal fat in it too. Wouldn't we all be better off without it? And what about butter and margarine? They are just about pure fat. Surely they should be treated as contraband in kids' lunchboxes! [/sarcasm].

And will "this generation of Western children be the first in history to lead shorter lives than their parents did"? This idea emanates from a much-cited editorial in a prominent medical journal that said so. Yet this editorial offered no statistical basis for its opinion -- an opinion that flies directly in the face of the available evidence.


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