Tuesday, January 01, 2008



Anorexia inherited through sex hormones in womb?

The stuff about estrogen below is all speculation. The results could be equally well-explained by genetics

Sex hormones in the womb could be a cause of the eating disorder anorexia, a study has found. The suspicion is that oestrogen may be overproduced by some mothers, affecting the baby’s brain and making it susceptible to the eating disorder. Psychiatrists investigating the cause of the illness did so by studying records of thousands of Swedish twins, held in a database. They found, not unexpectedly, that the risk of developing anorexia was higher in girl twins than in boy twins. Anorexia is far commoner in girls than in boys.

But an exception to the pattern arose in the case of twins of different sexes. Boys who shared the womb with girl twins were found to be ten times more likely to develop the disorder in later life. Many claims have been made that girls who become anorexic have been influenced by images of stick-thin models. The findings do not disprove this, but suggest that biology as well as culture plays an important part.

Marco Procopio, a psychiatrist from the University of Sussex and one of the authors of the study in Archives of General Psychiatry, said: “We know that women are ten times more likely to develop anorexia than men and this study goes a long way to explaining why. We know that oestrogen and other hormones can have a powerful effect on the body and it would seem that there is an ‘overexpression’ of oestrogen by the mother and the girl twin in some pregnancies. “Oestrogen would be present in the amniotic fluid that bathes babies in the womb and would be swallowed by both the male and female twin. Oestrogen is needed in development of females but it is possible that too much affects the structure of the brain.”

The new study supports research from the United States that found that the brains of anorexics behaved in a different way to non-anorexics. Dr Procopio said: “Research into twins is a way to examine the factors involved, as the single most important period for brain development is during the months of pregnancy. “The one thing we are certain of is that there is a genetic disposition to anorexia. Some scientists have suggested that upbringing may be a factor in the gender difference in rates of occurrence of the disorder, but studies haven’t borne this out.”

Dr Procopio does not believe that thin models account for the condition. “If that were the case, we would have many more anorexics,” he said. “There might be an effect on some girls but I doubt if these are truly anorexic but more likely a passing phase.” He believes it may be possible one day to monitor pregnant women for higher than normal oestrogen levels.

Dee Dawson, who runs the pioneering North London Rhodes Farm clinic for teenage anorexics said: “It’s an interesting study and there may well be some truth in the findings. “I think that there is a genetic predisposition and the problem may well be to do with the formation of the brain in pregnancy. “But often the triggers are problems at home so if you are susceptible in your brain make-up it could be triggered off by events in a teenager’s life.”

Source




Bone Density Tests Do Predict Women's Fracture Risk

Largest, longest study ever supports screening and prevention of osteoporosis

One bone mineral density test can accurately predict a woman's chance of spinal fractures 15 years down the line, new research shows. And, according to the largest and longest prospective study of osteoporosis ever, women who had a spinal fracture at the beginning of the study had four times the risk of sustaining another fracture later on. The bottom line: "Women need to talk to their doctors about the risk of osteoporosis," according to Jane Cauley, lead author of the study and professor of epidemiology at the University of Pittsburgh Graduate School of Public Health.

Her team published the findings in the Dec. 19 issue of the Journal of the American Medical Association. "I agree with the guidelines that all women after the age of 65 have bone density tests, and Medicare will pay for that," Cauley said. "Women who are postmenopausal, 50 to 64 years of age, should consider having a bone density test if they have other risk factors for osteoporosis or if they want to know what their bone density is before they consider any other treatment."

The findings don't change current standard practice, experts said, and they don't change the basic message to women: Don't ignore bone health, especially in middle and old age. "The only really major advance here is that it's a longer term study. Mostly studies are five years typically. This one went out 15 years," said Paul Brandt, associate professor of neuroscience and experimental therapeutics at Texas A&M Health Science Center College of Medicine in College Station. "Women need to get their bone mineral density tested after they start menopause and if they stay on hormone replacement therapy or an anti-osteoporotic treatment." he said.

Postmenopausal women are particularly vulnerable to fractures resulting from osteoporosis, a degenerative weakening of the bones. Some 10 million Americans, including one in five American women over the age of 50, suffer from osteoporosis, which is the most common type of bone disease. Spinal fractures are the most common type of fracture resulting from osteoporosis, affecting 35 percent to 50 percent of women over 50 (about 700,000 vertebral fractures annually in the United States).

But many, if not most, of these fractures go undetected. "Osteoporosis is sometimes called the silent thief," Cauley said. "It basically robs the skeleton of strength and resources, and women don't really know about it. About 75 percent of all spine fractures actually occur silently." "Identifying risk factors for spine fractures is less well developed. You have to systematically look for them by repeated X-rays," Cauley continued.

The findings from this study are based on bone mineral density data from 2,300 women over the age of 65 who enrolled in the Study of Osteoporotic Fractures (SOF), initiated in 1986. After 15 years of follow-up, it was evident that 25 percent of women who had low BMD at the beginning of the study developed fractures of the spine, compared with only 9 percent of women with normal BMD.

"It was pretty much a strong gradient of risk," Cauley explained. "If you had normal bone density when you entered and did not have an [existing] fracture, the risk of having a new spine fracture was about 9 percent, compared to a risk of 56 percent in women who had osteoporosis and who had an existing fracture. So, the range of risk varied dramatically depending on bone density and previous spine fractures."

According to Brandt, one interesting finding from the study is that a previous vertebral fracture topped even bone mineral density as a predictor for future fracture. This indicates that women with an existing vertebral fracture should be treated for osteoporosis regardless of their BMD, the authors reported. "People think osteoporosis is an inevitable consequence of aging, but it is preventable and treatable," she said.

Source

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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].

9). And how odd it is that we never hear of the huge American study which showed that women who eat lots of veggies have an INCREASED risk of stomach cancer? So the official recommendation to eat five lots of veggies every day might just be creating lots of cancer for the future! It's as plausible (i.e. not very) as all the other dietary "wisdom" we read about fat etc.

10). And will "this generation of Western children be the first in history to lead shorter lives than their parents did"? This is another anti-fat scare that 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.

Even statistical correlations far stronger than anything found in medical research may disappear if more data is used. A remarkable example from Sociology:
"The modern literature on hate crimes began with a remarkable 1933 book by Arthur Raper titled The Tragedy of Lynching. Raper assembled data on the number of lynchings each year in the South and on the price of an acre's yield of cotton. He calculated the correlation coefficient between the two series at -0.532. In other words, when the economy was doing well, the number of lynchings was lower.... In 2001, Donald Green, Laurence McFalls, and Jennifer Smith published a paper that demolished the alleged connection between economic conditions and lynchings in Raper's data. Raper had the misfortune of stopping his analysis in 1929. After the Great Depression hit, the price of cotton plummeted and economic conditions deteriorated, yet lynchings continued to fall. The correlation disappeared altogether when more years of data were added."
So we must be sure to base our conclusions on ALL the data. But in medical research, data selectivity and the "overlooking" of discordant research findings is epidemic.

"What we should be doing is monitoring children from birth so we can detect any deviations from the norm at an early stage and action can be taken". Who said that? Joe Stalin? Adolf Hitler? Orwell's "Big Brother"? The Spanish Inquisition? Generalissimo Francisco Franco Bahamonde? None of those. It was Dr Colin Waine, chairman of Britain's National Obesity Forum. What a fine fellow!

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1 comment:

Laura Collins said...

Why couldn't anorexia be caused by both genetics AND prenatal environment?

Genetics is clearly 50-80% explanatory, but the environmental triggers are still being teased out.

Looking at prenatal environment is surely a better place to be looking than the usual suspects: society, anorexigenic moms, and the sight of skinny models.