Friday, July 06, 2007

Shocking news: Baby genetic screening highly counterproductive

It's been killing lots of babies. A very sad example of how destructive the "precautionary principle" can be

GENETIC screening, often seen as the best hope for older women undergoing IVF treatment to have a child, is ineffective and actually reduces rates of pregnancies, scientists say.

The surprise finding from a controlled clinical trial involving 408 women is a major setback for a technology that is used increasingly in fertility clinics worldwide. Couples aiming for a test-tube baby can pay between $3500 and $5830 for a pre-implantation genetic screening test. The idea is to study the genetic make-up of embryos before transfer to the womb to make sure they are likely to survive.

But, while the concept is plausible, Dutch researchers found screening in women aged 35 to 41 years made matters worse. After 12 weeks, only 25 per cent of women undergoing in vitro fertilisation whose embryos had been screened were pregnant, against 37 per cent in the control group. Eventual live birth rates were also lower, at 24 versus 35 per cent.

Just why screening cuts the chance of a viable pregnancy is unclear, but Sebastiaan Mastenbroek from the Academic Medical Centre of the University of Amsterdam said the test itself may be to blame. "It is possible that the biopsy of a cell from an early embryo on day three after conception hampers the potential of an embryo to successfully implant, though the effect of biopsy alone on pregnancy rates has not been studied," he said. Usually embryos have reached the eight-cell stage of development by day three but sometimes there may be as few as four cells, which could make the procedure riskier.

Other factors may be the limited number of chromosomes that can be analysed, which may lead to the transfer of embryos that appear normal but in fact contain faults, and many embryos are "mosaic", where a cell does not properly reflect the genetic make-up of the whole.

Dr Mastenbroek and colleagues presented the work at the annual meeting of the European Society of Human Reproduction and Embryology in France. The research was also published online by the New England Journal of Medicine, alongside a recommendation from the team that pre-implantation should no longer be performed routinely in older women undergoing IVF therapy.


All diets pretty useless

Looking for that perfect diet? Researchers have bad news - all diets have just about the same result, and none of them are great, US. researchers reported on Monday. A typical diet helps people lose an average of 6 per cent of their weight, typically 10 to 15 pounds (5 to 7 kg), and most people put it all back on after five years. Weight loss drugs are similarly ineffective in the long run, said Dr Michael Dansinger of the Tufts-New England Medical Center in Boston.

"It's disappointing but I am optimistic that we can do better in the future. We are learning some of the factors that improve the effectiveness (of diets)," said Dansinger, whose study is published in the Annals of Internal Medicine.

The news is bad for those who hoped a gentler approach to dieting might be more effective over the long-term. Programs that made people eat fewer calories worked better, as did those that involved more frequent visits to either diet groups or to a counsellor's office.

But there is good news - even a small, temporary weight loss can benefit health, Dansinger said. "A modest weight loss of 6 per cent that is partially maintained for five years is likely to have important health benefits such as delaying the onset of diabetes," he said in a telephone interview.

Dansinger and colleagues looked at the results of 46 trials that included nearly 12,000 people. About half were on diets. Dansinger said it was difficult to find good studies that included a control group not on a diet. It was also hard to find studies that followed people for more than three years. The only commercial program included in the study was Weight Watchers. Most were government or university-sponsored programs. No studies that included food or shakes were included because they did not include a non-dieting group for comparison. "The results we found, 6 per cent weight loss after one year, is in the same ballpark as most of the studies of weight loss, including studies of weight loss medications," Dansinger said.

"We also found the weight loss gradually goes away so that about half the weight loss was gone within three years and almost all the weight loss was gone within five years. That that is also similar to what has been found with weight loss medications." Dansinger said some of the studies included exercise, but his analysis was not designed to tell whether exercise helped weight loss last longer. Nearly two-thirds of US adults are overweight or obese, with a higher risk of diabetes, heart disease, high blood pressure, arthritis and cancer.


Herbal toxicity a threat

HERBAL remedies could cause liver failure in some people so severe they needed a transplant to survive, a leading gastro-enterologist warned yesterday. University of Queensland liver disease professor Darrell Crawford warned about the potential dangers of the over-the-counter remedies at the launch of the Australian Liver Foundation in Brisbane yesterday. He said the most common cause of herbal hepatitis was black cohosh, a herbal preparation used to treat menopausal symptoms. But he also warned about the dangers of valerian, sometimes taken to treat insomnia, and skullcap.

"I don't think there's a lot of awareness that herbal and complementary therapies can cause liver failure," Professor Crawford said. "They can be bought over the counter, non-scripted in most chemist shops or outlets."

One of the aims of the new foundation will be to increase community awareness about liver disease, which affects about two million Australians. Professor Crawford's warning comes only weeks after the death of a 62-year-old woman of Rosewood, west of Brisbane, from liver toxicity after drinking goji juice. The woman, who was taking medication for type 2 diabetes and arthritis, died after drinking about a litre of the juice in just over a month. Tests of the goji juice and from a liver biopsy are continuing to determine whether the juice may have been responsible.

Professor Crawford, the incoming president of the Gastroenterological Society of Australia, urged people who recommended natural products as alternative treatments to be aware of the potential adverse side-effects. He said herbal hepatitis could occur in people without evidence of pre-existing liver disease.

Queensland Health last week cracked down on two companies which distribute goji juice for illegally describing the product as a treatment for cancer and other diseases. The companies were directed to remove the claims from their promotional material because of breaches of the Food Standards Code. Professor Crawford said he was also concerned about the increase in the number of Australians, including children, with liver diseases directly linked to obesity.



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].

Trans fats:

For one summary of the weak science behind the "trans-fat" hysteria, see here. Trans fats have only a temporary effect on blood chemistry and the evidence of lasting harm from them is dubious. By taking extreme groups in trans fats intake, some weak association with coronary heart disease has at times been shown in some sub-populations but extreme group studies are inherently at risk of confounding with other factors and are intrinsically of little interest to the average person.


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