Wednesday, May 30, 2007


Most medical journals have their faults but the BMJ journals deliberately sacrifice good scholarship. Articles with a politically correct conclusion are almost certain to be accepted there regardless of their scholarly merit. The following hopelessly naive article is a case in point. It ignores the possibility that the group of "light" smokers are different to start with -- that many of them are smoking "light" because they already have real health concerns. The study therefore proves nothing. Journal abstract follows:

Light Cigarette Smoking Impairs Coronary Microvascular Functions as Severely as Smoking Regular Cigarette

By Hakan Gullu et al

Background: Smoking is the most prevailed and the most preventable risk factor for cardiovascular diseases. Smoking of low-tar, low-nicotine (light cigarette) cigarette looks like less hazardous than smoking regular cigarette for general population due to the lower nicotine and tar yield.

Purpose: In this study, we compared the chronic and acute effects of light cigarette and regular cigarette smoking on coronary flow velocity reserve (CFVR).

Methods: 20 Regular cigarette smokers (mean age:24.8~5.0) and 20 light cigarette smokers (mean age:25.6~6.4), and 22 nonsmoker healthy volunteers (mean age: 25.1~4.2) were included. In the first run, each subject underwent echocardiographic examination including CFVR measurement after 12 hours fast and smokeless period. Two days after, in the second run, each subject smoked two cigarettes, which were their usual cigarette, in a closed room within 15 minutes. Then, within 20-30 minutes, each subject underwent echocardiographic examination including CFVR measurement.

Results: CFVR values were significantly and similarly lower in the light cigarette smokers and the regular cigarette smokers compared to the controls (2.68~0.50, 2.65~0.61, 3.11~0.53, P=0.013) (Table 1). Post hoc Sheffe analysis revealed that in both smokers group, CFVR values were significantly lower than that in the controls. Before smoking and after smoking paired t test revealed that smoking of two light cigarettes acutely decreased CFVR from 2.68~0.50 to 2.05~0.43 (P=0.001), and smoking of two regular cigarettes acutely decreased CFVR from 2.65~0.61 to 2.18~0.48 (P=0.001).

Conclusion: Smoking of low-tar, low-nicotine cigarette impair CFVR as severely as regular cigarette.

A media summary below:

LOW-TAR "light" cigarettes are just as damaging to heart blood flow as regular cigarettes, finds a new study in the journal Heart . Researchers recruited 62 participants in their mid-20s with no history of heart disease. Twenty had smoked low-tar, low-nicotine cigarettes (8 milligrams tar, 0.6 milligrams nicotine) for at least three years. Another 20 had smoked regular cigarettes for the same period (12 milligrams tar, 0.9 milligrams nicotine), and the rest were non-smokers. All participants were given a fitness test, with the smokers tested 30 minutes after smoking two of their normal cigarettes within a 15-minute period. Coronary flow velocity reserve (CFVR) - a measure of how well the heart's blood vessels can stretch in response to increased blood flow - decreased from 2.68 to 2.05 after smoking in the low-tar group, and from 2.65 to 2.18 in the regular cigarette smokers, while CFVR was 3.11 in the non-smokers. The findings show that switching to "light" does not reduce the hazards of smoking, say the authors.

Bird flu antibodies look good

RESEARCHERS in Switzerland have successfully immunised mice against the H5N1 strain of bird flu using human antibodies taken from survivors of the deadly virus, according to a study released today. The antibodies, reproduced at the Institute for Research in Biomedicine, also vastly enhanced the survival rate of infected animals, pointing the way to a treatment for people stricken with the often lethal disease, said Antonio Lanzavecchia, co-author of the study and director of the Institute's immune regulation laboratory. "We are very confident that this data can be reproduced in humans,'' he told AFP, saying that the antibodies "provided immediate, short-term immunity'' in mice.

The H5N1 bird flu has killed millions of wild and domestic fowl across the world since it first emerged in the late 1990s, and has caused 185 fatalities out of 306 known cases - most since 2003 - in humans, according to the World Health Organisation. Experts fear that the virus could mutate into a form easily communicable among people as happened during the great flu epidemic of 1918, which caused some 50 million fatalities. In the experiments, mice were injected with antibodies generated from the blood of avian flu survivors in Vietnam, where more than 40 people have succumbed to the disease since 2003. The country's first human case of H5N1 in 18 months, meanwhile, remained in an intensive care unit yesterday in Hanoi.

The mice were then exposed to the same strains that proved so deadly in humans. The treatment provided virtually complete protection, according to the study, published in the open access journal PLoS Medicine. As important, said Mr Lanzavecchia, was the efficacy of the antibodies in neutralising the virus in mice that had been infected as much as 72 hours earlier. The antibodies significantly reduced the amount of virus found in the lungs - by a factor of 10 to 100 - and almost completely stopped it from reaching the brain or the spleen. By contrast, none of the untreated mice in a control group survived.

The development of a vaccine against a possible global H5N1 pandemic has been a major focus of scientists in the field, many of whom are gathering at the end of this week in Paris for the second International Conference on Avian Influenza in Humans. But relatively little attention had been devoted to antibodies, which acted differently, Mr Lanzavecchia said. A vaccine induces a long-term or permanent immune response, but typically takes weeks or months to take effect. Vaccines are also useless to a patient once the disease has struck.

Antibodies, however, worked immediately, and were relatively easy to manufacture on an industrial scale. But the protection was only likely to last a few months, he said. This could still be critical in saving the lives of those infected, who typically seek medical help only a couple of days after flu-like symptoms appear. Antibody treatment could also immunise frontline nurses and doctors during a possible pandemic.

Because it was not possible to conduct regular clinical trials due to the lack of cases, regulators in the US and Europe had authorised a ``fast track'' approval process for an antibody-based drug, Mr Lanzavecchia said. If a treatment showed the same results in two animal models, including one on primates, and then passed a safety analysis, it could then go to market. This process took between three and four years, he said. The research has been funded by Britain's Wellcome Trust, the second largest medical research charity in the world, as well as the US National Institute for Health and the Swiss National Science Foundation.



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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