Tuesday, December 18, 2007


The usual epidemiological crap. We read that people with lots of "good" cholesterol heal better after stroke. Why? The authors below appear just to assume that the relationship is a cause-effect one. It might not be. I will use my usual example of why not but that is only one possibility:

That middle class people for a variety of reasons might be more virtuous in the cholesterol department does not seem to be considered. And middle class people have better health for various reasons too. So are we just looking at a class effect? Who knows? Epidemiological correlations are basically uninformative by themselves. They are only useful for hypothesis formation. The fact that blacks did less well may however reinforce the social class explanation

Association of diabetes, homocysteine, and HDL with cognition and disability after stroke

By George C. Newman et al.

Objective: To delineate factors associated with cognitive function following stroke and test the hypothesis that vascular risk factors associated with oxidative stress impair recovery.

Method: We performed a post hoc analysis of the extensive longitudinal database from the 3,680 subjects (over 35 years old) entered between 1996 and 2003 into the Vitamin Intervention for Stroke Prevention trial using a linear mixed effects model. The primary outcome variables were scores on the Mini-Mental State Examination (MMSE) and modified Rankin Scale (mRS).

Results: MMSE and mRS gradually improved during the 2-year follow-up period. Increased age and nonwhite race, recurrent stroke, diabetes mellitus, left hemisphere cortical lesions, and values of high-density lipoprotein and homocysteine were independent predictors of less successful cognitive recovery. A strong interaction between homocysteine and age indicated a threshold effect beginning in the late 50s. No vitamin treatment effects were identified. Similar factors were identified for recovery of disability as assessed by the mRS, although there were qualitative and quantitative differences.

Conclusions: The finding that diabetes, high-density lipoprotein, and homocysteine predict poorer cognitive function and greater disability after stroke is consistent with the hypothesis that metabolic stress plays a significant role in the poststroke period.

NEUROLOGY 2007;69:2054-2062

Prawns offer hayfever hope

VOLUNTEERS are wanted to trial a world-first treatment for hayfever made from prawn shells which researchers say is showing promising signs of success. Sydney-based company Novotech is seeking hayfever sufferers aged 15 to 60 who are otherwise healthy to be volunteers to trial a nasal spray made from natural ingredients derived from prawn shells. The trial involves the Woolcock Institute of Medical Research along with six other centres in Queensland, NSW and Victoria, with trials are being conducted in Brisbane, Melbourne and Sydney.

More than three million Australians are affected by hayfever. Melbourne doctor Stephen Hall said the spray encouraged the body's immune system to have a less exaggerated response to allergens such as grass and pollen. He said the potential for side effects was low because the treatment was inhaled. Dr Hall said early signs were promising and if this continued, a decision on the treatment's public availability may be known mid-next year. "We're hopeful if all goes well that we have good data and quick recruitment, we'll be in a position to know by June or July," Dr Hall said.

Among the volunteers is Carol Jenkins, 52, of Glen Iris in Melbourne, who has suffered hayfever since she was a teenager. She spends each November to February nursing hayfever symptoms that cause her tiredness and sleepless nights and is hopeful of a cure. "I've had my medication over the years. But nothing cures it," she said. "It's constant sneezing and thinking twice before going outdoors. "It's debilitating."



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 correla-tion 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 condi-tions and lynchings in Raper's data. Raper had the misfortune of stopping his anal-ysis 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.


No comments: