Thursday, November 22, 2007


The study below had a fairly good range of controls, though the reliance on self-report is troubling. Nonetheless the controls used do confer some authority on the conclusion. A bit puzzling that they observed no brain changes that could explain the effect, however. More fine-grained brain observations may be needed or the reliance on self-report abandoned. Peer ratings would be one alternative to self-reports. Abstract below

Relation of cognitive activity to risk of developing Alzheimer disease

By R. S. Wilson et al.

Background: Frequent cognitive activity in old age has been associated with reduced risk of Alzheimer disease (AD), but the basis of the association is uncertain.

Methods: More than 700 old people underwent annual clinical evaluations for up to 5 years. At baseline, they rated current and past frequency of cognitive activity with the current activity measure administered annually thereafter. Those who died underwent a uniform postmortem examination of the brain. Amyloid burden, density of tangles, and presence of Lewy bodies were assessed in eight brain regions and the number of chronic cerebral infarctions was noted.

Results: During follow-up, 90 people developed AD. More frequent participation in cognitive activity was associated with reduced incidence of AD (HR = 0.58; 95% CI: 0.44, 0.77); a cognitively inactive person (score = 2.2, 10th percentile) was 2.6 times more likely to develop AD than a cognitively active person (score = 4.0, 90th percentile). The association remained after controlling for past cognitive activity, lifespan socioeconomic status, current social and physical activity, and low baseline cognitive function. Frequent cognitive activity was also associated with reduced incidence of mild cognitive impairment and less rapid decline in cognitive function. Among 102 persons who died and had a brain autopsy, neither global nor regionally specific measures of neuropathology were related to level of cognitive activity before the study, at study onset, or during the course of the study.

Conclusion: Level of cognitively stimulating activity in old age is related to risk of developing dementia.

NEUROLOGY 2007;69:1911-1920

Cannabis compound 'halts cancer'

I kinda think I have heard all this before

A compound found in cannabis may stop breast cancer spreading throughout the body, US scientists believe. The California Pacific Medical Center Research Institute team are hopeful that cannabidiol or CBD could be a non-toxic alternative to chemotherapy. Unlike cannabis, CBD does not have any psychoactive properties so its use would not violate laws, Molecular Cancer Therapeutics reports. The authors stressed that they were not suggesting patients smoke marijuana. They added that it would be highly unlikely that effective concentrations of CBD could be reached by smoking cannabis.

CBD works by blocking the activity of a gene called Id-1 which is believed to be responsible for the aggressive spread of cancer cells away from the original tumour site - a process called metastasis. Past work has shown CBD can block aggressive human brain cancers. The latest work found CBD appeared to have a similar effect on breast cancer cells in the lab.

Lead researcher Dr Sean McAllister said: "Right now we have a limited range of options in treating aggressive forms of cancer. "Those treatments, such as chemotherapy, can be effective but they can also be extremely toxic and difficult for patients. "This compound offers the hope of a non-toxic therapy that could achieve the same results without any of the painful side effects."

Dr Joanna Owens of Cancer Research UK said: "This research is at a very early stage. "The findings will need to be followed up with clinical trials in humans to see if the CBD is safe, and whether the beneficial effects can be replicated. "Several cancer drugs based on plant chemicals are already used widely, such as vincristine - which is derived from a type of flower called Madagascar Periwinkle and is used to treat breast and lung cancer. It will be interesting to see whether CBD will join them."

Maria Leadbeater of Breast Cancer Care said: "Many people experience side-effects while having chemotherapy, such as nausea and an increased risk of infection, which can take both a physical and emotional toll. "Any drug that has fewer side-effects will, of course, be of great interest." But she added: "It is clear that much more research needs to be carried out."



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 condi-tions 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.


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