DOES EXERCISE PREVENT ALZHEIMERS?

Short answer: No. These guys were smart enough to adjust for measures of social class and that wiped the initially apparent effect. Good to see that some medical researchers don't go around with their eyes closed. It makes yet another demonstration of how apparent physical causes can in fact be sociological causes.

Dementia due to problems in the supply of blood in the brain did however seem to be slightly reduced by exercise. Popular summary followed by abstract below.

Walking and moderate exercise may help to prevent dementia, claims new research in Neurology this week. A total of 749 men and women aged 65 and older took part in the study. They were surveyed about their levels of physical activity, including time spent walking, climbing stairs, doing housework and gardening. Over the next four years, 54 of the participants developed Alzheimer's disease and 27 developed dementia. Those with the highest physical activity levels were 24 per cent less likely to develop dementia than those with the lowest levels. When the different types of exercise were considered separately, researchers found walking provided the same level of protection against dementia as more demanding activities. The authors suggest exercise may protect the brain by improving its blood flow.

Physical activity and dementia risk in the elderly. Findings from a prospective Italian study

By G. Ravaglia et al.

Objective: To examine the effect of physical activity on risk of developing Alzheimer disease (AD) and vascular dementia (VaD) in the elderly.

Methods: Data are from a prospective population-based cohort of 749 Italian subjects aged 65 and older who, in 1999/2000, were cognitively normal at an extensive assessment for clinically overt and preclinical dementia and, in 2003/2004, underwent follow-up for incident dementia. Baseline physical activity was measured as energy expenditure on activities of different intensity (walking, stair climbing, moderate activities, vigorous activities, and total physical activity).

Results: Over 3.9 - 0.7 years of follow-up there were 86 incident dementia cases (54 AD, 27 VaD). After adjustment for sociodemographic and genetic confounders, VaD risk was significantly lower for the upper tertiles of walking (hazard ratio [HR] 0.27, 95% CI 0.12 to 0.63), moderate (HR 0.29, 95% CI 0.12 to 0.66), and total physical activity (HR 0.24, 95% 0.11 to 0.56) compared to the corresponding lowest tertile. The association persisted after accounting for vascular risk factors and overall health status. After adjustment for sociodemographic and genetic confounders, AD risk was not associated with measures of physical activity and results did not change after further adjustment for vascular risk factors and overall health and functional status.

Conclusions: In this cohort, physical activity is associated with a lower risk of vascular dementia but not of Alzheimer disease. Further research is needed about the biologic mechanisms operating between physical activity and cognition.

Neurology, December, 2007






NEW SLIMMING DRUG?

Side-effects are the worry. It may be worth noting that a related drub, rimonabant, was banned because it caused people to go mad! Popular summary followed by abstract below.

Marijuana is well-known to increase appetite, and it does this by stimulating receptors in the brain. Now scientists have designed a new drug that blocks these receptors and suppresses appetite, leading to significant weight loss in obese people in just 12 weeks. The drug, called taranabant, has been tested in people for the first time, and the results are reported in the current issue of Cell Metabolism. The trial involved 533 obese patients, who were randomly divided into five groups and given 0.5, 2, 4 or 6mg per day of taranabant or a placebo for 12 weeks. Compared to the placebo, taranabant caused significant weight loss at all of the doses studied. In a shorter trial involving 36 overweight or moderately obese patients, those taking a single dose of 12mg of taranabant consumed 27 per cent less calories in a 24-hour period than those taking a placebo. At higher doses, side effects of the drug included nausea, vomiting and irritability.

Taranabant Cuts the Fat: New Hope for Cannabinoid-Based Obesity Therapies?

By Tim C. Kirkham

Endocannabinoid/cannabinoid receptor signaling acts centrally and peripherally to govern appetite and energy balance. While system stimulation promotes eating and energy storage, receptor blockade can reduce food intake and facilitate weight loss. In this issue of Cell Metabolism, Addy et al., 2008 test the therapeutic antiobesity potential of taranabant, a cannabinoid 1 receptor inverse agonist.

Cell Metabolism, Vol 7, 1-2, 09 January 2008

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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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