Saturday, December 01, 2007


It is doubtful if the study below found anything at all. Old guys who were given both aspirin and beta carotene for many years were found to be a tiny bit more mentally competent than those on placebo. That a tiny effect was found to be statistically significant simply reflects the huge sample size. HOWEVER, was the finding due to the aspirin or the beta carotene? Who knows? The fact that the effect was tiny and the fact that it was not found in people taking the stuff for only about a year suggests an unreliable effect that does not even invite replication. That is probably a very good thing. Antioxidants tend to shorten your lifespan -- so the choice between going ga ga and dying prematurely might not be too pleasant. Popular summary below followed by journal abstract:

BRAIN function declines with age, but it may decline slower in men who take supplements of beta-carotene -- the antioxidant chemical that gives carrots their orange colour. A study in the Archives of Internal Medicine this week found that men who took beta-carotene supplements for more than 15 years had much slower loss of thinking, learning and memory skills than men who did not. In 1982, 4052 healthy men were randomly assigned to take 50mg of beta-carotene or an inactive placebo every other day. They were followed through to 2003, given yearly health surveys and at least one telephone interview between 1998 and 2002 to assess brain function. Men who took beta-carotene had significantly higher scores on several of the cognitive tests compared with men who took the placebo, suggesting that beta-carotene could be used to delay dementia. The authors caution that beta-carotene has also been shown to increase the risk of lung cancer in smokers.


A Randomized Trial of Beta Carotene Supplementation and Cognitive Function in Men

By Francine Grodstein et al.

Background: Oxidative stress contributes to brain aging. Antioxidant treatment, especially over the long term, might confer cognitive benefits.

Methods: We added cognitive testing to the Physicians' Health Study II (PHSII), a randomized trial of beta carotene and other vitamin supplements for chronic disease prevention. The PHSII is a continuation of the Physicians' Health Study (PHS), which had randomized male participants to low-dose aspirin and beta carotene. Participants include those continuing their original beta carotene assignment from the PHS, begun in 1982, and newer recruits randomized as of 1998. The beta carotene arm (50 mg, alternate days) was terminated; follow-up is ongoing for the remaining arms. Near the close of the beta carotene arm, we interviewed 5956 participants older than 65 years to assess general cognition, verbal memory, and category fluency. The primary end point was a global score averaging all tests (using z scores); the secondary end point was a verbal memory score combining results of 4 tests. We compared mean cognition among those assigned to beta carotene vs placebo. We separately examined new recruits and continuing participants.

Results: Among 1904 newly recruited subjects (mean treatment duration, 1 year), cognition was similar across treatment assignments. Among 4052 continuing participants from the PHS (mean treatment duration, 18 years), the mean global score was significantly higher in the beta carotene group than in the placebo group (mean difference in z scores, 0.047 standard units; P = .03). On verbal memory, men receiving long-term beta carotene supplementation also performed significantly better than the placebo group (mean difference in z scores, 0.063; P = .007).

Conclusion: We did not find an impact of short-term beta carotene supplementation on cognitive performance, but long-term supplementation may provide cognitive benefits.

Arch Intern Med. 2007;167(20):2184-2190


Would you believe that old people who can't see very well any more get depressed by that? Apparently we needed to be told:

IMPROVING the vision of nursing home residents leads to a better quality of life and fewer cases of depression, finds a new study in the Archives of Ophthalmology. The findings suggest that people in nursing homes can benefit greatly from access to basic eye care services, despite any other disability they may have. Researchers surveyed 142 people with vision problems living in nursing homes in the southern US state of Alabama. Seventy-eight of them received corrective eye glasses within a week and were surveyed again after two months. They were compared to a control group of 64 residents who only received their glasses after the follow-up survey. After two months of corrected vision, the immediate-correction group reported dramatic improvement in quality of life and less depression than the delayed-correction group. They had less difficulty performing daily activities, such as reading and watching TV, than the delayed-correction group, and were better able to join in group activities.



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.


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