Wednesday, October 31, 2007

Cholesterol is vital at the beginning of life

Low cholesterol levels in pregnant women increase the risk of preterm births and underweight babies.

Yesterday I have reported on a marginally (0.7 percent) elevated risk of heart disease that may be linked to, but is not necessarily caused by, a high level of blood cholesterol.

Besides being not so bad for health as is always said, a new study shows an adverse birth outcome among mothers with low serum cholesterol: Cholesterol, it seems, is of vital importance for the health of the newborn.

About a thousand mothers have been assessed, and about a hundred of them had a low level of blood cholesterol. Among these, twelve percent delivered preterm, compared to only five percent of mothers with medium cholesterol levels. In babies born at term, those of mothers with a low cholesterol level weighed less than those of mothers with a higher cholesterol level.

Obviously, we cannot say that a low cholesterol level, generally considered as good for health, is so at any moment of life. This may be true not only at the beginning of life but also in old age: Cholesterol levels tend to rise with age, and this may be an adaptation to a higher cholesterol demand of the ageing organism.

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Tuesday, October 30, 2007

Should we kill cholesterol, the bearer of bad news?

High cholesterol has been linked to heart disease and stroke risk in a big study but we should be careful with explanations and actions.

A study on cholesterol, diabetes and major cardiovascular diseases in the Asia-Pacific region included a third of a million persons whose blood cholesterol levels have been assessed and who have been followed up four years on average. Six thousand of them (1.8 percent) had a heart attack during that time. When linked to the cholesterol data, every one millimol per liter increase of blood cholesterol level was associated with a 41 percent higher relative risk of a heart attack. This may sound impressive, but it must be related to the absolute risk, therefore, the risk increase linked to cholesterol is a mere 0.7 percent. Nevertheless, the authors of the study conclude that

" (...) these data support aggressive lowering of total cholesterol and LDL-cholesterol levels for prevention of cardiovascular events."
That is, prescribing high doses of statin. Statins do in fact lower cholesterol levels but they have a couple of other effects, thus it remains unclear if their preventive action against heart attacks has anything to do with cholesterol. Other attempts, for instance low-cholesterol diets, have proven to be useless because the main amount of cholesterol is produced by the body who regulates its production up or down, according to the input.

Is cholesterol the culprit anyway?

In ancient times, bearers of bad news sometimes have been executed which was supposed to comfort the King but did not change the facts. Cholesterol may be regarded as a bearer of risk, if we think that 0.7 percent risk increase is really bad news. But cholesterol is not necessarily a cause of this risk increase.

A number of studies have shown that stress makes blood cholesterol rise and exercise makes it fall. Thus, stress and lack of exercise may be the real causes of heart attacks, and cholesterol levels may only be a side effect.

Interestingly, other studies have shown positive effects of high blood cholesterol levels - read more in my upcoming posts.

Related post: More statin may save lives after heart attack but so may red wine.

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Monday, October 29, 2007

Weight benefit in old age

old man
Beyond eighty years of age the so-called ideal weight may be bad for your health; the so-called obese turn out to live longest.

Regular readers of this blog will not be surprised because a number of studies have shown health benefits of a higher body weight in old age, for instance in elderly asthmatics, and two more studies are listed here.

Yet another study of this kind has just been published with this finding about body mass index and mortality in elderly persons: the higher the body mass index, the lower the mortality. More than four hundred elderly persons, about half of them women, have been admitted to an acute geriatric ward in Israel. The body mass index at admission day has been calculated, and their fate after the release has been followed-up four years on average. About half of them died during this time, and those who died had a lower body mass index (24.1) than those who survived (26.3). According to the WHO definition, death has been linked to "normal weight" and survival to "overweight". The fattest persons, with a body mass index higher than 28 (so-called "obese") had the lowest mortality, only 9.6 percent of them died per year. The thinnest persons, with a body mass index below 22 (generally labelled as "ideal weight") had the highest mortality, 24 percent of them died per year.

The question of sickness

Of course, findings gained in certain groups may not be generalized to all persons. For instance, the people of this Israeli study have been admitted to a hospital, so they have been sick, and the findings may not apply to healthy people. But it is important to note that they have been admitted due to acute conditions, such as accidents or infections, and not for a chronic illness which may have caused weight loss.

The researchers also applied a statistical filter to remove the direct influence of known risk factors such as male sex (men die earlier than women), age (life expectancy diminishes with age), renal failure and diabetes. Even after these filters, a higher weight turned out to remain beneficial in these elderly persons.

Take-aways: In persons beyond eighty years of age, a higher weight is linked to a longer life, but it remains to be shown to what extent this may be a benefit of body fat (as a vitality reserve) or rather the influence of serious diseases causing weight loss.

I'll be keeping tabs on the research...

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Friday, October 26, 2007

Puzzling news about weight and breast cancer risk

startled woman
A higher risk, linked to weight gain but not to weight in a very specially selected group of women, may not be a risk for women in general.

In a study on adiposity, adult weight change, and postmenopausal breast cancer risk, the following results have been found:

  • no link between weight at any age and breast cancer risk before menopause because these cases had been excluded from the study;
  • a lower breast cancer risk in women with a higher weight at age 18;
  • an equal breast cancer risk in women of any weight who have been weight-stable during their adult life;
  • an equal breast cancer risk in women who gained weight, even as much as 40 kg (6 stone) since age 18 and have taken hormones after menopause;
  • a higher, up to double breast cancer risk in women who gained the same weight but did not take hormones;
  • no risk change in women who lost weight in adult age.
Study details: More than three million questionnaires have been mailed to selected members of AARP, only about four percent of them responded, and every fifth of these has been excluded for various reasons. The remaining women, cancer-free at the beginning of the survey, have been asked questions about their weight and height at ages 18, 35, 50 and at the current age. The accuracy of this self-declaration has not been checked. The women have been followed up over the next five years in order to see if they developed breast cancer. This has been the case in more than two thousand women. The relative risks have been calculated comparing these cases with those not affected by cancer in different classes of weights and weight gains in different periods of life.

Nagging questions

The female hormone estrogen is considered one of the known risk factors for breast cancer. The longer a woman is exposed to it, for instance by an early beginning of puberty, the higher is her breast cancer risk in general. A number of studies show a higher breast cancer risk with hormone replacement therapy after menopause. Yet in this AARP study the results are opposite, indicating a lower risk for women taking hormones.

This is not easy to explain by biological mechanisms. Thus, it may be the result of bias in this study, caused by the specific selection of the cases and the controls or by the inaccurate recall of heights and weights long times ago. If, for instance, women with a lower education and a lower income would be less accurate in their weight and height estimates of early ages, higher weight differences may occur in this group. Low education and low income are known risk factors for many diseases, breast cancer included.

What if it were true?

It has not been proven without doubt, but let's be too generous and assume for the moment that an elderly woman may be at higher risk for breast cancer if she had been very thin when young, then has gained a lot of weight and does not take hormones. There is no use to tell her this bad news because weight loss will not lower her breast cancer risk, as the AARP study has shown. Best would be telling her not to worry about breast cancer but to be happy with her weight, and that a higher weight has been shown to prolong life in old age.

And what about warning young women from weight gain? Well, this is exactly what is happening these days in the world-wide war on obesity, with a number of unwanted side effects, see my earlier posts about distressed victims, dieting messages and youth suicide.

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Thursday, October 25, 2007

Backlash in the diagnosis of whiplash

MRI scan
MRI scans of head and neck spine ligaments have been suggested as a remedy against skeptical insurance companies but new MRI research does not dispel doubts but supports them. This is really bad news for victims of whiplash injuries. They suffer from various symptoms due to whiplash trauma but many insurance companies refuse to pay because no damage is visible in the X-ray.

Magnetic resonance imaging (MRI) is superior in displaying soft tissue such as the ligaments that stabilize the spine. Some of these, the alar ligaments, have been suspected to be overstretched or broken in whiplash injury. The alar ligaments connect the first neck vertebra with the head, stabilizing and limiting its movement in various directions.

While an earlier study has described damages of the alar ligaments detected by MRI, a review of recent studies on biomechanics, anatomical and clinical MRI scans has failed to show the usefulness of MRI in whiplash diagnosis: Biomechanical experiments reproducing the impact of whiplash did not cause ruptures in the alar ligaments, and the anatomical survey showed that there are plenty of normal variants in these ligaments with no well-defined "normal" standard that would allow to distinguish a damage.

Some of the authors say that MRI is excellent to visualize the ligaments, others deny. When asked to interpret MRI scans, different experts often came to different conclusions.

This does not sound like good news for all those who suffer from whiplash symptoms and struggle with their insurance companies. It is a backlash, but not necessarily a final one. There may still be hope in the future, due to better MRI scanners with a higher resolution and a better anatomical and functional insight.

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Wednesday, October 24, 2007

Hit the right note and read the right letter

music notes
Musical training may help to tackle dyslexia because it improves functions of the brain that are also used in language processing. This is the conclusion of a series of experiments with normal and dyslexic children and with adults in France.

The researchers at the Institut de Neurosciences Cognitives de la Méditerranée in Marseille have found that dyslexic children perform worse than normal readers in discriminating musical pitch changes. Such differences in skill mainly depend on musical practice rather than on innate musical talents. That is, they can be improved by training. Besides such behavioural experiments, the brains of the subjects have been scanned while they have been performing their tasks. The results show that there is a set of common processes in the brain, involved both in musical and in language processing.

Musical training for dyslexic children has been suggested earlier, based upon practical experience. The new French research adds more evidence to this rationale. After all it is common wisdom that every language has its own melody, just like music. Some Swiss dialects or Swedish really sound like sung, and in Chinese the rising or falling tone has a lexical meaning. Italian sounds like a belcanto opera. Thus, why not have your dyslexic child sing instead of read those difficult sentences? It may be worth a try.

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Tuesday, October 23, 2007

Rubens has been a very very long time ago

Today, women of good weight are at risk of suffering from depression and anxiety, and few of them may know that once they would have been of supermodel size.

Peter Paul Rubens, a very respected painter of the seventeenth century, knighted by the kings of England and of Spain, loved women of a size that nowadays is labeled as "obese" but then must have been the ideal of female beauty.

But we live in very different times now. Our supermodels are of a size near to starving, and they are on so many billboards, posters and screens that the inner standards of beauty have been changed inevitably. When a normal woman of today looks into a mirror, what she sees is a big difference to that standard. A difference that may make her unhappy.

This has been scientifically proven in a study about youth body weight and depression in later years: More than seven hundred young people of New York have been measured in height and weight back in 1983 and then, three more times during the following twenty years, their mood status has been observed. It came out that girls with the highest body mass index, so-called "obese", have a nearly fourfold risk of major depression and anxiety in their later life, compared to girls with a lower weight. In boys, weight does not play any such role.

Why men and women look differently at weight

Obviously, for men, being fat is much less of a problem than for women. Men are more concerned about the size of their bank accounts, knowing well that not the beautiful but the rich men are seen with the most beautiful women.

For women, even for modern women, beauty is of much more importance than for men. It seems that this is an old biological role model that never will change. But what should change, definitely, is the beauty standard of women. A standard that must be wrong because it throws millions of young, healthy, many of them very beautiful women into depression and anxiety. Why not return to Rubens?

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Health Blog Carnival Watch 1:12

Grand Rounds 4:5
Christian Sinclair presents the weekly best medical blog posts around a theme that is very important in medicine: prognostication.
October 23, 2007 at Pallimed

Grand Rounds 4:4
Adam presents a great bunch of posts from the ER point of view.
October 15, 2007 at NY Emergency Medicine

Skeptics Circle Puzzle Edition
This 71st edition is really special, because it encourages the reader to sharpen his brain in a great collection of logical puzzles, carefully selected along the presented posts. A sharp brain is most important for skeptical thinking. Great idea, performed in an excellent way.
October 11, 2007 at Infophilia

Grand Rounds 4:3
A great edition, covering the military health service theme.
October 8, 2007 at Nurse Ratched's Place

Grand Rounds 4:2
It is astonishing how the Grand Rounds editors find new, unique ways of presenting. This edition comes in rhymes. Well done, Dr. Rob!
October 2, 2007 at Musings of a Distractible Mind

Monday, October 22, 2007

Low fat food does not protect against cancer

bread and butter
This truth, told by one of the largest diet trials ever, is not necessarily inconvenient for those who care about healthy food. The main reason is this one: If low fat food does not prevent cancer, then high fat food will not cause cancer. Whenever science is able to kill food-related fears, this must be good news.

Let's turn to the details of the big intervention study about low-fat diet and cancer incidence: About twenty thousand elderly women have switched to a diet that provided twenty percent less energy from fat. About thirty thousand women, randomly assigned, stayed with their usual food. All women have been followed up for an average of eight years and their cancers have been assessed.

All cancers taken together, no difference has been found between the low-fat and the food-as-usual control group. Only in ovarian cancer, a very small difference has been found. In the first four years of comparison, more cancers have been found in the low-fat group (0.52 cases per thousand person-years) than in the control group (only 0.45 cases). In the next four years, things seemed to turn in favour of the low-fat diet, with only 0.38 cases compared to 0.64 cases in the control group. In other words, in the first four years of low-fat diet intervention we see a somewhat higher risk of the dieters and in the next four years a somewhat lower risk. The figures, all in all, are very low, indicating that these differences are just a result of chance.

Very low figures indeed. If we assume a real effect (which is not proven by this study), then a low-fat diet may reduce the incidence of ovarian cancers (only those) after the fourth year of dieting (not before) from 0.64 to 0.38 cases per thousand years. In other words: Four thousand years of dieting may at best prevent one single case of ovarian cancer eight years later. This is such a tiny effect that we quickly should forget about it.

Fat is not all and cancers are not all

Of course, there are many more aspects of healthy eating than just fat. There are also vitamins, minerals, fibers and all this healthy stuff. And there are many more diseases than cancer, such as heart attacks, strokes, diabetes and what else may occur.

Thus, this study is not a refutation of healthy eating as such. But it casts some healthy doubts and skepticism on all claims that try to make us believe that we should diet to stay healthy. In this sense: Enjoy your bread and butter!

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Thursday, October 18, 2007

Tooth loss may predict memory loss

With dementia, dental care gets worse, but tooth loss seems to be not only an outcome but also a risk factor for memory decline in late life. This is a new finding of the Nun Study, where data about tooth loss and dementia in more than a hundred deceased nuns have been analyzed over a longer period of time: The women with the fewest teeth had the highest risk of dementia.

Toothbrush and floss against Alzheimer's?

Sorry, but such a conclusion would overwork the results of this study. It only reports a link, a correlation, but does not tell us anything about a possible cause. For instance, it is not clear if bacteria that cause inflammation of the teeth and of the gums may harm the brain. Only in this case, fighting gum disease would have a preventive effect on dementia.

Many common causes may be hidden

One of them has been revealed by a study showing that self-discipline protects against Alzheimer's disease. Keeping his teeth in good health may just be one aspect of a careful, painstaking character, and the real protective effect may be some mechanism in the brain that we do not yet understand, rather than toxins from tooth bacteria.

In addition, a good dental care requires some manual skills, and the decline of these skills may precede a mental decline.

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Wednesday, October 17, 2007

Even low level weight control linked to youth suicide

extreme weight control
Extreme eating disorders are a known risk for suicide in young people, but the risk remains high even with less extreme weight control behaviour. This is the result of a study about suicidal behaviour in adolescents and its relationship to weight status, weight control behaviours, and body dissatisfaction.

More than four thousand boys and girls have been surveyed by researchers of the University of Minnesota. Only in boys, extreme weight control behaviours such as vomiting or excessive fasting has been linked to substantially higher odds of suicide thoughts and suicide attempts than less extreme weight control such as eating less or skipping meals. In girls, no big difference has been detected between extreme and less extreme weight control: both increased the odds of suicide thoughts and attempts to a similar extent. Body dissatisfaction showed quite exactly the same link to suicide as less extreme weight control in boys as well as in girls; it is no surprise at all that weight control goes together with bad feelings about the own body. After all, changing the body appearance is the only plausible reason for weight control.

One explanation of these results could have been that depression is the real cause of suicidal behaviour and that also weight control behaviour is an outcome of depression. But even after controlling for depression, a strong link between weight control and suicide behaviours remains.

Interestingly, the body mass index did not show any link to suicide. Therefore, only feeling fat but not being fat is linked to a suicide risk in young people. And it seems that many of those feeling fat are not really fat. This is a reason for concern about public weight loss messages.

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Monday, October 15, 2007

Adverse side effects of dieting messages

A study shows them to be effective, for instance in fostering weight concerns and eating disorders. The effects of dieting messages on psychological and weight control variables have been assessed in more than a hundred volunteers. Randomly assigned, a third of them has received a pro-dieting message, another third an anti-dieting message, and the rest a non diet-related control message. It came out that the pro-dieting message increased the intentions of bulimia and other eating disorders, produced a pressure to lose weight and left the subjects less satisfied with their body appearance. On the other hand, the anti-dieting message lowered the intentions of bulimia.

The conclusion of the study authors is interesting:

"The findings provide initial support for the short-term efficacy of the prodieting message to increase healthy eating behaviors; however, immediate increases in established risk factors for eating pathology also emerged."
With "healthy eating behaviour", the authors obviously mean "eating healthy food", whatever this may be. For instance, eating less fat and avoiding certain foods that are considered “unhealthy", but the side effects of such a behaviour put a big question mark over this behaviour.

The problem with public dieting messages is that they reach all people, regardless of their body weight, and raise weight concerns in people who should not be concerned at all. And when I look at those around me, I see that dieting and weight loss messages do reach the wrong people.

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Thursday, October 11, 2007

Low glycemic weight loss myth refuted

whole-grain bread
Yet another weight loss myth does not stand scientific scrutiny; you will not lose any weight by switching to foods with a low glycemic index. This index measures the relative speed of sugar uptake into the blood stream, compared to glucose which has a glycemic index (GI) of 100. Foods with a high GI challenge the body's control of blood sugar level, triggering a high production of insulin. A constantly high load of insulin may blunt the body's sensitivity to this hormone which is considered a first stage of diabetes. Thus, foods with a low glycemic index are considered healthier because they make it more easy for the body to maintain blood sugar balance.

While this is no question, the weight loss promoters have taken over the issue, claiming that low GI food may be helpful to curb the appetite and to lose weight. Nope, they are wrong, as a study about reduced glycemic index on satiety, energy intake and body weight has shown recently.

Research details: Nineteen women with a body mass index between 24 and 47 have been under two kinds of controlled diets for twelve weeks each. One diet had a GI of 56, the other 64. During both diet periods, the appetite, satiety, energy intake and weight remained unchanged. Conclusion of the authors:

"This study provides no evidence to support an effect of a reduced GI diet on satiety, energy intake or body weight in overweight/obese women. Claims that the GI of the diet per se may have specific effects on body weight may therefore be misleading."
Given the small number of test subjects and the small GI difference of 8, one might argue that a really extreme diet in a great number of persons may show an effect. But such a scenario sounds like being far from reality. Plus it is a fact that most weight loss methods have failed due to the body's self-regulation of weight under restricted food conditions.

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Wednesday, October 10, 2007

Underweight kids take most supplement pills

slim kid
False weight concerns in children and excessive use of vitamin and mineral supplements may be adverse side effects of a healthy lifestyle. This conclusion can be drawn from the 1999-2002 National Health and Nutrition Examination Survey (NHANES) in more than ten thousand children, according to a study about supplement use among infants, children, and adolescents in the United States: All in all, no less than thirty percent of U.S. children take supplements regularly, most often multivitamins and multiminerals.

Nutrition experts do not agree. They advise healthy children to get all necessary nutrients with food alone, because supplements may lead to an excessive supply, according to a vitamin study in infants and toddlers. Conclusion: Vitamin and mineral supplements may be useful for children with special needs, but they do no good and may even harm if healthy children are taking them.

Adverse effects of a healthy lifestyle?

Back to the NHANES study. It reveals that most supplements are taken by people with a higher income, living in a smoke-free environment, spending less time with TV, computers and video games and, as may be assumed (but not assessed in the study), doing more sports. In other words, living healthy.

It seems that the supplement industry has been very successful in advertising the claim that health can be purchased in form of capsules and bottles. Thus, supplement use may be regarded as sort of a lead symptom of a healthy lifestyle. When it comes to food, such a lifestyle tends to a more technical view of nutrition, that is, supplying the machinery of our organism with all necessary fuels. Good and bad foods, fear of fat and weight concerns are other symptoms of such a view.

This has been backed by the results of the NHANES supplement study: The highest supplement intakes have been recorded in children who are underweight or at risk of becoming underweight. This study adds more evidence to the view that weight concern messages targeted to the so-called overweights tend to reach the wrong target. In the shadow of the war against obesity we see a growing epidemic of anorexia, not only in adolescent girls but in ever younger kids.

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Monday, October 8, 2007

White sugar really no taboo for diabetics

fruits with sugar
New diabetic guidelines are more permissive to sweets, and a new trial backs this view for all those who still are afraid of sugar. In earlier days, refined, white sugar (sucrose) has been labeled as bad for diabetics which is a misbelief, because all carbohydrates, also those labeled as healthy, are changed in the body and become glucose which is one of the main components of sucrose. Also the speed of uptake into the blood, the glycemic index, is not highest in sucrose; there are many other carbohydrates with a higher index.

Obviously, there is still a number of skeptic diabetics who mistrust the sweets. Probably in order to convince them, a new trial has been undertaken with nine type 2 diabetics. Under close monitoring of insulin and blood sugar values, they have been told to substitute some of their daily carb intake by fifty grams (1.7 oz) of white sugar. Total calories have been unchanged. During three weeks of this sweet diet shift, neither the balance of blood sugar nor the insulin sensitivity has changed.

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Friday, October 5, 2007

Yet pregnant women target of weight loss hysteria

weight loss hysteria
Based upon a small number of special cases, obese pregnant women now are being told they should lose weight while larger studies just suggest them to curb weight gain to certain limits.

It is no secret that very heavy women, when pregnant, are at risk of getting a diabetes. In such a case, nothing can be said against interventions tackling this disease, in particular, a switch to eating healthier food and to more physical activity. Such an intervention has been undertaken in ninety-six women with gestational diabetes, using diet and exercise, in St. Louis, Missouri.

In these diabetic pregnant women, diet alone or diet plus exercise reduced the risk of big (macrosomic) babies if the women maintained a stable weight in spite of their pregnancy. A minority of women even lost some weight. Based upon this special and very limited experience, the general advice has been spread by certain media that heavy-weight pregnant women should lose weight.

Larger studies suggest to curb weight gain, not to lose weight

Interestingly, another study has just recently been published by the Missouri researchers, about weight gain and pregnancy outcomes in obese women. Based upon data of more than a hundred thousand pregnant women, the authors report:

"Gestational weight gain incidence for overweight or obese pregnant women, less than the currently recommended 15 lb, was associated with a significantly lower risk of preeclampsia, cesarean delivery, and large for gestational age birth and higher risk of small for gestational age birth." (emphasis mine)
While high blood pressure (preeclampsia), cesarean delivery and large babies are complications that may harm mother and baby, a low birth weight is a serious health risk for the baby. Given the wide variance in baby weights, the amount of recommended weight gain of mothers, in my opinion, cannot follow a general rule but must be based on the ultrasound pictures in every single case: If the fetus is large for his age, weight gain may be more restricted than in cases of a small fetus.

Swedish guidelines are not so harsh

In Sweden, the optimal pregnancy weight gain for body mass index categories of women has been assessed, using data of nearly three hundred thousand women of all weight categories. The upper limit of optimal weight gain in pregnancy is 22 lb (10 kg) for lean women up to a body mass index (BMI) of twenty-five, 20 lb (9 kg) for women up to BMI thirty, and 13 lb (6 kg) for a BMI above thirty.

Limited value of large numbers

If medical studies, based upon the law of large numbers, show certain effects such as a link between pregnancy weight gain and pregnancy outcome, these results cannot be applied to a single woman who is pregnant and anxious about her health and the future health of her baby. Thus, such guidelines must be seen with caution, and instead of looking anxiously at the scale, a woman most likely will fare better by listening to her body and its needs.

Thursday, October 4, 2007

What is good for your heart is also good for your knees

Even vigorous weight-bearing activity does not wear the cartilage but, on the contrary, makes it grow in volume. This has been shown in a study that assessed knee joints and physical activity in nearly three hundred healthy adults, fifty to seventy-nine years of age. The results dissipate all concerns about the strain that vigorous activity, as healthy as it may be for the heart, may impose on the knees. The good news: The knees are strong enough to support it. Even better, the joint cartilage grows stronger as the strain increases.

With the frequency and duration of vigorous weight-bearing activity, such as brisk walking, jogging, aerobics, cycling or strength training, this study has found an increase in the volume of the knee joint cartilage and a reduced risk of cartilage defects.

A word of caution: All subjects of this study never have had any knee injury or knee disease. Whoever feels pain in his knee should respect this signal and not overdo exercise. If jogging causes pain, walking or cycling may be better. If you have knee troubles, ask your physician about the best kind and intensity of exercise.

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Wednesday, October 3, 2007

Painstaking characters less struck by Alzheimer's

Self-discipline has shown to be protective against dementia in catholic nuns and priests, but this finding, hopefully, may also be true for postcard collectors and hobby gardeners.

The difference is striking: Compared to those with the lowest score of conscientiousness, those with the highest score have a risk of Alzheimer's disease reduced by 89 percent. This is the main outcome of a study about personality and dementia in 997 elderly nuns and priests. At the beginning of the study, all have been without any sign of dementia. Their personality has been assessed, and they have been followed up to twelve years. During this time, 176 developed Alzheimer's disease.

The study authors have expected such a result because a careful, painstaking character has been linked to a better health in old age in a number of previous studies.

The result is clear but its reason is not. A careful character is in most cases linked to a healthier lifestyle which may reduce the risks of Alzheimer's and other diseases. Conscientiousness may also activate the brain as an instance of self-control to a higher degree which may be protective against a decline of brain functions.

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Tuesday, October 2, 2007

Distressed victims of the war on obesity

distressed woman
Young women with a body mass index above 30 will, thirty years later, suffer from serious anxiety and depression five to six times as likely as slim women will, and this is not necessarily an adverse effect of body fat but rather of its negative reputation.

The three decade prospective study on obesity and mental diseases of women has just been published in the International Journal of Obesity: More than five hundred young mothers have been interviewed face by face at age 27 on average, and again thirty years later. Height and weight have been recorded by self report in these interviews, and although some of the women may have lied about their weight, it can be assumed that the values of body mass index (BMI) obtained by this method have been sufficiently accurate for dividing them into three classes: below 25, between 25 and 30, and above 30. When compared to the lowest weight class, the women with the highest weights have been suffering from anxiety disorder six times as likely and from major depression five times as likely at age 59 on average. The study authors conclude:

"Findings extend existing evidence of the mental health consequences of obesity in a representative sample of mothers, and suggest that obesity may have long-term implications for mental distress in women at a clinical level over the adult years."
Possible causes of distress

This study cannot tell anything about the possible causes of the "mental health consequences of obesity". But it may rather be the consequences of the "war on obesity" than body fat itself. Even in conditions like diabetes and heart diseases, there is no real evidence of a negative action of body fat cells. Thus, it seems to be very unlikely that these cells change the body hormones in a way that may have a negative impact on mood. Just look at a painting by Rubens: Do his models look distressed?

A better explanation of the study results, in my opinion, is the huge social pressure on women to be slim, not only imposed by the fashion industry but also fueled by public health that labels a body mass index above 25 as "overweight" - in other words "not normal" - and above 30 as "obesity" which is in itself considered a disease.

While the public health "war on obesity" has not yet proven to have made people healthier, this study, most likely, shows us the negative side effects of such campaigns.

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Monday, October 1, 2007

Double-edged training of medical researchers

It may raise as well as lower the quality of medical studies, and when it comes to money, the best fundraisers most likely will be the worst scientists. This conclusion is to be drawn from a study about the influence of training and mentoring on the misbehaviour of scientists: More than seven thousand social and biomedical researchers have been surveyed. All of them have received research support from the U.S. National Institutes of Health, partly early and partly in the middle of their careers.

The most important outcome is that scientists who early in their career have been supported in financial issues and in professional survival are more likely to show problematic behaviour that will lower the quality of their research than scientists who never have received this kind of support.

Even a training in research ethics at the beginning of a career is likely to increase the odds of handling data not properly. Only mentoring, that is, training plus monitoring of research ethics, will decrease the problematic behaviour and thus raise the quality of research.

The problematic influence of financial coaching is consistent with findings of other studies, stating that research funded by the industry is more likely to report positive effects of the products at stake, for instance in orthopedic research and for reporting effects in disputed remedies such as glucosamide against knee and hip pain.

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