Saturday, December 31, 2011
Monday, December 26, 2011
Holiday Myths
From the BMJ blog:
Sugar causes hyperactivity in children
While sugarplums may dance in children’s heads, visions of holiday sweets terrorise parents with anticipation of hyperactive behaviour. Regardless of what parents might believe, however, sugar is not to blame for out of control little ones. At least 12 double blind randomised controlled trials have examined how children react to diets containing different levels of sugar.2 None of these studies, not even studies looking specifically at children with attention-deficit/hyperactivity disorder, could detect any differences in behaviour between the children who had sugar and those who did not.3 This includes sugar from sweets, chocolate, and natural sources. Even in studies of those who were considered “sensitive” to sugar, children did not behave differently after eating sugar full or sugar-free diets.3
Scientists have even studied how parents react to the sugar myth. When parents think their children have been given a drink containing sugar (even if it is really sugar-free), they rate their children’s behaviour as more hyperactive.4 The differences in the children’s behaviour were all in the parents’ minds.4
Suicides increase over the holidays
Holidays can bring out the worst in us. The combined stresses of family dysfunction, exacerbations in loneliness, and more depression over the cold dark winter months are commonly thought to increase the number of suicides. While the holidays might, indeed, be a difficult time for some, there is no good scientific evidence to suggest a holiday peak in suicides.5 6 7
One study from Japan that looked at suicides in 1979-94 showed that the rate of suicide was lowest in the days before a holiday and highest in the days after the holiday.8 In contrast, in a study from the United States of suicides over a 35 year period, there was no increase before, during, or after holidays.9 Indeed, people might actually experience increased emotional and social support during holidays. In the US, rates of psychiatric visits decrease before Christmas and increase again afterwards.10 A smaller study of adolescents showed a peak in suicide attempts at the end of the school year,11 possibly reflecting a decrease in social support. Data from Ireland on suicide in 1990-8 also failed to connect suicides with the holidays.12 While Irish women were no more likely to commit suicide on holidays than on any other days, Irish men were actually significantly less likely to do so.
Further debunking myths about suicide, people are not more likely to commit suicide during the dark winter months. Around the world, suicides peak in warmer months and are actually lowest in the winter. In Finland, suicides peak in autumn and are lowest in the winter.13 In a 30 year study of suicides in Hungary, researchers again found the highest rates of suicides in the summer and the lowest in the winter.14Studies of suicide rates from India also show peaks in April and May.15 Studies from the US reflect this pattern, with lower rates in November and December than in typically warmer months.6
Of course, none of this evidence suggests that suicides do not happen over the holidays. The epidemiological evidence just does not support that the holidays are a time of increased risk.
Poinsettia toxicity
With flowers and leaves of red, green, and white, poinsettias are widely used in holiday decorations. Even though public health officials have reported that poinsettias are safe, many continue to believe this is a poisonous plant.16
In an analysis of 849 575 plant exposures reported to the American Association of Poison Control Centers,17 none of the 22 793 cases involving poinsettia resulted in considerable poisoning.17 No one died from exposure to or ingestion of poinsettia, and most (96%) did not even require medical treatment. In 92 of the cases, children ingested substantial quantities of poinsettias, but none needed medical treatment, and toxicologists concluded that poinsettia exposures and ingestions can be treated without referral to a healthcare facility.17 Another study, looking at poinsettia ingestion by rats, could not find a toxic amount of poinsettia, even at amounts that would be the equivalent of 500-600 poinsettia leaves or nearly a kilogram of sap.18
Excess heat loss in the hatless
As temperatures drop, hats and caps flourish. Even the US Army Field manual for survival recommends covering your head in cold weather because “40 to 45 percent of body heat” is lost through the head.19 If this were true, humans would be just as cold if they went without trousers as if they went without a hat. But patently this is just not the case.
This myth probably originated with an old military study in which scientists put subjects in arctic survival suits (but no hats) and measured their heat loss in extremely cold temperatures.20 Because it was the only part of the subjects’ bodies that was exposed to the cold, they lost the most heat through their heads. Experts say, however, that had this experiment been performed with subjects wearing only swimsuits, they would not have lost more than 10% of their body heat through their heads.20 A more recent study confirms that there is nothing special about the head and heat loss.21 Any uncovered part of the body loses heat and will reduce the core body temperature proportionally. So, if it is cold outside, you should protect your body. But whether you want to keep your head covered or not is up to you.
Nocturnal feasting makes you fat
Holiday feasts and festivities present us with many culinary options. A common suggestion to avoid unwanted weight gain is to avoid eating at night, and at first glance, some scientific studies seem to support this. In a study of 83 obese and 94 non-obese women in Sweden, the obese women reported eating more meals, and their meals were shifted to the afternoon, evening, or night.22 But just because obesity and eating more meals at night are associated, it does not mean that one causes the other. People gain weight because they take in more calories overall than they burn up. The obese women were not just night eaters, they were also eating more meals, and taking in more calories makes you gain weight regardless of when calories are consumed.
Other studies found no link at all between eating at night and weight gain. Swedish men did not show any evidence of gaining weight with night time meals.23 In a study of 86 obese and 61 normal weight men, there were no differences in the timing of when they ate.23 Another study of 15 obese people found that the timing of meals did not change the circadian rhythm pattern of energy expenditure.24 In a study of over 2500 patients, eating at night was not associated with weight gain, but eating more than three times a day was linked to being overweight or obese.25Studies have connected skipping breakfast with gaining more weight, but this is not because breakfast skippers eat more at night.26 Breakfast skippers eat more during the rest of the day. Records of calorie intake suggest that those who eat breakfast maintain healthy weights because their calorie intake is more evenly distributed over the day.26 27 In other words, when you eat three regular meals, you are not as likely to overeat at any one particular meal or time.
You can cure a hangover
From aspirin and bananas to Vegemite and water, internet searches present seemingly endless options for preventing or treating alcohol hangovers.28 Even medical experts offer suggestions.29
No scientific evidence, however, supports any cure or effective prevention for alcohol hangovers. A systematic review of randomised trials evaluating medical interventions for preventing or treating hangovers found no effective interventions in either traditional or complementary medicine.28 While a few small studies using unvalidated symptom scores showed minor improvements, the conclusion of the exhaustive review was that propranolol, tropisetron, tolfenamic acid, fructose or glucose, and dietary supplements including borage, artichoke, prickly pear, and Vegemite all failed to effectively “cure hangovers.” While more recent studies in rats show some potential for new products to alter mechanisms associated with hangovers,30 31 humans also face risks when using certain “hangover cures.”32A hangover is caused by excess alcohol consumption. Thus, the most effective way to avoid a hangover is to consume alcohol only in moderation or not at all.
Conclusions
Examining common medical myths reminds us to be aware of when evidence supports our advice, and when we operate based on unexamined beliefs. This was not a systematic review of either the evidence to refute these medical myths or of doctors’ beliefs. None the less, we applied rigorous search methods to compile data, and evidence of the prevalence of these medical beliefs is readily available. Only by investigation, discussion, and debate can we reveal the existence of such myths and move the field of medicine forward.
Notes
Cite this as: BMJ 2008;337:a2769
Footnotes
- The views expressed in this article are those of the authors and do not necessarily represent the view of the Indiana University School of Medicine.
Sunday, December 25, 2011
Saturday, December 24, 2011
Friday, December 23, 2011
Thursday, December 22, 2011
Wednesday, December 21, 2011
Tuesday, December 20, 2011
Monday, December 19, 2011
Sunday, December 18, 2011
Friday, December 16, 2011
How Bad Are Schools Today?
I'm always told how bad schools are today whenever I get around a group of retired folks. You know the folks - people who have rosy glasses whenever they think back to their "good ole days". The fact of the matter is the data usually doesn't support what they say. But now, they can go online, take a sample test that most high school students must pass to graduate, and email the results to their friends as proof school is much easier today. Click Reading Quiz | Math Quiz for Questions that came from the Florida Comprehensive Assessment Test (FCAT) for 10th grade - if you dare!
Read an article about what one school board member did and how he thinks the questions are not appropriate by clicking here. (from the Washington Post)
Read an article about what one school board member did and how he thinks the questions are not appropriate by clicking here. (from the Washington Post)
Two Thoughts For Today
In Heaven, the cops are British, the cooks are French, the engineers are German, the lovers are Italian, and it’s all organized by the Swiss.
In Hell, the cops are German, the cooks are British, the engineers are French, the lovers are Swiss, and it’s all organized by the Italians.
and...
Don’t tease fat kids, they have enough on their plates.
Wednesday, December 14, 2011
Tuesday, December 13, 2011
Coated Paper Troubles
A post from Dead Tree Eddition:
Monday, December 12, 2011
Why Mills Can't Keep the Coated Paper Market in Balance
There’s a simple way for North American mills to prevent the prices of coated paper from collapsing next year, the “Paper Guru” pointed out recently. Simple, but it won't work.
Responding to last week’s Dead Tree Edition article about the possibility of declining prices, Jack Miller, Printing Impressions’ Paper Guru, wrote, “Uncoated freesheet producers have reduced capacity, balanced supply and demand, and maintained prices.”
“With U.S. coated mills still under cost pressures from pulp and chemicals, and with margins where they are,” he suggested, the coated mills might take out capacity to keep the market in balance. But what works for uncoated freesheet will be hard to apply to coated paper.
The North American uncoated freesheet market is dominated by two big players, International Paper and Domtar, that are financially strong and have low-cost mills. That puts them in a position to idle machines or shut down mills if necessary to keep the market in balance.
But leadership of North America’s coated-paper market has one foot in the grave and the other on a banana peel. The #1 maker is NewPage, which is under Chapter 11 bankruptcy protection, making it nearly impossible to shut down a machine or mill in the short run. Besides, NewPage claims it has already mothballed all its high-cost machines.
The #2 manufacturer is Verso, a highly leveraged firm with a debt-to-equity ratio of about 18:1. Like NewPage, it’s not in much of a position to idle machines that could be generating cash.
SAPPI is the only other manufacturer with significant market share, but it produces coated freesheet almost exclusively. Coated groundwood (AKA coated mechanical) is where the big trouble lurks.
The bottom line is that no company with the financial strength to reduce capacity has enough North American market share to make much of a difference in the supply-demand balance. That’s why industry analyst Verle Sutton recently predicted that coated prices will decrease next year until losses force some companies to idle their machines.
Responding to last week’s Dead Tree Edition article about the possibility of declining prices, Jack Miller, Printing Impressions’ Paper Guru, wrote, “Uncoated freesheet producers have reduced capacity, balanced supply and demand, and maintained prices.”
“With U.S. coated mills still under cost pressures from pulp and chemicals, and with margins where they are,” he suggested, the coated mills might take out capacity to keep the market in balance. But what works for uncoated freesheet will be hard to apply to coated paper.
The North American uncoated freesheet market is dominated by two big players, International Paper and Domtar, that are financially strong and have low-cost mills. That puts them in a position to idle machines or shut down mills if necessary to keep the market in balance.
But leadership of North America’s coated-paper market has one foot in the grave and the other on a banana peel. The #1 maker is NewPage, which is under Chapter 11 bankruptcy protection, making it nearly impossible to shut down a machine or mill in the short run. Besides, NewPage claims it has already mothballed all its high-cost machines.
The #2 manufacturer is Verso, a highly leveraged firm with a debt-to-equity ratio of about 18:1. Like NewPage, it’s not in much of a position to idle machines that could be generating cash.
SAPPI is the only other manufacturer with significant market share, but it produces coated freesheet almost exclusively. Coated groundwood (AKA coated mechanical) is where the big trouble lurks.
The bottom line is that no company with the financial strength to reduce capacity has enough North American market share to make much of a difference in the supply-demand balance. That’s why industry analyst Verle Sutton recently predicted that coated prices will decrease next year until losses force some companies to idle their machines.
Saturday, December 10, 2011
Saturday, December 3, 2011
Thursday, December 1, 2011
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