RealClearScience Journal Club

Science Figures Interpreted and Analyzed by RealClearScience

Sit or Stand: How Should Men Pee?

Ross Pomeroy - July 23, 2014

In 2012, Viggo Hansen, a substitute member of the Sörmland County Council in central Sweden, made global headlines when he proposed a motion requiring men on the council to sit while urinating when using the office restrooms. Hansen argued that sitting would leave the toilets much cleaner, and also claimed that sitting reduces the risk of prostate cancer and endows men with a more robust sex life.

It's difficult to dispute Hansen's first point, but a new systematic review and meta-analysis published to PLoS ONE sheds a stream of light on his second.

Researchers in the Department of Urology at Leiden University Medical Center in the Netherlands pooled and analyzed eleven studies comparing the effects of sitting versus standing on three key "urodynamic parameters": maximum flow rate, voiding time (the time that it takes to pee), and post-void residual volume (the amount of urine remaining in the bladder).

In healthy men, the team found no differences across any of the variables. Sitting was no better than standing for urinary health. However, the meta-analysis showed that men with lower urinary tract symptoms (LUTS) were able to empty their bladders more completely (see figure below), leaving 25 fewer milliliters of urine in their bladders. Men with LUTS also had a stronger flow and took 0.62 seconds shorter to urinate, but these two results were just shy of statistical significance.

LUTS affects approximately 40% of older men and encompasses symptoms like increased urinary frequency, painful urination, and incomplete emptying of the bladder. The most common cause is a benign increase in the size of the prostate.

In light of the evidence, the researchers recommend that men with LUTS consider peeing in the sitting position. Residual urine in the bladder is associated with increased prevalence of bladder stones and urinary tract infection, and men with LUTS are better able to empty their bladders.

But contrary to the arguments of Leftists in Sweden, a quick search of PubMed yields no evidence whatsoever that sitting is associated with reduced risk of prostate cancer or a better sex life. There doesn't appear to be any direct health-related reason for healthy men to pee sitting down.

Source: de Jong Y, Pinckaers JHFM, ten Brinck RM, Lycklama à Nijeholt AAB, Dekkers OM (2014) Urinating Standing versus Sitting: Position Is of Influence in Men with Prostate Enlargement. A Systematic Review and Meta-Analysis. PLoS ONE 9(7): e101320. doi:10.1371/journal.pone.0101320

How to Make Your Dog Jealous

Alex B. Berezow - July 23, 2014

My best friend from childhood had two beautiful dogs, a German shepherd named Sari and an Australian shepherd named Chloe. Living on a large pasture in the Midwestern countryside, the dogs were both mellow and incredibly well-behaved... that is, until my friend and I decided to mess with them. No, we didn't engage in dog shaming (see photo above); instead, we did something much more ruthless.

Sari, the German shepherd, had a bit of a jealous side. Even if she had been petted first, Sari had a strict zero tolerance policy toward affection for Chloe. She simply could not tolerate bearing witness to Chloe being petted. If she saw it, she would try to wedge herself into the situation and steal attention from Chloe. Realizing the mischief we could make, my friend and I would simultaneously pet Chloe -- complete with ostentatious adulation -- causing Sari to go ballistic. She would whine and bark and bite at Chloe. On at least one occasion, we instigated a fight.

Cruel? Yes. But, little did we know that, scientifically, we were way ahead of our time. A new study in PLoS ONE has confirmed the existence of jealousy in dogs. And the authors' methods were frighteningly similar to ours.

The team recruited 36 dogs and their owners. The owners were told to ignore their own dog while they (1) played with a stuffed toy dog that barked and wagged its tail; (2) played with a jack-o-lantern as if it were a dog; and (3) read aloud from a children's book. Conditions #2 and #3 served as controls. Condition #2 determined if simply showing affection to anything other than the dog elicited a jealous response; Condition #3 examined if ignoring the dog caused jealousy. The dogs were videotaped, and their behavior was assessed:

As shown in the figure, the dogs had a real problem with the toy dog. They were likelier to snap, touch their owner, push the object, and whine if their owner was playing with the toy dog than if he was playing with the jack-o-lantern or reading from a book. Jealous much?

It is, of course, possible that dogs are simply disturbed by toys that look like dogs -- a sort of "uncanny valley" for canines. But, 86% of the dogs sniffed the toy's butt, indicating that they were at least temporarily fooled into believing the toy was a real dog. The other 14% that did not sniff the toy's rear exhibited fewer jealous behaviors. The authors suggest that these dogs were either super intelligent (because they knew the toy was fake) or super dumb (because they did not have enough sense to recognize the toy depicted a dog).

At the very least, 86% of you dog owners have a new way to torment your pooch. But, making your dog jealous isn't very nice, so I don't recommend it.

Source: Harris CR, Prouvost C. (2014) "Jealousy in Dogs." PLoS ONE 9(7): e94597. doi:10.1371/journal.pone.0094597

(AP Photo)

Evolution Needs to Be Seen to Be Believed

Alex B. Berezow - July 14, 2014

A substantial proportion of Americans reject evolution. This is perhaps partly due to evolution not being terribly intuitive. Life began over 3.5 billion years ago -- a timespan that is simply incomprehensible to our puny minds. If a species evolves over the course of 100,000 years, that is considered "quick" by evolutionary standards. Yet, most of us cannot get a mental grip on 100K years, either.

Because of this fundamental difficulty in teaching evolution, Dave van Ditmarsch and Joao Xavier propose a pedagogical solution in the journal Trends in Microbiology: Use bacteria, some of which can reproduce within 15-20 minutes, to teach evolution. After all, seeing is believing.

The authors grew a bacterium called Pseudomonas aeruginosa on Petri plates that allowed the bacteria to "swarm," i.e., grow outward from the middle of the plate in branch-like patterns. After 24 hours, the bacteria were collected, and a small fraction (1/1,500) of them were transferred to the middle of another plate. This process was repeated several times. By the final day of the experiment, the bacteria had evolved to become "hyperswarmers," i.e., they no longer grew in a branching pattern but covered the entire plate. (See figure.)

Bacteria with the ability to hyperswarm have an advantage over the mere swarmers because they acquire better access to nutrients. As shown in the image on the left, P. aeruginosa has a single "tail" (called a flagellum) that helps it swim. By Day 9, not only were the bacteria hyperswarming, but they also sported multiple flagella, as shown in the image on the right.

Digging around in the bacterial genome, the authors discovered that a mutation in the gene fleN was responsible for this. Strangely, deleting the gene entirely prevents the bacteria from swimming at all, but a slight tweak in the gene allows the bacteria to produce multiple flagella.

The authors repeated the experiment twice more, and both times, hyperswarming evolved. And both times, the bacteria grew multiple flagella. And both times, a mutation occurred in the gene fleN. Thus, to a limited extent, evolution is reproducible and possibly even predictable.

The take-home message from this experiment is that bacteria beautifully demonstrate how evolution works. It is much easier to understand evolution by observing how bacteria can dramatically change over the course of roughly a week than trying to imagine how life might have changed over billions of years. And, most strikingly, the experiment shows that what appears to be a major alteration to the bacterium's anatomy results from nothing more than a single mutation to a single gene.

Indeed, seeing is believing.

Source: Dave van Ditmarsch and Joao B. Xavier. "Seeing is believing: what experiments with microbes reveal about evolution." Trends Microbiol 22 (1): 2-4. (2014) DOI: http://dx.doi.org/10.1016/j.tim.2013.11.004

(AP Photo)

Low-Carb Diets: Quit Drinking the (Sugar-Free) Kool-Aid

Ross Pomeroy - July 14, 2014

There are few areas of scientific research murkier than nutrition. Thousands of studies have tackled the seemingly simple question of what we should eat in order to lose weight. But one study that points in one direction is inevitably countered by another pointing in the opposite. Every tiny change in study design could sway findings one way or the other. The result is maddening. Sifting through the literature reveals no overarching consensus beyond "eat less," "move more," and "go easy on the sugar."

But what about this never-ending "low carbohydrate" fad? Advocates of "Paleo," "Zone," or "Atkins," -- all forms of low-carb diets -- say that eating fewer grains produces more weight loss and better health outcomes than basic reduced-calorie diets.

Here again, scientists are conflicted. Some studies show that low-carb diets vastly outperform balanced, calorie-restricted diets, but other studies show no difference at all.

The best tool we have for detecting a pattern in the literature is the systematic review, where similar studies are grouped together and analyzed. If you're wondering whether low-carb diets are better than traditional weight loss diets, you're in luck. Researchers just completed a systematic review to answer that very question.

Scientists based out of Stellenbosch University poured through published records to find studies in which low-carb and balanced diets were directly compared. The team was very selective, including only randomized, controlled trials where the two comparison diets had the same number of calories, featured at least 10 subjects per group, were longer than 12 weeks (with long-term follow up), and were solely focused on diet. Only 19 studies survived the purge.

In these studies, subjects consuming low-carb diets received roughly 35% of their calories from carbohydrates, 35% from fat, and 30% from protein. Those consuming balanced diets received 55% from carbohydrates, 30% from fat, and 15% from protein, in line with government recommendations.

The review showed that both low-carb and balanced diets yielded similar weight loss in the long-term, with low-carb diets edging out the competition by a single pound after 1-2 years (a statistically insignificant amount). Differences in improvements to other health variables like cholesterol, triglycerides, and blood pressure were almost imperceptible.

In short, the review revealed that the purported revolutionary benefits of low-carb diets are likely overstated, and any associated weight loss results almost entirely from accompanying calorie restriction, not from specifically cutting out carbohydrates.

"It follows that when considering dietary strategies for weight loss, less emphasis should be placed on an ‘ideal’ macronutrient composition and more emphasis on reduction in total energy intake," the researchers state. 

Advocates of low-carb diets are technically correct about one thing: a calorie is not just a calorie. Protein, fat, and carbohydrates -- the three primary macronutrients -- are used by the body and transformed into energy in different ways. But those distinctions are -- when it comes to weight balance -- miniscule, and do not translate to anything game-changing for the health of modern humans.

Source: Naude CE, Schoonees A, Senekal M, Young T, Garner P, et al. (2014) Low Carbohydrate versus Isoenergetic Balanced Diets for Reducing Weight and Cardiovascular Risk: A Systematic Review and Meta-Analysis. PLoS ONE 9(7): e100652. doi:10.1371/journal.pone.0100652

Do Elephants Even Like to Paint?

Ross Pomeroy - July 10, 2014

Elephants are artists! Whether at a zoo, on the Internet, or on television, you've probably seen one of these awesome, hulking pachyderms wield a paintbrush.

Zookeepers commonly consider the activity a win-win: Humans get to see the animals showing off their cognitive and artistic abilities, and the elephants get to engage in an activity that enriches their lives in captivity.

But wait, hold the phone, do elephants even enjoy painting? As it turns out, nobody has ever explored that question scientifically. Until now, that is.

In a new study published in PeerJ, Megan English, Gisela Kaplan, and Lesley Rogers, all based out of Centre for Neuroscience and Animal Behaviour at the University of New England in Australia, detail their efforts to discern whether or not elephants truly derive tangible benefits from painting. The trio found paltry evidence that they do.

English, Kaplan, and Rogers spent four months observing the behavior of four elephants at the Melbourne Zoo. The animals routinely paint in front of a live audience every week.

Obviously, the team couldn't simply ask the elephants whether or not they like painting, so instead, the trio of scientists watched to see whether the pachyderms' behavior markedly changed on the days where they painted compared to the days where they didn't. Painting is considered a form of enrichment, so theoretically there should be a reduction in stress-related and non-interactive behaviors like weaving or pacing and an increase in positive and social behaviors like playing and ear-flapping.

Overall, there wasn't. One elephant -- by far the eldest at 33 years -- did display increased non-interactive behavior on days where she didn't paint, but the other elephants did not. Of note, the elephants showed reduced stress-related behavior on the mornings before they painted, but the researchers later learned that was because the keepers chose the least-stressed individuals to do it.

"A key purpose of including enrichment activities for captive animals is to at least reduce stress-related behaviour as well as encourage natural behaviour and stimulate the animals. The activity of painting does not appear to address this need adequately," the researchers wrote.

A key drawback of the study is that it was conducted on only four females at a single zoo. With such a limited sample size, it could easily be argued that the differences in behavior merely reflect that elephants are unique, cognitively complex animals with distinct personalities. Some may enjoy painting, while others might not.

But the authors contend that zoos should provide their own evidence that painting improves the lives of elephants before encouraging them to do it. If there isn't any, then they should provide the animals with other, more beneficial activities.

"Our results suggest that painting does not improve the welfare of elephants and that its main benefit is the aesthetic appeal of these paintings to the public and their subsequent sale of which a percentage of funds might be donated toward conservation of the species."

Source: English M, Kaplan G, Rogers LJ. (2014) Is painting by elephants in zoos as enriching as we are led to believe? PeerJ 2:e471 http://dx.doi.org/10.7717/peerj.471

Avoid Night Owls on Your Morning Commute

Alex B. Berezow - July 7, 2014

There are certain types of drivers that we should always strive to avoid. The speeders, the chronic lane changers, the texters, and the elderly -- who spend most of their time driving 40 mph in the fast lane with their left turn signal flashing -- are easy enough to identify. But, there's another group of drivers that also poses a threat, but is much harder to recognize: Night owls on the morning commute.

In a new study in Accident Analysis & Prevention, researchers analyzed 25 female volunteers who were selected based on their responses to a chronotype survey. Thirteen of the volunteers were early birds, and twelve of them were night owls. They were asked to complete a simulated driving test at 8 am and 8 pm. The track was incredibly boring, essentially a giant oval, and was purposefully selected to make the task as tedious as possible. The volunteers had to follow a green line down the middle of the road at 60 mph, constantly adjusting their driving to account for slight imperfections in the road. In each session, the volunteers had to drive for about 1 hour. How did they do?

A couple of the drivers crashed their cars, so maybe the task was too difficult for them. The rest, however, provided an interesting data set: Night owls did not perform as well as early birds in the morning commute. (See graph.)

As shown above, night owls had a hard time driving straight, and they performed progressively worse as time went by -- despite the fact that both early birds and night owls had similar levels of sleep the previous night. On the other hand, the early birds did just fine, both at 8 am and at 8 pm.

For you night owls, perhaps this study could be used to get your boss to allow you to clock in at work later in the morning. After all, you don't want to be a hazard to other drivers.

Source: Correa A, Molina E, Sanabria D. "Effects of chronotype and time of day on the vigilance decrement during simulated driving." Accident Analysis & Prevention 67: 113-118 (2014).

Pet Cats in Europe Are Infested with Parasites

Ross Pomeroy - July 1, 2014

One out of every two pet cats in Europe is infested with some sort of parasite, according to research published last week in the journal Parasites and Vectors. Ear mites and fleas were the most prevalent bugs found outside of the body, while intestinal worms and lung worms were most common inside.

In all, 1,519 cats were examined at veterinary hospitals in France (Maisons-Alfort and Nantes), Italy (Bari and Naples), Austria (Vienna), Belgium (Liège), Hungary (Budapest), Romania (Cluj-Napoca), and Spain (Madrid).

29.6% of cats had parasites on the outside of their bodies (ectoparasites) and 35.1% tested positive for parasites inside the body (endoparasites). 14% were infested with both.

Italian cats were the most flea-bitten. Pet felines in Bari and Naples were 2.5 and 5 times as likely as cats in Budapest, the reference city, to be infested with feline roundworm.

The biggest risk factors for parasitic infection among pet cats were access to the outdoors, number of cats in a household, and the frequency of parasite treatments. So Italy has a large population of crazy cat ladies who allow their pets to run rampant outdoors. Makes sense.

Precise data for cat parasites in the U.S. are scarce, but localized studies in major cities indicate that the rates are lower. If you're wondering about American dogs, their rate of parasitic infestation is between 35 and 55%, with canines in the southeastern states faring the most poorly.

The study highlights the importance of proper hygiene practices for pets. Millions of people become infected with parasites from their cat or dog every ear in the U.S. Already, around one out of every ten people in the U.S. plays host to Toxoplasma gondii, a mind-altering parasite transmitted to humans through cat feces.

Avoid infestation by de-worming your dog or cat on a regular basis, washing your hands frequently, and giving your pet a bath every once and a while. If you have a cat, clean its litter box every day and consider restricting its access to the outdoors.

Source: Beugnet et. al. "Parasites of domestic owned cats in Europe: co-infestations and risk factors." Parasites & Vectors 2014, 7:291 doi:10.1186/1756-3305-7-291

Found: Oldest Known Poop From a Human Ancestor

Ross Pomeroy - June 26, 2014

Archaeologists in Spain have dug up the oldest known feces from a human ancestor. Their find is detailed in PLoS ONE.

Retrieved from El Salt, an open-air site near Alicante, Spain, the samples date back around 50,000 years, firmly trouncing the previous record of 14,000 years.

Dr. Ainara Sistiaga and her team were able to identify the buried fecal matter by the predominance of coprostanol, a compund considered to be a clear biomarker of human excrement.

"5β-stanols, including coprostanol and 5β-stigmastanol, can be used as fecal biomarkers because they are uniquely formed in the intestinal tract of most higher mammals during metabolic reduction of cholesterol and phytosterols," Sistiaga told RCScience.

Besides advancing the quest to extend fart jokes further back into the Paleolithic, the find is important for a simple reason: if you want to know what went in, you have to examine what came out. Fossilized feces are the best clues we have for learning what our ancestors ate. The current discovery presents the first direct evidence that Neanderthals consumed an omnivorous diet of meat and vegetables.

Organic molecules called sterols permitted the researchers to glean that nugget of information. Divided into phytosterols (from plants) and zoosterols (from animals), they're hearty molecules that give cell membranes their structure. When we eat plants or animals, traces of these sterols will make it through digestion to be excreted in feces. The type of sterols in our poop gives away what we've been eating. In the case of the Neanderthal feces at El Salt, the researchers found evidence of a meat-dominated diet occasionally augmented by vegetables, probably some sort of tuber. Lot's of meat and a few potatoes.

"Our results also have implications regarding digestive systems and gut microbiota evolution," the researchers say.

They found evidence that cholesterol was converted to coprostanol, a process known to be carried out by gut bacteria. It would appear that Neanderthals had their own army of gut flora 50,000 years ago.

Source: Sistiaga A, Mallol C, Galva ́n B, Summons RE (2014) The Neanderthal Meal: A New Perspective Using Faecal Biomarkers. PLOS ONE 9(6): e101045. doi:10. 1371/journal.pone.0101045

A Genetic Link Between Schizophrenia & Pot?

Alex B. Berezow - June 24, 2014

It is known that there is a link between schizophrenia and smoking marijuana. However, much to the chagrin of researchers, it is not ethical to randomly assign people to smoke pot to determine if they develop schizophrenia at some point. As a result, it remains unknown if smoking pot causes schizophrenia, if schizophrenics are more likely to smoke pot, or if some unknown third variable links the two.

A new paper in Molecular Psychiatry attempts to answer this question. It appears that, to at least some extent, genetics can predispose an individual to both schizophrenia and marijuana use.

The authors determined the "polygenic risk score" for schizophrenia in 2,082 healthy people. (The polygenic risk score determines how likely a healthy person is to develop schizophrenia based on his genetic profile.) Their prediction was that people with higher risk scores would also be likelier to smoke pot. And that is exactly what they found, though the causative link was vanishingly small. (More on that below.) Interestingly, they also found that if a pair of twins had a high average polygenic risk score, both of them were likelier to smoke pot. (See graph.)

Overall, the link between a genetic predisposition for schizophrenia and smoking cannabis was statistically significant, but very small: Less than 1% of the variance in cannabis use could be explained by an underlying genetic predisposition to schizophrenia. That means more than 99% of the variance in cannabis use cannot be explained by such a genetic predisposition.

But, there are a few points worth making:

First, it is typical for these types of studies to show only very small links. It reflects our poor understanding of genetics and gene-environment interactions. Indeed, the polygenic risk score only explains about 2-7% of the variance in schizophrenia itself, so it is not surprising that the authors only found a very small causative link. Second, this study looked only at genes linked to schizophrenia. It is quite possible that there is a genetic predisposition to smoking pot, independent of a predisposition to schizophrenia. Third, as the authors indicate, there is plenty of evidence to suggest that smoking pot increases the risk of developing schizophrenia, though the risk here also appears small.

So, potheads (especially you teenagers), it looks like you should worry more about possibly losing 8 IQ points than developing a mental illness.

Source: RA Power et al. "Genetic predisposition to schizophrenia associated with increased use of cannabis." Molecular Psychiatry. Published: 24 June 2014. doi:10.1038/mp.2014.51

(AP Photo)

Researchers Identify New Type of Procrastination

Ross Pomeroy - June 4, 2014

In 2008, a nameless commenter at Procrastinator's Anonymous asked a question that garnered significant response:

"I often find myself delaying my bedtime hour, even when I have nothing important that keeps me from going to bed. It's an odd feeling, because I feel sleepy. Can we even call this 'procrastination'? I'm not sure."

Six years later, researchers from Utrecht University have an answer: Yes.

The Centers for Disease control labels insufficient sleep a "public health epidemic." Thirty percent of adults report sleeping fewer than six hours per night. That's not healthy. According to the CDC, "Persons experiencing sleep insufficiency are... more likely to suffer from chronic diseases such as hypertension, diabetes, depression, and obesity, as well as from cancer, increased mortality, and reduced quality of life and productivity." Even more startling, a 2009 survey found that one in twenty individuals admitted to dozing off behind the wheel in the previous month.

Clearly, we need more sleep. So why aren't we getting it? Some of the more popular reasons include artificial lighting, stress, and restrictive work hours. Now, in a new study published to Frontiers in Psychology, Floor Kroese, an assistant professor in psychology at Utrecht University, and a team of researchers put forward the notion that we don't get enough sleep because... meh.

In other words, we procrastinate.

The textbook definition of procrastination is a “voluntary delay of an intended course of action despite expecting to be worse off for the delay." At least half of college students do it on academics and a tenth of the general population procrastinates chronically.

In her study, Kroese surveyed 177 individuals via Amazon's Mechanical Turk on all sorts of lifestyle and demographic factors, sleep and inclination to procrastinate among them. Bedtime procrastination was gauged by assessing subjects' level of agreement with statements like "I go to bed later than I had intended" and "I easily get distracted by things when I actually would like to go to bed." Digging into the data, Kroese found moderate levels of bedtime procrastination among the survey population. She also found that it was negatively correlated with reported hours of sleep and positively correlated with fatigue and insufficient sleep.

But the results prompt some obvious skepticism. It's not like sleep is a chore, so why would people procrastinate on it?

"We speculate that it is not so much a matter of not wanting to sleep, but rather of not wanting to quit other activities," Kroese explains. Instead of going to sleep, it's "one more episode" on Netflix or "one more quest" on that video game.

"Bedtime procrastination may be a relatively modern phenomenon," she adds.

For those bedtime procrastinators out there, fixing their problem could be a tall task. Sleep is nice, but watching people get beheaded on Game of Thrones, well, that's hard to contend with.

Source: Kroese F, De Ridder D, Evers C and Adriaanse M (2014). Bedtime Procrastination: Introducing a New Area of Procrastination. Front. Psychol. 5:611. doi: 10.3389/fpsyg.2014.00611

More Journal Club

And Now... a Spider Masquerading as Bird Poop
May 29, 2014

Life as a spider isn't the easiest. As hydraulic beasts, the tiniest wound in the right spot could render...

Lift Weights, Binge on Protein, Gain No Fat?
May 22, 2014

A new study finds that consuming an additional 150 grams of extra protein each day, equal to 600 calories,...

How to Ask for a Favor. Or, How to Get Free Pizza
May 16, 2014

Almost everyone needs a favor at one time or another. Maybe a family member suffered a devastating accident...

Journal Club Archives