TIME Research

America’s Smoking Rate Continues to Drop

Smoking
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But there are some at-risk groups, including LGBT people and Native Americans

The smoking rate for American adults has continued to fall, according to a new report.

The national smoking rate stands at 17% this year, a drop from the 18% reported in 2013, the Centers for Disease Control and Prevention found. Smoking rates were actually even lower earlier this year, when they were hovering around 15%, but some say the lower number is attributable to New Year’s resolutions.

Other demographic trends were released in the report. Multiracial people had the highest smoking rates, at 26.8%, with those of Native American ancestry close behind at 26.1%; experts believe that ceremonial use of tobacco affects Native American smoking rates. Men were more likely to smoke than women, as were those who identified as LGBT. More than 29% of smokers were below the poverty line.

The CDC notes that smoking is “the single largest preventable cause of death and disease” in the U.S., with 480,000 deaths per year being traced to cigarettes.

TIME Aging

Weight at Age 50 Connected to When a Person Gets Alzheimer’s

Being overweight may bring symptoms of the disease on earlier

Middle-aged Americans have one more reason to keep an eye on the scale as they age: research shows that people who are overweight when they are 50 years old may be more likely to develop Alzheimer’s sooner than those that are a healthy weight.

Scientists at the National Institutes of Health studied midlife obesity’s connection to Alzheimer’s and announced in a study published Tuesday in the journal Molecular Psychiatry that they had found a connection between being overweight or obese in middle age and developing Alzheimer’s.

“Maintaining a healthy BMI at midlife is likely to have long-lasting protective effects,” Dr. Madhav Thambisetty, lead author of the study and a researcher at the NIH’s National Institute on Aging, told the Associated Press.

BMI stands for body mass index, a common medical indicator that takes the ratio of a person’s weight to height. The medical community normally considers a BMI of 25 to be overweight.

Read More: New Study Identifies 9 Risk Factors for Alzheimer’s Disease

The research team used the Baltimore Longitudinal Study of Aging, a project developed to track how healthy people age, to find the correlation. The study used the records of approximately 1,400 people who’d taken regular cognitive tests for 14 years; 142 of them developed Alzheimer’s. The researchers then used the records of those 142 people to figure out their BMI and discovered that every increasing step up on BMI charts meant Alzheimer’s struck 6 1/2 months sooner.

Researchers aren’t sure if the reverse—having a healthy BMI and being slim—are indicators of not developing Alzheimer’s later on. They’re also not sure if losing weight after age 50 lessens the impact or delays Alzheimer’s.

Regardless, it’s a result that has many worried, particularly given the increasingly large population of obese middle-aged adults across the world. About 46 million people currently suffer from Alzheimer’s disease, with the number projected to double in the next 20 years.

TIME Research

Your Kid’s Gigantic Backpack Is a Health Risk

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Like adorable turtles, their little limbs poking out from under outsized shells, kids shuffle their ways to school bearing on their shoulders ever-heavier backpacks. Even high schoolers have to bend forward beneath books and binders to cart their cargo to and from school. They’re burdensome (and can be goofy-looking), but are they dangerous?

Yes, say many experts.

“Since at least 1998, we’ve noticed backpacks getting bigger and heavier, and not in proportion to the kids’ sizes,” says Dr. Karen Jacobs, a clinical professor at Boston University and spokesperson for the American Occupational Therapy Association (AOTA), which sponsors a school backpack awareness day. Jacobs says crowded schools and scant locker space appear to be driving the phenomenon.

A 2010 study from the University of California, San Diego, concludes, “backpack loads are responsible for a significant amount of back pain in children.” The same study says a full third of kids aged 11 to 14 report back pain. Other research from 2011 came to a similar conclusion.

“Kids are saying ‘My back hurts, my neck and my shoulders hurt,’” Jacobs says. “A heavy backpack can also contribute to headaches and problems concentrating at school.”

Like the frame of a house, the spine what keeps your child’s body sturdy and upright. Put too much weight on this frame while a young body is still developing, and it could change a kid’s posture, compress his spine, and impair growth, says Rob Danoff, a doctor of osteopathic medicine and a certified family physician with Philadelphia’s Aria Health System. “It also might contribute to back problems or injuries when your child’s older,” Danoff says.

How heavy is too heavy? “As a general rule, research shows the backpack should be no more than 10 to 20 percent of your child’s body weight to avoid pain or potential injury,” Jacobs says. “We like to err on the side of caution and recommend 10 percent.” (Danoff’s recommendation—no more than 15 percent—falls in line with Jacob’s.)

For an elementary school child who weighs just 50 or 60 pounds, a couple textbooks and lunch could push a pack beyond the safe threshold. For that reason, Jacobs says it’s important to check your child’s backpack every day to ensure she’s carrying only what she needs. “We’ve noticed that students are taking lots and lots of water to school with them, which is a lot of unnecessary weight,” Jacobs says. “We’re telling parent to send empty water bottles and have their kids fill them at school.”

She also recommends positioning the heaviest items in the middle of the pack and close to your child’s back.

Danoff says proper fit and design are important to relieve pressure from your little guy or girl’s spine and shoulders. You want a backpack made for someone your child’s size, he says. Padded shoulder straps and a cushioned back will also prevent aches and pains.

Finally, for crafty parents who may be considering non-backpack options—like a small roller bag—Jacobs says some schools have already started banning rollers because they pose tripping hazards, or may litter classroom aisles or hallways in the event of a fire.

If all this is exasperating, take heart: it probably won’t be long before every text or course packet your child needs is digitized, and schools stock tablets in every classroom. At which point, we can start to panic about tech neck instead.


TIME Research

Your Kids Should Know About the Dangers of Drinking By Age 10, Doctors Say

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Kids should know about the dangers of alcohol before their first sip

Health care professionals should be talking to children about the risks of alcoholic drinks when they are as young as nine, according to a new report from the American Academy of Pediatrics (AAP).

“Surveys indicate that children start to think positively about alcohol between ages 9 and 13 years,” the AAP authors write in the report. “The more young people are exposed to alcohol advertising and marketing, the more likely they are to drink, and if they are already drinking, this exposure leads them to drink more. Therefore, it is very important to start talking to children about the dangers of drinking as early as 9 years of age.”

In the United States, alcohol is the substance most commonly abused by kids and adolescents. The new report says that 21% of young people say they had more than a sip of an alcoholic beverage before they were 13 years old, and 79% have tried alcoholic drinks by the time they were seniors in high school.

The study also found that 80% of adolescents say their parents are the biggest influence on whether they drink or not, which suggests parents have a role as well. “We must approach drinking in children, particularly binge drinking, differently than we do in adults,” said co author and pediatrician Dr. Lorena Siqueira, a member of the AAP Committee on Substance Abuse. “Given their lack of experience with alcohol and smaller bodies, children and adolescents can have serious consequences — including death — with their first episode of binge drinking.”

Other research reviewed by the AAP committee suggested that continued use of alcohol at a young age can hinder brain development, lead to alcohol-induced brain damage, and increase the risk of substance use problems later on. The AAP says every pediatrician should screen their adolescent patients for alcohol use during appointments and offer preventative messaging.

The report authors focused specifically on the risks of binge drinking, which is classified as three or more drinks in a two-hour period for girls between ages nine and 17. For boys it’s three or more drinks in two hours between age 9 to 13, four or more drinks for boys ages 14 to 15, and five or more drinks for boys ages 16 to 17. The authors note that drinking rates increase in high school with 36 to 50% of high school students drinking and 28% to 60% binge drinking.

TIME Research

Only a Third of Psych Studies Are Reliable. Now What?

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We must stop treating single studies as unassailable authorities of the truth

The ability to repeat a study and find the same results twice is a prerequisite for building scientific knowledge. Replication allows us to ensure empirical findings are reliable and refines our understanding of when a finding occurs. It may surprise you to learn, then, that scientists do not often conduct – much less publish – attempted replications of existing studies.

Journals prefer to publish novel, cutting-edge research. And professional advancement is determined by making new discoveries, not painstakingly confirming claims that are already on the books. As one of our colleagues recently put it, “Running replications is fine for other people, but I have better ways to spend my precious time.”

Once a paper appears in a peer-reviewed journal, it acquires a kind of magical, unassailable authority. News outlets, and sometimes even scientists themselves, will cite these findings without a trace of skepticism. Such unquestioning confidence in new studies is likely undeserved, or at least premature.

A small but vocal contingent of researchers – addressing fields ranging from physics to medicine to economics – has maintained that many, perhaps most, published studies are wrong. But how bad is this problem, exactly? And what features make a study more or less likely to turn out to be true?

We are two of the 270 researchers who together have just published in the journal Science the first-ever large-scale effort trying to answer these questions by attempting to reproduce 100 previously published psychological science findings.

Attempting to re-find psychology findings

Publishing together as the Open Science Framework and coordinated by social psychologist Brian Nosek from the Center for Open Science, research teams from around the world each ran a replication of a study published in three top psychology journals – Psychological Science; Journal of Personality and Social Psychology; and Journal of Experimental Psychology: Learning, Memory, and Cognition. To ensure the replication was as exact as possible, research teams obtained study materials from the original authors, and worked closely with these authors whenever they could.

Almost all of the original published studies (97%) had statistically significant results. This is as you’d expect – while many experiments fail to uncover meaningful results, scientists tend only to publish the ones that do.

What we found is that when these 100 studies were run by other researchers, however, only 36% reached statistical significance. This number is alarmingly low. Put another way, only around one-third of the rerun studies came out with the same results that were found the first time around. That rate is especially low when you consider that, once published, findings tend to be held as gospel.

The bad news doesn’t end there. Even when the new study found evidence for the existence of the original finding, the magnitude of the effect was much smaller — half the size of the original, on average.

One caveat: just because something fails to replicate doesn’t mean it isn’t true. Some of these failures could be due to luck, or poor execution, or an incomplete understanding of the circumstances needed to show the effect (scientists call these “moderators” or “boundary conditions”). For example, having someone practice a task repeatedly might improve their memory, but only if they didn’t know the task well to begin with. In a way, what these replications (and failed replications) serve to do is highlight the inherent uncertainty of any single study – original or new.

More robust findings more replicable

Given how low these numbers are, is there anything we can do to predict the studies that will replicate and those that won’t? The results from this Reproducibility Project offer some clues.

There are two major ways that researchers quantify the nature of their results. The first is a p-value, which estimates the probability that the result was arrived at purely by chance and is a false positive. (Technically, the p-value is the chance that the result, or a stronger result, would have occurred even when there was no real effect.) Generally, if a statistical test shows that the p-value is lower than 5%, the study’s results are considered “significant” – most likely due to actual effects.

Another way to quantify a result is with an effect size – not how reliable the difference is, but how big it is. Let’s say you find that people spend more money in a sad mood. Well, how much more money do they spend? This is the effect size.

We found that the smaller the original study’s p-value and the larger its effect size, the more likely it was to replicate. Strong initial statistical evidence was a good marker of whether a finding was reproducible.

Studies that were rated as more challenging to conduct were less likely to replicate, as were findings that were considered surprising. For instance, if a study shows that reading lowers IQs, or if it uses a very obscure and unfamiliar methodology, we would do well to be skeptical of such data. Scientists are often rewarded for delivering results that dazzle and defy expectation, but extraordinary claims require extraordinary evidence.

Although our replication effort is novel in its scope and level of transparency – the methods and data for all replicated studies are available online – they are consistent with previous work from other fields. Cancer biologists, for instance, have reported replication rates as low as 11%25%.

We have a problem. What’s the solution?

Some conclusions seem warranted here.

We must stop treating single studies as unassailable authorities of the truth. Until a discovery has been thoroughly vetted and repeatedly observed, we should treat it with the measure of skepticism that scientific thinking requires. After all, the truly scientific mindset is critical, not credulous. There is a place for breakthrough findings and cutting-edge theories, but there is also merit in the slow, systematic checking and refining of those findings and theories.

Of course, adopting a skeptical attitude will take us only so far. We also need to provide incentives for reproducible science by rewarding those who conduct replications and who conduct replicable work. For instance, at least one top journal has begun to give special “badges” to articles that make their data and materials available, and the Berkeley Initiative for Transparency in the Social Sciences has established a prize for practicing more transparent social science.

Better research practices are also likely to ensure higher replication rates. There is already evidence that taking certain concrete steps – such as making hypotheses clear prior to data analysis, openly sharing materials and data, and following transparent reporting standards – decreases false positive rates in published studies. Some funding organizations are already demanding hypothesis registration and data sharing.

Although perfect replicability in published papers is an unrealistic goal, current replication rates are unacceptably low. The first step, as they say, is admitting you have a problem. What scientists and the public now choose to do with this information remains to be seen, but our collective response will guide the course of future scientific progress.

This article originally appeared on The ConversationThe Conversation

TIME Mental Health/Psychology

A New Theory of Why Neurotics Are Creative

A wandering mind might explain why creative leaders tend to be neurotic.

Adam Perkins is a psychologist and a self-proclaimed neurotic, contemplating things to the point of obsession. He can get anxious about things that might seem mundane to another person. And he’s admittedly quite sensitive.

Perkins also has a new theory, described in a piece published Thursday in the journal Trends in Cognitive Sciences, about why he and many others like him channel their neuroticism into creativity and problem solving. He argues it comes from how certain people daydream.

Neuroticism and creative thinking have long been correlated: some of history’s more exciting minds, from Isaac Asimov to Winston Churchill to Woody Allen, have been famously anxious with a tendency to brood. The trait is also often associated with being risk-averse; neurotic people are often considered “threat sensitive,” a classification that the psychologist Jeffrey Gray first pinpointed while developing a test that predicted a person’s tendency to be neurotic. Gray’s test showed that high scorers on the neuroticism test tended to avoid “dangerous” jobs, preferring occupations that kept them out of harm’s way—hence the association with more analytical jobs, which require creative problem solving, as opposed to physical ones.

But Gray’s analysis seemed simplistic, Perkins says. “Why should having a magnified view of threat make you good at coming up with solutions to difficult problems?” he tells TIME. “It doesn’t add up. On one hand, it’s a clever theory—it shows the difficulty of holding down a dangerous job, for example—but on the other hand, it doesn’t explain why [neurotic people] tend to feel unhappy or why they’re more creative.”

Perkins had an epiphany when he attended co-author Jonathan Smallwood’s lecture on mind wandering. Smallwood, an expert who studies the neuroscience of daydreaming, was describing self-generated thought and its origins in the brain’s medial prefrontal cortex, a part of the brain that has been linked with memories and recall.

“He started describing how people whose minds wander are better at things like creativity, delaying gratification and planning. He also talked about the way that daydreamers’ minds wander when they’re feeling kind of blue,” Perkins says. “And my ears perked up.”

Smallwood had run a series of tests on volunteers, where he’d put them through an MRI scanner with no instructions. Naturally, the volunteers began daydreaming. Those with negative thoughts would display greater activity in the medial prefrontal cortex. “If you have a high level of activity in this particular brain area, then your mind wandering tends to be threat-related,” he says.

That’s what happens in the brains of neurotic people when their minds wander.

And of course, no surprise, the longer one dwells on a problem, unwilling to let it go, the more likely they are to come up with a solution—making that a potential upside to neurotic daydreaming.

“There’s costs and benefits to being a neurotic,” Perkins says. “What’s interesting is that you can be neurotic and have a creative benefit, but we still don’t understand it.”

TIME diabetes

Antibiotics Are Linked To Type-2 Diabetes

Antibiotic use is associated with type-2 diabetes diagnoses, the latest research reveals

A new study published in the Journal of Clinical Endocrinology & Metabolism finds that people who develop type-2 diabetes used significantly more antibiotics—even 15 years before they were diagnosed—than people without the disease.

The researchers used data from citizens of Denmark, since the country has a single-payer national health insurance system with detailed health and pharmacy records. Using national health registries, the researchers looked at 170,504 people who had type-2 diabetes and tracked their prescriptions for antibiotics. They matched those people with 1.3 million other Danish citizens of the same age and sex who did not have diabetes and compared data from the two groups.

People with type-2 diabetes were more likely to receive more courses of antibiotics (0.8 prescriptions per year) than those who didn’t have the disease (0.5 prescriptions per year). An increased use of antibiotics was detected up to 15 years before people with type-2 diabetes were even diagnosed; an increased usage was also found after diagnosis.

MORE: How This Common Drug Can Have Lasting Effects On Kids

The study wasn’t designed to be able to determine a cause, but the authors point out two interpretations of the results. One is that people who go on to develop type-2 diabetes are more vulnerable to infections years before they’re diagnosed, so it would make sense for them to take more antibiotics. The other theory is that antibiotics raise the risk of type-2 diabetes.

This second theory is derived largely from research in rodents, and it’s the one that compels Dr. Martin Blaser, professor of medicine and microbiology at New York University Langone Medical Center and a longtime researcher of the effects of antibiotics. (Blaser was not involved with this study but is familiar with the research.)

“When you take antibiotics,” he says, “you change the composition of the microbiota”—your personal collection of bacteria in the body that communicates with human cells. Blaser has a hypothesis for how this might work in children who develop type-1 diabetes: the change in composition from taking antibiotics also alters metabolism, possibly making people more likely to become diabetic. “This work coming out that antibiotics might be affecting adults in a similar fashion is a little surprising to me, but in no way shocking,” he says. “I thought by the time you’re adult things are pretty much fixed, but maybe they’re not.”

The results of the study are not conclusive. But Blaser says they add to the body of research about the potential risks of antibiotics. “It’s evidence consistent with the idea that antibiotics have cost—not just monetary cost, but a biological cost in terms of potentially causing long-term effects,” he says. “As we’re studying it more and more, it suggests that things may bounce back, but it may not be the same normal, and it may predispose to other diseases—including important diseases, common diseases, like type-2 diabetes.”

TIME Sex/Relationships

Couples Who Do This Together Are Happier

A study shows that giggling in tandem is a good indicator the relationship's going to last.

Study after study has shown that laughing is good for the soul. But now we know something else: sharing giggles with a romantic partner keeps the lovey-dovey feelings going, according to a study published in the journal Personal Relationships.

Laura Kurtz, a social psychologist from the University of North Carolina, has long been fascinated by the idea of shared laughter in romantic relationships. “We can all think of a time when we were laughing and the person next to us just sat there totally silent,” she says. “All of a sudden that one moment takes a nosedive. We wonder why the other person isn’t laughing, what’s wrong with them, or maybe what’s wrong with us, and what might that mean for our relationship.”

Kurtz set out to figure out the laugh-love connection by collecting 77 heterosexual pairs (154 people total) who had been in a relationship for an average of 4 years. She and her team did video recordings of them recalling how they first met. Meanwhile, her team counted instances of spontaneous laughing, measured when the couple laughed together as well as how long that instant lasted. Each couple also completed a survey about their relational closeness.

“In general, couples who laugh more together tend to have higher-quality relationships,” she says. “We can refer to shared laughter as an indicator of greater relationship quality.”

It seems common sense that people who laugh together are likely happier couples, and that happier couples would have a longer, healthier, more vital relationship—but the role that laughter plays isn’t often center stage. “Despite how intuitive this distinction may seem, there’s very little research out there on laughter’s relational influence within a social context,” Kurtz says. “Most of the existing work documents laughter’s relevance to individual outcomes or neglects to take the surrounding social context into account.”

Kurtz noted that some gender patterns emerged that have been reported by previous studies. “Women laughed more than males,” she notes. “And men’s laughs are more contagious: When men laugh, they are 1.73 times more likely to make their partner laugh.”

There’s also evidence that laughing together is a supportive activity. “Participants who laughed more with their partners during a recorded conversation in the lab tended to also report feeling closer to and more supported by their partners,” she says. On the flip side, awkward chuckles, stunted grins and fake guffaws all are flags that there may be something amiss.

This harkens back to a classic psychological experiment conducted in 1992, where 52 couples were recorded telling their personal, shared histories. The team noted whether the couples were positive and effusive or were more withdrawn and tired in telling these stories, then checked in with the couples three years later. They saw a correlation in how couples told stories about their past and the success of their partnership: the more giddy the couple was about a story, the more likely they remained together; the less enthusiastic the couple was, the more likely the couple’s partnership had crumbled.

While there are cultural differences in laughter display—Kurtz says that Eastern cultures tend to display appreciation with close-mouthed smiles, not the heartier, toothy laughs that are more Western—there’s no question that laughter is important. “Moments of shared laughter are potent for a relationship,” she says. “They bring a couple closer together.”

TIME Research

Marijuana Does Not Affect Brain Volume, Study Finds

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Illustration by Sydney Rae Hass for TIME

The latest research adds to the debate over marijuana's effects on the brain

Using marijuana does not cause changes in brain volume, a new study suggests.

Public health experts have cited concerns that using marijuana could be associated with structural changes in the brain. However, a new trial comparing the brains of marijuana users and non-users to their siblings reveals that marijuana use likely does not cause changes in brain volume.

In the study, published in the journal JAMA Psychiatry, researchers looked at a large group of siblings ages 22 to 35. Of the 483 people, 262 reported ever using marijuana, even just once. The researchers then split the men and women into groups: sibling pairs who had never used marijuana, sibling pairs where both had reported using marijuana, and sibling pairs where one had used marijuana and one had not. Overall, they noticed that people who reported using marijuana had smaller volumes in certain parts of the brain—like the left amygdala, which is involved in emotional processing. However, these differences still fell within a range of volume that is considered normal.

The researchers hypothesized that in the sibling pairs where one had used marijuana and one had not, they would see differences in brain volume. But instead, they found that the exposed and unexposed siblings had the same amygdala volume. “We found no evidence for the causal influence of cannabis exposure on amygdala volume,” the authors concluded.

The researchers suggest that differences in volume could be due to other factors, like genetics or living environment. “Our study suggests that cannabis use, or at least the simple index of it that we used, does not directly impact changes in brain volumes,” says study author Arpana Agrawal, an associate professor at Washington University School of Medicine. “Instead, any relationship that we did see between cannabis use and brain volumes was due to predisposing factors that influence both cannabis use and brain volumes.”

The study did not find that brain volume has any effect on whether or not a person uses marijuana.

Another study, also published by different authors in the same journal, found that using marijuana could alter the brains of males at high risk for schizophrenia in potentially meaningful ways.

More research needs to be done to understand whether marijuana does or does not have potentially harmful effects on the brain, or whether the risks are different from one person to the next.

TIME global health

Over 46 Million People Now Have Dementia Worldwide

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Dementia is often caused by Alzheimer's Disease

More than 46 million people around the world suffer from dementia, according to a report released Tuesday.

The World Alzheimer Report, published by Alzheimer’s Disease International and King’s College London, says the number of people affected by dementia has increased quickly from the 35 million estimated in 2009, and researchers warn that number could double in the next 20 years.

Dementia is a collective term for progressive, degenerative brain syndromes affecting cognitive functions. Alzheimer’s disease is a common cause of dementia.

The report also noted that 58% of all people with dementia reside in developing countries. By 2050, 68% of those with dementia will be located in low and middle income countries, where services are limited and populations are aging quickly.

There is no cure for dementia.

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