Well: Training Dogs to Sniff Out Cancer

Photo McBaine, a cancer detection dog.Credit Penn Vet Working Dog Center

PHILADELPHIA — McBaine, a bouncy black and white springer spaniel, perks up and begins his hunt at the Penn Vet Working Dog Center. His nose skims 12 tiny arms that protrude from the edges of a table-size wheel, each holding samples of blood plasma, only one of which is spiked with a drop of cancerous tissue.

The dog makes one focused revolution around the wheel before halting, steely-eyed and confident, in front of sample No. 11. A trainer tosses him his reward, a tennis ball, which he giddily chases around the room, sliding across the floor and bumping into walls like a clumsy puppy.

McBaine is one of four highly trained cancer detection dogs at the center, which trains purebreds to put their superior sense of smell to work in search of the early signs of ovarian cancer. Now, Penn Vet, part of the University of Pennsylvania's School of Veterinary Medicine, is teaming with chemists and physicists to isolate cancer chemicals that only dogs can smell. They hope this will lead to the manufacture of nanotechnology sensors that are capable of detecting bits of cancerous tissue 1/100,000th the thickness of a sheet of paper.

"We don't ever anticipate our dogs walking through a clinic," said the veterinarian Dr. Cindy Otto, the founder and executive director of the Working Dog Center. "But we do hope that they will help refine chemical and nanosensing techniques for cancer detection."

Since 2004, research has begun to accumulate suggesting that dogs may be able to smell the subtle chemical differences between healthy and cancerous tissue, including bladder cancer, melanoma and cancers of the lung, breast and prostate. But scientists debate whether the research will result in useful medical applications.

Photo Trainers tend to notice early on that certain dogs have natural talents that make them better suited for specific kinds of work.Credit Penn Vet Working Dog Center.

Dogs have already been trained to respond to diabetic emergencies, or alert passers-by if an owner is about to have a seizure. And on the cancer front, nonprofit organizations like the In Situ Foundation, based in California, and the Medical Detection Dogs charity in Britain are among a growing number of independent groups sponsoring research into the area.

A study presented at the American Urological Association's annual meeting in May reported that two German shepherds trained at the Italian Ministry of Defense's Military Veterinary Center in Grosseto were able to detect prostate cancer in urine with about 98 percent accuracy, far better than the prostate-specific antigen (PSA) test. But in another recent study of prostate-cancer-sniffing dogs, British researchers reported that promising initial results did not hold up in rigorous double-blind follow-up trials.

Dr. Otto first conceived of a center to train and study working dogs when, as a member of the Federal Emergency Management Agency's Urban Search and Rescue Team, she was deployed to ground zero in the hours after the Sept. 11 attacks.

"I remember walking past three firemen sitting on an I-beam, stone-faced, dejected," she says. "But when a handler walked by with one of the rescue dogs, they lit up. There was hope."

Today, the Working Dog Center trains dogs for police work, search and rescue and bomb detection. Their newest canine curriculum, started last summer after the center received a grant from the Kaleidoscope of Hope Foundation, focuses on sniffing out a different kind of threat: ovarian cancer.

"Ovarian cancer is a silent killer," Dr. Otto said. "But if we can help detect it early, that would save lives like nothing else."

Dr. Otto's dogs are descended from illustrious lines of hunting hounds and police dogs, with noses and instincts that have been refined by generations of selective breeding. Labradors and German shepherds dominate the center, but the occasional golden retriever or springer spaniel — like McBaine — manages to make the cut.

The dogs, raised in the homes of volunteer foster families, start with basic obedience classes when they are eight weeks old. They then begin their training in earnest, with the goal of teaching them that sniffing everything — from ticking bombs to malignant tumors — is rewarding.

"Everything we do is about positive reinforcement," Dr. Otto said. "Sniff the right odor, earn a toy or treat. It's all one big game."

Trainers from the center typically notice early on that certain dogs have natural talents that make them better suited for specific kinds of work. Search and rescue dogs must be tireless hunters, unperturbed by distracting environments and unwilling to give up on a scent – the equivalent of high-energy athletes. The best cancer-detection dogs, on the other hand, tend to be precise, methodical, quiet and even a bit aloof — more the introverted scientists.

"Some dogs declare early, but our late bloomers frequently switch majors," Dr. Otto said.

Handlers begin training dogs selected for cancer detection by holding two vials of fluid in front of each dog, one cancerous and one benign. The dogs initially sniff both but are rewarded only when they sniff the one containing cancer tissue. In time, the dogs learn to recognize a unique "cancer smell" before moving on to more complex tests.

What exactly are the dogs sensing? George Preti, a chemist at the Monell Chemical Senses Center in Philadelphia, has spent much of his career trying to isolate the volatile chemicals behind cancer's unique odor. "We have known for a long time that dogs are very sensitive detectors," Dr. Preti says. "When the opportunity arose to collaborate with Dr. Otto at the Working Dog Center, I jumped on it."

Dr. Preti is working to isolate unique chemical biomarkers responsible for ovarian cancer's subtle smell using high-tech spectrometers and chromatographs. Once he identifies a promising compound, he tests whether the dogs respond to that chemical in the same way that they respond to actual ovarian cancer tissue.

"I'm not embarrassed to say that a dog is better than my instruments," Dr. Preti says.

Photo The dogs, raised in the homes of volunteer foster families, begin their training at 8 weeks of age, starting with basic obedience classes.Credit Penn Vet Working Dog Center.

The next step will be to build a mechanical, hand-held sensor that can detect that cancer chemical in the clinic. That's where Charlie Johnson a professor at Penn who specializes in experimental nanophysics, the study of molecular interactions between microscopic materials, comes in.

He is developing what he calls Cyborg sensors, which include biological and mechanical components – a combination of carbon nanotubes and single-stranded DNA that preferentially bond with one specific chemical compound. These precise sensors, in theory, could be programmed to bind to, and detect, the isolated compounds that Dr. Otto's dogs are singling out.

"We are effectively building an electronic nose," said Dr. Johnson, who added that a prototype for his ovarian cancer sensor will probably be ready in the next five years.

Some experts remain skeptical.

"While I applaud any effort to detect ovarian cancer, I'm uncertain that this research will have any value," said Dr. David Fishman, a gynecologic oncologist at Mount Sinai Hospital in New York City. One challenge, he notes, is that any cancer sensor would need to be able to detect volatile chemicals that are specific to one particular type of cancer.

"Nonspecificity is where a lot of these sort of tests fail," Dr. Fishman said. "If there is an overlap in volatile chemicals — between colon, breast, pancreatic, ovarian cancer — we'll have to ask, 'What does this mean?' "

And even if sensors could be developed that detect ovarian cancer in the clinic, Dr. Fishman says, he doubts that they would be able to catch ovarian cancer in its earliest, potentially more treatable, stages.

"The lesions that we are discussing are only millimeters in size, and almost imperceptible on imaging studies," Dr. Fishman says. "I don't believe that the resolution of the canine ability will translate into value for these lesions."

McBaine remains unaware of the debate. After correctly identifying yet another cancerous plasma sample, he pranced around the Working Dog Center with regal flair, showing off his tennis ball to anyone who would pay attention. In an industry saturated with hundreds of corporations and thousands of scientists all hunting for the earliest clues to cancer, working dogs are just another set of (slightly furrier) researchers.

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Well: Training Dogs to Sniff Out Cancer

Photo McBaine, a cancer detection dog.Credit Penn Vet Working Dog Center

PHILADELPHIA — McBaine, a bouncy black and white springer spaniel, perks up and begins his hunt at the Penn Vet Working Dog Center. His nose skims 12 tiny arms that protrude from the edges of a table-size wheel, each holding samples of blood plasma, only one of which is spiked with a drop of cancerous tissue.

The dog makes one focused revolution around the wheel before halting, steely-eyed and confident, in front of sample No. 11. A trainer tosses him his reward, a tennis ball, which he giddily chases around the room, sliding across the floor and bumping into walls like a clumsy puppy.

McBaine is one of four highly trained cancer detection dogs at the center, which trains purebreds to put their superior sense of smell to work in search of the early signs of ovarian cancer. Now, Penn Vet, part of the University of Pennsylvania's School of Veterinary Medicine, is teaming with the university's chemistry and physics departments to isolate cancer chemicals that only dogs can smell. They hope this will lead to the manufacture of nanotechnology sensors that are capable of detecting bits of cancerous tissue 1/100,000th the thickness of a sheet of paper.

"We don't ever anticipate our dogs walking through a clinic," said the veterinarian Dr. Cindy Otto, the founder and executive director of the Working Dog Center. "But we do hope that they will help refine chemical and nanosensing techniques for cancer detection."

Since 2004, research has begun to accumulate suggesting that dogs may be able to smell the subtle chemical differences between healthy and cancerous tissue, including bladder cancer, melanoma and cancers of the lung, breast and prostate. But scientists debate whether the research will result in useful medical applications.

Photo Trainers tend to notice early on that certain dogs have natural talents that make them better suited for specific kinds of work.Credit Penn Vet Working Dog Center.

Dogs have already been trained to respond to diabetic emergencies, or alert passers-by if an owner is about to have a seizure. And on the cancer front, nonprofit organizations like the In Situ Foundation, based in California, and the Medical Detection Dogs charity in Britain are among a growing number of independent groups sponsoring research into the area.

A study presented at the American Urological Association's annual meeting in May reported that two German shepherds trained at the Italian Ministry of Defense's Military Veterinary Center in Grosseto were able to detect prostate cancer in urine with about 98 percent accuracy, far better than the prostate-specific antigen (PSA) test. But in another recent study of prostate-cancer-sniffing dogs, British researchers reported that promising initial results did not hold up in rigorous double-blind follow-up trials.

Dr. Otto first conceived of a center to train and study working dogs when, as a member of the Federal Emergency Management Agency's Urban Search and Rescue Team, she was deployed to ground zero in the hours after the Sept. 11 attacks.

"I remember walking past three firemen sitting on an I-beam, stone-faced, dejected," she says. "But when a handler walked by with one of the rescue dogs, they lit up. There was hope."

Today, the Working Dog Center trains dogs for police work, search and rescue and bomb detection. Their newest canine curriculum, started last summer after the center received a grant from the Kaleidoscope of Hope Foundation, focuses on sniffing out a different kind of threat: ovarian cancer.

"Ovarian cancer is a silent killer," Dr. Otto said. "But if we can help detect it early, that would save lives like nothing else."

Dr. Otto's dogs are descended from illustrious lines of hunting hounds and police dogs, with noses and instincts that have been refined by generations of selective breeding. Labradors and German shepherds dominate the center, but the occasional golden retriever or springer spaniel — like McBaine — manages to make the cut.

The dogs, raised in the homes of volunteer foster families, start with basic obedience classes when they are eight weeks old. They then begin their training in earnest, with the goal of teaching them that sniffing everything — from ticking bombs to malignant tumors — is rewarding.

"Everything we do is about positive reinforcement," Dr. Otto said. "Sniff the right odor, earn a toy or treat. It's all one big game."

Trainers from the center typically notice early on that certain dogs have natural talents that make them better suited for specific kinds of work. Search and rescue dogs must be tireless hunters, unperturbed by distracting environments and unwilling to give up on a scent – the equivalent of high-energy athletes. The best cancer-detection dogs, on the other hand, tend to be precise, methodical, quiet and even a bit aloof — more the introverted scientists.

"Some dogs declare early, but our late bloomers frequently switch majors," Dr. Otto said.

Handlers begin training dogs selected for cancer detection by holding two vials of fluid in front of each dog, one cancerous and one benign. The dogs initially sniff both but are rewarded only when they sniff the one containing cancer tissue. In time, the dogs learn to recognize a unique "cancer smell" before moving on to more complex tests.

What exactly are the dogs sensing? George Preti, a chemist at the Monell Chemical Senses Center in Philadelphia, has spent much of his career trying to isolate the volatile chemicals behind cancer's unique odor. "We have known for a long time that dogs are very sensitive detectors," Dr. Preti says. "When the opportunity arose to collaborate with Dr. Otto at the Working Dog Center, I jumped on it."

Dr. Preti is working to isolate unique chemical biomarkers responsible for ovarian cancer's subtle smell using high-tech spectrometers and chromatographs. Once he identifies a promising compound, he tests whether the dogs respond to that chemical in the same way that they respond to actual ovarian cancer tissue.

"I'm not embarrassed to say that a dog is better than my instruments," Dr. Preti says.

Photo The dogs, raised in the homes of volunteer foster families, begin their training at 8 weeks of age, starting with basic obedience classes.Credit Penn Vet Working Dog Center.

The next step will be to build a mechanical, hand-held sensor that can detect that cancer chemical in the clinic. That's where Charlie Johnson a professor at Penn who specializes in experimental nanophysics, the study of molecular interactions between microscopic materials, comes in.

He is developing what he calls Cyborg sensors, which include biological and mechanical components – a combination of carbon nanotubes and single-stranded DNA that preferentially bond with one specific chemical compound. These precise sensors, in theory, could be programmed to bind to, and detect, the isolated compounds that Dr. Otto's dogs are singling out.

"We are effectively building an electronic nose," said Dr. Johnson, who added that a prototype for his ovarian cancer sensor will probably be ready in the next five years.

Some experts remain skeptical.

"While I applaud any effort to detect ovarian cancer, I'm uncertain that this research will have any value," said Dr. David Fishman, a gynecologic oncologist at Mount Sinai Hospital in New York City. One challenge, he notes, is that any cancer sensor would need to be able to detect volatile chemicals that are specific to one particular type of cancer.

"Nonspecificity is where a lot of these sort of tests fail," Dr. Fishman said. "If there is an overlap in volatile chemicals — between colon, breast, pancreatic, ovarian cancer — we'll have to ask, 'What does this mean?' "

And even if sensors could be developed that detect ovarian cancer in the clinic, Dr. Fishman says, he doubts that they would be able to catch ovarian cancer in its earliest, potentially more treatable, stages.

"The lesions that we are discussing are only millimeters in size, and almost imperceptible on imaging studies," Dr. Fishman says. "I don't believe that the resolution of the canine ability will translate into value for these lesions."

McBaine remains unaware of the debate. After correctly identifying yet another cancerous plasma sample, he pranced around the Working Dog Center with regal flare, showing off his tennis ball to anyone who would pay attention. In an industry saturated with hundreds of corporations and thousands of scientists all hunting for the earliest clues to cancer, working dogs are just another set of (slightly furrier) researchers.

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Phys Ed: Drink Soda? Take 12,000 Steps

Photo Credit Getty Images

Phys Ed

Gretchen Reynolds on the science of fitness.

People who consume the sweetener fructose — which is most people nowadays — risk developing a variety of health problems. But the risk drops substantially if those people get up and move around, even if they don't formally exercise, two new studies found.

Most of us have heard that ingesting fructose, usually in the form of high-fructose corn syrup, is unhealthy, which few experts would dispute. High-fructose corn syrup is used to sweeten many processed foods and nearly all soft drinks.

The problem with the sweetener is that, unlike glucose, the formal name for common table sugar, fructose is metabolized primarily in the liver. There, much of the fructose is transformed into fatty acids, some of which remain in the liver, marbling that organ and contributing to nonalcoholic fatty liver disease.

The rest of the fatty acids migrate into the bloodstream, causing metabolic havoc. Past animal and human studies have linked the intake of even moderate amounts of fructose with dangerous gyrations in blood sugar levels, escalating insulin resistance, Type 2 diabetes, added fat around the middle, obesity, poor cholesterol profiles and other metabolic disruptions.

But Amy Bidwell, then a researcher at Syracuse University, noticed that few of these studies had examined interactions between physical activity and fructose. That was a critical omission, she thought, because movement and exercise change how the body utilizes fuels, including fructose.

Dr. Bidwell sought out healthy, college-aged men and women who would agree to drink soda in the pursuit of science. They were easy to find. She gathered 22.

The volunteers showed up at the university's physiology lab for a series of baseline tests. The researchers assessed how their bodies responded to a fructose-rich meal, recording their blood sugar and insulin levels, and other measures of general and metabolic health, including cholesterol profiles and blood markers of bodily inflammation. The students also completed questionnaires about their normal diets and activity levels and subsequently wore an activity monitor for a week to gauge how much they generally moved.

Then half of the volunteers spent two weeks moving about half as much as they had before. The other 11 volunteers began moving around about twice as much as before, for a daily total of at least 12,000 steps a day, or about six miles.

After a rest period of a week, the groups switched, so that every volunteer had moved a lot and a little.

Throughout, they also consumed two fructose-rich servings of a lemon-lime soda, designed to provide 75 grams of fructose a day, which is about what an average American typically consumes. The sodas contained about 250 calories each, and the volunteers were asked to reduce their nonfructose calories by the same amount, to avoid weight gain.

After each two-week session, the volunteers returned to the lab for a repeat of the metabolic and health tests.

Their results diverged widely, depending on how much they'd moved. As one of two new studies based on the research, published in May in Medicine & Science in Sports & Exercise, reports, after two weeks of fructose loading and relative inactivity, these young, healthy volunteers displayed a notable shift in their cholesterol and health profiles. There was a significant increase in their blood concentrations of dangerous very-low-density lipoproteins, and a soaring 116-percent increase in markers of bodily inflammation.

The second study, published this month in The European Journal of Clinical Nutrition, focused on blood-sugar responses to fructose and activity, and found equally striking changes among the young people when they didn't move much. Two weeks of extra fructose left them with clear signs of incipient insulin resistance, which is typically the first step toward Type 2 diabetes.

But in both studies, walking at least 12,000 steps a day effectively wiped out all of the disagreeable changes wrought by the extra fructose. When the young people moved more, their cholesterol and blood sugar levels remained normal, even though they were consuming plenty of fructose every day.

The lesson from these studies is not that we should blithely down huge amounts of fructose and assume that a long walk will undo all harmful effects, said Dr. Bidwell, who is now an assistant professor of exercise science at the State University of New York in Oswego. "I don't want people to consider these results as a license to eat badly," she added.
But the data suggests that "if you are going to regularly consume fructose," she said, "be sure to get up and move around."

The study did not examine how activity ameliorates some of the worst impacts of fructose, but it's likely, Dr. Bidwell said, that the "additional muscular contractions" involved in standing and taking 12,000 steps a day produce a cascade of physiological effects that alter how the body uses fructose.

Interestingly, the young people in the study did not increase the lengths of their normal workouts to achieve the requisite step totals, and most did not formally exercise at all, Dr. Bidwell said. They parked their cars further away from stores; took stairs instead of elevators; strolled the campus; and generally "sat less, moved more," she said. "That's a formula for good health, in any case," she added, "but it appears to be key," if you're determined to have that soda.

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Well: The Problem With Reclining Airplane Seat Design

The Well Column

Tara Parker-Pope on living well.

To recline or not to recline? That is the question now being hotly debated among air travelers after three flights were forced to land after passengers on board began fighting about reclining seats.

But are passengers really the problem? The real issue may be that most airline seats are not designed to fully accommodate the human body in its various shapes and sizes.

"We are fighting each other, but the seats are not designed right," said Kathleen M. Robinette, professor and head of the department of design, housing and merchandising at Oklahoma State University. "The seats don't fit us."

Dr. Robinette would know. She is the lead author of a landmark anthropometric survey conducted by the Air Force with a consortium of 35 organizations and published in 2002. It is widely used by seat makers and other designers.

The survey, called the Civilian American and European Surface Anthropometry Resource project, measured the bodies of 4,431 people in North America, the Netherlands and Italy. The survey collected a voluminous amount of data about its subjects, ranging from height and weight to shoe and bra size. Dr. Robinette and her colleagues made 3D scans of their subjects, allowing for detailed measurements in sitting and standing positions.

For seat designers, the most relevant data came from measurements of people sitting, which included distances from the buttock to the knee, the breadth of the hips and the height of the knees.

The data gave an accurate view of the variations in the human form, Dr. Robinette said, but the measurements have not been used correctly.

Seat designers often make the assumption that nearly everyone will be accommodated if they design a seat for a man in the 95th percentile of measurements, meaning that they are larger than all but 5 percent of other men — and, theoretically, all women. But even in that group, there are big differences.

Take the buttock-to-knee measurement of the largest men in the study: In the North American group, the average measurement was 26.5 inches, but the Dutch men were larger, measuring 27.6 inches. Factor in the fact that nobody on an airplane sits upright with the knees bent at a 90 degree angle, plus variations in calf length and thigh length.

The result is that the measurements don't really account for different body shapes and variations in the way people sit.In addition, choosing the 95th percentile of men as a cutoff means at least 5 percent, as many as 1 in 20 men, on the plane will be using seats that are too small for them. "That's about 10 people on every plane who are dis-accommodated, as well as all the people sitting next to them," Dr. Robinette said.

A big flaw in seat design, however, is that men in the 95th percentile are not necessarily larger than women, particularly in the parts of the body that are resting on the seat.

In terms of hip width, women are bigger than men. In the study, North American women in the 95th percentile had hip breadth measurements of 19.72 inches, compared to 17.15 inches for North American men.

According to SeatGuru.com, which collects data on seat sizes from dozens of airlines, the typical economy class airline seat ranges from 17 to 18 inches across. This means that seats will be snug on many bodies; for about 1 in 4 women, the seat will be too small at the hips, causing them to spill over into the adjacent seat.

Further, the widest part of the body is actually the shoulders, which is why so many of us end up knocking elbows and shoulders with the passengers next to us, or leaning into the window or aisle to avoid pressing against our seat neighbor.

The issue goes beyond passenger comfort. Dr. Robinette notes that travelers who are squeezed together and touching continually are more likely to spread cold viruses or other illnesses to a fellow passenger. People who are confined to tight seats and who can't move comfortably are at risk for painful "hot spots" — precursors to the bed sores that occur in nursing home patients who aren't moved frequently.

Of greater concern is the risk of blood clots, including a potentially deadly condition called deep vein thrombosis.

"When sitting in a way so you can't move, you start to get spots that are compression spots after maybe a half-hour or so," Dr. Robinette said. "Pain and discomfort is your body telling you something is wrong, and on an airplane there is a risk of blood clots. It's a serious problem that we are all discounting."

When it comes to reclining a seat, the most important measure of comfort is seat pitch, which is the distance from any point on one seat to the exact same point on the seat in front or behind it.

According to SeatGuru, seat pitch is a good approximation of how much seat and leg room a passenger can expect. The measurement on short-haul flights averages about 31 inches on most flights, ranging from a tight 28 inches on some airlines to a roomy 38 to 39 inches on a few.

"Seat pitch is what most fliers are concerned about," said Jami Counter, senior director of SeatGuru and TripAdvisor. "When you are talking about 31 inches as the standard, that's pretty tight; 28 inches is incredibly tight. Airlines are feeling really crowded and really cramped."

Officials at Recaro Aircraft Seating, a German seat manufacturer, said that seat design had to take into account safety requirements, weight, passenger comfort and airplane space needs, and have enough flexibility that seats can be used in various aircraft layouts.

Recaro has introduced a new seat with a slimmer back rest, giving the passenger behind the seat more space for knees and shins. The designers also moved the seat pocket above the tray table to allow for more knee room.

Recaro has received orders for more than 200,000 of the seats since introducing the model in late 2010.

"Of course, it is possible to install seats in an aircraft at a more comfortable distance from each other, so that everybody has sufficient knee and leg space," Rene Dankwerth, the vice president of research and development at Recaro, said in a written response. "However, the ticket price would definitely rise."

At 6 feet 6 inches, Chicago economics professor Devin Pope knows the risk of sitting behind someone who chooses to recline the seat. Dr. Pope likened it to a classic economics experiment called the Dictator game, in which a person is given $10 and allowed to keep it all, or share it with another person. Surprisingly, the dictator often chooses to share the money.

"It suggests that people really do care about other people sometimes," said Dr. Pope, associate professor of behavioral science at the University of Chicago's Booth School of Business. "I think it suggests why a lot of people don't lean the seat back."

 

A version of this article appears in print on 09/09/2014, on page D1 of the NewYork edition with the headline: Taking a Position on Plane Comfort.

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Well: In Prediabetes, a Chance to Avert Crisis

Personal Health

Jane Brody on health and aging.

After a routine test of her blood sugar eight years ago, Randi Sue Baker, a seriously overweight 64-year-old, learned that Type 2 diabetes was bearing down.

With that test result, she joined the 79 million Americans over the age of 20 who have prediabetes. Up to 70 percent of them will go on to develop diabetes, but 90 percent don't even know they are at risk. In fact, as many as 28 percent of adults with full-blown diabetes don't know they have it, according to Edward W. Gregg, a senior epidemiologist at the Centers for Disease Control and Prevention.

Ms. Baker, who lives in Brooklyn, considers herself lucky to have been forewarned. She realized that while she was still relatively healthy, she could make a concerted effort to stay that way.

For the last several years she has kept track of her caloric intake, the kinds and amounts of the carbohydrates she eats, and the overall healthfulness of her diet. She exercises five days a week, walking for 30 minutes and then swimming for an hour at the local Y. She is down 50 pounds from her top weight.

Ms. Baker also daily monitors her blood sugar, or glucose, level and takes a drug called metformin to help keep it within a normal range. Periodically, her doctor checks her blood level of hemoglobin A1C, another indicator of diabetes, to be sure it hasn't risen.

Could Ms. Baker do more? If she were willing to undergo bariatric surgery, perhaps. The operation has risks but has been shown to "cure" diabetes in about a third of patients.

But what Ms. Baker already is doing to keep diabetes at bay is far more than most people who are likely to develop it do.

Diabetes is now an out-of-control epidemic responsible for a devastating toll in health, lives and medical care costs. In 2012 the condition accounted for $245 billion in health care expenses, about one in five health care dollars.

Among its serious complications are heart disease, stroke, kidney damage, nerve damage, eye disease (which can lead to blindness), foot damage (which can lead to amputations) and hearing loss.

Diabetes is the No. 1 cause of blindness, kidney failure and amputations, Dr. Elizabeth Seaquist, an endocrinologist and diabetes expert at the University of Minnesota, said in an interview. The condition even has been linked to dementia, including Alzheimer's disease.

The two primary causes of Type 2 diabetes — obesity and inactivity — have thus far resisted countless efforts to reverse or prevent them. National data from 2000 to 2011 show that about 40 percent of adults face a lifetime risk of developing diabetes, an increase of up to 20 percent since the late 1980s, Dr. Gregg and his colleagues recently reported.

If this tsunami continues to roll forward, experts predict that by 2050 the number of adults with diabetes will reach one in three.

The risk of developing diabetes rises with age. Currently about one in four Americans ages 65 and older has diabetes, and the number will grow as the population ages.

In theory, it is possible to avert the impending health crisis. Because complications typically take 20 years to become apparent, identifying people at risk of diabetes early and taking corrective action could delay onset of the disease and its devastating consequences, perhaps for the rest of their lives.

The American Diabetes Association has created a simple seven-question test to help people assess their risk; a paper copy can be found at www.diabetes.org. Important factors include a family history of the disease, prior gestational diabetes, being overweight or obese, physical inactivity and older age.

A dozen years ago in its journal, Diabetes Care, the association noted "growing evidence that at glucose levels above normal but below the threshold diagnostic for diabetes, there is a substantially increased risk of cardiovascular disease and death."

A person with prediabetes has a blood glucose level higher than normal but not yet in the range of diabetes. While not everyone with the condition will progress to full-blown diabetes, over time, prediabetes can cause much the same underlying damage to body tissues and organs.

The trouble starts even before glucose levels begin rising, when the body becomes resistant to the effects of insulin, the pancreatic hormone that regulates how much glucose circulates freely in blood.

Insulin's main job is to move glucose from the blood into cells to be used for energy or stored for future needs. Insulin resistance, the portend of prediabetes, prompts the beta cells of the pancreas to produce more and more of this hormone to keep blood glucose levels normal.

Gradually, pancreatic cells wear out, setting the stage for rising blood glucose, prediabetes and diabetes.

The risk of developing diabetes is highest among African-Americans, Hispanics and Native Americans, but no ethnic or racial group is spared.

While excess weight is the leading risk factor, even people of normal weight can develop the disease if they carry too much fat in their abdomen. So-called central obesity may explain why the Japanese and others of Asian descent often develop diabetes at weights well below the range of obesity, Dr. Seaquist said.

She called prediabetes "a wake-up call" and emphasized that "modest weight loss can help. You don't have to lose 100 pounds to prevent diabetes." A loss of 7 percent to 10 percent of body weight can be effective.

Nor do you have to become an exercise fanatic. "Moderate activity, 30 minutes a day five or more days a week, is helpful and can even be broken up into 10-minute segments," Dr. Seaquist said. "More is better, but it's a place to start."

She also offered advice for Americans in general: "Probably we all should consider ourselves at risk. We eat too much, more than we need, and that's not healthy even if we don't get diabetes."

"We should be avoiding drinks that are high in calories," she added. "They make it too hard to regulate food intake. Drinking water is safest all around — it's natural and organic."

 

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Well: Ask Well: Is Horseback Riding Good Exercise?

Ask Well

Your health questions answered by Times journalists and experts.

Photo Credit Kike Calvo for The New York Times

A

It's very good exercise for the horse and, depending on how you ride, can be moderate or even strenuous exercise for you, too. According to a comprehensive and periodically updated scientific compilation of the energy costs of various physical activities, riding a horse requires in general about 5.5 METs, according to 2011 measurements. A MET is the metabolic equivalent of a task and measures how much energy is used during that movement, compared with being still. Sitting quietly is a 1 MET activity. For comparison, other activities at or close to 5.5 METs include recreational badminton and playing golf if you walk the course, pulling your bag of clubs.

The METs change with your mount's gait. Riding a horse at full gallop is a 7.3-MET activity, according to the compilation, similar in intensity to recreational roller blading or squash. The required exertion is a bit less than that if the horse is trotting, to 5.8 METs, and it falls drastically when riding a walking horse. That requires only 3.8 METs, the same as bowling.

Horseback riding improves muscular strength, particularly in the legs. In one study, adolescent girls who regularly rode horses had much stronger quadriceps and hamstring muscles than girls of the same age who did not ride. The equestrians did not have better bone density, though, underscoring that riding is not a weight-bearing activity, except for the horse.

Finally, if you want an even better workout from being around horses, muck out your mount's stall yourself. That work qualifies as a moderate 4.3-MET activity, the compilation finds.

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Well: Put the Physical in Education

Photo Credit Illustration by Ben Wiseman

Phys Ed

Gretchen Reynolds on the science of fitness.

When confronted with an overly active child, many exasperated teachers and parents respond the same way: "Sit still!" It might be more effective, though, to encourage the child to run. Recent research suggests that even small amounts of exercise enable children to improve their focus and academic performance.

By now it's well known that diagnoses of attention deficit hyperactivity disorder are increasingly widespread among American children: The label has been applied to about 11 percent of those between the ages of 4 and 17, according to the latest federal statistics. Interestingly, past studies have shown a strong correlation between greater aerobic fitness and attentiveness. But these studies did not answer the question of which comes first, the fitness or the attentional control.

Addressing that mystery was a goal of a study published last year in The Journal of Pediatrics. Researchers at the University of Illinois at Urbana-Champaign recruited 40 8-to-10-year-old boys and girls, half of whom had A.D.H.D. They all took a series of computerized academic and attentional tests. Later, on one occasion they sat and read quietly for 20 minutes; on another, they walked briskly or jogged for 20 minutes on treadmills. After each task, the children wore caps containing electrodes that recorded electrical activity in the brain as they repeated the original tests.

The results should make administrators question the wisdom of cutting P.E. classes. While there were few measurable differences in any of the children's scores after quiet reading, they all showed marked improvements in their math and reading comprehension scores after the exercise. More striking, the children with A.D.H.D. significantly increased their scores on a complicated test, one in which they had to focus on a single cartoon fish on-screen while other cartoon fish flashed on-screen to distract them. Brain-wave readings showed that after exercise, the children with A.D.H.D. were better able to regulate their behavior, which helped them pay attention. They responded more nimbly to mistakes like incorrect keystrokes. In short, the children with A.D.H.D. were better students academically after exercise. So were the students without A.D.H.D.

"In terms of a nonpharmacological means of dealing with attentional-control problems in children, exercise looks as if it could be quite beneficial," says Charles Hillman, the professor of kinesiology at the University of Illinois who oversaw the study. "Especially since it seems to also improve the academic performance of children who don't have attentional-control problems."

What's more, adds Matthew Pontifex, now an assistant professor at Michigan State University and the study's lead author, "You don't need treadmills." Just get restless children to march or hop or in some fashion be physically active for a few minutes. Coax their peers to join in.

Of course, even as it reinforces the accumulating evidence that exercise is good for brains, this short-term study leaves many questions unanswered: How much and what kind of physical activity is optimal? Does it permanently lessen attentional problems? Does exercise directly affect attention at all? In their study, the researchers speculate that exercise might sharpen mental focus in part by increasing brain activity in the frontal lobe. But understanding its mechanisms may not be needed for teachers and parents to consider deploying movement to counter wandering attentions.

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Well: Can Exercise Cause A.L.S.?

Phys Ed

Gretchen Reynolds on the science of fitness.

Photo Ever since the great Yankees first baseman Lou Gehrig -- pictured here scoring first run of the 1938 World Series -- died of A.L.S. in 1941, many Americans have vaguely connected A.L.S. with athletes and sports.Credit Associated Press

Amyotrophic lateral sclerosis has been all over the news lately because of the ubiquitous A.L.S. ice bucket challenge. That attention has also reinvigorated a long-simmering scientific debate about whether participating in contact sports or even vigorous exercise might somehow contribute to the development of the fatal neurodegenerative disease, an issue that two important new studies attempt to answer.

Ever since the great Yankees first baseman Lou Gehrig died of A.L.S. in 1941 at age 37, many Americans have vaguely connected A.L.S. with athletes and sports. In Europe, the possible linkage has been more overtly discussed. In the past decade, several widely publicized studies indicated that professional Italian soccer players were disproportionately prone to A.L.S., with about a sixfold higher incidence than would have been expected numerically. Players were often diagnosed while in their 30s; the normal onset is after 60.

These findings prompted some small, follow-up epidemiological studies of A.L.S. patients in Europe. To the surprise and likely consternation of the researchers, they found weak but measurable associations between playing contact sports and a heightened risk for A.L.S. The data even showed links between being physically active — meaning exercising regularly — and contracting the disease, raising concerns among scientists that exercise might somehow be inducing A.L.S. in susceptible people, perhaps by affecting brain neurons or increasing bodily stress.

But these studies were extremely small and had methodological problems. So to better determine what role sports and exercise might play in the risk for A.L.S., researchers from across Europe recently combined their efforts into two major new studies.

The more impressive of these, which was published in May in Annals of Neurology, involved almost two dozen researchers from five nations, who developed a deceptively simple but scientifically rigorous research approach. They asked 652 A.L.S. patients if they'd be willing to talk about their lives and activities and did the same with 1,166 people of matching ages, genders and nationalities. They conducted extensive in-person interviews with each volunteer, asking them how active they had been in professional or amateur sports, at their jobs and during leisure time. They also asked about past histories of injuries and accidents, including concussions and other head trauma but also other injuries.

They then compared answers from the people with A.L.S. to those of healthier people.

The results should reassure those of us who exercise. The numbers showed that physical activity — whether at work, in sports or during exercise — did not increase people's risk of developing A.L.S. Instead, exercise actually appeared to offer some protection against the disease. Even pro athletes showed no heightened risk, although they represented such a tiny subset of the patients with A.L.S. that firm conclusions cannot be drawn, the researchers say.

One aspect of people's lives did significantly increase their risk of developing A.L.S.: a history of multiple hits to the head. Men and women who had sustained at least two concussions or other serious head injuries were much more likely than other people, including never-concussed athletes, to develop A.L.S.

These results coincide closely with those of the other new study, a review article published in July in the European Journal of Epidemiology, which gathered data from 50 years' worth of epidemiological studies related to A.L.S. risk (including the other new study) and teased out the effects of physical activity. Most of the studies were limited in scope, but they amplified one another's validity when combined, the researchers thought.

And their main finding was that "in the general population, physical activity is not a risk factor for A.L.S.," said Dr. Benoit Marin, a neuroepidemiologist at the French Institute of Health and Medical Research in Paris who oversaw the new review.

But as Dr. Marin also pointed out, the studies involved were all associational, meaning that they cannot establish cause and effect. Exercise and a reduced risk for A.L.S. might be linked to other lifestyle factors, such as a healthy diet, and not to each other.

The new studies also cannot dispel the lingering and troubling questions about the effects of head injuries from contact sports.

"I would not consider this issue settled," said Ettore Beghi, a neuroscientist at the Mario Negri Institute for Pharmacological Research in Milan and senior author of the study published in May in Annals of Neurology.

In the United States, a few researchers have begun to look at football and A.L.S. risk, a plausible research concern, Dr. Beghi said, given evidence that head trauma sustained playing football might contribute to neurodegenerative diseases. But to date, the football data has been inconclusive.

For now, he and other scientists are continuing to study Italian soccer players, as well as athletes in other sports, including rugby, which, for some reason, confers no increased risk of A.L.S., although it involves considerable contact. Such research may ultimately "shed some light on the underlying mechanisms of the disease, which are still poorly understood," Dr. Beghi said.

The greatest obstacle to advancing the research, he added, is "the lack of funding," a situation that could be ameliorated, somewhat, with all of that ice dousing.

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Well: Of Little Help to Older Knees

Middle-aged and older patients are unlikely to benefit in the long term from surgery to repair tears in the meniscus, pads of cartilage in the knee, a new review of studies has found.

Researchers at McMaster University combined data from seven randomized, placebo-controlled trials involving more than 800 subjects treated for meniscal tears with surgery, sham surgery or nonoperative care. The subjects' average age was 56.

In six of the trials, the surgery provided a significant improvement in short-term functioning. But the pooled data showed no significant difference in long-term functioning among patients in the three groups. Nor did surgery provide either short- or long-term pain relief.

Dr. Moin Khan, a research fellow at the university and lead author of the study, published in the Canadian Medical Journal, said that its conclusion does not pertain to an acute meniscus tear in a young person. That requires surgery.

"But chronic pain from a small meniscus tear in a middle-aged person may not benefit from surgery," he said.

"Treatment with weight loss, anti-inflammatory medicine and physical therapy may be helpful for many patients."

A version of this article appears in print on 09/02/2014, on page D4 of the NewYork edition with the headline: Prognosis: Of Little Help to Older Knees.

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Well: Don’t Catch What Ails Your House

Photo Credit Tim Robinson

Personal Health

Jane Brody on health and aging.

In 1982, my husband and I bought a vacation home in the foothills of the Catskills. The inspector who checked out the property failed to note three critical facts: The house had three flat roofs (in snow country), no drainage from the muddy crawl space and no insulation under the floors.

In a few years, ours had become a "sick" house, with mini-lakes on sagging roofs, wet insulation underneath and a small pond in the crawl space. All of it contributed to rampant mold inside the house.

My husband was especially sensitive to mold, and he reacted with extreme fatigue whenever we visited. My sister-in-law, who lived in the house year round, complained of chronic headaches and sinus problems. I could smell the mustiness, and found mold growing on the wood cabinets and a leather love seat.

The moisture problem had to be fixed. Slanted roofs were constructed; wet insulation was replaced; downspouts were directed away from the house. We fitted the crawl space with a drain and a heavy plastic vapor barrier, and the floors above it were insulated.

Mold had to be removed from furniture and cupboards and their contents. Clothing was dry cleaned, or washed and heat-dried, to get rid of the odor.

Natural disasters like Hurricanes Katrina and Sandy left hundreds of thousands of people with flooded homes that quickly became infested with mold, unlivable and sometimes unfixable. Given moisture, mold will grow and reproduce behind wallboard, paneling, wallpaper and furniture, in ceiling tiles and insulation, on wood floors, around appliances like refrigerators and dishwashers, and under carpets and pads if not quickly dried.

But as my experience demonstrated, you don't need a flood to develop a mold problem. It can happen anywhere moisture is present — a hidden leak, for example, or condensation around windows or pipes. You may not even be aware of the problem, only the distress it causes.

Typical symptoms resemble those of an allergy like hay fever: a runny nose, sneezing, red or itchy eyes, throat irritation and coughing. Some people develop a skin rash; those with asthma may have an attack. According to research by the Mayo Clinic, an immunological response to mold may cause most cases of chronic sinusitis.

Mold can even infect the central nervous system, often fatally, as occurred in a 2012 outbreak of meningitis from epidural injections contaminated by Exserohilum rostratum. Of the 751 people infected across the country, 64 died.

The types of mold usually found in homes do not produce dangerous toxins. But they can bring misery and are best controlled by preventing their growth.

Molds are a type of fungus, and they grow by releasing spores into the air. The spores are not visible to the naked eye, but when they land on a moist surface (or when the surface they are on becomes moist), they begin to grow. Outdoors, molds play an important role in the decomposition of organic matter, like leaves and fallen trees.

Even the driest buildings contain mold spores, and those with indoor moisture may have thousands in every cubic foot of air. The spores are ubiquitous and can survive extreme dryness and cold, remaining dormant until moisture and oxygen provide a chance to grow.

These measures can reduce the buildup of indoor mold:

■ Fix leaks immediately, and thoroughly dry the affected area.

■ Regularly clear debris from roof gutters.

■ Keep air conditioner and refrigerator drip pans clean.

■ Insulate cold-water pipes.

■ Use an air conditioner or a dehumidifier, or both, and change the filters regularly to maintain a relative humidity below 60 percent. (The lower, the better.)

■ Vent appliances like clothes dryers that generate moisture to the outside.

■ Use an exhaust fan or open a window when washing dishes, cooking or showering.

■ Keep crawl space vents clear.

Do not use carpets in potentially moist areas like a laundry room, bathroom and basement. Replace sponges and dishcloths often, or wash and dry them with the regular laundry.

Roof leaks can be especially challenging, leaving wet insulation and moisture behind walls. Roofing is best restored or replaced on a schedule before a leak occurs.

Keeping a house warm suppresses mold growth. Alas, my house still gets musty in winter; to save oil and money, I set the thermostat at 55 degrees when I'm not there.

Some people, especially those with severe allergies, chronic lung disease or suppressed immunity, are affected by outdoor mold in compost piles, cut grass and wooded areas. When cleaning the yard and raking or sweeping dead leaves, they should consider wearing a face mask or an N-95 respirator (a fancy dust mask that costs $12 to $25).

Cleaning up mold requires care. Limit your exposure by wearing goggles, a face mask and long rubber, neoprene or PVC gloves. You need not use chlorine bleach; soap and water, or a nontoxic commercial cleaner and a scrubbing sponge or brush, will work well on hard surfaces. Dry the area thoroughly after cleaning.

If you do use a bleach solution (no stronger than one cup of bleach to one gallon of water), never mix it with ammonia or a product that contains ammonia.

Do not paint over or caulk moldy surfaces. Clean away the mold first, and then use paint with a mold inhibitor.

Porous materials like ceiling tiles and carpets that have become moldy can be difficult to clean adequately and usually must be replaced.

You may need a professional contractor skilled in mold cleanup if the affected area is larger than 10 square feet. The Environmental Protection Agency recommends checking references and making sure the contractor consults its guide, Mold Remediation in Schools and Commercial Buildings, available at www.epa.gov/mold. The agency also provides a guide to cleaning contaminated heating and air conditioning systems.

 

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