At present, virtual colonoscopy requires a full bowel prep to make the colon wall visible to the CT scan. But a new, experimental version does it digitally. The team, led by Dr. Michael Zalis of Harvard-affiliated Massachusetts General Hospital (MGH), used sophisticated computer software to make stool in the colon disappear — akin to Photoshopping blemishes from still photos.

Reluctance to undergo the bowel prep hinders more widespread testing for cancer and precancerous polyps. According to the American Cancer Society, colorectal cancer screening rates hover around 50% in some states. Virtual colonoscopy without a day-long bowel prep beforehand could help remedy the problem.

“Laxative-free CT colonography has the potential to reach some of the unscreened population and save lives,” says Dr. Zalis, an associate professor of radiology at MGH and director of CT colonography at MGH Imaging.

Aversion to colon prep

Public health guidelines urge people 50 or older to be checked for colon cancer and polyps. There are several options, including a simple stool test. But the gold standard is colonoscopy using a flexible, lighted instrument called a colonoscope. A doctor looks through the colonoscope and inspects the colon. If he or she finds a pre-cancerous polyp, a device on the end of the colonoscope is used to remove it from the colon wall. Removing precancerous growths helps prevent cancer, and research strongly suggests it prevents premature deaths from colon cancer—a critical test for any screening method to pass.

Colonoscopy’s ability to both find and remove polyps is an advantage over other screening options. “The trouble is a lot of the people at risk of colorectal cancer have a strong aversion to the laxative prep that is required for colonoscopy,” Dr. Zalis told me.

Enter laxative-free virtual colonoscopy, known in the medical world as CT colonography or CTC.

An experimental version of the virtual colonoscope digitally removes stool from the colon, allowing doctors to see polyps and other abnormalities. (Photo courtesy Dr. Michael Zalis.)

Colon photoshopping

In the study, Zalis and his colleagues recruited 605 volunteers at four medical centers, including MGH and nearby Brigham and Women’s Hospital. For two days before the their scans, the volunteers drank small amounts of a contrast agent with meals. This chemically “tagged” the stool, allowing software to detect it and subtract it from the CT scan. What remained was a 3D image of the colon wall that radiologists then searched for polyps, as shown in the image to the right.

The laxative-free method identified 91% of the people with precancerous polyps that were 1 centimeter or larger, which is about as accurate as conventional colonoscopy. Zalis says that more than 90% of polyps that develop into cancer are 1 centimeter or larger.

Two factors that limit virtual colonoscopy’s wider adoption today are that it still requires a colon prep and, if polyps are discovered, you still need to have a full colonoscopy. Laxative-free CTC removes one of those limits.

Larger studies are needed to fully understand the potential of laxative-free CTC, but the latest research is an important step toward expanding colorectal cancer screening to people who would otherwise put it off or avoid it entirely—and put themselves at higher risk of developing colon cancer or dying prematurely. “The study opens the door to a laxative-free and more patient-friendly version of colon cancer screening,” Dr. Zalis says.

It’s a dilemma for parents. Is it okay to let your daughter play with your phone so you can get five minutes of quiet in a restaurant, or will that permanently scuttle her attention span?

Ann Densmore, Ed.D., an expert in speech and language development and co-author of Your Successful Preschooler, offers some practical advice for parents. “Screen time is here to stay for young children and we can’t stop it,” she told me. “The world is now inescapably online and digital. Even schools are replacing textbooks with iPads and digital texts. So moms and dads really need to figure out what’s right for their families.”

Data on the risks and benefits of screen time are both limited and conflicting. A small study published in 2010 in the journal Pediatrics suggests that children who spend two or more hours a day watching TV or on the computer are more prone to psychological difficulties. In contrast, iPad apps and games designed for preschoolers seem to offer opportunities for learning. Densmore knows more about this than most because there are several iPad apps that are useful tools in speech and language therapy. But outside of a therapeutic setting, how should parents evaluate the apps their kids play with on mobile devices?

“In my opinion, the goal of a child’s interaction with screen-based games should be to help him or her learn a concept, to formulate and organize ideas, to help with communication, or to develop basic preschool skills,” says Densmore. The keys to beneficial screen time, she explains, are interactivity and adult participation, whether the child is playing a computer game, using an iPad app, or watching TV. A study from the Children’s Media Center at Georgetown University, published in the Journal of Applied Developmental Psychology showed that interactivity and adult modeling helped children to learn a task better than passive viewing of the same material.

“A teacher or parent needs to be present to help the child grasp the overall concepts, so the child doesn’t get stuck on the exciting graphics and the fast pace of the program,” says Densmore. “Good apps or games should facilitate conversation between parents and children during this play, not get in the way of it.”

As a speech therapist working with young families, and the mother of two adult daughters, Ann Densmore understands the complexities of daily life with young children. While she doesn’t advocate the use of screen time as a de facto babysitter, she advises parents not to beat themselves up if, on a really tough day, some extra time on the computer, iPad, or in front of the TV helps maintain household peace and parents’ sanity. “Do the best you can to strike a balance. If there ends up being a lot of screen time on a long rainy day, or when a child is sick, try to cut back for the next couple of days.”

Commonsense Media is an organization that offers parents information on kids and media. It offers some useful guidelines for determining the educational value of apps for kids. Although parental attention is often focused these days on mobile devices and gaming systems, don’t forget to pay attention to TV hours. In an alarming October 2011 report, Commonsense Media reminds us that television is the main form of screen time for children between the ages of 0 and 8 years.

In an upcoming blog, Dr. Densmore will share her thoughts on apps she thinks are particularly good for young kids and offer some advice on how to choose and monitor screen time activities.

As for me, I felt like I’d dodged a bullet when recently, on one of those crazy days, I asked my five-year-old son if he’d like the iPad and his response was “No thanks mom, I’d rather go out in the back yard.”

Your Successful Preschooler, published by Jossey-Bass in partnership with Harvard Medical School, offers parents concrete advice and strategies for helping their young children develop the social skills that will set them up for learning and enable them to develop and maintain friendships with more ease.

That’s the conclusion of a study just published in the Journal of the American Medical Association. A team of California-based researchers combined the results of 63 randomized trials pitting probiotics versus placebo among almost 12,000 men and women taking antibiotics. Those who took antibiotics plus probiotics were 42% less likely to develop diarrhea as those who got the placebo.

About one in three people who take antibiotics develop diarrhea. The symptoms usually start on the last day or two of antibiotic therapy, or a day or so after it has ended. The diarrhea is usually mild, with two to four loose stools per a lasting for a couple days. In most cases, it gets better quickly without treatment. That said, antibiotic-associated diarrhea makes some people very sick. The most severe form, called C. difficile colitis, can be life threatening.

Probiotics are live bacteria, yeast, and other microbes thought to be beneficial to human health. They’ve been widely promoted as a way to keep your body in balance. The evidence for many of these claims is slim. Perhaps the strongest evidence a benefit of probiotics is for antibiotic-associated diarrhea.

Antibiotics upset intestinal balance

Thousands of species of bacteria, yeast, and other microorganisms live on our skin, in our intestines, and on other body surfaces. They’re known as our “normal flora.” When it is in balance, these microbes stay put and many of them contribute to good health. Bacteria in the gut, for example, help break down food.

Antibiotics kill these “good” microbes along with bacteria that are causing an infection. This upsets the balance of the normal flora in the intestines. The result is often loose, watery stools known as antibiotic-associated diarrhea.

The idea behind using probiotics is that they may help populations of good bacteria recover more quickly and restore order to the intestines. There’s no good evidence that probiotics are helpful in otherwise healthy people. But earlier research has suggested they can be helpful in:

• treating recurrent or persistent C. difficile colitis, when repeated courses of other therapies have not been successful
• preventing complications from pancreatitis
• decreasing persistent or recurring vaginal yeast infections

Not a cure-all

Although the results of this study sound impressive, I won’t be recommending probiotics every time I write a prescription for antibiotic. But I will advise some of my patients to try a probiotic. They include:

• people who have had antibiotic-associated diarrhea in the past. This is especially true for those that have had a C. difficile infection.
• people who must take antibiotics for more than 10 days. (Other doctors might use more than 5 days).
• people who have switched from one antibiotic to another over a relatively short period of time.

The researchers were not able to answer two very important questions:

• Which probiotics are the most effective in preventing and treating antibiotic associated diarrhea?
• Which antibiotics are more likely to cause diarrhea?

The medical bottom line

Antibiotics are wonderful medicines. But this study of probiotics and many other studies show they also have a dark side. The best way to avoid antibiotic-associated diarrhea is to limit your use of antibiotics. For example, you likely don’t need an antibiotic for an uncomplicated ear or sinus infection or bronchitis. Most often the culprits are viruses, which don’t respond to antibiotics anyway.

The best way to keep your normal flora in balance is to only take antibiotics when necessary.

The report, which used data from the National Health and Nutrition Examination Survey (NHANES), found that the percentage of women with high cholesterol slipped from 19.1% to 14.3%, while the percentage of men with it dropped from 17.2% to 12.2% over the last decade. Men under age 60 did a better job of controlling cholesterol than women, while women over age 60 had greater improvements in cholesterol than men. Whether these numbers will translate into a lower risk for heart disease, heart attacks, and strokes remains to be seen—but it’s a good start.

Keeping harmful low-density lipoprotein (LDL) cholesterol as low as possible is especially important for women after menopause. Before menopause, estrogen boosts the supply of protective high-density lipoprotein (HDL) cholesterol that helps remove LDL from the bloodstream. After menopause, women no longer have access to that heart-protective hormone. Men need to watch their cholesterol levels over a longer stretch of time because their risk for heart disease starts earlier—in their mid-40s.

Overall, 13.4% of adults currently have high cholesterol, which beats the government’s Healthy People 2010 target of 17% or less. Where we’re falling just short is in checking our cholesterol. About 70% of women and 66% of men had their cholesterol tested in the past 5 years—slightly under the 80% objective.

You should be getting that test, which measures total cholesterol, LDL cholesterol, HDL cholesterol, and triglycerides, at least once every five years. Ideally, you want these results:

• total cholesterol—less than 200 milligrams per deciliter (mg/dL)
• protective HDL cholesterol—60 mg/dL or higher
• harmful LDL cholesterol—less than 100 mg/dL
• triglycerides—less than 150 mg/dL

If your numbers aren’t quite where they should be, there are a number of ways you can help bring them back into a healthy range. Many people turn to a statin or other cholesterol-lowering medication. But it makes sense to try diet and exercise first.

Different foods lower cholesterol in various ways. Some deliver soluble fiber, which binds cholesterol in the digestive system and drags them out of the body before they get into circulation. Some give you polyunsaturated fats, which directly lower LDL. And some contain plant sterols and stanols, which block the body from absorbing cholesterol.

Many foods can help lower cholesterol. Here are 10 described in the Harvard Heart Letter. (You can read the full article here.)

• oats
• barley and other whole grains
• beans
• eggplant and okra
• nuts
• liquid vegetable oils (canola, sunflower, etc.) when used in place of butter, lard, or shortening
• apples, grapes, strawberries, and citrus fruits
• margarines and other foods fortified with sterols and stanols
• soy
• fatty fish

The guidelines define a survivor as “anyone who has been diagnosed with cancer, from the time of diagnosis through the rest of their life.” According to the ACS, one in every 25 Americans is a cancer survivor.

The evidence is reasonably solid that people who have been treated for cancer live longer if they exercise, says Dr. I-Min Lee, an associate professor of medicine at Harvard Medical School and an expert on the health benefits of exercise.  “The evidence for exercise extending survival after cancer therapy is promising. There have been about half dozen studies on this, for breast, prostate, and colorectal cancers,” says Dr. Lee. A healthy diet helps, too. (An earlier Harvard Health blog describes some of the mental and emotional challenges that cancer survivors face.)

Feeling better and living longer

Many cancer survivors look to diet and exercise in the hope of preventing recurrence of their disease, extending their lifespans, or just feeling better after a rigorous course of treatment.

To help them do this, the ACS assembled a group of experts to review and summarize what science had to say about the role of diet and exercise for cancer survivors. It turns out that the same things that prevent cancer from developing in the first place also help keep it from coming back.

The ACS guidelines provide specific advice for survivors of a variety of major cancers: prostate, colorectal, lung, breast, ovarian, endometrial, upper GI, head and neck, and hematologic. Here are some highlights:

• Cancer survivors seeking evidence-based nutrition advice should ask their health care provider or oncology provider for a referral to a registered dietitian with special certification in cancer care.
• If you are having trouble taking in enough calories each day, consider eating smaller and more frequent meals and eating special fortified or nutrient-dense food products.
• Use dietary supplements cautiously. There isn’t good evidence that taking more than the recommended daily amounts (RDA) of vitamins and minerals improves treatment outcomes or long-term survival. In fact, preliminary findings suggest that supplementation could actually interfere with some cancer treatments.
• Exercise can help fight fatigue, keep you functioning, and improve the quality of life. When to start exercising after treatment, and how much, is an individualized decision for you and your doctor.
•  The evidence is pretty solid that obesity increases the risk of breast cancer recurrence, and evidence of this or other cancers is building. If you are carrying too many pounds, losing weight and keeping it off can help improve survival.

A 2010 study published in the journal Nature included 11,430 men and women between the ages of 18 and 60 who were randomly assigned to one of three online brain exercise programs. One focused on reasoning, planning, and problem solving. Another focused on broader tasks of memory, attention, mathematics, and other skills. The third (the control) involved searching online for answers to obscure questions. After six weeks, people in the first and second groups boosted their scores on their assigned brain-training exercises. But they showed no improvement (compared with the control group) when they repeated several general memory and thinking skills testing that had been done at the start.

An earlier study, sponsored by Posit Science, the company that created the popular Brain Fitness Program, used standard memory tests to assess 487 people over age 65. Half were then assigned to complete the program’s 40 hour-long sessions. The other half—the control group—watched educational DVDs and were quizzed on the material. The software users boosted their memory and attention scores more than the control group. But self-reported improvement in everyday situations was fairly similar: 48% for the Brain Fitness group versus 40% for the controls.

There are no studies comparing one commercially available program to another or to mind-stimulating hobbies. Other factors that make it tricky to assess the worth of brain-building computer programs are the potential effect of programs that become more challenging as the player becomes more successful; the effect of competitive features in a program; and the player’s desire to get his or her money’s worth from buying the software, some of which costs nearly $400.

So far, it looks like simply playing games that require concentration won’t help you remember important names, faces, and appointments. What can work are practical tools designed to address specific problems encountered in daily life. You can learn some memory-training techniques in the free excerpt of Improving Memory.

To stay sharp, your mind needs regular workouts in creative thinking, problem solving, and intellectual focus. To stretch and exercise your brain, choose an activity you enjoy—reading, playing cards, or doing crossword puzzles are some good examples. If you’re feeling ambitious, try learning to speak a new language or play a musical instrument. Most of these activities come at a much lower cost than brain-training programs, and you’ll probably find them to be a lot more enjoyable, too.

More complete information on memory loss and how to prevent it is available in the new Harvard Medical School report, Improving Memory: Understanding age-related memory loss. You can read a free excerpt or buy the full 50-page report at www.health.harvard.edu.

“The headache would get worse until it was a smashing weight, sending red pain through his head and neck with every pulse beat. Bright lights would make his eyes water helplessly and send darts of agony into the flesh just behind his eyes. Small noises magnified, ordinary noises insupportable. The headache would worsen until it felt as if his head were being crushed inside an inquisitor’s lovecap…. He would be next to helpless.”

Migraine was once largely unpreventable and untreatable. Today there are dozens of prescription and over-the-counter medications, and even a few herbal preparations, proven to prevent migraine. Unfortunately, only about one-third of people who could benefit from a preventive therapy take one. New guidelines from the American Academy of Neurology and the American Headache Society highlight effective treatments, which should make choosing a medications easier and safer for migraine sufferers. The guidelines were published in today’s issue of the journal Neurology.

Choosing an anti-migraine medicine

Whether to take something every day to prevent migraine is a personal choice. When deciding this with your doctor, consider the following:

• The number of migraines you have each month
• The severity of your migraines—do they routinely keep you from work or school?
• Whether your migraines stop quickly if you take a medicine immediately after an aura or headache begins.

A good place to start might be with a daily herbal or over-the-counter product. According to the new guidelines, there’s good evidence that an extract of the butterbur plant is effective at preventing migraine. Other simple preventives include ibuprofen (Motrin, Advil, generic versions), naproxen (Aleve, generic versions), riboflavin (vitamin B₂), and an extract of feverfew known as MIG-99.

When it comes to prescription medicines, the guidelines recommended these as being supported by the most solid evidence for preventing migraine

•   anti-seizure medicines, specifically divalproex sodium (Depakote), sodium valproate, and topiramate (Topamax)

•   beta blockers, specifically propranolol (Inderal, generic versions), metoprolol (Lopressor, generic versions), and timolol

•   frovatriptan (Frova) for perimenstrual migraine

There is no definite first choice for any of the above. Your choice should depend upon whether you have another condition that might also be helped with the same medicine. For example, someone with arthritis and migraines might start with daily naproxen.

Be patient if the first or even second one you and your doctor choose doesn’t help. The guidelines list even more medicines that might be right for you.

Prevention important for many

Several medications are available that can stop a migraine in its tracks, or at least blunt its course. But these don’t work for many migraineurs. For them, prevention is key to avoiding novelist Joan Didion’s compelling description of her migraines in the essay “In Bed”:

“Migraine gives some people mild hallucinations, temporarily blinds others, shows up not only as a headache but as a gastrointestinal disturbance, a painful sensitivity to all sensory stimuli, an abrupt overpowering fatigue, a strokelike aphasia, and a crippling inability to make even the most routine connections. When I am in a migraine aura (for some people the aura lasts fifteen minutes, for others several hours), I will drive through red lights, lose the house keys, spill whatever I am holding, lose the ability to focus my eyes or frame coherent sentences, and generally give the appearance of being on drugs, or drunk. The actual headache, when it comes, brings with it chills, sweating, nausea, a debility that seems to stretch the very limits of endurance. That no one dies of migraine seems, to someone deep into an attack, an ambiguous blessing.”

Buffett announced to Berkshire Hathaway shareholders last week that he has early stage prostate cancer that “is not remotely life-threatening or even debilitating in any meaningful way.” If Buffett’s cancer had been detected because he was having symptoms, such as trouble urinating or bone pain, I wouldn’t be writing this column, and instead would be privately wishing him well and discussing optimal medical treatment.

Instead, at age 81, Buffett reportedly had a blood test for prostate-specific antigen (PSA), a controversial test used to detect hidden prostate cancer. This would be a good thing if prostate cancer was a fast-growing, deadly cancer like lung or pancreatic cancer. But it isn’t. Prostate cancer generally grows slowly and usually doesn’t affect a man’s health or longevity. We are also led to believe that the cancer cells detected in Buffett’s prostate gland were neither highly aggressive nor widespread.

The United States Preventive Services Task Force and other medical organizations urge men over age 75, and their doctors, to avoid the PSA test. Sure, it might detect silent prostate cancer. But the vast majority of older men would die of something else in the 10 to 20 years that it would generally take for the cancer to make itself known. At that point, there would still be time to treat the cancer.

Buffett’s PSA test set off a disastrous chain of events that will probably do the legendary money manager more harm than good. The high PSA result triggered a prostate biopsy. (On Twitter, cancer specialist Benjamin Davies of the University of Pittsburgh School of Medicine said “If one of my residents biopsied an 81yo (with no mets [metastases]) I would fire them on the spot.”) The biopsy showed some cancerous cells in the walnut-sized gland. And that is leading Buffett to a two-month course of radiation therapy.

If Buffett’s PSA level was very high, or had been increasing rapidly, or the biopsy showed highly abnormal, fast-growing cancer cells, radiation therapy is one of several reasonable options. But if his PSA is stable, his Gleason score (a measure of how closely cancer cells resemble normal ones) is low, and he isn’t experiencing any prostate-related symptoms, undergoing radiation therapy right now doesn’t make sense.

Although quite safe, radiation therapy isn’t a risk-free procedure. As we describe in HarvardMedicalSchool’s 2012 Annual Report on Prostate Diseases, it has immediate side effects, such as fatigue and bowel problems. Over the long term, about 50% to 70% of men lose the ability to get or sustain an erection or experience rectal bleeding.

A different approach

For my patients with early-stage prostate cancer and a low Gleason score, I recommend something called active surveillance with delayed intention to treat (once known as watchful waiting). These men have their PSA levels checked three to four times a year and have periodic prostate biopsies. These steps keep tabs on the tumor. If they indicate that the tumor is getting bigger or becoming more aggressive, then it’s time to consider surgery or radiation therapy. A consensus panel of experts convened last year by the National Institutes of Health concluded that active surveillance is a “viable option that should be offered to patients with low-risk prostate cancer.”

Deferring treatment until it’s needed makes more sense than rushing to treatment. Surgery, radiation therapy, and other treatments are still available later on, and the data indicate that the outcome is just as good for those who delay treatment.

I worry that Buffett’s decision to have a PSA test at age 81, and to announce he will undergo radiation therapy to treat his apparently localized, early-stage prostate cancer, sends the message to older men that PSA screening and immediate treatment are the right thing to do. For many men in this situation, it’s the wrong thing to do.

Type 2 diabetes occurs when a person’s muscle cells stop responding to insulin, a hormone made by the pancreas. You can think of insulin as a tiny molecular key that opens the door through which glucose (blood sugar) flows into cells. When muscle cells resist insulin’s “open up” signal, glucose builds up in the bloodstream. Over time, this harms tissues throughout the body, from the brain to the toes. It can damage nerves, rob vision, and cause heart disease.

A simple way to check blood sugar is to measure the percentage of hemoglobin molecules (the oxygen-carrying protein in red blood cells) that have become coated with glucose. This is known as the hemoglobin A1c (HbA1c) test. The higher the average daily blood sugar over a three-month period, the higher the HbA1c value.

People who don’t have diabetes have HbA1C readings below 5.7%. For years, the American Diabetes Association recommended that almost everyone with type 2 diabetes should aim for an HbA1c level less than 7%. Keeping blood sugar as low as possible, called “tight control,” was thought to limit the havoc caused by diabetes.

But a series of studies have shown that tight control for people who have had diabetes for many years doesn’t improve quality of life or longevity. And for some people, trying to keep blood sugar low enough to hit the HbA1C target of 7% or lower means experiencing episodes of low blood sugar (hypoglycemia). Hypoglycemia can cause blackouts, seizures and strokes. In older people, frequent bouts of low blood sugar can worsen brain function.

One size doesn’t fit all

The new guidelines acknowledge that people are different. TheADAnow recommends that individuals and their doctors decide together on a blood sugar target.

For people who are newly diagnosed with type 2 diabetes but who are otherwise in good health, the ADA still suggests aiming for tight control. For them, an HbA1C of 6.0% to 6.5% is ideal. This is especially true if the goal can be met with lifestyle changes only (such as losing weight and exercising more), or with lifestyle plus the medication metformin (generic, Glucophage, Fortamet).

For people who have had diabetes for a while, an HbA1c goal of 7.5% to 8.0%, or even higher, may be more appropriate. Reasons for “looser” blood sugar control include:

• Older age
• Frequent bouts of hypoglycemia
• The presence of other medical conditions requiring multiple medicines and needing more than 2 drugs to lower blood sugars
• Limited financial resources

Controlling blood sugar is only one part of managing type 2 diabetes to limit its effects on health. Controlling weight and blood pressure are very important, as are efforts to prevent heart disease, stroke, and kidney disease, all of which can occur as a result of diabetes.

These new patient-centered recommendations are a breath of fresh air. They will be good for people with type2 diabetes and for their doctors. Patient-centered care should be main theme of all health guidelines.

Being overweight is a big risk factor for becoming diabetic. Researchers long thought that the poor eating habits that went along with poor sleep were at the root of sleep-related diabetes. With the help of 21 volunteers who lived in a sleep lab for almost six weeks, researchers from Harvard-affiliated Brigham and Women’s Hospital have shown that lack of sleep plays an even more complex and powerful role.

Each of the volunteers followed a carefully scheduled daily program of eating, physical activity, and sleeping. They started out well rested, getting 10 hours of sleep a night for the first six nights. Over the next three weeks, they spent just 5.6 hours in bed each night, and it came later and later each day. The schedule was meant to mimic rotating shift work or extended jet lag.

This sleep pattern completely threw off the body’s sleep-wake rhythm, which influences the daily rise and fall of body temperature and blood pressure, and the secretion of many hormones.

During the three weeks of abnormal sleep, the participants’ bodies stopped releasing enough insulin after a meal. Muscles need this hormone to absorb sugar (glucose) from the bloodstream. As a result, their blood sugar levels went haywire. Some of the people had blood sugar levels high enough to have been diagnosed as prediabetic.

At the same time, the volunteers’ rates of metabolism slowed. Because they were eating a controlled diet, they did not gain weight. But if they had eaten as much as they did during the first few days of the study, when they were getting plenty of sleep, the researchers estimated the volunteers would have gained the equivalent of 10 to 12 pounds over a year. The results were reported in the journal Science Translational Medicine.

Improving sleep

We’ve known for some time that being overweight increases the risk of developing diabetes, as does lack of physical activity. This work reported in Science Translational Medicine, by Dr. Orfeu Buxton and his colleagues, offers a look at how poor sleep might lead to type 2 diabetes, the kind most likely to affect older individuals. Sleep troubles have also been linked to the development of high blood pressure, heart disease, and some cancers.

The U.S. Centers for Disease Control and Prevention estimates that up to 70 million Americans live with chronic sleep problems. Here are a few recommendations for getting more—or better—sleep:

• Establish a regular bedtime and a relaxing bedtime routine.
• Use your bed only for sleeping or lovemaking. Avoid reading or watching television in bed.
• If you can’t sleep after 15 to 20 minutes, get out of bed and go into another room. Read quietly with a dim light. Don’t watch television since the light from the TV has an arousing effect. When you feel sleepy, get back into bed. Don’t delay your scheduled wake-up time to make up for lost sleep.
• Whenever possible, schedule stressful or demanding tasks early in the day and less challenging activities later. This helps to wind down at the end of your day.
• Limit caffeine; to be on the safe side, don’t have any beyond midafternoon.
• Avoid alcohol after dinnertime. Although many people think alcohol acts like a sedative, it can actually disrupt your sleep.
• If you work nights, try wearing yellow- or orange-tinted glasses on the trip home. These block some blue light from reaching your eyes, which can wake you up. Go straight to bed when you get home.

Excellent information on sleep problems, and how to overcome them, is available from the online Sleep and Health Education Program, sponsored by Harvard Medical School’s Division of Sleep Medicine.