Studies reinforce life-saving benefits of colon cancer screening

If you’ve ever had a kidney stone, you surely remember it. The pain can be unbearable, coming in waves until the tiny stone passes through your urinary plumbing and out of the body. For many, kidney stones aren’t a one-time thing: in about half of people who have had one, another appears within seven years without preventive measures.

Preventing kidney stones isn’t complicated, but it does take some determination.

Kidney stones form when certain chemicals become concentrated enough in the urine to form crystals. The crystals grow into larger masses (stones), which can make their way through the urinary tract. If the stone gets stuck somewhere and blocks the flow of urine, it causes pain.

Most stones occur when calcium combines with one of two substances: oxalate or phosphorous. Stones can also form from uric acid, which forms as the body metabolizes protein.
Kidney stonesHow to avoid kidney stones

Preventing kidney stones means preventing the conditions that support their formation. I asked Dr. Melanie Hoenig, an assistant professor of medicine at Harvard-affiliated Beth Israel Deaconess Medical Center, for the top ways to prevent kidney stones. Here are her recommendations:

Drink plenty of water: Drinking extra water dilutes the substances in urine that lead to stones. Strive to drink enough fluids to pass 2 liters of urine a day, which is roughly eight standard 8-ounce cups. It may help to include some citrus beverages, like lemonade and orange juice. The citrate in these beverages helps block stone formation.

Get the calcium you need: Getting too little calcium in your diet can cause oxalate levels to rise and cause kidney stones. To prevent this, make sure to take in an amount of calcium appropriate to your age. Ideally, obtain calcium from foods, since some studies have linked taking calcium supplements to kidney stones. Men 50 and older should get 1,000 milligrams (mg) of calcium per day, along with 800 to 1,000 international units (IU) of vitamin D to help the body absorb the calcium.

Reduce sodium: A high-sodium diet can trigger kidney stones because it increases the amount of calcium in your urine. So a low-sodium diet is recommended for the stone prone. Current guidelines suggest limiting total daily sodium intake to 2,300 mg. If sodium has contributed to kidney stones in the past, try to reduce your daily intake to 1,500 mg. This will also be good for your blood pressure and heart.

Limit animal protein: Eating too much animal protein, such as red meat, poultry, eggs, and seafood, boosts the level of uric acid and could lead to kidney stones. A high-protein diet also reduces levels of citrate, the chemical in urine that helps prevent stones from forming. If you’re prone to stones, limit your daily meat intake to a quantity that is no bigger than a pack of playing cards. This is also a heart-healthy portion.

Avoid stone-forming foods: Beets, chocolate, spinach, rhubarb, tea, and most nuts are rich in oxalate, and colas are rich in phosphate, both of which can contribute to kidney stones. If you suffer from stones, your doctor may advise you to avoid these foods or to consume them in smaller amounts.

For everyone else, particular foods and drinks are unlikely to trigger kidney stones unless consumed in extremely high amounts. Some studies have shown that men who take high doses of vitamin C in the form of supplements are at slightly higher risk of kidney stones. That may be because the body converts vitamin C into oxalate. One key instruction in the operating manual for healthy aging is remaining ever vigilant about osteoporosis. That’s because loss of bone can lead to fractures that worsen quality of life and may even shorten life. The quest to identify osteoporosis early, so it can be treated, has led to widespread testing of bone mineral density (BMD), the key measure of bone strength.

The influential National Osteoporosis Foundation recommends checking for osteoporosis beginning at age 65 for women and 70 for men. Medicare pays for the gold-standard test, dual-energy X-ray absorptiometry (DEXA), every two years. Individuals can keep going back every two years, regardless of whether their previous scan was normal or not.

A study published today in the Journal of the American Medical Association (JAMA) raises a fundamental question: Is repeating testing of older people with normal bone strength every two years too much?

The study was led by public health researcher Dr. Sarah D. Berry of the Harvard-affiliated Institute for Aging Research at Hebrew SeniorLife in Boston. The researchers tracked 310 men and 492 women with an average age of 75 years for up to 10 years after they had an initial bone-density measurement.

Repeat testing four years after the first test found relatively few instances where someone lost enough bone mass to put them at heightened risk for hip fractures. Overall, repeat bone-density testing after four years improved the ability to identify those at higher risk by only 4%.
Time to slow down testing?

This is not the first study to suggest that frequent testing may be overkill for many older adults. The test itself is not especially dangerous, but it does come with inconvenience and large costs to the healthcare system. Is it time to reconsider testing bone density every two years in older people?

Based on this one study, that might be premature. “It’s not going to be a practice-changer,” says endocrinologist Dr. David Slovik, associate professor of medicine at Harvard Medical School and medical editor of Osteoporosis: A Guide to Prevention and Treatment, a Harvard Medical School Special Health Report. “This might get us to think more about how often to get bone density measurements, but there still a lot more study that needs to go into it.”

A lot of research has tried to nail the best interval down, but “it really depends on so many things,” Dr. Slovik says. They include age, of course, but also a previous fracture, family history of osteoporosis, and alcohol and tobacco use. That means the “sweet spot” for bone density testing depends a lot on whom you are testing.

However, if someone with normal bone density and would like to get tested less often than every other year, it’s perfectly reasonable to consider it. “It’s obviously up to the patient and the doctor,” Dr. Slovik says.
How to protect your bones

Though it’s wise to avoid tests and procedures you don’t need, it’s also important not to miss a sharp decline in bone strength. Simply put, a hip fracture in an older person can kill—not because of the break itself, but the downward spiral in health problems it often triggers.

Your doctor can help you figure out whether it makes sense for you to be tested for low bone density and how often it makes sense for you to be tested. The National Osteoporosis Foundation lists several factors that put an individual at risk for bone loss:

    age 50 or older
    being female
    a family history of osteoporosis
    low body-mass index
    loss of height
    lack of physical activity
    not enough calcium and vitamin D in the diet
    not eating enough fruits and vegetables
    drinking too much alcohol

Various diseases and medications can also lead to osteoporosis

The single best thing anyone can do to protect bone health is to exercise daily in a way that exerts force on bones. High-impact weight-bearing exercises like stair climbing, high-impact aerobics, and dancing are good, as is resistance training with weights or elastic bands. These kinds of exercise trigger the body’s natural bone-maintaining machinery. It’s also important to get adequate calcium and vitamin D every day, preferably from food. Current guidelines suggest adults older than 50 should get 1,000 mg to 1,200 mg per day of calcium and 800 to 1,000 IU of vitamin D, which helps the body absorb calcium. Carrying too many pounds is a solid signal of current or future health problems. But not for everyone. Some people who are overweight or obese mange to escape the usual hazards, at least temporarily. This weight subgroup has even earned its own moniker—metabolically healthy obesity.

Health professionals define overweight as a body-mass index (BMI) between 25.0 and 29.9, and obesity as a BMI of 30 or higher. (BMI is a measure of weight that takes height into consideration. You can calculate your BMI here.)

Most people who are overweight or obese show potentially unhealthy changes in metabolism. These include high blood pressure or high cholesterol, which damage arteries in the heart and elsewhere. Another harmful metabolic change is resistance to the hormone insulin, which leads to high blood sugar. As a result, people who are overweight or obese are usually at high risk for having a heart attack or stroke, developing type 2 diabetes, or suffering from a host of other life-changing conditions.

But some people who are overweight or obese manage to avoid these changes and, at least metabolically, look like individuals with healthy weights. “Obesity isn’t a homogeneous condition,” says Dr. Frank Hu, professor of nutrition and epidemiology at the Harvard School of Public Health. “It appears that it doesn’t affect everyone in the same ways.”

Dr. Hu and three colleagues wrote a “Personal View” article in Lancet Diabetes and Endocrinology reviewing what is known about metabolically healthy obesity. They identified several characteristics of metabolically healthy obesity. These include a high BMI with

    a waist size of no more than 40 inches for a man or 35 inches for a woman
    normal blood pressure, cholesterol, and blood sugar
    normal sensitivity to insulin
    good physical fitness

BMI isn’t perfect

BMI is not a perfect measure of weight or obesity. It often identifies fit, muscular people as being overweight or obese. That’s because muscle is more dense than fat, and so weighs more. But muscle tissue burns blood sugar, a good thing, while fat tissue converts blood sugar into fat and stores it, a not-so-good thing.

“Further exploration of metabolically healthy obesity could help us fine-tune the implications of obesity,” says Dr. Hu. “It supports the idea that we shouldn’t use BMI as the sole yardstick for health, and must consider other factors.”

Genes certainly play a role in how a person’s body and metabolism respond to weight. Some people may be genetically protected from developing insulin resistance. Others are genetically programmed to store fat in the hips or thighs, which is less metabolically hazardous than storing fat around the abdomen.

The concept of metabolically healthy obesity could be used to help guide treatment. Currently, exercise and a healthy diet are the foundation for treating obesity. When those efforts aren’t enough, weight-loss surgery (bariatric surgery) is sometimes an option. Such surgery is appropriate for people with metabolically unhealthy obesity, the authors suggest, but for people with metabolically healthy obesity it might make more sense to intensify the lifestyle approach rather than have surgery. This idea, however, needs to be tested in clinical studies, says Dr Hu.
Don’t rest easy

Metabolically healthy obesity isn’t common. And it may not be permanent, warns Dr. Hu. Just because a person has metabolically healthy obesity at one point doesn’t it will stay that way. With aging, a slowdown in exercise, or other changes, metabolically healthy obesity can morph into its harmful counterpart.

It’s also important to keep in mind that obesity can harm more than just metabolism. Excess weight can damage knee and hip joints, lead to sleep apnea and respiratory problems, and contributes to the development of several cancers. Checking seemingly healthy people for cancer—what doctors call screening—seems like a simple process: Perform a test and either find cancer early and cure it or don’t find it and breathe easy.

Yet it’s actually not so simple. For many types of cancer, there is no test that can reliably detect the disease at a curable stage. The available tests aren’t always accurate. Testing may be invasive, risky, inconvenient, uncomfortable, or expensive. And some cancers (such as certain prostate tumors) are harmless, so detecting them can do more harm than good.

For colon cancer, we have several effective screening tests:

    Colonoscopy. A doctor inspects the entire colon using a flexible tube with a light and camera at its tip. If a cancerous or precancerous tumor is seen, it can be removed.
    Sigmoidoscopy. This is similar to a colonoscopy, but only the last portion of the colon is inspected.
    Stool testing. A sample of stool is tested for tiny amounts of blood. Blood may indicate the presence of colon cancer.

There is some uncertainty about just how much benefit these tests provide. Two new studies in yesterday’s New England Journal of Medicine aim to quantify the benefits.

In the first study, researchers tracked nearly 89,000 adults for 22 years. Some had colonoscopy or sigmoidoscopy. Others had no colon cancer tests. About 2% of the total group developed colon cancer, and 0.5% died of the disease.

Colonoscopy and sigmoidoscopy were linked with a lower risk of colon cancer. Those who had no problems found during a colonoscopy were about 56% less likely to develop colon cancer than those not screened. Those who had a polyp removed during sigmoidoscopy or colonoscopy or had no problems found during sigmoidoscopy were about 40% less likely to develop colon cancer than those not screened. Even more important, those screened by colonoscopy or sigmoidoscopy were less likely to have died of colon cancer.

In the second study, more than 46,000 adults were randomly divided into three groups. Two groups received stool testing either every year or every other year. A comparison group received “usual care,” and few people in this group had stool tests. The screening tests were done during two six-year periods. Up to 30 years later, about 2% of the total group had died of colon cancer.

Compared with the usual-care group, colon cancer deaths were 32% lower in the group that got yearly stool tests and 22% lower in the group that got the test every two years.

Taken together, these findings support the current recommendation that adults have a screening colonoscopy beginning at age 50. Sigmoidoscopy may be a worthwhile alternative, though its benefit was less. Doctors may recommend stool testing, too. But the ideal combination of tests has not been well studied.

People with average risk of colon cancer are advised to get a repeat colonoscopy every 10 years. These findings suggest that this may be more frequent than necessary.

People with risk factors for colon cancer may need to start earlier or have more frequent testing. Risk factors include a family history of inherited colorectal cancer syndromes, a first-degree relative (parent, sibling, or child) who developed colorectal cancer or polyps before age 60, a personal history of colorectal cancer or polyps, or a personal history of chronic inflammatory bowel disease, such as ulcerative colitis or Crohn’s disease.
Focus on prevention

There are a number of things you can do to prevent colon cancer.

Get screened. Talk to your doctor about when to begin testing, which test is best for you and how often to repeat it.

Exercise more. Studies suggest that regular exercise may reduce the risk of colon cancer.

Change your diet. A diet that is low in saturated fats may lower your cancer risk.

Don’t smoke. Cigarette smoking has been linked to many types of cancer, including colon cancer.

There is some evidence that taking a daily aspirin or folic acid may reduce the risk of colon cancer. However, this is not proven. Review these options with your doctor as well.

The biggest challenge for colon cancer screening is getting people to have the available tests. About 50,000 Americans die of colon cancer each year—many of these can be prevented with early screening. I am hopeful that this research and public health messages will help colon cancer screening become more widespread. The hottest trend in mobility right now is not a smart phone or wireless gadget. The mobility that’s making health headlines is the kind that lets us do what we need to do: walk and move. Mobility is essential for getting through the day, whether you need to walk across a room to the bathroom or kitchen, get out of bed or a chair, or walk through a grocery store.

Loss of mobility, which is common among older adults, has profound social, psychological, and physical consequences. “If you’re unable to get out then you can’t go shopping, you can’t go out with your friends to eat dinner or go to the movies, and you become dependent on other people to get you places. So you become a recluse, you stay home, you get depressed. With immobilization comes incontinence, because you can’t get to the bathroom, you can develop urinary infections, skin infections. The list goes on,” says geriatrician Dr. Suzanne Salamon, an instructor at Harvard Medical School.

The cascade of negative effects that comes with immobility can often be prevented or limited, according to a review in today’s JAMA. Researchers from the University of Alabama at Birmingham looked at dozens of mobility studies published over the years. They discovered common factors that lead to loss of mobility, such as older age, low physical activity, obesity, impaired strength and balance, and chronic diseases such as diabetes and arthritis. Less common red flags included symptoms of depression, problems with memory or thinking skills, being female, a recent hospitalization, drinking alcohol or smoking, and having feelings of helplessness. Individuals with one or more of these factors is at risk for immobility.

Given that so many things that can lead to immobility, you’d think primary care physicians would be able to spot older adults at risk of losing mobility. But it’s not so simple, says Dr. Salamon. “There are so many other things that doctors have to pay attention to—heart problems and lung problems—that screening for mobility gets pushed to the background. However, it’s one of the most important, because it makes the difference between living at home or living in a facility,” she explains. She also points out that loss of mobility puts you at greater risk for falling, which often results in a hip fracture. “That’s the worst, because within a year 20% of people with hip fractures die from complications. So we try to avoid that at all costs,” says Dr. Salamon.

Checking a person’s mobility is fairly simple. Dr. Salamon likes the Get Up and Go Test, where she asks a person to stand up from sitting in a chair, walk 10 feet, turn around, walk back to the chair, and sit down. “You look at how long that takes and how steady the person is,” she says. Another way is just to watch how quickly people walk. They should walk faster than a yard per second. If you walk that or faster, you’re normal; if you’re slower, you have a gait problem, which increases your chances of falling,” she says.

The University of Alabama researchers suggest asking these two questions:

    For health or physical reasons, do you have difficulty climbing up 10 steps or walking one-quarter of a mile?
    Because of underlying health or physical reasons, have you modified the way you climb 10 steps or walk a quarter of a mile?

The beauty of the “test” is that you don’t have to go to a doctor to get an answer. You probably know already if you’re having trouble climbing stairs. And walking one-quarter of a mile? That’s one lap around a medium-sized mall’s upper level. Can you walk around it without difficulty?

If stairs and walking are difficult, it’s an indication that you’re on the road to less travel, and you’ll need to see your doctor. The good news is that your physician can help you address what’s causing the difficulty before it progresses to a loss of mobility. A variety of solutions are available. They can include physical therapy to improve balance and strength training. Occupational therapy can help improve a person’s ability to perform daily living activities and the living environment with tools such as elevated bathroom fixtures and grab bars. Social support can help eliminate mobility barriers such as lack of transportation. Referrals to subspecialists may be needed to treat medical conditions that can lead to immobility. Finally, the use of devices such as canes, walkers, wheelchairs, and scooters can open the door to greater mobility.

There are a few tools you can check out online, including the Get Up and Go test as well as the Performance-Oriented Mobility Assessment. Take the test with a friend or loved one who can help you if needed; don’t try it at home if you’re unsteady on your feet.

Loss of mobility is a real problem, but one that is often preventable or treatable. Take steps now to make sure you can take the steps you need in the years ahead.


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