Tuesday, June 30, 2009

Exercise lowers the risk of colon cancer

An ambitious new study has added considerable weight to the claim that exercise can lower the risk for colon cancer. Researchers at Washington University School of Medicine in St. Louis and Harvard University combined and analyzed several decades worth of data from past studies on how exercise affects colon cancer risk. They found that people who exercised the most were 24 percent less likely to develop the disease than those who exercised the least.

"What's really compelling is that we see the association between exercise and lower colon cancer risk regardless of how physical activity was measured in the studies," says lead study author Kathleen Y. Wolin, Sc.D., a cancer prevention and control expert with the Siteman Cancer Center at Barnes-Jewish Hospital and Washington University. "That indicates that this is a robust association and gives all the more evidence that physical activity is truly protective against colon cancer."

Colorectal cancer is the third most common type of cancer. Each year more than 100,000 people in the United States are diagnosed with colon cancer and about 40,000 are diagnosed with rectal cancer. The study suggests that if the American population became significantly more physically active, up to 24 percent, or more than 24,000, fewer cases of colon cancer would occur each year.

Wolin's report was published Feb. 10, 2009 through advance online publication in the British Journal of Cancer. In the study, she and her colleagues gathered the results from all relevant studies published in English on the effect of physical activity on colon cancer risk.

They eliminated from consideration any studies that combined both colon and rectal cancer because exercise has not been shown to affect rectal cancer risk — including such studies would have led to an underestimation of the effect of exercise on colon cancer risk. In all, they analyzed 52 studies going back as far as 1984, making their analysis the most comprehensive to date.

They found that the protective effect of exercise held for all types of physical activity, whether that activity was recreational, such as jogging, biking or swimming, or job related, such as walking, lifting or digging.

"The beneficial effect of exercise holds across all sorts of activities," says Wolin, also assistant professor of surgery. "And it holds for both men and women. There is an ever-growing body of evidence that the behavior choices we make affect our cancer risk. Physical activity is at the top of the list of ways that you can reduce your risk of colon cancer."

The difference between people who were the most physically active and those who were the least varied from study to study in Wolin's analysis. As an example, in a 2007 study by Wolin and colleagues, women who walked the most realized a 23 percent reduction in their risk of colon cancer. Those highly active women walked briskly for five to six hours each week. By comparison, the women in that study who walked the least walked only a half hour each week.

Monday, June 29, 2009

Vigorous Exercise May Help Prevent Vision Loss

There's another reason to dust off those running shoes. Vigorous exercise may help prevent vision loss, according to a pair of studies from the U.S. Department of Energy's Lawrence Berkeley National Laboratory. The studies tracked approximately 31,000 runners for more than seven years, and found that running reduced the risk of both cataracts and age-related macular degeneration.

The research, which is among the first to suggest that vigorous exercise may help prevent vision loss, offers hope for people seeking to fend off the onset of eye disease.

"In addition to obtaining regular eye exams, people can take a more active role in preserving their vision," says Paul Williams, an epidemiologist in Berkeley Lab's Life Sciences Division who conducted the research. "The studies suggest that people can perhaps lessen their risk for these diseases by taking part in a fitness regimen that includes vigorous exercise."

A cataract, which is a cloudy opacity of the eye lens, is the leading cause of blindness. More than one-half of people in the U.S. over the age of 65 suffer from some form of cataracts. Age-related macular degeneration, which is damage to the retina, is the leading cause of irreversible vision loss in older white Americans, affecting 28 percent of people aged 75 and older.

The diseases have several known risk factors, such as sunlight exposure and diabetes in the case of cataracts, but few interventions. Now, it appears that vigorous cardiovascular exercise may be one way to derail the diseases.

To conduct the research, Williams analyzed data collected in the National Runners' Health Study, which he established in 1991 to determine the health benefits of running.

In this case, he followed approximately 29,000 male runners and 12,000 female runners for more than seven years. Of these people, 733 men reported being diagnosed with cataracts on a questionnaire filled out at the end of the study. Too few women reported cataracts to track.

Men who ran more than 5.7 miles per day had a 35 percent lower risk of developing cataracts than men who ran less than 1.4 miles per day. The study also analyzed men's 10-kilometer race performances, which is a good indicator of overall fitness. The fittest men boasted one-half the risk of developing cataracts compared to the least-fit men.

A second study found that running appeared to reduce the risk of age-related macular degeneration. In the study, 152 men and women reported being diagnosed with the disease. Compared to people who ran less than 1.2 miles per day, people who averaged between 1.2 and 2.4 miles per day had a 19 percent lower risk for the disease, and people who ran more than 2.4 miles per day had between 42 percent and 54 percent lower risk of the disease.

"These findings are compelling because of the large size of the study, and the fact that we are looking at something that is fairly well defined: vigorous exercise, as opposed to more moderate exercise," says Williams.

Most of the runners in the study exceeded the current public health recommendations for physical activity, which is at least 30 minutes of moderate-intensity activities such as brisk walking five days a week, or smaller doses of more vigorous exercise such as running. It is unclear whether people might also lower their risk for cataracts and age-related macular degeneration by walking.

"We know there are important health benefits to walking, including lowering heart disease risk," says Williams. "It is quite likely that the studies' results might apply to a lesser extent to smaller doses of more moderate exercise."

Williams also adds that further research is needed to explore why there is a link between vigorous exercise and a decreased risk for eye disease.

"We know some of the physiological benefits of exercise, and we know about the physiological background of these diseases, so we need to better understand where there's an overlap," says Williams.

The studies are published in the January 2009 issue of Investigative Ophthalmology and Visual Science. They were supported in part by grants from the National Heart Lung and Blood Institute.

Prostate cancer screening has yet to prove its worth

The recent release of two large randomized trials suggests that if there is a benefit of screening, it is, at best, small, says a new report in CA: A Cancer Journal for Clinicians. Authored by Otis W. Brawley, M.D. of the American Cancer Society and Donna Ankerst, Ph.D. and Ian M. Thompson, M.D. of the University of Texas Health Science Center at San Antonio, the review says because prostate cancer is virtually ubiquitous in men as they age, it is clear that a goal of "finding more cancers" is not acceptable. Instead, public health principles demand that screening must reduce the risk of death from prostate cancer, reduce the suffering from prostate cancer, or reduce health care costs when compared with a non-screening scenario. The authors suggest prostate cancer screening has yet to reach one of these standards to date.

No major medical group, including the American Cancer Society, currently recommends routine prostate cancer screening for men at average risk. In the United States, prostate cancer will affect one man in six men during his lifetime. Since the mid-1980s, screening with the prostate–specific antigen (PSA) blood test has more than doubled the risk of a prostate cancer diagnosis. The review says a decrease in prostate cancer death rates has been observed since that time, but the relative contribution of PSA testing as opposed to other factors, such as improved treatment, has been uncertain.

The report says a computer modeling study using National Cancer Institute's Surveillance, Epidemiology, and End Results (SEER) registries estimated that more than one in four cancers detected in whites (29 percent) and nearly half of cancers detected in blacks (44 percent) were overdiagnosed cancers. A similar model using data from Europe estimated a 50 percent overdiagnosis rate. The authors say patients who are diagnosed with clinically insignificant tumors are subject to unnecessary diagnostic tests and unneeded treatment and suffer psychosocial harms. They are also labeled "a cancer patient," which can have negative economic consequences. Also, say the authors, overdiagnosis significantly affects 5–year survival statistics, making them uninformative in demonstrating progress in cancer control.

The report says the future of prostate cancer will include better screening tests, better methods to assess a man's risk of prostate cancer, and prevention strategies, including the use of finasteride, a drug currently used for the treatment of urinary symptoms related to prostate enlargement.

In a separate but related editorial, Peter Boyle, Ph.D., D.Sc., of the International Prevention Research Institute, Lyon, France and report co-author Dr. Brawley say "the real impact and tragedy of prostate cancer screening is the doubling of the lifetime risk of a diagnosis of prostate cancer with little if any decrease in the risk of dying from this disease." They say in 1985, before PSA screening was available, an American man had an 8.7 percent lifetime risk of being diagnosed with prostate cancer and a 2.5 percent lifetime risk of dying from the disease. Twenty years later, in 2005, an American man had a 17 percent lifetime risk of being diagnosed with prostate cancer and a 3 percent risk of dying from the disease. They add that even in the best case scenario, applying the findings of a European trial that found PSA led to a 20 percent reduction in the risk of death, the average man who chooses screening decreases his risk of prostate cancer death from a lifetime risk of 3 percent to a lifetime risk of 2.4 percent. In exchange, he doubles the chances of becoming a prostate cancer patient, his risk of diagnosis rising from about nine percent to at least 17 percent.

They conclude that "men should discuss the now quantifiable risks and benefits of having a PSA test with their physician and then share in making an informed decision," and that "the weight of the decision should not be thrown into the patient's lap."

Exercise Fights Breast Cancer: 2 Studies

Physically Fit Women Less Likely to Die from Breast Cancer

Physically fit women are less likely to die from breast cancer, according to a study by researchers at the University of South Carolina Arnold School of Public Health.

The findings are published in the April issue of Medicine & Science in Sports & Exercise®, the official scientific journal of the American College of Sports Medicine.

The study of more than 14,000 women found that those with moderate or high aerobic fitness levels were much less likely to die from breast cancer, said Dr. Steve Blair, an Arnold School researcher and a past president of the American College of Sports Medicine.

“Women in the study’s lowest fitness category were nearly three times more likely to die from breast cancer than women in the most fit group,” he said.

“We believe this is the first study to evaluate the association of objectively measured fitness and risk of dying from breast cancer,” he said. “The results suggest a stronger protective effect than has been seen in most studies on self-reported physical activity and breast cancer, probably because the objective laboratory test of fitness is more accurate that self-reports of activity.”

Blair and his research team studied women from 20 to 83 years of age who had no previous history of breast cancer. The study participants received an initial medical examination that included a maximal exercise test on a treadmill, between 1973 and 2001, and were monitored for breast cancer mortality through 2003.

“The good news is that women who do at least 150 minutes of moderate-intensity activity, like walking, per week will escape the low fitness category,” he said. “Even better for some women, this activity can be accumulated in 10-minute bouts.”

This level of exercise meets the federal “Physical Activity Guidelines for Americans” recommendations, and can be easily achieved in 30 minutes of exercise five days/week.

To develop the highest fitness category in this study, Blair said, women should aim for the “high activity” level recommended by federal guidelines, which includes 300 minutes of moderate-intensity activity, such as walking, over the course of the week. This can be achieved through 150 minutes/week of more vigorous activity, such as jogging or taking an aerobics class.

“With more than 40,000 women dying each year from this disease, finding a strong association between fitness, which can be improved by the relatively inexpensive lifestyle intervention of regular physical activity, such as walking, is exciting,” Blair said.

In addition, the study found that women with high aerobic fitness had lower body mass index, better cholesterol levels, lower blood pressure, and fewer chronic conditions such as diabetes and cardiovascular disease.

“This study is more evidence that physical activity is critical to health across our lifespan,” Blair said.

The study’s findings correlate with the message of ACSM’s Exercise is Medicine™ program, which calls for physical activity to be a standard part of health care and preventive treatment.



Study Examines Power of Exercise to Prevent Breast Cancer



Women With Family History May Cut Their Risk Through Regular Workouts





A new federally funded University of Pennsylvania School of Medicine study aims to learn whether women at high risk of breast cancer can use exercise to meaningfully reduce their risk of getting the disease. Building on evidence that reducing estrogen in the body reduces cancer risk, and that elite female athletes experience a drop in estrogen levels that often cause them to stop ovulating and menstruating, the WISER Sister trial will investigate two different levels of regular treadmill exercise as a possible intervention for breast cancer risk reduction.

The stakes for women who carry BRCA genetic mutations are high – as many as 80 percent of them will develop breast or ovarian cancer during their lives – but options for risk reduction are drastic and few, and the choices may be unacceptable to some women. Previous Penn research shows that prophylactic mastectomy slashes carriers’ breast cancer risk by 90 percent, while prophylactic oophorectomy, or ovary removal, halves their breast cancer risk and reduces their chances of getting of ovarian cancer by about 85 to 90 percent. Though the surgeries are highly effective, they usher in quality of life concerns – particularly with regard to body image and sexuality – and the early menopause that results from ovary removal brings a woman’s childbearing years to an end. And the procedures aren’t recommended for women who have a family history of breast cancer but don’t carry the mutated genes.

“The decision to have these surgeries is so difficult that many women delay them, sometimes with terrible consequences. We would like to find out if exercise could buy high-risk women time they need to more safely think through their options,” says Kathryn Schmitz, PhD, MPH, an assistant professor in the Center for Clinical Epidemiology and Biostatistics who is leading the new study, in partnership with Susan Domchek, MD, director of the Abramson Cancer Center’s Cancer Risk Evaluation Program. “Exercise also has a number of health and stress reduction benefits that make it even more attractive for this population.”

Over the next three years, Schmitz's team will enroll 160 women ages 18 to 40, who must have an elevated risk of getting breast cancer based on her family history of the disease. BRCA carriers will be included among eligible women. However, participants will not be required to undergo genetic testing.

Previous research on estrogen exposure strongly suggests that reducing estrogens will result in reduced breast cancer risk in this population. The investigators plan to use their findings to offer effective exercise guidelines for high-risk women. Unlike surgery, exercise is a low-cost intervention with few side effects, so Schmitz is hopeful that the study results will offer risk-reduction tools to a larger swath of high-risk women, including minorities and other groups that may be underserved or lack access to genetic testing or proper early screening.

“We are interested in rigorously investigating all potential options to decrease cancer risk,” says Domchek, an associate professor of Medicine in the division of Hematology/Oncology. “Exercise is a wonderful intervention due to its numerous health benefits. However, it is important for us to quantify the amount of exercise needed and the potential benefits such exercise might provide.”

Although it is unknown how much the exercise interventions tested in the trial will reduce estrogen exposure, Schmitz says even evidence of marginal risk reduction -- that exercise may help delay breast cancer onset, decrease breast density to improve the accuracy of early screening tests, or result in smaller tumors -- could be of help to women planning risk reduction strategies during their 20s and 30s.

Trial participants will be placed into three randomized groups who will be followed for seven months. Each participant will receive a treadmill to use at home, which she will get to keep after the study is over. A “low dose” group will complete 150 minutes of exercise each week, the same amount recommended for general health and fitness, while a “high dose” group will do 300 minutes of exercise each week, similar to the workouts recommended for weight control. A third group, serving as the control, will continue doing their usual activities for the duration of the study and will receive the treadmill at the end of study completion.

Each woman will give daily urine samples at points during the trial, which will allow investigators to measure their levels of estrogen, progesterone and other sex hormones. The women’s body composition will also be measured, and they will receive breast MRIs at no cost to them before and after the study to examine changes in the density of their breast tissue.

“It is frightening to face high risk for breast cancer at a young age. Most of us think of cancer as something that happens later in life. Young women may not even want to approach the issue of getting genetic testing yet, but may want to do something. The WISER Sister study offers those women an option,” Schmitz says. “The benefits of the study will have a ripple effect to other good health habits, too, by helping women adopt a regular exercise regimen.”

Exercise Reduces Migraine Suffering

While physical exercise has been shown to trigger migraine headaches among sufferers, a new study describes an exercise program that is well tolerated by patients. The findings show that the program decreased the frequency of headaches and improved quality of life. The study is published in Headache: The Journal of Head and Face Pain.

The study used a sample of migraine sufferers who were examined before, during and after an aerobic exercise intervention. The program was based on indoor cycling (for continuous aerobic exercise) and was designed to improve maximal oxygen uptake without worsening the patients’ migraines.

After the treatment period, patients’ maximum oxygen uptake increased significantly. There was no worsening of migraine status at any time during the study period and, during the last month of treatment, there was a significant decrease in the number of migraine attacks, the number of days with migraine per month, headache intensity and amount of headache medication used.

Individuals with headache and migraine typically are less physically active than those without headache. Patients with migraine often avoid exercise, resulting in less aerobic endurance and flexibility. Therefore, well designed studies of exercise in patients with migraine are imperative.

“While the optimal amount of exercise for patients with migraine remains unknown, our evaluated program can now be tested further and compared to pharmacological and non-pharmacological treatments to see if exercise can prevent migraine,” says Dr. Emma Varkey, co-author of the study.

Exercise keeps the brain young

New research from the University of North Carolina at Chapel Hill School of Medicine finds that aerobic activity may keep the brain young.

In the study published July 9 in the American Journal of Neuroradiology, physically active elderly people showed healthier cerebral blood vessels.

Researchers led by Elizabeth Bullitt, M.D., Van L. Weatherspoon Distinguished Professor of neurosurgery, used non-invasive magnetic resonance (MR) angiography to examine the number and shape of blood vessels in the brains of physically active elderly people, 7 men and 7 women, ages 60 to 80.

The study subjects were equally divided into 2 groups. The high activity group reported participating in an aerobic activity for a minimum of 180 minutes per week for the past 10 consecutive years, and the low activity group told investigators they had no history of regular exercise and currently spent less than 90 minutes a week in any physical activity. (The researchers did not know into which group participants were placed.)

This is the first study to compare brain images of elderly subjects who exercise with those that do not.

Aerobically active subjects exhibited more small-diameter vessels with less tortuosity, or twisting, than the less active group, exhibiting a vessel pattern similar to younger adults.

The authors, who were sponsored in part by the National Institutes of Health’s National Institute of Biomedical Imaging and Bioengineering, identified significant differences in the left and right middle cerebral artery regions confirmed by more than one statistical analysis.

The brain’s blood vessels naturally narrow and become more tortuous with advancing age, but the study showed the cerebrovascular patterns of active patients appeared “younger” than those of relatively inactive subjects. The brains of these less active patients had increased tortuosity produced by vessel elongation and wider expansion curves.

The pilot study lays the foundation for future research to determine whether aerobic activity improves anatomy, if older patients with “younger” brains are more likely to engage in physical activity, and whether elderly adults who begin a program of aerobic activity can reverse the cerebrovascular, anatomic and functional changes associated with advancing age.

Friday, June 26, 2009

Latest Health Research Summary

There's an awful lot of interesting new health research published this week –the most exciting to me was the news that Overweight People Live Longest! My weight has always been pointed out as an increased health risk, and is probably the reason I try to do everything possible to protect my health (except lose weight, which I simply cannot seem to do, and even if I could, I am convinced that I would gain it back soon anyhow.) It’s great to know that it’s not such a problem after all – now if I could only convince my life insurance company.

Other new, not such good news: eating white bread and other high glycemic products can give you a heart attack.

Selenium can prevent prostate cancer, or make it worse, confirming other research that has suggested that antioxidants could be protective if you don't have cancer, but once you do, then antioxidants may be a bad thing, but green tea fights prostate cancer.

Just when I thought I had found a viable alternative to statins more evidence comes to light about all the great things statins do, (in addition to their main function of reducing cholesterol and thus preventing heart attacks), like:
fighting liver cancer and gall bladder disease,

improving lung function
and urologic health
now we find that statins fight Alzeihemer’s.

I had previously written about the benefits of the Mediterranean diet here and here.

Now new research focuses in on what parts of the diet are actually beneficial:
“Eating more vegetables, fruits, nuts, pulses (beans, peas and lentils) and olive oil, and drinking moderate amounts of alcohol, while not consuming a lot of meat or excessive amounts of alcohol is linked to people living longer.

However, the study also claims, that following a Mediterranean diet high in fish, seafood and cereals and low in dairy products were not indicators of longevity.”

There’s a new wonder supplement that makes you more fit without exercise: Quercitin (but watch out, its an anti-oxidant)

I have written often about the benefits of Vitamin D, including here and here.

But here’s even more new research:

Vitamin D may go beyond its traditionally known role in maintaining bone integrity. It may play a role in preventing autoimmune diseases such as multiple sclerosis and rheumatoid arthritis, , some types of cancer (breast, ovarian, colorectal and prostate), types I and II diabetes—possibly even schizophrenia...
Research also shows a correlation between high vitamin D status and improved lower body muscle function in men and women over 60 years old.”


And last, and yes, least, in addition to its other health benefits, drinking black coffee fights bad breath.