Health news worldwide - October/November 2006

Postmenopausal women who want to significantly decrease their breast-cancer risk would be wise to exercise regularly and keep their weight within a normal range for their height, according to new findings from the Women's Health Initiative to be published in the journal Obesity.

The multicenter team of researchers, led by Anne McTiernan, M.D., Ph.D., of Fred Hutchinson Cancer Research Center, found that women who had the lowest body-mass index, or BMI, and the highest physical-activity levels had the lowest levels of circulating estrogens, sex hormones that can fuel breast-cancer growth.

Specifically, they found a significant decrease in the two most common, biologically active forms of estrogen, estrone and estradiol, among the most active, lean women studied. The researchers found that women with high BMI and low physical-activity had mean estrogen concentrations that were 50 percent to 100 percent higher than that of women with low BMI and high activity levels.

"Women with high levels of estrogens have a two-to-four-times-higher risk of breast cancer than women with very low levels," said McTiernan, a member of the Hutchinson Center's Public Health Sciences Division and co-investigator of the Women's Health Initiative Clinical Coordinating Center, which is based at the Center. "If a woman can keep her own natural estrogens lower after menopause, it is probably going to be beneficial in terms of reducing her risk of breast cancer."

The study, based on a random sample of 267 postmenopausal women nationwide selected from the WHI Dietary Modification Trial, is the first of its kind to examine the dual impact of body weight and physical activity on levels of various circulating sex hormones thought to impact cancer risk.

"Other studies have looked at the impact of body weight by itself or physical activity by itself but this is the first to look at both together regarding their influence on hormone levels," McTiernan said. "This gives us a new understanding that combining weight control with high levels of physical activity is necessary for keeping estrogens at a healthy level in postmenopausal women." Exercising vigorously for 30 to 60 minutes a day, five days a week would achieve this benefit, McTiernan said.

The National Heart, Lung and Blood Institute, U.S. Department of Health and Human Services, funded the study, which also involved investigators from Harbor-UCLA Research and Education Institute, Albert Einstein College of Medicine, University of Pittsburgh, University of Florida, University of Southern California and Northwestern University.

Public release date: 9-Oct-2006

Stroke symptoms common among general population

As many as 18 percent of adults who have no history of stroke report having had at least one symptom of stroke, according to results of a large national study published in the Archives of Internal Medicine.

Using brain imaging to screen individuals without a history of stroke reveals that many have had an undiagnosed or silent stroke, according to background information in the article. One previous study found that 11 percent of individuals age 55 to 64, 22 percent of those ages 65 to 69 and 43 percent of those older than 85 years show evidence of stroke despite never having been diagnosed with the condition. Because awareness of stroke symptoms is low, it is possible that these individuals had symptoms but did not recognize them or that the symptoms did not reach the threshold necessary for a stroke diagnosis.

Virginia J. Howard, M.S.P.H., of the University of Alabama at Birmingham, and colleagues analyzed data from the REasons for Geographic and Racial Differences in Stroke (REGARDS) study, a random sample of 18,462 adults older than 45 years (average age 65.8) who had not been diagnosed with stroke. To ensure including many individuals at risk for stroke, the researchers included 7,567 African Americans (41 percent of the total sample, a higher ratio than in the general population) and 6,534 (35.4 percent of the sample) residents of the so-called "stroke belt," which includes eight Southeastern states with increased rates of stroke. In telephone interviews, participants provided information about demographics, general quality of life and medical history, including whether a physician had ever told them they had a stroke and whether they had experienced the sudden onset of any of six stroke symptoms. Brief physical examinations were conducted three to four weeks later. A stroke risk score was calculated for each individual based on demographics, behaviors and other risk factors, with higher scores indicating a greater risk for stroke.

A total of 3,292 (17.8 percent) of the participants reported having had one or more stroke symptoms. Eight and one-half percent reported sudden numbness on one side of the body; 5.8 percent sudden weakness on one side of the body; 4.6 percent sudden vision loss in one or both eyes; 2.7 percent sudden loss of the ability to understand what others were saying; and 3.8 percent suddenly could not express themselves in speech or writing.

"The last finding suggests that at least some of these symptoms may represent stroke events that did not reach the threshold required for clinical diagnosis," the authors write. "These undiagnosed or unrecognized events could have a substantial impact on cognitive functioning or personality and could also be powerful harbingers of subsequent major strokes."

It is not known whether these individuals visited a physician for their symptoms, but previous studies have shown that many people do not seek medical care for stroke symptoms and if they do, they do not seek it immediately. "Targeted education on the warning signs of stroke and risk factor reduction efforts for individuals who report stroke symptoms may be helpful in improving early recognition and in the prevention of stroke," the authors conclude.

Public release date: 8 October 2006

10 top Australian scientists predict major medical advances

Within a decade Australians will be able to find out how good their genes are at fighting disease, which environmental risks they are susceptible to and steps they should take to prevent the onset of ill-health. And by the turn of the century it will be commonplace to have a bad combination of genes repaired to avoid disease.

'Then, Now...Imagine', a new report compiled by Research Australia in consultation with 10 of the country's leading health and medical researchers including two Nobel Prize winners and four Australians of the Year, predicts individual gene profiling from blood samples will revolutionise healthcare within ten years.

2006 Australian of the Year, Professor Ian Frazer, who discovered the technology that led to the newly released cervical cancer vaccine, said the upshot will be the ability to develop personalised healthcare plans - a roadmap for health from the day of birth.

"Doctors will be able to predict what health problems we might get so we can take appropriate precautions. They will also be able to assess what treatments will work best on an individual basis to achieve optimum health results. Long-term it will be possible to avoid certain diseases altogether through gene therapy," he said.

The report has been released by Research Australia to commemorate "Thank You" Day (14 November 2006), Australians' annual opportunity to send personal messages of appreciation to medical researchers whose work is special to them via www.thankyouday.org or 0428THANKS.

Five other key forecasts

Growing new body parts

Further advances in understanding how 'blank' or 'uncoded' cells in their very early stages of development switch on to become specific types of cells, like liver, skin and nerve cells, mean cures for diseases like Parkinson's, Diabetes and Multiple Sclerosis will be entirely possible. With the right prompts these 'stem cells' - which everybody has - can develop into organs and tissue to replaced damaged areas.

Smart drugs

As a result of DNA technology 'smart drugs' will increasingly be used to target cancer at the source. Current chemotherapy attacks all cells in the body with healthy ones recovering first. One of the first smart drugs, Herceptin, binds to the surface of specific breast cancer cells and slows their ability to reproduce. With further research, more smart drugs with increasing power will be available for all manner of cancers, reducing the trauma of treatment and dramatically improving outcomes.

A Raft of New Vaccines

The world-first cervical cancer vaccine is only the first of its kind. Scientists predict viruses will be found to play a role in many other cancers and in the course of the next few decades we can expect a raft of new vaccines to prevent their onset.

Therapeutic vaccines are also well advanced in development and involve re-educating the immune system to recognise cancer cells as intruders and attack them.

And over the next few decades we are likely see vaccines for many viral infections like HIV/AIDS and Hepatitis C, and for major diseases like diabetes. In fact Melbourne's Diabetes Vaccine Development Centre is about to start clinical trials for a new vaccine for Type 1 Diabetes.

Building New Nerve Pathways

Australian-invented bionic ears, or Cochlear implants, that allow deaf children to hear will be further advanced to deliver high-fidelity hearing, with a carbon tube built molecule by molecule carrying the electricity needed to stimulate nerve cells.

This technology will also be applied to other disabilities. We will be able to reconnect electrical wiring in damaged spinal columns, stimulate nerve growth and allow messages to be relayed to the brain. Further into the future, this could ultimately allow quadriplegics and paraplegics to walk again. Other applications are likely to include correcting the faulty circuits that create epileptic episodes and creating transport systems for slow release of insulin to diabetics.

Operating before birth

Advances in microsurgery and the capacity of ultrasound to monitor development will soon see unborn babies undergoing complex surgery to correct abnormalities like holes in the heart and facial malformations, strengthening their chances of survival and improving their quality of life.

Scientists Who Contributed To 'Then, Now...Imagine'

Dr Robin Warren, Nobel Laureate 2005 - with Barry Marshall, proved a bacteria called helicobacter pylori caused gastritis and stomach ulcers and that most ulcers could be permanently cured with antibiotics.

Professor Peter Doherty, Nobel Laureate 1996 - Discovered that T-cells, the foot soldiers in our bloodstream, were expert at killing cells that had viruses locked inside. This has led to new and better vaccines, healthy organ transplants and better treatment of conditions like Multiple Sclerosis and Diabetes.

Professor Ian Frazer, Australian of the Year 2006 - Gained international fame for developing the world's first vaccine to combat cervical cancer.

Dr Fiona Wood, Australian of the Year 2004 - Headed up the team of doctors who treated the burns victims of the 2002 Bali bombing. Her use of 'spray on skin' sped up the recovery process for those who had suffered horrific burns.

Professor Fiona Stanley, Australian of the Year 2003 - With Carol Bower, as part of an international collaboration, discovered the link between folate intake and spina bifida. This led to women being advised to increase folate intake before and during pregnancy and supplementation of some foods with folate.

Sir Gustav Nossal, Australian of the Year 2000 - Discovered the magic 'one cell-one antibody' rule which led to the development of effective new therapies for heart disease, breast cancer and severe arthritis.

Professor Terry Dwyer - Led the team which proved the link between a baby's sleeping position and Sudden Infant Death Syndrome. They found that a baby sleeping on its stomach has ten times the risk of SIDS than babies who sleep in other positions.

Professor Graeme Clark - Pioneered the multiple-channel cochlear implant which has brought hearing and speech understanding to tens of thousands of people with severe-to-profound hearing loss in more than 70 countries.

Professor Judith Whitworth - Discovered how steroids raise blood pressure. Former Chief Medical Officer for the Commonwealth Department of Health and Family Services and current Chair of the World Health Organisation (WHO) Global Advisory Committee on Health Research.

Professor John Shine - First to clone a human hormone gene and discovered a gene sequence, the Shine-Dalgarno sequence, which is important for the control of protein synthesis. Former Chair of the National Health and Medical Research Council and current member of the Prime Minister's Science, Engineering & Innovation Council.

Public release date: 6 October

Consuming cola may up osteoporosis risk for older women

Epidemiological study finds that cola is associated with bone mineral density loss

In Australia osteoporosis, a disease of porous and brittle bones that causes higher susceptibility to bone fractures, affects 1 in 2 women and 1 in 3 men over the age of 60 years.

Katherine Tucker, PhD, director of the Epidemiology and Dietary Assessment Program at the Jean Mayer USDA Human Nutrition Research Center on Aging at Tufts University, and colleagues have reported findings in the American Journal of Clinical Nutrition that cola, a popular beverage for many people, may contribute to lower bone mineral density in older women, a condition which increases risk for osteoporosis.

Tucker, also a professor at the Friedman School of Nutrition Science and Policy at Tufts, and colleagues analysed dietary questionnaires and bone mineral density measurements at the spine and three different hip sites of more than 2,500 people in the Framingham Osteoporosis Study whose average age was just below 60. In women, cola consumption was associated with lower bone mineral density at all three hip sites, regardless of factors such as age, menopausal status, total calcium and vitamin D intake, or use of cigarettes or alcohol.

However, cola consumption was not associated with lower bone mineral density for men at the hip sites, or the spine for either men or women. The results were similar for diet cola and, although weaker, for decaffeinated cola as well.

Men reported drinking an average of six carbonated drinks a week, with five being cola, and women reported consuming an average of five carbonated drinks a week, four of which were cola. Serving size was defined as one bottle, can or glass of cola. "The more cola that women drank, the lower their bone mineral density was," says Tucker, who is corresponding author of the study. "However, we did not see an association with bone mineral density loss for women who drank carbonated beverages that were not cola."

"Carbonated soft-drink consumption increased more than three-fold" between 1960 and 1990, cite the authors. They also note that more than 70 percent of the carbonated beverages consumed by people in the study were colas, all of which contain phosphoric acid, an ingredient that is not likely to be found in non-cola carbonated beverages.

While previous studies have suggested that cola contributes to bone mineral density loss because it replaces milk in the diet, Tucker determined that women in the study who consumed higher amounts of cola did not have a lower intake of milk than women who consumed fewer colas. However, the authors did conclude that calcium intake from all sources, including non-dairy sources such as dark leafy greens or beans, was lower for women who drank the most cola. On average, women consumed 1,000 milligrams of calcium per day, and men consumed 800 milligrams per day, both lower than the daily recommended 1,200 daily milligrams for adults over age 50.

"Physiologically, a diet low in calcium and high in phosphorus may promote bone loss, tipping the balance of bone remodeling toward calcium loss from the bone. Although some studies have countered that the amount of phosphoric acid in cola is negligible compared to other dietary sources such as chicken or cheese," Tucker says, "further controlled studies should be conducted to determine whether habitual cola drinkers may be adversely affecting their bone health by regularly consuming doses of phosphoric acid that do not contain calcium or another neutralizing ingredient."

Tucker stresses that as with any epidemiological study, the results should be taken with caution. "We are not certain why women who drank more cola also had lower bone mineral density," says Tucker. Although adjustment for fruit juice intake did not change results, women in the study who drank a considerable amount of cola not only consumed less calcium, but less fruit juice as well. Previous studies have also shown that low fruit and vegetable intake may affect bone mineral density.

The message from experts is clear that overall nutritional choices can affect bone health, but "there is no concrete evidence that an occasional cola will harm the bones," says Tucker. "However, women concerned about osteoporosis may want to steer away from frequent consumption of cola until further studies are conducted."

Public release date: 6 October

Prescribe exercise for older adults for better health

For many older adults, a visit to the doctor is not complete without the bestowal of at least one prescription.

What if, in addition to prescribing medications as necessary, physicians also prescribed exercise? Ann Yelmokas McDermott, PhD, a researcher in the Lipid Metabolism Laboratory at the Jean Mayer USDA Human Nutrition Research Center on Aging (USDA HNRCA) at Tufts University, and Heather Mernitz, PhD, now of the Nutrition and Cancer Biology Laboratory at the USDA HNRCA, propose using the familiar concept of a prescription to help physicians incorporate exercise recommendations into their routine practice. In the journal American Family Physician, McDermott and Mernitz provide clinicians with explicit guidelines for giving their older patients effective "exercise prescriptions."

Their motto for determining an exercise prescription is 'FITT-PRO':

Frequency
Intensity
Type
Time
Progression

According to FITT-PRO principles, an exercise prescription must explicitly instruct the patient regarding what type of exercise to do, how often, how hard, and for how long. The exercises must also progress over time as the patient becomes more physically fit. McDermott and Mernitz caution that, as with medication prescriptions, these exercise parameters must be personalized to suit each patient's health status and goals.

McDermott, who is also a licensed nutritionist, points out that fewer than half of older adults report ever having received a suggestion to exercise from their physicians. "Clinicians shouldn't feel like they have to be fitness experts to discuss exercise with their patients," she says. "These guidelines are intended to serve as a how-to manual for health care providers." The article provides sample prescriptions, as well as instructive tables and figures for clinicians to follow in creating individualized exercise prescriptions for their patients.

The authors explain, "There are four ways to improve physical fitness: aerobic exercise, resistance training, flexibility, and lifestyle modification." All programs should include combinations of these types of activities, and be tailored toward the individual's fitness goals. "For example," McDermott says, "when the goal is to improve functional capacity in activities of daily living, a cross-training program emphasizing the core muscle groups of the back, thighs, and abdomen is preferred."

"Only 30 percent of America's senior citizens engage in regular exercise," notes McDermott, "yet there is compelling evidence suggesting that people in all conditions of health and at all fitness levels benefit from regular physical activity. In fact, the most de-conditioned individuals have the greatest and fastest response." Mernitz adds, "Seniors tend to have less access than other demographic groups to physical activity information and programming. In contrast, they have relatively more contact with their health care providers."

"Starting an exercise program later in life can significantly modify risk factors, even if a person has been sedentary in prior years," McDermott concludes. "Health care providers can play a major role in offering effective and inexpensive primary or adjunct therapies, encourage appropriate physical activity, and dispel myths that persist as barriers to exercise in the elderly."

Among the useful resources McDermott and Mernitz reference is a book created by colleagues at the John Hancock Center for Physical Activity and Nutrition at the Friedman School of Nutrition Science and Policy at Tufts University, along with experts from the Centers for Disease Control and Prevention (CDC). The book, available as a PDF on the CDC web site, is called Growing Stronger: Strength Training for Older Adults, and contains detailed explanations and useful illustrations of strength-training exercises. It is intended to help seniors make strength training part of a regular exercise routine.

Public release date: 5 October

Fruit juice intake among preschool children not associated with weight

Consumption of 100 percent fruit juices is not linked with US preschoolers being overweight, finds a new research study just published. This latest analysis of the largest US government database on food consumption (NHANES - National Health and Nutritional Examination Survey 1999-2002) finds no connection between 100 percent fruit juice consumption and weight status among preschool children ages 2 to 5.

In this new study published in October Pediatrics, researchers looked at data accumulated over several years and conclude there is no association between preschoolers' 100 percent fruit juice consumption and body mass index (BMI), even among those children who consume the most juice (greater than 12 ounces a day). The BMI used in this study is a number calculated from a child's weight and height and is based on special criteria established for children by the Centers for Disease Control and Prevention.

"These findings support conclusions from several previous research studies that also have found no connection between 100 percent fruit juice consumption and overweight status in preschoolers," says Sue Taylor, R.D., director of nutrition communications for the Juice Products Association.

This latest research concludes that while increased consumption of 100 percent fruit juice, and increased intake of other beverages, is associated with increased total caloric intake, it does not translate into increased BMI. The research paper states that this analysis "suggests that preschool children are consuming, on average, appropriate amounts of 100 percent juice." The data show that mean consumption of 100 percent fruit juice among preschool children was 4.7 ounces. This amount is well within guidelines established by the AAP of 4-6 ounces per day as being appropriate juice consumption levels for the ages of the children studied.

The importance of 100 percent fruit juices in the diet was recently confirmed in the U.S. government's 2005 Dietary Guidelines Advisory Committee Report. This report states that with the exception of fiber, fruit juices provide several vitamins and minerals in higher amounts than do whole fruits. These nutrients include vitamin C, potassium and magnesium.

"100 percent juices, along with fruits and vegetables, also contain many phytonutrients not found in other foods or beverages," notes Taylor.

Consumed in moderation, 100 percent fruit juices provide an excellent complement to whole fruit intake and can play a vital role in increasing total fruit consumption in preschooler's diets.

Public release date: 26 September 2006

New study finds a positive association between periodontal disease and coronary heart disease

Periodontal disease and coronary heart disease are widespread conditions; therefore, an association between the two is an important scientific subject from a preventive outlook.

Researchers found an increased risk of coronary heart disease for people below the age of 60 who have more than four millimeters of alveolar bone loss (the bone that holds the teeth in the mouth) from periodontal disease, according to a new study in the Journal of Periodontology.

It was found that participants with coronary heart disease had an increase of periodontal disease indicators, including alveolar bone loss, clinical attachment loss and bleeding compared to the group without coronary heart disease.

"This study is distinctive because to our knowledge, it is the first to include both the alveolar bone loss and full mouth recording of clinical attachment loss as measurements of periodontal disease," explains Dr. Karen Geismar, Department of Periodontology, School of Dentistry, Faculty of Health Science, University of Copenhagen, Denmark. "Alveolar bone loss was recently found to be the periodontal variable that had the strongest association to coronary heart disease."

The association between periodontal disease and coronary heart disease has been that chronic infections and the inflammatory response from diseases such as periodontal disease may be involved in the initiation and progression of atherosclerosis.

"A number of pathways are suspected to be involved," said Geismar. "One way is that periodontal bacteria directly invade the arterial wall and another way is that bacterial products from the periodontal pocket exert a systemic effect on atherosclerosis development based on the immune system."

"This is one of many studies suggesting that the spread of bacteria and bacterial products from the periodontal lesion to the bloodstream may contribute to coronary heart disease," said Preston D. Miller, DDS and AAP President. "However, it is still uncertain whether or not the association between periodontal disease and coronary heart disease is causal. Until we know more, it is very important that people talk to their dentist or periodontist about their periodontal health."

Public release date: 18 September

'No time to exercise' is no excuse

A new study, published in The Journal of Physiology, shows that short bursts of very intense exercise - equivalent to only a few minutes per day - can produce the same results as traditional endurance training.

"The most striking finding from our study was the remarkably similar improvements in muscle health and performance induced by two such diverse training strategies," says Martin Gibala, an associate professor of kinesiology at McMaster University.

Gibala's team made headlines last year when they suggested that a few minutes of high-intensity exercise could be as effective as an hour of moderate activity. However, their previous work did not directly compare sprint versus endurance training.

The new study was conducted on 16 college-aged students who performed six training sessions over two weeks. Eight subjects performed between four and six 30-second bursts of "all out" cycling separated by 4 minutes of recovery during each training session. The other eight subjects performed 90-120 minutes of continuous moderate-intensity cycling each day. Total training time commitment including recovery was 2.5 hours in the sprint group, whereas the endurance group performed 10.5 hours of total exercise over two weeks. Despite the marked difference in training volume, both groups showed similar improvements in exercise performance and muscle parameters associated with fatigue resistance.

"Our study demonstrates that interval-based exercise is a very time-efficient training strategy," said Gibala. "This type of training is very demanding and requires a high level of motivation. However, short bursts of intense exercise may be an effective option for individuals who cite 'lack of time' as a major impediment to fitness."

*The inclusion of the above links does not imply any endorsement of the linked website or information.

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Content created October 11, 2006
Page updated April 29, 2008

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