Colonoscopy Reduces Advanced Cancer Risk by 70 Percent

A new study finds that getting screening colonoscopies may reduce the risk of developing advanced colon cancer.

In average-risk people, screening colonoscopies were associated with a 70 percent reduction in risk for new, late-stage colon cancer, including hard-to-detect cancers on the right side of the colon. Advanced colon cancer is the least curable form.

Although colonoscopy is widely used as a screening test for colon cancer, there is little research that proves it is effective in reducing colon cancer deaths, according to the study authors. The researchers wanted to answer a simple question: If you ended up with late-stage cancer, were you more or less likely to have had a screening colonoscopy as many as 10 years before the disease was discovered?

The study authors also wanted to show whether a colonoscopy is able to evaluate the entire colon, including the right side, which is harder to adequately cleanse before the test, more difficult to reach, and often has pre-cancerous areas that are tougher to spot and identify.

"Colonoscopy has the ability to identify both left- and right-sided colon cancers before they have progressed to an advanced stage," said lead study author Dr. Chyke Doubeni, associate professor in the department of family medicine at the University of Pennsylvania.

The researchers also discovered that screening sigmoidoscopy, a less costly procedure that enables a physician to look at the part of the large intestine closest to the rectum, was linked to a significant reduction in late-stage disease in most of the large intestine, but not in the right colon.

However, the study does not show that colonoscopy or sigmoidoscopy is better than the much easier, far less expensive "fecal occult blood test" (FOBT), which is done at home by swiping a tiny amount of stool onto a card for three days, said Doubeni. "There is strong evidence showing the effectiveness of the [fecal occult blood test] when done annually. There is no reason, based on the knowledge we currently have, that you should switch to a colonoscopy if you're getting a FOBT every year," said Doubeni.

If simpler tests are effective, why are patients encouraged to undergo a colonoscopy? "Let me just say there are other factors beyond the evidence that are driving the use of colonoscopy in the U.S.," said Doubeni. "No other country uses colonoscopy for screening purposes as much as the United States, although Germany comes close," he noted.

The U.S. Preventive Services Task Force recommends that people 50 to 75 years old be screened for colon cancer in one of three ways: a home fecal occult blood test every year; a sigmoidoscopy every five years combined with a home fecal occult blood test every three years; or a colonoscopy every 10 years.

A colonoscopy examines the inside of the large intestine with a camera-tipped tube. The test enables the physician to remove any precancerous growths -- adenomatous polyps -- which sometimes develop into cancer. Colorectal tumors are a major cause of death from cancer in the United States, with about 137,000 new cases and 52,000 deaths every year, according to the U.S. Centers for Disease Control and Prevention.

For the study, published in the March 5 issue of the Annals of Internal Medicine, the authors reviewed health records of more than 1,000 average-risk adults between the ages of 55 and 85 who were members in four health management organizations (HMOs).

The researchers identified 474 people with late-stage colon cancer and then looked back 10 years to see if they had been screened for the disease with colonoscopy or sigmoidoscopy. They compared them to 538 "control" patients and used additional information from state or local tumor registries to see whether there was an association between having had a colonoscopy or sigmoidoscopy and developing cancer.

Dr. David Bernstein, a gastroenterologist at North Shore University Hospital in Manhasset, N.Y., said the study had a critical design flaw. "Making assumptions that any cancers that were found would have been seen 10 years prior doesn't make sense," he said. "It doesn't prove that these cancers didn't occur two years ago."

A key part of effective colon screening is getting the tests at the recommended interval, experts say. To better understand what might be effective in prodding people to get screening, another study published this month in the same journal found that people who were mailed a letter, a pamphlet and a fecal occult blood test kit completed recommended screening twice as often and for less cost than those who were not reminded or got automated and other reminders by nurse coaches.

Doubeni recommends something far more simple: doing the fecal occult blood test every year right around the time of your birthday.

Physical Activity and Health

by Gregory J. Colman, Dhaval M. Dave - #18858 (HE)

Abstract:

While the link between physical activity and health has been studied,
there are several limitations that persist in this literature
relating to external and internal validity of the estimates,
potential measurement error in self-reported weight and risk factors,
failure to account for physical activity beyond exercise, and failure
to separate the effects of exercise from other forms of physical
activity. This study addresses these gaps and assesses plausibly
causal effects of recreational exercise and other physical activity
(including work-related activity) on the risk factors for heart
disease, utilizing a population-based longitudinal dataset that
contains objective information on key risk factors.

There are four key patterns of results that emerge:

First, the lagged effect of physical activity is almost
always larger than the current effect. This suggests that current
risk factors, not only obesity but also high blood pressure and heart
rate, take years to develop, which underscores the importance of
consistent physical activity to ward off heart disease.

Second, in general physical activity reduces risk factors for heart
disease even after controlling, to some extent, for unobservable
confounding influences.

Third, not only recreational but work-related physical activity
appears to protect against heart disease.

Finally, there is evidence of a dose-response relationship
such that higher levels of recreational exercise and other physical
activity have a greater protective effect.

Declines in high levels of recreational exercise and other physical
activity can potentially account for between 12-30% of the increase
in obesity, hypertension, diabetes, and heart disease observed over
the sample period.

Contaminated diet contributes to phthalate and bisphenol A exposure

Even organic foods not stored, prepared or cooked in plastic containers can contain these contaminants

While water bottles may tout BPA-free labels and personal care products declare phthalates not among their ingredients, these assurances may not be enough. According to a study published February 27 in the Nature Journal of Exposure Science and Environmental Epidemiology, people may be exposed to these chemicals in their diets, even if their meals are organic and foods are prepared, cooked and stored in non-plastic containers. And children may be most vulnerable.

"Current information we give families may not be enough to reduce exposures," said Dr. Sheela Sathyanarayana, lead author on the study and an environmental health pediatrician in the University of Washington School of Public Health and at Seattle Children's Research Institute. She is an assistant professor of pediatrics at the UW School of Medicine and an attending physician at Harborview Medical Center's Pediatric Environmental Health Specialty Unit.

Phthalates and bisphenol A (BPA) are synthetic endocrine-disrupting chemicals. Previous studies have linked prenatal exposure to phthalates to abnormalities in the male reproductive system. Associations have also been shown between fetal exposure to BPA and hyperactivity, anxiety, and depression in girls.

The researchers compared the chemical exposures of 10 families, half who were given written instructions on how to reduce phthalate and BPA exposures, handouts developed by the national Pediatric Environmental Health Specialty Units, a network of experts on environmentally related health effects in children. For five days the other families received a local, fresh, organic food catered diet that was not prepared, cooked or stored in plastic containers

When the researchers tested the urinary concentrations of metabolites for phthalates and BPA, they got surprising results. The researchers expected the levels of the metabolities to decrease in those adults and children eating the catered diet.

Instead, the opposite happened. The urinary concentration for pthalates were 100-fold higher than the those levels found in the majority of the general population, The comparison comes from a study conducted by the National Health and Nutrition Examination Survey (NHANES), a program of studies managed by the Centers for Disease Control and Prevention and designed to assess the health and nutritional status of adults and children in the United States. The concentrations were also much higher for children as compared to the adults.

Then, the researchers tested the phthalate concentrations in the food ingredients used in the dietary intervention. Dairy products—butter, cream, milk, and cheese—had concentrations above 440 nanograms/gram. Ground cinnamon and cayenne pepper had concentrations above 700 ng/g, and ground coriander had concentrations of 21,400 ng/g.

"We were extremely surprised to see these results. We expected the concentrations to decrease significantly for the kids and parents in the catered diet group. Chemical contamination of foods can lead to concentrations higher than deemed safe by the U.S. Environmental Protection Agency," said Sathyanarayana.

Using the study results, the researchers estimated that the average child aged three to six years old was exposed to 183 milligrams per kilogram of their body weight per day. The U.S. Environmental Protection Agency's recommended limit is 20 mg/kg/day.

"It's difficult to control your exposure to these chemicals, even when you try," said Sathyanarayana. "We have very little control over what's in our food, including contaminants. Families can focus on buying fresh fruits and vegetables, foods that are not canned and are low in fat, but it may take new federal regulations to reduce exposures to these chemicals."

Dietary cholesterol is good for your heart?

A 98-year-old researcher argues that, contrary to decades of clinical assumptions and advice to patients, dietary cholesterol is good for your heart – unless that cholesterol is unnaturally oxidized (by frying foods in reused oil, eating lots of polyunsaturated fats, or smoking).

The researcher, Fred Kummerow, an emeritus professor of comparative biosciences at the University of Illinois, has spent more than six decades studying the dietary factors that contribute to heart disease. In a new paper in the American Journal of Cardiovascular Disease, he reviews the research on lipid metabolism and heart disease with a focus on the consumption of oxidized cholesterol – in his view a primary contributor to heart disease.

"Oxidized lipids contribute to heart disease both by increasing deposition of calcium on the arterial wall, a major hallmark of atherosclerosis, and by interrupting blood flow, a major contributor to heart attack and sudden death," Kummerow wrote in the review.

Over his 60-plus-year career, Kummerow has painstakingly collected and analyzed the findings that together reveal the underlying mechanisms linking oxidized cholesterol (and trans fats) to heart disease.

Many of Kummerow's insights come from his relentless focus on the physical and biochemical changes that occur in the arteries of people with heart disease. For example, he has worked with surgeons to retrieve and examine the arteries of people suffering from heart disease, and has compared his findings with those obtained in animal experiments.

He and his colleagues first reported in 2001 that the arteries of people who had had bypass operations contained elevated levels of sphingomyelin (SFING-oh-my-uh-lin), one of several phospholipids (phosphate-containing lipids) that make up the membranes of all cells. The bypass patients also had significantly more oxidized cholesterols (oxysterols) in their plasma and tissues than people who had not been diagnosed with heart disease.

Human cells incubated with the blood plasma of the cardiac patients also picked up significantly more calcium from the culture medium than cells incubated in the plasma of healthy patients. When the researchers added oxysterols to the healthy plasma, the proportion of sphingomyelin in the cells increased, as did the uptake of calcium.

Earlier research, including studies conducted by medical pioneer Michael DeBakey, noted that the most problematic plaques in patients with heart disease occurred at the branch-points of the arteries of the heart. Kummerow followed up on these reports by looking at the phospholipid content of the arterial walls in pigs and humans. He found (and reported in 1994) that the branch points of the arteries in humans and in swine also had significantly more sphingomyelin than other regions of the same arteries.

For Kummerow, the increase in sphingomyelin was a prime suspect in the blocked and calcified arteries of the cardiac patients. He had already found that the arteries of the newborn human placenta contained only about 10 percent sphingomyelin and 50 percent phosphatidylcholine (FOSS-fuh-tih-dul-COH-lean), another important phospholipid component of cell membranes.

"But when we looked at the arteries of people who had had bypass operations, we found up to 40 percent sphingomyelin and about 27 percent phosphatidylcholine," Kummerow said. "It took us many more years to discover that when you added large amounts of oxysterols to the cells, then the phosphatidylcholine changed to sphingomyelin."

Further evidence supported sphingomyelin's starring role in atherosclerosis. When Kummerow and his colleagues compared the blocked and unblocked arteries of patients needing second bypass operations, they found that the arteries with blockages contained twice as much sphingomyelin as the unblocked arteries. The calcium content of the blocked arteries (6,345 parts per million) was also much higher than that of the unblocked arteries (182 ppm).

Other studies had demonstrated a link between increases in sphingomyelin and the deposit of calcium in the coronary arteries. The mechanism by which this occurred was unclear, however. Kummerow's team searched the literature and found a 1967 study that showed that in the presence of certain salts (in the blood, for example), lipids like sphingomyelin develop a negative charge. This explains the attraction of the positively charged calcium to the arterial wall when high amounts of sphingomyelin are present, Kummerow said.

"So there was a negative charge on the wall of this artery, and it attracted calcium from the blood until it calcified the whole artery," he said.

Oxidized fats contribute to heart disease (and sudden death from heart attacks) in an additional way, Kummerow said. He and his collaborators found that when the low-density lipoprotein (LDL, the so-called "bad cholesterol") is oxidized, it increases the synthesis of a blood-clotting agent, called thromboxane, in the platelets.

If someone eats a diet rich in oxysterols and trans fats and also smokes, he or she is endangering the heart in three distinct ways, Kummerow said. The oxysterols enhance calcification of the arteries and promote the synthesis of a clotting agent. And the trans fats and cigarette smoke interfere with the production of a compound, prostacyclin, which normally keeps the blood fluid.

"And that causes 600,000 deaths in this country each year," Kummerow said.

Kummerow is the author of "Cholesterol Won't Kill You, But Trans Fats Could."

Moving about more could be more important than vigorous exercise to reduce isk of type 2 diabetes

New research led at the University of Leicester reveals that individuals at high risk of developing type 2 diabetes would benefit from being told to sit less and move around more often- rather than simply exercising regularly. The experts suggest that reducing sitting time by 90 minutes in total per day could lead to important health benefits.

Currently, at risk patients are advised to engage in moderate-to-vigorous physical activity (MVPA) for at least 150 mins per week. But the new study published in Diabetologia (The journal of the European Association for the Study of Diabetes) suggests that patents should in fact be advised to reduce their sedentary time (time spent moving very little or not at all, for example sitting or lying down).The research was led by Joseph Henson and colleagues from the Diabetes Research Unit, University of Leicester and National Institute for Health Research (NIHR) Leicester Loughborough Diet, Lifestyle and Physical Activity Biomedical Research Unit (BRU), UK.

Henson and colleagues analysed patients from two studies: 153 from project STAND (Sedentary Time and Diabetes study, mean age 33 years, 29% men) and the Walking Away from Diabetes study (mean age 64 years, 65% men). The team examined the extent to which sedentary time, breaks in sedentary time, MVPA and total physical activity were independently associated with cardiometabolic risk factors in a population with known risk factors for type 2 diabetes. Accelerometers were used to assess sedentary time, MVPA, and total physical activity. Breaks in sedentary time were defined as a transition from a sedentary to an active state.

The researchers found that for these patients with known risk factors for type 2 diabetes recruited from primary care, sedentary time was detrimentally associated with 2 h glucose, triacylglycerol and HDL-cholesterol, independent of measured confounders. These results remained significant after further adjustment for MVPA and adiposity.

Furthermore, the findings were consistent across groups with diverse age ranges, providing evidence that the negative consequences of excess sedentary time exist across young to old adults. Interestingly, sedentary time was shown to have stronger associations with several important cardiometabolic markers (2 h glucose, triacylglycerol and HDL-cholesterol) compared with total physical activity and MVPA, after adjustment for each other and other important confounders.

"These studies provide preliminary evidence that sedentary behaviour may be a more effective way to target the prevention of type 2 diabetes, rather than just solely focusing on MVPA. Moreover, sedentary time occupies large portions of the day, unlike MVPA," says Henson.

He adds that the new data raise questions regarding the possible prescription of optimal daily movement for health. He concludes: "Diabetes and cardiovascular prevention programmes concentrating solely on MVPA may overlook an area that is of fundamental importance to cardiometabolic health. Along with messages related to accumulating at least 150 min/week of MVPA, which form the cornerstone of diabetes prevention programmes, such interventions may be more effective still if individuals are further encouraged to simply sit less and move more, regardless of the intensity level."

He concludes: "This approach requires a paradigm shift, so that individuals at high risk of developing type 2 diabetes think about the balance of sedentary behaviour and physical activity throughout the day."

Too much vitamin D during pregnancy can cause food allergies

A study published in the February issue of the medical journal Allergy indicates a link between high vitamin D levels in expectant mothers and increased infant allergy risks.

Vitamin D has always had a good reputation: it strengthens bones, protects against infections particularly during the cold winter months and aids the nervous and muscular systems. Especially in the prevention and treatment of rickets, it has been given to babies and infants around the world for around 50 years. However, recent scientific investigations are increasingly questioning the positive aspect of the “bone vitamin”. At the end of the 1990’s, for the first time people’s attention was drawn to a link between high vitamin D levels and the development of allergies.

To pursue the problem, together with Prof. Gabriele Stangl’s group from the Institute of Agricultural and Nutritional Sciences at the Martin-Luther University in Halle-Wittenberg, Dr. Kristin Weiße from the Helmholtz Centre for Environmental Research in Leipzig devoted herself to the following task: can it be proved that there is a correlation between the concentration of vitamin D in the blood of expectant mothers and in cord blood of the babies? The researchers from the UFZ in Leipzig were furthermore interested in the association between vitamin D levels during pregnancy and at birth, the immune status and allergic diseases of the children later in life. Or, in other words: does the vitamin D level of pregnant women affect the allergy risk of their children?

To investigate the question, Dr. Kristin Weiße’s team from Leipzig used samples from the LiNA cohort that the Helmholtz Centre for Environmental Research (UFZ) had established together with the St. Georg municipal clinic between 2006 and 2008 headed by Dr. Irina Lehmann. In total, it was possible to include 622 mothers and their 629 children in the long-term study “Lifestyle and environmental factors and their impact on the newborn allergy risk”.

The level of vitamin D was tested in the blood of the pregnant mothers and also in the cord blood of the children born. In addition to this, questionnaires were used to assess the occurrence of food allergies during the first two years of the children’s lives.

The result was clear: in cases where expectant mothers were found to have a low vitamin D level in the blood, the occurrence of food allergies among their two-year old children was rarer than in cases where expectant mothers had a high vitamin D blood level. In reverse, this means that a high vitamin D level in pregnant women is associated with a higher risk of their children to develop a food allergy during infancy. Furthermore, those children were found to have a high level of the specific immunoglobulin E to food allergens such as egg white, milk protein, wheat flour, peanuts or soya beans.

The UFZ scientists also got evidence fot the mechanism that could link vitamin D and food allergies. Dr. Gunda Herberth – also from the Department of Environmental Immunology at the UFZ – took a closer look at the immune response of the affected children and analysed regulatory T-cells in cord blood in particular. The cells are capable of preventing the immune system from overreacting to allergens, with the result that they protect against allergies.

The UFZ researchers know from earlier analyses that the allergy risk increases in cases where too few regulatory T-cells are present in cord blood. The interesting result of the current research project: the higher the level of vitamin D found in the blood of mothers and children, the fewer regulatory T-cells could be detected. The correlation could mean that vitamin D suppresses the development of regulatory T-cells and thus increases the risk of allergy.

Apart from diet, Dr. Kristin Weiße explained that the level of vitamin D is mainly affected by conditions such as season, exposure to the sun and the amount of time spent outdoors - these factors were also taken into account in the current risk analyses of vitamin D and food allergy. Even though the occurrence of food allergies is undoubtedly affected by many other factors than just the vitamin D level, it is still important to take this aspect into consideration. The UFZ researchers would rather advise pregnant women not to take vitamin D supplements. “Based on our information, an excess of vitamin D can increase the risk of children developing a food allergy in the first two years of their life.”

Publication:
Weisse, K., Winkler, S., Hirche, F., Herberth, G., Hinz, D., Bauer, M., Roeder, S., Rolle-Kampczyk, U., von Bergen, M., Olek, S., Richter, T., Diez, U., Borte, M., Stangl, G.I., Lehmann, I. (2013): Maternal and newborn vitamin D status and its impact on food allergy development in the German LiNA cohort study. Allergy 68 (2), 220 – 228.
http://dx.doi.org/10.1111/all.12081

Pessimism about the future may lead to longer, healthier life

Optimistic older adults face greater risk of disabilities and death

Older people who have low expectations for a satisfying future may be more likely to live longer, healthier lives than those who see brighter days ahead, according to new research published by the American Psychological Association.

"Our findings revealed that being overly optimistic in predicting a better future was associated with a greater risk of disability and death within the following decade," said lead author Frieder R. Lang, PhD, of the University of Erlangen-Nuremberg in Germany. "Pessimism about the future may encourage people to live more carefully, taking health and safety precautions." The study was published online in the journal Psychology and Aging.

Lang and colleagues examined data collected from 1993 to 2003 for the national German Socio-Economic Panel, an annual survey of private households consisting of approximately 40,000 people 18 to 96 years old. The researchers divided the data according to age groups: 18 to 39 years old, 40 to 64 years old and 65 years old and above. Through mostly in-person interviews, respondents were asked to rate how satisfied they were with their lives and how satisfied they thought they would be in five years.

Five years after the first interview, 43 percent of the oldest group had underestimated their future life satisfaction, 25 percent had predicted accurately and 32 percent had overestimated, according to the study. Based on the average level of change in life satisfaction over time for this group, each increase in overestimating future life satisfaction was related to a 9.5 percent increase in reporting disabilities and a 10 percent increased risk of death, the analysis revealed.

Because a darker outlook on the future is often more realistic, older adults' predictions of their future satisfaction may be more accurate, according to the study. In contrast, the youngest group had the sunniest outlook while the middle-aged adults made the most accurate predictions, but became more pessimistic over time.

"Unexpectedly, we also found that stable and good health and income were associated with expecting a greater decline compared with those in poor health or with low incomes," Lang said. "Moreover, we found that higher income was related to a greater risk of disability."

The researchers measured the respondents' current and future life satisfaction on a scale of 0 to 10 and determined accuracy in predicting life satisfaction by measuring the difference between anticipated life satisfaction reported in 1993 and actual life satisfaction reported in 1998. They analyzed the data to determine age differences in estimated life satisfaction; accuracy in predicting life satisfaction; age, gender and income differences in the accuracy of predicting life satisfaction; and rates of disability and death reported between 1999 and 2010. Other factors, such as illness, medical treatment or personal losses, may have driven health outcomes, the study said.

The findings do not contradict theories that unrealistic optimism about the future can sometimes help people feel better when they are facing inevitable negative outcomes, such as terminal disease, according to the authors. "We argue, though, that the outcomes of optimistic, accurate or pessimistic forecasts may depend on age and available resources," Lang said. "These findings shed new light on how our perspectives can either help or hinder us in taking actions that can help improve our chances of a long healthy life."