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Eating cured meats frequently can lead to lower lung function and potential COPD

Frequent consumption of cured meats results in lower lung function test scores and increases the odds of developing chronic obstructive pulmonary disease (COPD), according to a large cross-sectional survey of adults in the U.S.

The study results appear in the second issue for April 2007 of the American Journal of Respiratory and Critical Care Medicine, published by the American Thoracic Society.

Rui Jiang, M.D., Dr.P.H., of Columbia University Medical Center in New York, and three associates showed that the "odds ratio" for developing COPD among individuals who consumed cured meat products 14 times or more per month was 1.93, as compared with those who did not consume cured meats. An odds ratio greater than 1 implies that the event is more likely to occur within that group.

"Cured meats, such as bacon, sausage, luncheon meats and cured hams, are high in nitrites, which are added to meat products as a preservative, an anti-microbial agent, and a color fixative," said Dr. Jiang. "Nitrates generate reactive nitrogen species that may cause damage to the lungs, producing structural changes resembling emphysema."

Although certain rodent studies suggest that inhalation of nitrogen dioxide may contribute to emphysema, no other human studies to date have examined the relationship between consumption of cured meats and COPD, which is the fourth leading cause of death in the U.S.

In 2004, more than 11 million U.S. adults were estimated to suffer from COPD, which results from chronic bronchitis and emphysema, two inflammatory lung diseases that frequently co-exist and interfere with breathing.

The study cohort consisted of 7,352 individuals who participated in the Third National Health and Nutrition Examination Survey, conducted from 1988 to 1994 by the National Center for Health Statistics. The average age of participants was 64.5 years, and 48 percent were male.

"Individuals who consumed cured meats frequently were more likely to be male, of lower socioeconomic status, to be tobacco users, and were less likely to report physician-diagnosed asthma than individuals who never consumed cured meats," said Dr. Jiang. "Those who consumed cured meats more frequently had lower intakes of vitamin C, beta-carotene, fish, fruits, vegetables, and vitamin or mineral supplements. They also had higher intakes of vitamin E and total energy."

The hazard ratio from cured meats associated with lower lung function test results and increased odds for COPD did not change after researchers made adjustments for multiple dietary and other risk factors.

"Adjustment for these factors in our analyses did not appreciably change our findings, suggesting that the observed association between cured meats and lung function was unlikely to be explained by potential dietary confounding factors reported in previous studies," said Dr. Jiang.

The researchers noted that high dietary nitrite intake warrants further evaluation in prospective longitudinal studies as a novel risk factor for COPD.

Breastfeeding reduces risk of breast cancer for women who delay childbirth

Study presented at AACR meeting suggests that breastfeeding has protective benefit for both receptor positive and negative tumors

Breastfeeding can offset the increased risk of invasive breast cancer for women who had their first full-term pregnancy after the age of 25, a study led by researchers at the University of Southern California (USC) suggests.

The findings of the study were presented at a news conference on Monday, April 16 at the 2007 annual meeting of the American Association for Cancer Research held in Los Angeles.

"Breastfeeding may have a protective effect that negates the increased risk of breast cancer associated with late pregnancies," says Giske Ursin, M.D., Ph.D, associate professor of preventive medicine at the Keck School of Medicine of the University of Southern California. "As more women may choose to delay pregnancy until after 25, it is important to note that breastfeeding provides protection against both estrogen and progesterone receptor positive and negative tumors."

While having a first full-term pregnancy before the age of 25 and having many children protect against the type of breast cancers that express estrogen and progesterone receptors, these factors do not protect against the rarer tumors that do not have these receptors. Breastfeeding, however, appears to protect against both types of breast tumors, Ursin says.

Researchers analyzed data for women aged 55 and older—including 995 invasive breast cancer patients–who participated in the Women's Contraceptive and Reproductive Experiences (CARE) Study. The women varied by their age at first birth, their breastfeeding history and hormone receptor status.

Previous results from the Women's CARE Study have shown that early age at first pregnancy (younger than 25) and having many children (defined as four or more) are associated with a lower risk of breast cancer, Ursin says. Researchers sought to gain a better understanding of the associations between reproductive factors and breast cancer risk in women with a late age at first birth, she says.

Breastfeeding appears to have a protective effect regardless of when women started giving birth, Ursin says. This is important since having many children was only protective among women who gave birth early, she says. Giving birth after age 25—the average age that women in the U.S. first give birth, according to Census data—was associated with increased risk of hormone receptor negative breast cancer.

"Evidence suggests that women who have children after age 25 can reduce their risk of breast cancer by choosing to breastfeed," Ursin says.

While mellowing with age has often been thought to have positive effects, a Purdue University researcher has shown that doing so could also help you live longer.
Dan Mroczek (pronounced Mro-ZAK), an associate professor of child development and family studies at Purdue University, compared neurotic and non-neurotic men over time and tied change in the trait with mortality.

"We found that neurotic men whose levels dropped over time had a better chance at living longer," Mroczek said. "They seemed to recover from any damage high levels of the trait may have caused. On the flip side, neurotic men whose neuroticism increased over time died much sooner than their peers."

A neurotic personality was defined as a person with the tendency to worry, feel excessive amounts of anxiety or depression and to react to stressful life events more negatively than people with low levels of the trait. Neuroticism levels were measured using a standardized personality test.

Results of the study will be published in the print edition of the journal Psychological Science in late May. The study is available online at http://www.psychologicalscience.org.

In the study, researchers tracked the change in neuroticism levels of 1,663 aging men over a 12-year period. Using the data gathered in the first analysis, researchers calculated the men's mortality risk over an 18-year period using the average levels and rates of change.

By the end of the study, half of those men classified as highly neurotic with increasing levels of neuroticism had died while those whose levels decreased or were classified as less neurotic had between a 75 percent and 85 percent survival rate.

Even small increases in neuroticism were shown to have negative effects. Participants with as little as a one-unit increase in neuroticism over the course of the study were shown to have a 40 percent higher chance of death than a participant who showed no change.

Data was taken from the Veterans Affairs Normative Aging Study, a longitudinal investigation of aging in men founded at the Boston Veterans Affairs Outpatient Clinic in 1963. In 1988, the beginning of this study, the men ranged in age from 43 to 91.

Mroczek and Avron Spiro, an associate professor of epidemiology at Boston University's School of Public Health, also controlled the data for age, depression levels and both subjective and objective ratings of overall health.

"We found that neuroticism levels are a clear indicator of how long one can expect to live," Mroczek said. "The link between mortality and the rate of change in neuroticism is similar to the way we think about change in high blood pressure and risk of heart attack. If you have high blood pressure but make sure to lower it, you are likely to reduce your heart attack risk."

While those who were very neurotic and grew worse over time had a higher death rate, those who were the least neurotic and improved over time did not die at a significantly lower rate.

Mroczek said the anomaly could be traced to how these types of attitudes affect personal choices.

"It's possible that the key with neuroticism is having just the right amount," Mroczek said. "If you are too laid back, you may not be taking your health seriously enough. These folks might be engaging in more risky behaviors like smoking or drinking to excess because they don't believe anything bad will happen to them."

Mroczek, a member of Purdue's Center on Aging and the Life Course, said he sees a future in which doctors and other health practitioners include some form of personality assessments with routine medical screenings. Learning to deal with some of the potentially negative aspects of human personalities in a positive way could become part of a balanced and healthy lifestyle.

"For example, very neurotic people can work toward dealing better with stress," he said. "They can seek therapy, take up yoga, schedule daily walks to help themselves unwind, listen to calming music or even meditate."

While participants in the study were male and more than 90 percent Caucasian, Mroczek said there is little reason to believe that results for women or other ethnicities would show vastly different results.

"You can find the full range of personalities in any ethnic or gender group," Mroczek said. "There are those who are laid back and then there are those who worry, who react very poorly to stress, who are always on edge."

Mroczek will begin testing later this year to determine why higher levels of neuroticism increase mortality. He plans a study which tests cortisol levels in neurotic men to determine if they have higher levels of the damaging stress hormone that could contribute to early death. Other possible contributing factors might include unhealthy coping techniques, such as overeating or drinking to excess.

The first phase of a caloric restriction study in human subjects at the Jean Mayer US Department of Agriculture Human Nutrition Research Center on Aging (USDA HNRCA) at Tufts University found evidence suggesting that calorie-restricted diets differing substantially in glycemic load can result in comparable long-term weight loss. The study, part of the multi-center Comprehensive Assessment of Long-term Effects of Restricting Intake of Energy (CALERIE) trial, funded by the National Institute on Aging, accounted for dietary factors that affect hunger and satiety, used laboratory techniques to measure adherence, and was the first of its kind to provide a complete set of meals and snacks to its participants. Recruitment is currently underway for participation in the second phase of the CALERIE study at Tufts, which will examine the relationship between calorie-restricted diets, aging, and age-related disease.

"Participants in our pilot study achieved and maintained comparable weight loss after one year, regardless of whether they were on a low-glycemic-load or a high-glycemic-load diet," says corresponding author Susan Roberts, PhD, director of the USDA HNRCA's Energy Metabolism Laboratory. "The goal was for both groups to restrict calories by 30 percent and, after one year, both groups had lost an average of 8 percent of their original body weight. We found that the two groups did not differ significantly in their average body fat loss, energy intake, metabolic rate, or reports of hunger and satiety."

The two study diets were carefully matched for factors known to influence food intake during weight-loss efforts, such as palatability, dietary variety, and fiber. "Because there was careful attention to factors that influence hunger and satiety, participants were generally satisfied on a calorie-restricted diet," says Roberts, who is also a professor at the Friedman School of Nutrition Science and Policy at Tufts.

Thirty-four overweight but otherwise healthy men and women were assigned randomly to a low-glycemic-load (LG) or high-glycemic-load (HG) diet. At six months, the LG group had lost an average of 10.4 percent body weight, while the HG group had lost an average of 9 percent body weight. By 12 months, participants in both the LG and HG groups had lost an average of 8 percent of their starting body weight.

"Unlike several other long-term studies, which have reported greater weight loss with low GL diets at six months but no differences by 12 months, our data show no significant short-term or long-term differences," notes Sai Das, PhD, scientist at the USDA HNRCA and first author of the study. "However, we did detect a greater tendency for weight and body-fat regain among LG participants. This finding suggests that reduced calorie intake may be harder to sustain on LG diets over time."

The LG diet contained 40 percent carbohydrate, 30 percent fat, and 30 percent protein; while the HG diet contained 60 percent carbohydrate, 20 percent fat, and 20 percent protein. A food's glycemic load is a relative measure of how much carbohydrate is in the food and how quickly that food is converted in the body to blood sugar. Examples of foods provided as part of the LG diet include bean and barley stew, low-fat cottage cheese, and pumpernickel bread. The HG diet included foods like bagels, candied sweet potatoes and shepherd's pie with mashed potatoes.

Both diets were designed to restrict calories by 30 percent, relative to a person's baseline energy requirements, while providing the recommended amounts of vitamins, minerals, and essential fatty acids. All participants attended weekly behavioral support groups and met individually with a dietitian.

To measure objectively actual dietary intakes, the researchers used a laboratory technique involving doubly labeled water. They determined that both groups ate more calories than study foods provided; at six months the HG group averaged a 16 percent calorie-restricted diet and the LG group averaged a 17 percent calorie-restricted diet. Although participants did consume additional calories, the degree of non-adherence was not significantly different between the LG and HG groups when measured at various points throughout the study.

"An important difference between our study and other weight-loss trials is that we did not rely on self-reported intakes," says Das, who is also an assistant professor at the Friedman School. "Underreporting of caloric intake can vary between 5 and 50 percent. By providing the study food for the first six months, we did not have to worry as much about lifestyle factors like shopping and cooking habits interfering with dietary change."

Roberts previously conducted a pilot study showing that a diet's overall glycemic load may be an important determinant of weight loss for people with high levels of insulin secretion, such as people with diabetes. "We have observed that for some groups, glycemic load may impact weight loss. However, in terms of calorie-restricted diets, we see little difference among diets of varying glycemic load when we account for factors that affect dietary adherence."

People watching the Super Bowl who saw how much they had already eaten -- in this case, leftover chicken-wing bones -- ate 27 percent less than people who had no such environmental cues, finds a new Cornell study.

The difference between the two groups -- those eating at a table where leftover bones accumulated compared with those whose leftovers were removed -- was greater for men than for women.

"The results suggest that people restrict their consumption when evidence of food consumed is available to signal how much food they have eaten," said Brian Wansink, the John S. Dyson Professor of Marketing and of Applied Economics at Cornell, and author of the 2006 book, "Mindless Eating: Why We Eat More Than We Think."

The study, conducted with Cornell postdoctoral researcher Collin R. Payne, is published in the April issue of Perceptual and Motor Skills. It included 50 graduate students at a sports bar where an open buffet featured chicken wings during the Super Bowl; some tables were bused and some were left unbused.

To use environmental cues to curb overeating and overdrinking, Wansink suggested that college parties could encourage (or require) fresh plastic glasses for each drink and that the glasses be stacked as they accumulate for each person; dinner parties could use fresh glasses for refills while empty glasses, or even empty bottles, are left on the table.

Got milk? Weightlifters will want to raise a glass after a new study found that milk protein is significantly better than soy at building muscle mass.

The study, conducted by a team of researchers at McMaster University’s Department of Kinesiology, was recently published in the American Journal of Clinical Nutrition. It compared how much muscle protein young men gained after completing a heavy weight workout followed by consumption of equivalent amounts of protein as either fluid skim milk or a soy drink.

"Our thinking going into the study was that milk would be better than soy. We suspected this would be the case because of work done by French researchers. However, we were really impressed by how much greater the gains in muscle protein with milk were," says Sarah Wilkinson, lead researcher and a graduate student in the department of kinesiology.

The findings would suggest that if men consume only skim milk (two cups) after each of their workouts, they would gain almost twice as much muscle in 10 weeks than if they drank the same amount of protein as a soy drink.

"This is an interesting finding, since soy and milk proteins are considered to be complete proteins that are basically equivalent from a nutritional standpoint," explains Stuart Phillips, associate professor of kinesiology, who was also involved in the study. "Our findings clearly show that milk proteins are a superior source of protein in producing muscle mass gains in response to weightlifting."

Scientists also analyzed the composition of milk and soy proteins and did not find remarkable differences. At this stage, researchers are uncertain why milk proteins were so much more effective than soy. However, the two main types of proteins in milk, whey and casein, may have intrinsic properties that are advantageous in terms of supporting muscle growth.

A Meta-analysis

Background Epidemiological evidence suggests blood pressure–lowering effects of cocoa and tea. We undertook a meta-analysis of randomized controlled trials to determine changes in systolic and diastolic blood pressure due to the intake of cocoa products or black and green tea.

Methods MEDLINE, EMBASE, SCOPUS, Science Citation Index, and the Cochrane Controlled Trials Register were searched from 1966 until October 2006 for studies in parallel group or crossover design involving 10 or more adults in whom blood pressure was assessed before and after receiving cocoa products or black or green tea for at least 7 days.

Results Five randomized controlled studies of cocoa administration involving a total of 173 subjects with a median duration of 2 weeks were included. After the cocoa diets, the pooled mean systolic and diastolic blood pressure were –4.7 mm Hg (95% confidence interval [CI], –7.6 to –1.8 mm Hg; P = .002) and –2.8 mm Hg (95% CI, –4.8 to –0.8 mm Hg; P = .006) lower, respectively, compared with the cocoa-free controls. Five studies of tea consumption involving a total of 343 subjects with a median duration of 4 weeks were selected. The tea intake had no significant effects on blood pressure. The estimated pooled changes were 0.4 mm Hg (95% CI, –1.3 to 2.2 mm Hg; P = .63) in systolic and –0.6 mm Hg (95% CI, –1.5 to 0.4 mm Hg; P = .38) in diastolic blood pressure compared with controls.

Conclusion Current randomized dietary studies indicate that consumption of foods rich in cocoa may reduce blood pressure, while tea intake appears to have no effect.

Should all women in their 40s be routinely screened for breast cancer? Not necessarily, according to the American College of Physicians. In a new set of guidelines for clinicians of 40-something patients, the group recommends that mammography screening decisions be made on a case-by-case basis. It advises clinicians to discuss the benefits and harms of screening with the patient, as well as each woman's individual cancer risk and preference about screening.

The organization based its recommendations, which will be published in the April 3 issue of Annals of Internal Medicine, on a rigorous review of evidence showing there is variation in the benefits and harms associated with mammography among women in their 40s. The American College of Physicians is the leading professional organization for internal medicine specialists, with a membership of 120,000.

"There are important benefits to screening mammography, but we believe the decision to be screened should be based on an informed conversation between a patient and her physician," said health policy expert Douglas K. Owens, MD, MS, a researcher with the Veterans Affairs Palo Alto Health Care System and a professor of medicine at the Stanford University School of Medicine, who chaired the committee that developed the guidelines. "In our view, the evidence doesn't support a blanket recommendation for women in this age group."

Breast cancer is the second-leading cause of cancer related death among women in the United States; according to the American Cancer Society, 25 percent of all diagnosed cases are among women younger than age 50. Among these younger women, the risk of breast cancer varies greatly - from less than 1 percent for a 40-year-old woman with no risk factors to 6 percent for a 49-year-old woman with multiple risk factors, which include family history of breast cancer, older age at the birth of her first child and younger age at the onset of menstruation.

Physicians and medical groups have for years debated the merits of screening mammography for women in their 40s. While it is well-established that mammography reduces mortality from breast cancer in 50- to 70-year-old women - and that women in this age-group should be routinely screened - the evidence isn't as clear-cut for younger women.

Five years ago, the U.S. Preventive Services Task Force, an independent panel of experts in primary care and prevention, examined data from numerous clinical trials and estimated that screening mammography every one or two years in women in their 40s resulted in a 15 percent decrease in breast cancer mortality after 14 years of follow-up. But a separate Canadian study published in the same issue of the journal found that women in this age-group received no benefit from mammography.

Past analyses have also made note of the potential harms of screening, including radiation exposure, procedure-associated pain, false-positive results, over-diagnosis and potentially unnecessary treatment.

Based in part on the conflicting evidence, medical groups have differing screening recommendations for women under age 50. The U.S. Preventive Services Task Force and the American College of Obstetricians and Gynecologists both recommend screening mammography every one to two years for women in their 40s, while the 2006 American Cancer Society guideline recommends yearly mammograms starting at age 40.

Because of the ongoing controversy, the American College of Physicians' Clinical Efficacy Assessment Subcommittee decided to take its own look at the evidence related to screening in women in their 40s. After their review, the group concluded that screening mammography for women in this age group likely provides a modest reduction in breast cancer mortality, but - as with any screening intervention - it also comes with the risk of potential harms. Based on this, it recommended that clinicians:

Periodically perform individualized assessment of risk for breast cancer to help guide decisions about screening mammography

Inform women ages 40 to 49 of the potential benefits and harms of screening mammography

Base screening mammography decisions on benefits and harms of screening as well as a woman's preferences and breast cancer risk profile

In the new guidelines, the organization emphasizes the importance of using a woman's concerns about breast cancer and screening to help guide decision-making about mammography. Women's thoughts about mammography or their risks of developing breast cancer will likely vary greatly, the group notes, but it expects the potential reduction in breast cancer mortality associated with screening to outweigh other considerations for many women.

"We still think many women will choose to get mammography, and we're supportive of that," said Owens. "The most important thing is that women be well-informed about the decision they're making."

Study suggests need to examine current pregnancy weight guidelines

Pregnant women who gain excessive or even appropriate weight, according to current guidelines, are four times more likely than women who gain inadequate weight to have a baby who becomes overweight in early childhood. These findings are from a new study at the Department of Ambulatory Care and Prevention of Harvard Medical School and Harvard Pilgrim Health Care and are published in the April issue of the American Journal of Obstetrics and Gynecology.

"Maternal weight gain during pregnancy is an important determinant of birth outcomes," says lead author Emily Oken, MD, MPH, instructor in the Department of Ambulatory Care and Prevention. "These findings suggest that pregnancy weight gain can influence child health even after birth and may cause the obstetric community to rethink current guidelines."

Oken and colleagues examined data from 1,044 mother-child pairs in Project Viva, a prospective study of pregnant women and their children based at the Department of Ambulatory Care and Prevention's Obesity Prevention Program. The authors studied whether pregnancy weight gain within or above the recommended range increased the risk of a child being overweight at age 3 years.

In 1990, the Institute of Medicine (IOM) published guidelines for gestational weight gain ("Nutrition During Pregnancy") that were motivated by evidence that low weight gain in pregnant women may cause low birth weight. These guidelines call for smaller gains in mothers with a higher body mass index (BMI) and generally permit greater gains than previous recommendations.

The IOM report remains the standard for clinical recommendations regarding gestational weight gain. However, some have questioned whether evidence is sufficient that greater gains promote better birth outcomes in modern developed nations. More weight gain may cause undesirable birth outcomes, such as increased rates of babies born at high birth weight and cesarean section, and is associated with higher postpartum weight retention and later risk of maternal obesity.

In this study, 51 percent of women gained excessive weight, 35 percent gained adequate weight, and 14 percent gained inadequate weight, according to the IOM guidelines. Women with adequate or excessive gain were approximately four times more likely than those with inadequate gain to have an overweight child, as measured at age 3. The authors defined overweight as a BMI greater than the 95th percentile for the child's age and sex.

"Our study shows that excessive weight gain during pregnancy was directly associated with having an overweight child," says Oken. "Just like adults, children who are overweight are at higher risk for a number of health conditions such as high blood pressure, diabetes, and high cholesterol."

The likelihood of having a baby that was heavy for gestational age was greater in women with excessive gain. Children of mothers who gained more weight also had somewhat higher systolic blood pressure, a cardiovascular risk factor related to weight even in young children.

The authors calculated total gestational weight gain as the difference between the last weight recorded before delivery and self-reported prepregnancy weight. The authors categorized women as having gained inadequate, adequate, or excessive weight according to the IOM guidelines. These guidelines recommend that women with a prepregnancy BMI between 19.8 and 26 kg/m2, (considered normal by the IOM guidelines) should gain 11.5 to 16kg (25 to 35 pounds); that women with a BMI of less than 19.8 kg/m2 (considered underweight by the IOM guidelines) should gain 7 to 11.5 kg (15 to 25 pounds); and that women with a BMI of more than 29 kg/m2 (considered obese by the IOM guidelines) should gain at least 6 kg (13 pounds).

Gestational weight gain may be linked to child overweight through several potential pathways. Mothers who gain weight readily because of genetic, dietary, or other behavioral factors may have children who are more likely to gain weight. Also, the amount of weight gained during pregnancy may alter the intrauterine environment, not only influencing fetal growth but also possibly resulting in persistent programming of child weight.

"Because childhood obesity is increasing in prevalence and effective treatment remains elusive, preventing childhood obesity remains critical," says Oken. "The IOM may need to reevaluate its recommendations for gestational weight gain, considering not only birth outcomes but also risk of obesity for both mother and child. While our study signals the potential need to adjust guidelines, further studies will need to occur to determine just what the appropriate weights should be."

Like the United States population as whole, many mothers and their children in this study were overweight. Even mothers with adequate gain according to the IOM guidelines had a substantially higher risk than mothers with inadequate weight gain of having overweight children, with no difference in risk of undesirable birth outcomes, such as small or large size for gestational age or birth by cesarean section.

"It has been 17 years since the IOM came out with its last set of recommendations, before the obesity epidemic hit with full force," says Matthew Gillman, MD, associate professor in the Department of Ambulatory Care and Prevention and senior author of the study. "Now, women are coming into pregnancy at higher weights and likely gaining excessively more than they used to. We need to find out how to counter this trend--but not go too far back in the other direction when women were gaining too little weight."

The amount of prostate-specific antigen (PSA) in a man’s bloodstream at the time of his prostate cancer diagnosis or its rate of change over the course of the disease does not adequately predict lethal prostate cancer, according to a study in the April 4 Journal of the National Cancer Institute.

Although men with untreated localized prostate cancer have high long-term survival rates, many patients undergo treatment anyway. In order to avoid unnecessary treatment, researchers want to identify methods to determine which patients will develop lethal prostate cancer. The rate of increase of PSA—a protein produced by the prostate—before prostate cancer treatment has been associated with the patient’s prognosis, which suggests that early measurements of PSA may predict the behavior of the tumor.

To assess the accuracy of using PSA to predict prostate cancer outcome, Katja Fall, M.D., Ph.D., of the Karolinska Institute in Stockholm, and colleagues analyzed the rate of change of PSA levels in 267 men from Sweden, Finland, and Iceland who were diagnosed with early localized prostate cancer between 1989 and 1999. The researchers recorded the PSA levels for the first two years after diagnosis to capture the patients’ early PSA patterns. The men in the study received no curative treatment for the first two years but were closely watched for signs of progression, which is called watchful waiting.

At the end of the follow-up in December 2003, 34 patients had died from prostate cancer, and 18 had developed metastatic prostate cancer but were still alive. Although initial PSA values and the rate of change were associated with later development of lethal prostate cancer, they were not accurate enough to predict lethal cancer.

"We conclude that PSA measurement is associated with prostate cancer prognosis and continues to be an important monitoring tool," the authors write. "However, early PSA characteristics perform poorly in distinguishing those who develop a lethal prostate cancer from those at low or no risk of disease progression. Therefore, better decision tools are needed for active monitoring of patients with early disease."

In an accompanying editorial, Dipen Parekh, M.D., of the University of Texas Health Science Center at San Antonio, and colleagues compared the results of this new study with their own work and found consistent results regarding PSA, as well as other measures that were related to prostate cancer risk. "These data demand that clinical trials commence now to examine surveillance strategies to help patients and their physicians identify and treat tumors that will otherwise be life threatening and to carefully follow those that will not. Our limited health care resources and the quality of life of an enormous number of men will benefit from this for decades to come," the authors write.

Will you lose weight and keep it off if you diet? No, probably not, UCLA researchers report in the April issue of American Psychologist, the journal of the American Psychological Association.

"You can initially lose 5 to 10 percent of your weight on any number of diets, but then the weight comes back," said Traci Mann, UCLA associate professor of psychology and lead author of the study. "We found that the majority of people regained all the weight, plus more. Sustained weight loss was found only in a small minority of participants, while complete weight regain was found in the majority. Diets do not lead to sustained weight loss or health benefits for the majority of people."

Mann and her co-authors conducted the most comprehensive and rigorous analysis of diet studies, analyzing 31 long-term studies.

"What happens to people on diets in the long run?" Mann asked. "Would they have been better off to not go on a diet at all? We decided to dig up and analyze every study that followed people on diets for two to five years. We concluded most of them would have been better off not going on the diet at all. Their weight would be pretty much the same, and their bodies would not suffer the wear and tear from losing weight and gaining it all back."

People on diets typically lose 5 to 10 percent of their starting weight in the first six months, the researchers found. However, at least one-third to two-thirds of people on diets regain more weight than they lost within four or five years, and the true number may well be significantly higher, they said.

"Although the findings reported give a bleak picture of the effectiveness of diets, there are reasons why the actual effectiveness of diets is even worse," Mann said.

Mann said that certain factors biased the diet studies to make them appear more effective than they really were. For one, many participants self-reported their weight by phone or mail rather than having their weight measured on a scale by an impartial source. Also, the studies have very low follow-up rates — eight of the studies had follow-up rates lower than 50 percent, and those who responded may not have been representative of the entire group, since people who gain back large amounts of weight are generally unlikely to show up for follow-up tests, Mann said.

"Several studies indicate that dieting is actually a consistent predictor of future weight gain," said Janet Tomiyama, a UCLA graduate student of psychology and co-author of the study. One study found that both men and women who participated in formal weight-loss programs gained significantly more weight over a two-year period than those who had not participated in a weight-loss program, she said.

Another study, which examined a variety of lifestyle factors and their relationship to changes in weight in more than 19,000 healthy older men over a four-year period, found that "one of the best predictors of weight gain over the four years was having lost weight on a diet at some point during the years before the study started," Tomiyama said. In several studies, people in control groups who did not diet were not that much worse off — and in many cases were better off — than those who did diet, she said.

If dieting doesn't work, what does?

"Eating in moderation is a good idea for everybody, and so is regular exercise," Mann said. "That is not what we looked at in this study. Exercise may well be the key factor leading to sustained weight loss. Studies consistently find that people who reported the most exercise also had the most weight loss."

Diet studies of less than two years are too short to show whether dieters have regained the weight they lost, Mann said.

"Even when you follow dieters four years, they're still regaining weight," she said.

One study of dieting obese patients followed them for varying lengths of time. Among those who were followed for fewer than two years, 23 percent gained back more weight than they had lost, while of those who were followed for at least two years, 83 percent gained back more weight than they had lost, Mann said. One study found that 50 percent of dieters weighed more than 11 pounds over their starting weight five years after the diet, she said.

Evidence suggests that repeatedly losing and gaining weight is linked to cardiovascular disease, stroke, diabetes and altered immune function. Mann and Tomiyama recommend that more research be conducted on the health effects of losing and gaining weight, noting that scientists do not fully understand how such weight cycling leads to adverse health effects.

Mann notes that her mother has tried different diets, and has not succeeded in keeping the weight off. "My mother has been on diets and says what we are saying is obvious," she said.

While the researchers analyzed 31 dieting studies, they have not evaluated specific diets.

Medicare raised the issue of whether obesity is an illness, deleting the words "Obesity is not considered an illness" from its coverage regulations in 2004. The move may open the door for Medicare to consider funding treatments for obesity, Mann noted.

"Diets are not effective in treating obesity," said Mann. "We are recommending that Medicare should not fund weight-loss programs as a treatment for obesity. The benefits of dieting are too small and the potential harm is too large for dieting to be recommended as a safe, effective treatment for obesity."

From 1980 to 2000, the percentage of Americans who were obese more than doubled, from 15 percent to 31 percent of the population, Mann noted.

A social psychologist, Mann, taught a UCLA graduate seminar on the psychology of eating four years ago. She and her students continued the research when the course ended. Mann's co-authors are Erika Westling, Ann-Marie Lew, Barbra Samuels and Jason Chatman.

"We asked what evidence is there that dieting works in the long term, and found that the evidence shows the opposite" Tomiyama said.

Protective effect of fruits, vegetables and the Mediterranean diet on asthma and allergies among children in Crete

A "Mediterranean" diet rich in fruits, vegetables and nuts protects against allergic rhinitis and asthma symptoms, suggests research published ahead of print in Thorax.

The researchers assessed the dietary habits, respiratory symptoms, and allergic reactions of almost 700 children living in four rural areas on the Greek island of Crete.

The children were all aged between 7 and 18 years of age.

Skin allergies are relatively common in Crete, but respiratory allergies, such as asthma and allergic rhinitis are relatively rare.

Parents completed detailed questionnaires on their children's allergic and respiratory symptoms and dietary habits.

Whether the children ate a "Mediterranean" diet was measured against a set of 12 foodstuffs, including fruits, vegetables, whole-grains, legumes, nuts, and olive oil.

Eight out of 10 children ate fresh fruit, and over two thirds of them ate fresh vegetables, at least twice a day.

The effect of diet was strongest on allergic rhinitis, but it also afforded protection against asthma symptoms and skin allergy.

Children who ate nuts at least three times a week were less likely to wheeze.

Nuts are a rich source of vitamin E, the body's primary defence against cellular damage caused by free radicals. And they contain high levels of magnesium, which other research suggests, may protect against asthma and boost lung power.

And a daily diet of oranges, apples, and tomatoes also protected against wheezing and allergic rhinitis.

Grapes in particular seemed to protect against current and previous wheezing and allergic rhinitis, even after adjusting for other potentially influential factors.

Red grape skin contains high levels of antioxidants as well as resveratrol, a potent polyphenol, known to curb inflammatory activity, say the authors.

But high consumption of margarine doubled the chances of asthma and allergic rhinitis, the findings showed.

Study links propensity toward worry to early death

There is broad consensus today that personality traits are best described by the "Big Five": Extraversion, agreeableness, conscientiousness, emotional stability, and openness to experience. Each of these broad measures can be broken down into smaller ones, but in general, this taxonomy appears to take in most of what we think of as personhood. When you think of someone as "steady" or "flaky" or "gloomy" or "daring," what you’re really doing is unconsciously taking a measure of these five traits and crunching them together.

So what makes a healthy personality? Psychologists have been studying this important question, and at least two of these five traits appear to be directly related to physical well being and longevity: Emotional stability and conscientiousness. More to the point, wellness is linked to changes in these traits over time.

Consider emotional stability. Or, rather, it’s polar opposite, which psychologists call neuroticism. Neuroticism is the tendency toward hand wringing and negative thinking. People with a heavy dose of neuroticism do not handle stress well, and are often anxious and moody. Such negativity has been linked to increased mortality in a number of studies, but for Purdue University psychologist Daniel Mroczek this finding raised as many questions as it answered. Does it follow that this inherited trait is a death sentence? Or can people with this propensity change their destiny?

Mroczek decided to explore this idea. Using a standard measure of neuroticism, he tracked more than 1600 men over 12 years, recording not only how neurotic they were at the start but also whether they got more or less neurotic over time. He also looked at mortality risk for these same men over an 18-year span. As reported in the May issue of Psychological Science, those who increased over time in neuroticism was a ticket to an early grave. In other words, these men—all middle age or older to begin with—did not grow old gracefully. They likely got more and more stressed, worried or fretful, and this downward spiral increased their risk for dying, mostly from cancer and heart disease.

The good news is that men with a fretful temperament, if they managed for whatever reason to calm down a bit over time, had survival rates similar to those of emotionally stable men.

Apple's benefits reach into the womb, found to be protective against childhood asthma

Eating apples while pregnant may give new meaning to an apple a day keeping the doctor away. Compelling new research has concluded that mothers who eat apples during pregnancy may protect their children from developing asthma later in life. The study was published in Thorax online.

This unique longitudinal study tracked dietary intake by nearly 2000 pregnant women, then examined the effects of the maternal diet on airway development in more than 1200 of their children five years later. Among a wide variety of foods consumed and recorded by the pregnant women, the researchers concluded that the children of mothers who ate apples had a significantly reduced risk for the development of asthma and childhood wheezing.

This study focuses on medical evaluations for asthma and related symptoms (i.e., wheezing) when the children were five years old. As a result of the evaluations cited in this research, other than apples, there were no consistent associations found between prenatal consumption of a range of healthful foods and asthma in the 1253 children who were evaluated.

Children of mothers who ate apples during pregnancy were much less likely to exhibit symptoms of asthma (including wheezing), say the researchers who hail from institutions in The Netherlands and Scotland. These same researchers previously reported positive associations between maternal consumption of vitamins A, E, D and zinc with reduced risk of asthma, wheeze and eczema in children.

The only other positive association found between prenatal food intake and risk reduction in the children was with fish, for which the researchers found that children of mothers who ate fish had a lowered incidence of doctor-confirmed eczema.

According to the research, "The present study suggests beneficial associations between maternal apple intake during pregnancy and wheeze and asthma at age five years." They add that their findings "suggest an apple specific effect, possibly because of its phytochemical content, such as flavonoids." The research paper cites other related studies on apples, including those which found that "intake of apples as a significant source of flavonoids and other polyphenols has been beneficially associated with asthma, bronchial hypersensitivity, and lung function in adults."

In 2004, the National Center for Health Statistics reported that nine million U.S. children have been diagnosed with asthma at one point in their lives and four million children suffered from asthma attacks that year. Others suffer from "hidden asthma" – undetected or undiagnosed asthma, according the American Lung Association. The cost of this disease is great – statistics show asthma to be the third-ranking cause of hospitalization among children under 15 and is among the leading causes of school absenteeism.