Signs of Depression

NEW YORK (Reuters Health) - People who experience high levels of stress and anxiety appear to be more likely to develop irritable bowel syndrome (IBS) following a severe gastric infection, UK and New Zealand researchers report

A variety of studies have suggested that the cause of IBD has psychological and behavioral components, Dr. Rona Moss-Morris of the University of Southampton and Dr. Meagan J. Spence of the University of Auckland point out in the medical journal Gut.

"This study shows that various psychological factors, particularly stress, anxiety and a tendency to push oneself to keep going when ill and then collapse in response, interact with the physical illness in causing IBS," Moss-Morris told Reuters Health.

In their study, the researchers looked at 620 patients who tested positive for stomach inflammation from a bout of infection with a bug called Campylobacter. None of the participants had previously suffered from IBS or serious bowel conditions.

The subjects completed a questionnaire, covering aspects of personality and their behavior at the time of the initial infection. They were then checked 3 and 6 months later to see if they had developed IBS. The researcher found that 49 of the patients had the condition at both follow-up points.

Depression and perfectionism were not significantly associated with the onset of IBS. However, a variety of other factors were.

These included significantly higher levels of perceived stress and anxiety. IBS patients were also significantly less likely to rest in the face of their illness, and exhibited "all-or-nothing" behavior by continuing their activities despite their symptoms until they were forced to stop.

These patients were prone to view illness in a particularly pessimistic fashion. Being female was also an important risk factor.

The UK author of an accompanying editorial, Dr. Francis Creed of the University of Manchester, told Reuters Health that the study "shows more clearly than most the psychological factors that are associated with the development of IBS."

SOURCE: Gut, August 2007.

NEW YORK (Reuters Health) - Black and Hispanic adults with arthritis are more likely than whites to become disabled from the joint disease, new research findings suggest.

In a study that followed nearly 7,300 Americans with arthritis for six years, researchers found that African-American patients were twice as likely to develop a disability as their white counterparts. The same was true of Hispanic adults who spoke Spanish as their primary language, but not primarily English-speaking Hispanic patients.

A range of factors -- from poorer overall health to lack of insurance to less-healthy lifestyles -- together explained the racial disparity, the study found.

Jing Song and colleagues at Northwestern University in Chicago report the findings in the journal Arthritis & Rheumatism. The results are based on a national survey of 7,257 adults age 51 and up who had arthritis but were free of major disabilities at the outset. Participants were interviewed every two years between 1998 and 2004.

During that time, 28 percent of both African-Americans and Spanish-speaking Hispanic adults developed at least one disability in "activities of daily living," such as problems with getting out of bed, dressing or bathing.

That compared with 16 percent of white adults and 19 percent of English-speaking Hispanic study participants.

About half of the racial disparity could be explained by health factors, according to Song's team. Minorities were more likely to have co-existing health conditions like high blood pressure and diabetes, and they tended to have higher rates of obesity and lower rates of regular exercise.

Access to medical care was also a prime factor, the study found. Minorities had lower incomes and less wealth, and lack of health insurance was "particularly problematic," the researchers conclude.

Spanish-speaking Hispanic adults were worst off when it came to insurance, with 20 percent having no coverage and more than one-third relied on Medicaid, the government program for low-income Americans.

In contrast, less than 4 percent of white arthritis sufferers were uninsured, and 58 percent had private insurance.

According to Song's team, black and Hispanic arthritis sufferers need better treatment of their co-existing conditions, and more encouragement to make lifestyle changes, like taking up regular exercise.

Future studies, the researchers add, should test ways to reach minority arthritis patients more effectively.

SOURCE: Arthritis & Rheumatism, August 2007.

NEW YORK (Reuters Health) - Peanuts may be more notorious, but cashews seem to trigger more severe allergic reactions in children. In a study of 141 children with allergies to cashews or peanuts, British researchers found that cashew reactions were generally more serious.

For the study, led by Dr. Andrew T. Clark of Addenbrookes Hospital in Cambridge, 47 children with cashew allergy were matched up one-to-two with 94 children with peanut allergy. Children with cashew reactions were eight times more likely to suffer wheezing, and nearly 14 times more likely to have potentially severe cardiovascular symptoms, like heartbeat disturbances or a drop in blood pressure.

Overall, 10 of the children with cashew allergies had what the researchers defined as a severe reaction -- extreme difficulty breathing and/or loss of consciousness. That compared with just one child with peanut allergy.

The findings appear in the current issue of the journal Allergy.

It's known that tree nuts, such as cashews and walnuts, can trigger serious allergic reactions. However, this is the first study to show that children's allergies to cashews may be more severe than peanut allergies, according to Clark's team.

What's more, studies suggest that cashew allergies are becoming more common, possibly because consumption is on the rise.

Besides being eaten as whole cashews, the nuts are also found in a range of desserts and candies, in many Asian dishes and in commercially prepared pesto sauces, Clark and his colleagues note.

Other potential sources include cereals, granola bars, dressings and sauces, and even shampoos and lotions.

In general, people with an allergy to any tree nut are advised to avoid all tree nuts and peanuts as a precaution. Some people are prescribed injectable epinephrine that they can administer themselves in an emergency.

The current findings, Clark and his colleagues write, suggest that children with cashew allergies are at particular risk of severe reactions requiring epinephrine. They advise doctors to consider this when deciding whether to prescribe the emergency treatment.

SOURCE: Allergy, August 2007.

By Ed Stoddard

HALIFAX, Nova Scotia (Reuters) - Doctors recommend a good dose of salmon or tuna in the diet because of its benefits to the heart. But is it good for the environment?

Surging demand for salmon in particular has been spurred in part by numerous studies touting the health benefits of omega-3 fatty acids, which are present in some kinds of fish.

A study published in June in the American Heart Association journal Circulation said a diet with liberal servings of fish, nuts and seeds rich in such nutrients can help lower a person's blood pressure. Other studies have shown benefits to eye and brain development and preventing heart disease, Alzheimer's disease and eye disorders.

Conservationists point out that while global fish stocks were getting hammered long before sushi became chic, health trends could add pressure to already vulnerable fisheries.

"Over-fishing has predated the interest in omega-3 and healthy eating. But now there are places where it is certainly going to accentuate it," said Jason Clay, vice president of markets at the World Wildlife Fund (WWF).

"The FAO (U.N. Food and Agriculture Organization) estimates that by 2030 average annual per capita global consumption of fish will increase by 1.5 kgs (3.4 pounds) and some of it will be driven by health-related demand," he said.

SUSTAINABLE VERSUS UNSUSTAINABLE

When it comes to omega-3 fatty acids, not all fish are equal. Fatty fish such as trout, salmon, mackerel and Alaska pollock are rich in this crucial group of nutrients.

Tuna are, too, but few wild tuna fisheries are regarded by conservationists as sustainable.

"It depends on your source ... Omega-3s are very high in wild salmon and the Alaskan salmon fishery is well-managed," said Phil Kline, an ocean campaigner with Greenpeace.

Alaska salmon are among the fisheries that have been certified as sustainable by the British-based Marine Stewardship Council. It uses stringent criteria for a fishery to get its seal of approval and the right to bear its eco-label.

It has not yet given its blessing to any tuna fishery but is assessing the sustainability of the U.S. Pacific coast albacore tuna industry.

Demand for salmon has certainly been soaring.

According to the U.S. National Fisheries Institute, American per capita consumption of salmon has risen from 0.87 pounds (0.39 kg) per year in 1992 to 2.026 pounds (0.92 kg) in 2006. The species also went from being America's sixth most popular fish to eat to its third over the same period of time.

In a well-managed situation, such demand can lead to conservation: it's in no one's interest to deplete something of value.

"In the long run, the more valuable wild salmon are the better they are likely to be protected," said Gunnar Knapp, a professor of economics at the University of Alaska's Institute of Social and Economic Research.

He said high demand and prices gave people an incentive to protect vital salmon habitat such as spawning grounds in rivers from other industries such as logging and mining.

"In Alaska, even if the price of salmon were to quadruple it would not lead to too many fish being caught because the limiting factor is not the price but how much the managers allow the fishermen to catch, and they make that assessment purely on biological grounds," Knapp told Reuters by phone from Anchorage.

But he said Russia's salmon fishery, for example, was not so well managed and could suffer overfishing as prices rise.

Much of the burgeoning demand for salmon is being met by the rapidly growing aquaculture industry, but experts say there are environmental concerns linked to that, too.

WWF's Clay said fish being caught for fishmeal to feed the aquaculture industry include species such as anchovies, which are rich in omega-3s but which have questions over their sustainability.

"One out of every three fish that is caught right now is used to make feed for other fish," he said.

Fish don't actually produce omega-3 fatty acids, they capture it from the food chain.

And there are plenty of substitutes out there such as walnuts, flaxseed and canola oil, which can provide the same omega-3-related benefits as fish.

In the past, children in many parts of the world were given cod liver oil as a health supplement. These days, they are more likely to take fish oil capsules made from other species.

For conservationists, the question is whether the latest health trend will result in salmon and other species going the same way as eastern Canada's cod fishery, once one of the world's richest which utterly collapsed last decade.

By Will Boggs, MD

NEW YORK (Reuters Health) - Children who suffer from hay fever, due to allergies to mold or pollen, are less likely to go on to develop asthma if they get immunotherapy to combat their sensitivity to allergy-triggers, researchers say.

Immunotherapy aims to build up tolerance to substances that set off allergic reactions by slowly exposing the affected person to gradually increasing doses of the allergen, either by injections or administration under the tongue. The process can take months or years to achieve full desensitization.

The current study, a follow-up of the Preventive Allergy Treatment (PAT) study, showed that specific immunotherapy for children with hay fever, or "seasonal allergic rhinoconjunctivitis," helps prevent the development of asthma for up to 7 years after treatment ends.

The PAT study investigated whether the effects of 3 years of immunotherapy persist in children with seasonal allergic rhinoconjunctivitis caused by birch and/or grass pollen allergy as they grow up. The results at 10 years after the start of treatment are reported in the medical journal Allergy.

Dr. L. Jacobsen from ALK-Abello, Horsholm, Denmark and colleagues found that, among 117 children who were free of asthma at the start of the study, those given immunotherapy were 4.6 times more likely than those treated with an inactive "placebo" to remain free of asthma during the 10 years of follow-up.

Of 53 patients given placebo, 24 developed asthma, whereas among the 64 patients in the immunotherapy group, 16 became asthmatic.

Furthermore, the beneficial effect of immunotherapy in easing allergy symptoms, like runny noses and itchy eyes, also persisted 7 years after completion of 3 years of treatment.

"This 10-year follow-up study demonstrates that specific immunotherapy for 3 years with high-dose standardized allergen extracts shows persistent long-term effect on clinical symptoms after termination of treatment and long term, preventive effect on later development of asthma in children with seasonal rhinoconjunctivitis," Jacobsen's team concludes.

"In this light," they write, "specific immunotherapy should be recognized not only as first line therapeutic treatment for allergic rhinoconjunctivitis but also as secondary preventive treatment for respiratory allergic disease."

SOURCE: Allergy, August 2007.