Sunday, May 22, 2005

Scientists Say Sunshine May Prevent Cancer

Put Away the Sunblock? Scientists Say Moderate Amounts of Sunshine May Prevent Cancer
The Associated Press

May. 21, 2005 - Scientists are excited about a vitamin again. But unlike fads that sizzled and fizzled, the evidence this time is strong and keeps growing. If it bears out, it will challenge one of medicine's most fundamental beliefs: that people need to coat themselves with sunscreen whenever they're in the sun.

Doing that may actually contribute to far more cancer deaths than it prevents, some researchers think.

The vitamin is D, nicknamed the "sunshine vitamin" because the skin makes it from ultraviolet rays. Sunscreen blocks its production, but dermatologists and health agencies have long preached that such lotions are needed to prevent skin cancer.

Now some scientists are questioning that advice.

The reason is that vitamin D increasingly seems important for preventing and even treating many types of cancer. In the last three months alone, four separate studies found it helped protect against lymphoma and cancers of the prostate, lung and, ironically, the skin. The strongest evidence is for colon cancer.

Many people aren't getting enough vitamin D. It's hard to do from food and fortified milk alone, and supplements are problematic.

So the thinking is this: Even if too much sun leads to skin cancer, which is rarely deadly, too little sun may be worse.

No one is suggesting that people fry on a beach. But many scientists believe that "safe sun" 15 minutes or so a few times a week without sunscreen is not only possible but helpful to health.

One is Dr. Edward Giovannucci, a Harvard University professor of medicine and nutrition who laid out his case in a keynote lecture at a recent American Association for Cancer Research meeting in Anaheim, Calif.

His research suggests that vitamin D might help prevent 30 deaths for each one caused by skin cancer.

"I would challenge anyone to find an area or nutrient or any factor that has such consistent anti-cancer benefits as vitamin D," Giovannucci told the cancer scientists. "The data are really quite remarkable."

The talk so impressed the American Cancer Society's chief epidemiologist, Dr. Michael Thun, that the society is reviewing its sun protection guidelines. "There is now intriguing evidence that vitamin D may have a role in the prevention as well as treatment of certain cancers," Thun said.

Even some dermatologists may be coming around. "I find the evidence to be mounting and increasingly compelling," said Dr. Allan Halpern, dermatology chief at Memorial Sloan-Kettering Cancer Center in New York, who advises several cancer groups.

The dilemma, he said, is a lack of consensus on how much vitamin D is needed or the best way to get it.

No source is ideal. Even if sunshine were to be recommended, the amount needed would depend on the season, time of day, where a person lives, skin color and other factors. Thun and others worry that folks might overdo it.

"People tend to go overboard with even a hint of encouragement to get more sun exposure," Thun said, adding that he'd prefer people get more of the nutrient from food or pills.

But this is difficult. Vitamin D occurs naturally in salmon, tuna and other oily fish, and is routinely added to milk. However, diet accounts for very little of the vitamin D circulating in blood, Giovannucci said.

Supplements contain the nutrient, but most use an old form D-2 that is far less potent than the more desirable D-3. Multivitamins typically contain only small amounts of D-2 and include vitamin A, which offsets many of D's benefits.

As a result, pills might not raise vitamin D levels much at all.

Government advisers can't even agree on an RDA, or recommended daily allowance for vitamin D. Instead, they say "adequate intake" is 200 international units a day up to age 50, 400 IUs for ages 50 to 70, and 600 IUs for people over 70.

Many scientists think adults need 1,000 IUs a day. Giovannucci's research suggests 1,500 IUs might be needed to significantly curb cancer.

How vitamin D may do this is still under study, but there are lots of reasons to think it can:

Several studies observing large groups of people found that those with higher vitamin D levels also had lower rates of cancer. For some of these studies, doctors had blood samples to measure vitamin D, making the findings particularly strong. Even so, these studies aren't the gold standard of medical research a comparison over many years of a large group of people who were given the vitamin with a large group who didn't take it. In the past, the best research has deflated health claims involving other nutrients, including vitamin E and beta carotene.

Lab and animal studies show that vitamin D stifles abnormal cell growth, helps cells die when they are supposed to, and curbs formation of blood vessels that feed tumors.

Cancer is more common in the elderly, and the skin makes less vitamin D as people age.

Blacks have higher rates of cancer than whites and more pigment in their skin, which prevents them from making much vitamin D.

Vitamin D gets trapped in fat, so obese people have lower blood levels of D. They also have higher rates of cancer.

Diabetics, too, are prone to cancer, and their damaged kidneys have trouble converting vitamin D into a form the body can use.

People in the northeastern United States and northerly regions of the globe like Scandinavia have higher cancer rates than those who get more sunshine year-round.

During short winter days, the sun's rays come in at too oblique an angle to spur the skin

to make vitamin D. That is why nutrition experts think vitamin D-3 supplements may be especially helpful during winter, and for dark-skinned people all the time.

But too much of the pill variety can cause a dangerous buildup of calcium in the body. The government says 2,000 IUs is the upper daily limit for anyone over a year old.

On the other hand, D from sunshine has no such limit. It's almost impossible to overdose when getting it this way. However, it is possible to get skin cancer. And this is where the dermatology establishment and Dr. Michael Holick part company.

Thirty years ago, Holick helped make the landmark discovery of how vitamin D works. Until last year, he was chief of endocrinology, nutrition and diabetes and a professor of dermatology at Boston University. Then he published a book, "The UV Advantage," urging people to get enough sunlight to make vitamin D.

"I am advocating common sense," not prolonged sunbathing or tanning salons, Holick said.

Skin cancer is rarely fatal, he notes. The most deadly form, melanoma, accounts for only 7,770 of the 570,280 cancer deaths expected to occur in the United States this year.

More than 1 million milder forms of skin cancer will occur, and these are the ones tied to chronic or prolonged suntanning.

Repeated sunburns especially in childhood and among redheads and very fair-skinned people have been linked to melanoma, but there is no credible scientific evidence that moderate sun exposure causes it, Holick contends.

"The problem has been that the American Academy of Dermatology has been unchallenged for 20 years," he says. "They have brainwashed the public at every level."

The head of Holick's department, Dr. Barbara Gilchrest, called his book an embarrassment and stripped him of his dermatology professorship, although he kept his other posts.

She also faulted his industry ties. Holick said the school has received $150,000 in grants from the Indoor Tanning Association for his research, far less than the consulting deals and grants that other scientists routinely take from drug companies.

In fact, industry has spent money attacking him. One such statement from the Sun Safety Alliance, funded in part by Coppertone and drug store chains, declared that "sunning to prevent vitamin D deficiency is like smoking to combat anxiety."

Earlier this month, the dermatology academy launched a "Don't Seek the Sun" campaign calling any advice to get sun "irresponsible." It quoted Dr. Vincent DeLeo, a Columbia University dermatologist, as saying: "Under no circumstances should anyone be misled into thinking that natural sunlight or tanning beds are better sources of vitamin D than foods or nutritional supplements."

That opinion is hardly unanimous, though, even among dermatologists.

"The statement that 'no sun exposure is good' I don't think is correct anymore," said Dr. Henry Lim, chairman of dermatology at Henry Ford Health System in Detroit and an academy vice president.

Some wonder if vitamin D may turn out to be like another vitamin, folate. High intake of it was once thought to be important mostly for pregnant women, to prevent birth defects. However, since food makers began adding extra folate to flour in 1998, heart disease, stroke, blood pressure, colon cancer and osteoporosis have all fallen, suggesting the general public may have been folate-deficient after all.

With vitamin D, "some people believe that it is a partial deficiency that increases the cancer risk," said Hector DeLuca, a University of Wisconsin-Madison biochemist who did landmark studies on the nutrient.

About a dozen major studies are under way to test vitamin D's ability to ward off cancer, said Dr. Peter Greenwald, chief of cancer prevention for the National Cancer Institute. Several others are testing its potential to treat the disease. Two recent studies reported encouraging signs in prostate and lung cancer.

As for sunshine, experts recommend moderation until more evidence is in hand.

"The skin can handle it, just like the liver can handle alcohol," said Dr. James Leyden,

professor emeritus of dermatology at the University of Pennsylvania, who has consulted for sunscreen makers.

"I like to have wine with dinner, but I don't think I should drink four bottles a day."

On the Net:

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Saturday, May 14, 2005

Study Finds Direct Association Between Cardiovascular Disease and Periodontal Bacteria

BETHESDA, MD -- February 8, 2005 -- Researchers report this week that older adults who have higher proportions of four periodontal-disease-causing bacteria inhabiting their mouths also tend to have thicker carotid arteries, a strong predictor of stroke and heart attack. The study, published in the current issue of the journal Circulation, was supported by four agencies of the National Institutes of Health. According to the authors, these data mark the first report of a direct association between cardiovascular disease and bacteria involved in periodontal disease, inflammation of the gums that affects to varying degrees an estimated 200 million Americans. But the researchers say the findings are not proof that the bacteria cause cardiovascular disease, directly or indirectly. "What was interesting to us was the specificity of the association," said Moïse Desvarieux, M. D., Ph. D., the study's lead author and an infectious disease epidemiologist at Columbia University's Mailman School of Public Health and the University of Minnesota. "These same four bacteria were there, they were always there in the analysis, and the relationship seems to be pretty much, with one exception, limited to them." Desvarieux stressed that although the new data further illuminate a long-standing scientific issue, they shed little light on the broader public health question related to cardiovascular disease. The 657 people in the study had their oral bacteria and carotid thickness evaluated at the same point in time. So Desvarieux said, "It's impossible to know which comes first, the periodontal disease or thickening of the carotid artery." The answer to that question is fundamental to establishing causality--in this case, whether chronic inflammation or infection could have led to the atherosclerosis of the carotid arteries. He and his colleagues noted that the public health information could come soon. "We will re-examine the participants in less than three years, and, at that point, we can better evaluate the progression of the atherosclerosis and, hopefully, begin to establish a time frame underlying the diseases," said Ralph Sacco, M.D., M.S., associate chair of Neurology, professor of Neurology and Epidemiology, and the director of the Stroke and Critical Care Division of Columbia University College of Physicians and Surgeons. He also is an author on the paper. The idea that oral bacteria shed from chronic gum infections, enter the circulatory system, and possibly contribute to diseases of the heart and other body organs once was widely accepted in medicine. The concept, known as the "focal infection theory," fell out of fashion by the 1940s, then resurfaced four decades later with the publication of new data proposing a link. Since then, a major sticking point in advancing the research has been simply how to pursue the hypothesis. Lacking the scientific tools to track oral bacteria in the body over several decades to determine if they directly trigger heart disease, most previous studies pursued indirect evidence. These included various measures of oral and cardiovascular health, which researchers then extrapolated to the influence of the oral pathogens. Conspicuously missing from the debate has been a large, well-designed study that in some way directly evaluates the role of the oral pathogens themselves. To fill this void, the National Institute of Dental and Craniofacial Research launched the Oral Infections and Vascular Disease Epidemiology Study (INVEST), a multi-disciplinary endeavor whose principal investigator is Dr. Desvarieux. The study, which is the source of the paper published this week in Circulation, will monitor the oral and cardiovascular health of a large, racially mixed group of people. All enrollees in the study live in a northern section of Manhattan in New York City and are age 55 or older. Participants are also members of the Northern Manhattan Study (NOMAS), a prospective cohort study supported by NIH's National Institute of Neurological Disorders and Stroke. Dr. Sacco is principal investigator of the companion NOMAS study. "Although more than 600 bacteria have been shown to colonize the mouth, each person tends to carry different proportions of these microbes," said Panos N. Papapanou, D.D.S, Ph.D., an author on the paper and professor and chair of the Section of Oral and Diagnostics Sciences and director of the Division of Periodontics at Columbia University School of Dental and Oral Surgery. He noted that only a subset of bacteria tend to be dominant in dental plaque. "We wanted to know during the baseline examination of the participants whether it was true that the greater the proportion of so-called 'bad' bacteria in the mouth, the higher the likelihood of a thickened carotid artery," added Papapanou, whose laboratory performed the periodontal microbiological analysis. To get their answer, Desvarieux and colleagues collected on average seven dental plaque samples from a total of 657 older adults enrolled in INVEST who had not lost their teeth. The samples, taken from predetermined sites in the mouth, both diseased and healthy, were measured for 11 oral bacteria, including four bacteria widely regarded to be involved in causing periodontal disease: Actinobacillus actinomycetemcomitans, Porphyromonas gingivalis, Tannerella forsythia, and Treponema denticola. The other seven bacteria served as controls, as their role in periodontal disease was either neutral or has not yet been established. Then, to evaluate their cardiovascular health, the participants received a carotid intima-media thickness (IMT) measurement and provided a blood sample to determine their C-reactive protein levels. C-reactive protein has been reported to be elevated in people with periodontal disease, and recent studies found that testing for this protein may be predictive of developing heart disease. Controlling for several risk factors that might skew their data - such as smoking and diabetes, both of which are independently associated with these conditions - the scientists found the higher the levels of these periodontal-disease-causing bacteria, the more likely people were to have thicker carotid arteries. Interestingly, they noted no association between IMT, the periodontal pathogens, and C-reactive protein levels, suggesting the protein is involved in another cardiovascular disease pathway. Next, the scientists wondered whether the broad association might be due to the four pathogens involved in causing periodontal disease, which combined accounted for only 23 percent of the bacteria in dental plaque. If so, the finding would provide added specificity to strengthen the case for the association. "After re-analyzing the data, we found, with the exception of an oral bacterium called Micromonas micros, the relationship was limited to these four established oral pathogens," said David Jacobs, Ph. D., another author and a professor in the Division of Epidemiology at the University of Minnesota School of Public Health. "In other words, it was exactly what we hypothesized," said Desvarieux. However, he cautioned, "It now becomes crucial to follow the participants over time and see whether these baseline findings hold up and further translate into clinical disease." The study was supported by the NIH's National Institute of Dental and Craniofacial Research, the National Institute of Neurological Disorders and Stroke, National Heart, Lung, and Blood Institute, and National Center for Research Resources. SOURCE: NIH/National Institute of Dental and Craniofacial Research

Friday, May 13, 2005

Crohn's disease

From Wikipedia, the free encyclopedia.
Crohn's disease is a chronic inflammatory disease of the digestive tract and it can involve any part of it - from the mouth to the anus. It typically affects the terminal ileum as well as demarcated areas of large bowel, with other areas of the bowel being relatively unaffected. It is often associated with auto-immune disorders outside the bowel, such as aphthous stomatitis and rheumatoid arthritis. Crohn's disease should not be confused with a non-progressive and non-degenerative digestive disorder called irritable bowel syndrome. IBS is not an autoimmune disease. Ulcerative colitis is a sibling autoimmune disease to Crohn's but only impacts the colon while Crohn's can impact any part of the digestive tract. Furthermore, Crohn's tends to impact multiple layers of the bowel lining which can lead to many additional and hard to treat complications.------Read online

Wednesday, May 11, 2005

The Mystery Behind the Silence: Typical Presentation of Autism Spectrum Disorders


Recently, the category of neurodevelopmental disorders referred to as the autism spectrum disorders (ASDs) has been receiving increased attention from professional and lay audiences. Questions about prevalence, effective interventions, and approaches for screening and diagnosis have been raised concerning these conditions, which are also referred to as pervasive developmental disorders (PDDs). The ASDs include several disorders that share a range of impairments in the areas of communication development, social relationships, and repetitive and restricted behavioral patterns. The prototypical ASD is autistic disorder, which, according to the criteria defined by the Diagnostic and Statistical Manual of Mental Disorders, fourth edition, text revision,[1] includes delay in language development and usage, problems in social relatedness, and marked restricted and repetitive behavioral patterns. Autistic disorder is associated with mental retardation in the majority of cases. Asperger's disorder is defined as a condition in which language development is normal, but social interaction is impaired, and interests are narrow and repetitive as with autistic disorder. Most people with Asperger's disorder are higher-functioning, and many demonstrate intellectual ability in the normal range. Other ASDs include PDD not otherwise specified (PDD NOS), childhood disintegrative disorder (CDD), and Rett's syndrome. Children with PDD NOS have many features of autistic disorder but do not meet full criteria for the diagnosis. Children with CDD have apparently normal development for the first 2 years or longer followed by a prominent regression in skills in most areas with a course of worsening severity. Rett's syndrome is a highly genetic disorder in girls that is characterized by unique motor behaviors, microcephaly, and gradual regression in skills beginning in early childhood.-----continued online