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Category: brain

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Here are some more articles that I found regarding psychobiotics or the use of probiotics to affect behavior and treat psychiatric disorders.  A probiotic is a microorganism introduced into the body for its beneficial properties. Even though the articles are from 2013, they all give slightly different information about this emerging and exciting new field. Please note that psychotropic means having an effect on how the mind works (and it usually refers to drugs that affect a person's mental state). Remember that this area of research and terminology used is in its infancy. From Medscape (November 2013):

Probiotics a Potential Treatment for Mental Illness

Probiotics, which are live bacteria that help maintain a healthy digestive system, are now often promoted as an important part of dietary supplements and natural food products. "Many of the numerous health-improvement claims have yet to be supported scientifically..."

They note that the term "psychobiotic" was created as recent studies have begun to explore a possible link between probiotics and behavior.  "As a class of probiotic, these bacteria are capable of producing and delivering neuroactive substances such as gamma-aminobutyric acid [GABA] and serotonin, which act on the brain-gut axis," they write.

For this review, the investigators sought to examine studies that assessed whether ingesting these bacteria "in adequate amounts" could potentially lead to an effective treatment for depression and other stress-related disorders. In 1 of the preclinical studies examined, mice that ingested L rhamnosus showed reduced anxiety scores and "altered central expression" on both the GABA type A and type B receptors.

And a study of human patients with chronic fatigue syndrome showed that those who consumed an active strain of L casei 3 times a day had significantly higher improvement scores on anxiety measures than did those who received matching placebo. This provides "further support for the view that a probiotic may have psychotropic effects," write the researchers.

Still, Dr. Dinan called for caution. "What is clear at this point is that, of the large number of putative probiotics, only a small percentage have an impact on behavior and may qualify as psychobiotics," said Dr. Dinan. He added that for now, the field needs to wait for large-scale, placebo-controlled trials to provide definitive evidence of benefit and to detect which probiotics have psychobiotic potential.

Dr. Camille Zenobia wrote this in August 2013. From Real Clear Science:

Can 'Psychobiotic' Bacteria Affect Our Mood?

But what about your brain? Apparently, bacteria influence what’s going on up there, too. Within the last several years, a blossoming field of study called “microbial endocrinology” has provided some provocative insights about the relationship between our GI microbiota and our mood and behavior.

Studies in the field of microbial endocrinology have implicated GI microbes as a factor that can regulate the endocrine system. This could have both good and bad effects since the endocrine system is responsible for the production of hormones and coordinates metabolism, respiration, excretion, reproduction, sensory perception and immune function.

From Nov. 2013 Popular Science:

Forget Prozac, Psychobiotics Are The Future Of Psychiatry

The answer lies in the fact that many psychiatric illnesses are immunological in nature through chronic low level inflammation. There is a plethora of evidence showing the link between gut microbiota and inflammation and studies on probiotic strains have revealed their ability to modulate inflammation and bring back a healthy immunological function.  In this regard, by controlling inflammation through probiotic administration, there should be an effect of improved psychiatric disposition.

The authors bring up another reason why psychobiotics are so unique in comparison to most probiotics.  These strains have another incredible ability to modulate the function of the adrenal cortex, which is responsible for controlling anxiety and stress response. Probiotic strains, such as Lactobacillus helveticus and Bifdobacterium longum have shown to reduce levels of stress hormones and maintain a calmer, peaceful state.  There may be a host of other probiotic bacteria with the same ability although testing has been scant at best.

Finally, the last point in support of psychobiotics is the fact that certain strains of bacteria actually produce the chemicals necessary for a happy self.  But as these chemicals cannot find their way into the brain, another route has been found to explain why they work so well.  They stimulate cells in the gut that have the ability to signal the vagus nerve that good chemicals are in the body.  The vagus nerve then submits this information to the brain, which then acts as if the chemicals were there.  

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Lately some articles have been mentioning the amazing possibility of new treatments for psychiatric disorders using bacteria as psychobiotics. Think of probiotics (microorganisms that have beneficial effects when consumed) that affect the brain. Researchers promoting the use of this term define a psychobiotic as "a live organism that, when ingested in adequate amounts, produces a health benefit in patients suffering from psychiatric illness". This new emerging field is just in its infancy. Lots of speculation and anecdotal evidence, and a few tantalizing studies.

I think the following article is a good introduction to this research area of the gut and mind/brain interaction, even though it was published in late 2013. Or you could order the newly published scholarly book "Microbial Endocrinology: The Microbiota-Gut-Brain Axis in Health and Disease" (Editors M.Lyte and J.F.Cryan) with a $189. purchase price (!).  From November 2103 NPR:

Gut Bacteria Might Guide The Workings Of Our Minds

Could the microbes that inhabit our guts help explain that old idea of "gut feelings?" There's growing evidence that gut bacteria really might influence our minds. 

"I'm always by profession a skeptic," says Dr. Emeran Mayer, a professor of medicine and psychiatry at the University of California, Los Angeles. "But I do believe that our gut microbes affect what goes on in our brains." Mayer thinks the bacteria in our digestive systems may help mold brain structure as we're growing up, and possibly influence our moods, behavior and feelings when we're adults. "It opens up a completely new way of looking at brain function and health and disease," he says.

So Mayer is working on just that, doing MRI scans to look at the brains of thousands of volunteers and then comparing brain structure to the types of bacteria in their guts. He thinks he already has the first clues of a connection, from an analysis of about 60 volunteers. Mayer found that the connections between brain regions differed depending on which species of bacteria dominated a person's gut. 

But other researchers have been trying to figure out a possible connection by looking at gut microbes in mice. There they've found changes in both brain chemistry and behavior. One experiment involved replacing the gut bacteria of anxious mice with bacteria from fearless mice. "The mice became less anxious, more gregarious," says Stephen Collins of McMaster University in Hamilton, Ontario, who led a team that conducted the research. It worked the other way around, too — bold mice became timid when they got the microbes of anxious ones. And aggressive mice calmed down when the scientists altered their microbes by changing their diet, feeding them probiotics or dosing them with antibiotics. 

Scientists also have been working on a really obvious question — how the gut microbes could talk to the brain. A big nerve known as the vagus nerve, which runs all the way from the brain to the abdomen, was a prime suspect. And when researchers in Ireland cut the vagus nerve in mice, they no longer saw the brain respond to changes in the gut. "The vagus nerve is the highway of communication between what's going on in the gut and what's going on in the brain," says John Cryan of the University College Cork in Ireland, who has collaborated with Collins.

Gut microbes may also communicate with the brain in other ways, scientists say, by modulating the immune system or by producing their own versions of neurotransmitters. "I'm actually seeing new neurochemicals that have not been described before being produced by certain bacteria," says Mark Lyte of the Texas Tech University Health Sciences Center in Abilene, who studies how microbes affect the endocrine system. "These bacteria are, in effect, mind-altering microorganisms."

This research raises the possibility that scientists could someday create drugs that mimic the signals being sent from the gut to the brain, or just give people the good bacteria — probiotics — to prevent or treat problems involving the brain. Experiments to test whether changing gut microbes in humans could affect the brain are only just beginning. 

One team of researchers in Baltimore is testing a probiotic to see if it can help prevent relapses of mania among patients suffering from bipolar disorder."The idea is that these probiotic treatments may alter what we call the microbiome and then may contribute to an improvement of psychiatric symptoms," says Faith Dickerson, director of psychology at the Sheppard Pratt Health System.

Mayer also has been studying the effects of probiotics on the brain in humans. Along with his colleague Kirsten Tillisch, Mayer gave healthy women yogurt containing a probiotic and then scanned their brains. He found subtle signs that the brain circuits involved in anxiety were less reactive, according to a paper published in the journal Gastroenterology.

But Mayer and others stress that a lot more work will be needed to know whether that probiotic — or any others — really could help people feel less anxious or help solve other problems involving the brain. He says, "We're really in the early stages."

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Research reports and articles on the benefits of exercise have been piling up. Here are some worth looking at. From Science Daily:

Sitting too much, not just lack of exercise, is detrimental to cardiovascular health

Cardiologists have found that sedentary behaviors may lower cardiorespiratory fitness levels. New evidence suggests that two hours of sedentary behavior can be just as harmful as 20 minutes of exercise is beneficial.

From Science Daily:

Out of shape? Your memory may suffer

Here's another reason to drop that doughnut and hit the treadmill: A new study suggests aerobic fitness affects long-term memory. "The findings show that lower-fit individuals lose more memory across time," said a co-author. The study is one of the first to investigate young, supposedly healthy adults. 

From Science Daily:

Less exercise, not more calories, responsible for expanding waistlines

Sedentary lifestyle and not caloric intake may be to blame for increased obesity in the US, according to a new analysis. A study reveals that in the past 20 years there has been a sharp decrease in physical exercise and an increase in average body mass index (BMI), while caloric intake has remained steady. 

From Science Daily:

Older adults: Build muscle and you'll live longer

The more muscle mass older Americans have, the less likely they are to die prematurely, new research shows. The findings add to the growing evidence that overall body composition -- and not the widely used body mass index, or BMI -- is a better predictor of all-cause mortality. "In other words, the greater your muscle mass, the lower your risk of death," said the study's co-author. "Thus, rather than worrying about weight or body mass index, we should be trying to maximize and maintain muscle mass."

From Medical Xpress:

Keeping active pays off in your 70s and 80s

Older people who undertake at least 25 minutes of moderate or vigorous exercise everyday need fewer prescriptions and are less likely to be admitted to hospital in an emergency, new research has revealed.

Researchers from the Universities of Bath, Bristol and UWE-Bristol looked at data from 213 people whose average age was 78. Of people studied, those who carried out more than 25 minutes of moderate to vigorous physical activity per day – such as walking quickly, cycling or swimming - received 50 per cent fewer prescriptions than those who were more active over a four to five year period.

Such physical activity leads to a higher metabolism and better circulation, reducing the risk of conditions and diseases common in older age such as high blood presure, type 2 diabetes, coronary heart disease, and strokes.

From Everyday Health:

The Best Anti-Aging Medicine? Exercise

Everyone knows that exercise is good for you — it helps manage weight, improves muscle and bone strength, and even lifts your spirits. It can also add years to your life.“People have been looking for the secret to a long and healthy life for millennia,” said Neil Resnick, MD, chief of the division of geriatrics and director of the University of Pittsburgh Institute on Aging. “It turns out the most powerful intervention is exercise.”

A recent study conducted at Harvard found that exercise can be at least as effective as prescription drugs when it comes to preventing common conditions such as heart disease, stroke, and diabetes.

Exercise at any age is beneficial. From Science Daily:

Seniors who exercise regularly experience less physical decline as they age

Older adults in retirement communities who reported more exercise experienced less physical decline than their peers who reported less exercise, although many adults -- even those who exercised -- did not complete muscle-strengthening exercises, which are another defense against physical decline.

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The researchers of this study looked at proximity to farm fields (how close a pregnant woman lives to a farm) and certain farm pesticides and found a link between exposure to farm pesticides during pregnancy and having a child with autism. But too bad they didn't also include pesticide exposures from homes (for pest control), gardens, and yards which would have given a more accurate measure of total exposure. However, it's a start. From Science Daily:

Association found between maternal exposure to agricultural pesticides and autism

Pregnant women who lived in close proximity to fields and farms where chemical pesticides were applied experienced a two-thirds increased risk of having a child with autism spectrum disorder or other developmental delay, a study by researchers with the UC Davis MIND Institute has found. The associations were stronger when the exposures occurred during the second and third trimesters of the women's pregnancies.

The large, multisite California-based study examined associations between specific classes of pesticides, including organophosphates, pyrethroids and carbamates, applied during the study participants' pregnancies and later diagnoses of autism and developmental delay in their offspring. It is published online in Environmental Health Perspectives. "... the message is very clear: Women who are pregnant should take special care to avoid contact with agricultural chemicals whenever possible."

California is the top agricultural producing state in the nation, grossing $38 billion in revenue from farm crops in 2010. Statewide, approximately 200 million pounds of active pesticides are applied each year, most of it in the Central Valley, north to the Sacramento Valley and south to the Imperial Valley on the California-Mexico border. While pesticides are critical for the modern agriculture industry, certain commonly used pesticides are neurotoxic and may pose threats to brain development during gestation, potentially resulting in developmental delay or autism.

The study was conducted by examining commercial pesticide application using the California Pesticide Use Report and linking the data to the residential addresses of approximately 1,000 participants in the Northern California-based Childhood Risk of Autism from Genetics and the Environment (CHARGE) Study. The study includes families with children between 2 and 5 diagnosed with autism or developmental delay or with typical development. "We mapped where our study participants' lived during pregnancy and around the time of birth. In California, pesticide applicators must report what they're applying, where they're applying it, dates when the applications were made and how much was applied," Hertz-Picciotto said. "What we saw were several classes of pesticides more commonly applied near residences of mothers whose children developed autism or had delayed cognitive or other skills."

Organophosphates applied over the course of pregnancy were associated with an elevated risk of autism spectrum disorder, particularly for chlorpyrifos applications in the second trimester. Pyrethroids were moderately associated with autism spectrum disorder immediately prior to conception and in the third trimester. Carbamates applied during pregnancy were associated with developmental delay.

Exposures to insecticides for those living near agricultural areas may be problematic, especially during gestation, because the developing fetal brain may be more vulnerable than it is in adults. Because these pesticides are neurotoxic, in utero exposures during early development may distort the complex processes of structural development and neuronal signaling, producing alterations to the excitation and inhibition mechanisms that govern mood, learning, social interactions and behavior.

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Please note that in the following study 200 grams is a measure of weight, and a little over a cup of many fruits and vegetables. Some examples: blueberries 1 cup=190 grams, green peas 1 cup=145 grams, but young salad greens 1 cup=20 grams. From Medical Daily:

Consuming Up To 200 Grams Of Fruits And Vegetables Will Decrease Your Stroke Risk

It’s not surprising that fruits and vegetables are the key to various health benefits, and now researchers are emphasizing their importance for reducing the risk of stroke.

In the study, researchers found that the stroke risk declined by 32 percent for the participants who ate 200 grams of fruit per day — and decreased by 11 percent for every 200 grams of daily vegetables. “Improving diet and lifestyle is critical for heart and stroke risk reduction in the general population,” Dr. Yan Qu, senior study author and director of the intensive care unit at Qingdao Municipal Hospital in China, said in a news release. “In particular, a diet rich in fruits and vegetables is highly recommended because it meets micronutrient and macronutrient and fiber requirements without adding substantially to overall energy requirements.”

Authors of the study reviewed 20 studies over the course of 19 years that involved over 760,000 people throughout the U.S., Asia, and Europe. The beneficial effects of fruits and vegetables were apparent across the board in both men and women. 

 

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It would be exciting if vitamin D supplementation improves cognitive function in the elderly. From Science Daily:

Vitamin D deficiency, cognition appear to be linked in older adults

Vitamin D deficiency and cognitive impairment are common in older adults, but there isn't a lot of conclusive research into whether there's a relationship between the two.

"This study provides increasing evidence that suggests there is an association between low vitamin D levels and cognitive decline over time," said lead author Valerie Wilson, M.D., assistant professor of geriatrics at Wake Forest Baptist. "Although this study cannot establish a direct cause and effect relationship, it would have a huge public health implication if vitamin D supplementation could be shown to improve cognitive performance over time because deficiency is so common in the population."

Wilson and colleagues were interested in the association between vitamin D levels and cognitive function over time in older adults. They used data from the Health, Aging and Body composition (Health ABC) study to look at the relationship. The researchers looked at 2,777 well-functioning adults aged 70 to 79 whose cognitive function was measured at the study's onset and again four years later. Vitamin D levels were measured at the 12-month follow-up visit.

The Health ABC study cohort consists of 3,075 Medicare-eligible, white and black, well-functioning, community-dwelling older adults who were recruited between April 1997 and June 1998 from Pittsburgh, Pa., and Memphis, Tenn.

"With just the baseline observational data, you can't conclude that low vitamin D causes cognitive decline. When we looked four years down the road, low vitamin D was associated with worse cognitive performance on one of the two cognitive tests used," Wilson said. "It is interesting that there is this association and ultimately the next question is whether or not supplementing vitamin D would improve cognitive function over time."

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The benefits of exercise and being fit keeps growing. From Medical Daily:

Physical Fitness In Your 20s Can Help Preserve Your Thinking Skills Later On In Life

If you need some motivation to get up off the couch and in your running shoes than how about this; a new study has proved that those who are fitter in their 20s are sharper thinkers in their middle age. So not only does exercise improve your health, slim your waistline, and lift your mood, but apparently it can also make you smarter. 

The study was carried out by researchers at the University of California, San Francisco. It started in 1985 and was conducted on nearly 3,000 19- to 30-year-olds in the U.S. The participants were asked to do a treadmill test and undergo physical examinations. They were asked to run for as long as they could without becoming exhausted or short of breath, according to the BBC. Then, 20 years later, the participants agreed to repeat the physical test. Five years after the second physical exam the participants underwent brain testing. These included a word recall test, a number-based test of attention, thinking speed and memory, and a test of how well people can focus while tuning out distractions. Results showed that the better people did on the treadmill test 20 years earlier, the better they did on the memory test. Also, those who had kept up their fitness later on in life scored the best overall in the memory tests. The researchers took into account factors such as weight, sex, drinking, smoking, and education. Still, those who did better on the treadmill test seemed to do better on the memory tests years later. 

The reasoning for this is that the brain uses a lot of oxygen and people who are fitter make more efficient use of oxygen. Also, exercise improves mitochondrial function, which is necessary in making use of energy. It is emphasized that this increase in brain function cannot be attributed to exercise alone. People who are physically fit are less likely to be sat in front of a television and more likely to interact with people and be engaged in life. “Just moving around — being engaged in family and life as opposed to sitting down and watching TV and pretty much not doing anything, they are going to preserve brain function. This is really about engagement in life,” lead researcher David Jacobs told NBC News. The study will continue by observing whether physical fitness in youth makes individuals less likely to develop Alzheimer’s disease later on in life. “Investment in research is vital to better understand how we can protect our brains as we age,” Jacobs concluded.

This research also ties in with another study released this week that showed young adults who had better heart health, as measured by blood pressure, have better thinking skills in middle age than those with high blood pressure.

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A totally off the wall study that I think will interest those who have wondered if we can control our dreams. This is especially appealing for everyone wanting pleasant dreams and wanting to avoid nightmares. From Science Daily:

Mass participation experiment reveals how to create the perfect dream

Today psychologist Professor Richard Wiseman from the University of Hertfordshire announces the results of a two-year study into dream control. The experiment shows that it is now possible for people to create their perfect dream, and so wake up feeling especially happy and refreshed.

In 2010, Professor Wiseman teamed-up with app developers YUZA to create 'Dream:ON' -- an iPhone app that monitors a person during sleep and plays a carefully crafted 'soundscape' when they dream. Each soundscape was carefully designed to evoke a pleasant scenario, such as a walk in the woods, or lying on a beach, and the team hoped that these sounds would influence people's dreams. At the end of the dream, the app sounded a gentle alarm and prompted the person to submit a description of their dream.

The app was downloaded over 500,000 times and the researchers collected millions of dream reports. After studying the data, Professor Wiseman discovered that the soundscapes did indeed influence people's dreams.

Richard Wiseman, professor in the Public Understanding of Psychology at the University of Hertfordshire, said: "If someone chose the nature landscape then they were more likely to have a dream about greenery and flowers. In contrast, if they selected the beach soundscape then they were more likely to dream about the sun beating down on their skin."

"In 2013, neuroscientists from the University of Basel discovered that people experience more disturbed sleeping patterns around the time of a full Moon," remarked Wiseman. "We have seen a similar pattern, with more bizarre dreams being associated with a full moon."

Finally, the team also found that certain soundscapes produced far more pleasant dreams.

The findings are described in Professor Wiseman's book on sleep and dreaming, Night School. The Dream:ON app and all of the soundscapes are currently available free of charge.

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Article about the growing body of research supporting exercise in the treatment of depression. From The Atlantic:

For Depression, Prescribing Exercise Before Medication

Depression is the most common mental illness—affecting a staggering 25 percent of Americans—but a growing body of research suggests that one of its best cures is cheap and ubiquitous. In 1999, a randomized controlled trial showed that depressed adults who took part in aerobic exercise improved as much as those treated with Zoloft. A 2006 meta-analysis of 11 studies bolstered those findings and recommended that physicians counsel their depressed patients to try it. A 2011 study took this conclusion even further: It looked at 127 depressed people who hadn’t experienced relief from SSRIs, a common type of antidepressant, and found that exercise led 30 percent of them into remission—a result that was as good as, or better than, drugs alone.

Though we don’t know exactly how any antidepressant works, we think exercise combats depression by enhancing endorphins: natural chemicals that act like morphine and other painkillers. There’s also a theory that aerobic activity boosts norepinephrine, a neurotransmitter that plays a role in mood. And like antidepressants, exercise helps the brain grow new neurons.

But this powerful, non-drug treatment hasn’t yet become a mainstream remedy. In a 2009 study, only 40 percent of patients reported being counseled to try exercise at their last physician visit.

Instead, Americans are awash in pills. The use of antidepressants has increased 400 percent between 1988 and 2008. They’re now one of the three most-prescribed categories of drugs, coming in right after painkillers and cholesterol medications.

After 15 years of research on the depression-relieving effects of exercise, why are there still so many people on pills? The answer speaks volumes about our mental-health infrastructure and physician reimbursement system, as well as about how difficult it remains to decipher the nature of depression and what patients want from their doctors.

When it comes to non-drug remedies for depression, exercise is actually just one of several promising options. Over the past few months, research has shown that other common lifestyle adjustments, like meditating or getting more sleep, might also relieve symptoms. Therapy has been shown to work just as well as SSRIs and other medications. In fact, a major JAMA study a few years ago cast doubt on the effectiveness of antidepressants in general, finding that the drugs don't function any better than placebo pills for people with mild or moderate depression.

The half-dozen psychiatrists I interviewed said they’ve started to incorporate non-drug treatments into their plans for depressed patients. But they said they’re only able to do that because they don’t accept insurance. (One of the doctors works for a college system and only sees students.)

That’s because insurers still largely reimburse psychiatrists, like all other doctors, for each appointment—whatever that appointment may entail—rather than for curing a given patient. It takes less time to write a prescription for Zoloft than it does to tease out a patient’s options for sleeping better and breaking a sweat. Fewer moments spent mapping out jogging routes or sleep schedules means being able to squeeze in more patients for medications each day.

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This is really an important finding. For a while now many scientists have thought there was an environmental exposure (such as pesticides) link to autism. From Science Daily:

Autism, intellectual disability incidence linked with environmental factors

An analysis of 100 million US medical records reveals that autism and intellectual disability (ID) rates are correlated at the county level with incidence of genital malformations in newborn males, an indicator of possible congenital exposure to harmful environmental factors such as pesticides.

Autism rates -- after adjustment for gender, ethnic, socioeconomic and geopolitical factors -- jump by 283 percent for every one percent increase in frequency of malformations in a county. Intellectual disability rates increase 94 percent. Slight increases in autism and ID rates are also seen in wealthier and more urban counties.

The study, published by scientists from the University of Chicago March 13 in PLOS Computational Biology, confirms the dramatic effect of diagnostic standards. Incidence rates for Autism and ID on a per-person basis decrease by roughly 99 percent in states with stronger regulations on diagnosis of these disorders.

"Autism appears to be strongly correlated with rate of congenital malformations of the genitals in males across the country," said study author Andrey Rzhetsky, PhD, professor of genetic medicine and human genetics at the University of Chicago. "This gives an indicator of environmental load and the effect is surprisingly strong."

Although autism and intellectual disability have genetic components, environmental causes are thought to play a role. To identify potential environmental links, Rzhetsky and his team analyzed an insurance claims dataset that covered nearly one third of the US population. They used congenital malformations of the reproductive system in males as an indicator of parental exposure to toxins.

Male fetuses are particularly sensitive to toxins such as environmental lead, sex hormone analogs, medications and other synthetic molecules. Parental exposure to these toxins is thought explain a large portion of congenital reproductive malformations, such as micropenis, hypospadias (urethra on underside of the penis), undescended testicles and others.

The researchers created a statistical baseline frequency of autism and ID across the country. They then looked at the actual rates of these disorders, county-by-county. Deviations from the baseline are interpreted as resulting from local causes. Factors such as age, ethnicity, socioeconomic groups and geopolitical statuses were analyzed and corrected for.

The team found that every one percent increase in malformations in a county was associated with a 283 percent increase in autism and 94 percent increase in ID in that same county. Almost all areas with higher rates of autism also had higher rates of ID, which the researchers believe corroborates the presence of environmental factors. In addition, they found that male children with autism are almost six times more likely to have congenital genital malformations. Female incidence was linked with increased malformation rates, but weakly so. A county-by-county map of autism and ID incidence above or below the predicted baseline for the entire US is included in the study.

Non-reproductive congenital malformations and viral infections in males were also associated with double digit increases in autism and ID rates. Additionally, income appeared to have a weak effect -- every additional $1,000 of income above county average was correlated with around a three percent increase in autism and ID rates. An increased percentage of urban population in a county also showed a weak increase in rates.