Barnyard dust could hold the answer to asthma

Scientists say they may have found a magic elixir, of sorts, when it comes to stopping childhood asthma: dust containing microbes from farm animals. The results of their research were published Wednesday in The New England Journal of Medicine and have opened up the possibility of developing a spray for children who do not have access to barnyard animals, Gina Kolata reports for The New York Times. "It is a pressing problem because as many as 10.6 percent of grade-school children have asthma, according to data from the Centers for Disease Control and Prevention," Kolata writes. There is currently no cure for asthma.

The research began around the notion that perhaps kids develop asthma because the places in which they grow up are too germ-free. "If children are exposed to microbes that stimulate their immune systems in the first few years of life, they will be protected against asthma, the hypothesis says. As asthma rates climbed, researchers published study after study supporting what has become known as the hygiene hypothesis," Kolata notes.

This particular study began when a group of researchers noticed stark differences among two
seemingly similar groups: the Amish of Indiana and the Hutterites of North Dakota. Asthma affects only 2 to 4 percent of the Amish, Kolata writes, but affects 15 to 20 percent of the Hutterites. The groups are very similar in genetic background, diet and lifestyle. "There was one difference, though: farming methods," Kolata explains. "The Amish live on single-family dairy farms. They do not use electricity, and use horses to pull their plows and for transportation. Their barns are close to their homes, and their children play in them. The Hutterites have no objection to electricity and live on large, industrialized communal farms. Their cows are housed in huge barns, more like hangars, away from their homes. Children do not generally play in Hutterite barns."

A Hutterite dairy farm in North Dakota

In a preliminary study, researchers found that the none of the Amish children studied had asthma and all had "a large proportion of neutrophils — white blood cells that are the immune system’s paramedics and are part of what is known as the innate immune system," Kolata writes. By contrast, six of the 30 Hutterite children in the preliminary study had asthma, "and all of them had far fewer neutrophils in their blood. . . . Instead, their blood was swarming with another type of immune cell, eosinophils, which provoke allergic reactions." (The New York Times photo by Carole Ober.)

After analyzing the dust from Amish and Hutterite homes, researchers found that Amish dust was packed with debris from bacteria; Hutterite dust was not. Researchers sent the dust to Dr. Donata Vercelli, an associate director of the asthma and airway research center at the University of Arizona, for testing in mice. "She put dust — Amish or Hutterite — into the airways of mice 14 times over a month and then exposed the animals to allergens," Kolata explains. "We found exactly what we found in the children," Vercelli told Kolata. "If we give the Amish dust, we protect the mice. If we give the Hutterite dust, we do not protect them."

The impact could be far-reaching. Dr. Talal Chatila, an immunologist at Harvard Medical School, told Kolata, "It is not far-fetched to start thinking of how one could harness those bacteria for a therapeutic intervention."

Johns Hopkins study correlates fracking to asthma

Living close to natural-gas wells using hydraulic fracturing is associated with asthma attacks, says a study by the Johns Hopkins Bloomberg School of Public Health, published in JAMA Internal Medicine. Researchers found that people who live near bigger or larger numbers of wells are one and a half to four times more likely to have asthma attacks than people who live farther away. (Johns Hopkins map)

The study, which used data from 2005 through 2012 in 40 Pennsylvania counties, identified 35,000 asthma patients between the ages of five and 90 years, logging 20,749 mild attacks (requiring a corticosteroid prescription), 1,870 moderate ones (requiring an emergency room visit) and 4,782 severe attacks (requiring hospitalization).

Researchers were unable to identify why asthma attacks increased near natural gas wells, but said "air pollution and increased stress levels from the noise, traffic and other community impacts associated with the industry could play a role. In previous research, stress has been implicated in substantially increasing the risk of asthma attacks." (Read more)

Farm dust helps children raised on dairy farms have reduced allergies and asthma, study says

A study published Thursday in Science says that "growing up on a dairy farm protects children from allergy, hay fever and asthma." Using mice as subjects, researchers said "that chronic exposure to low-dose endotoxin or farm dust protects mice from developing house dust mite induced asthma." Researchers said children growing up on dairy farms "breathe air containing bacterial components, which reduce the overall reactivity of the immune system."

The research is related to the hygiene hypothesis, "where a lack of exposure to microbes as a tyke leads to more allergy and asthma," Rachel Feltman reports for The Washington Post. "There's increasing evidence that farms have the best germs for preventing respiratory problems and allergic reactions later in life. One study found that just 25 percent of children living on Swiss farms reacted to common allergens like dust mites, pollen, animals and mold, while 45 percent of children in the general population reacted." Among Amish children, the rate is 8 percent.

"Scientists believe that the bacteria native to farms, especially ones that house livestock, may trigger something in children who live nearby," Feltman writes. "Scientists induced dust mite allergies in mice, then showed that exposure to dust from a dairy farm made early in life made them immune. Then, they studied the mechanism that was protecting the mice, making their mucous membranes less likely to react to the allergens. They found a protein called A20, which the mice were producing when exposed to the farm dust. When the researchers knocked out the A20 in their subjects' lungs, the farm dust stopped protecting them from allergic reactions." (Read more)

Poverty and asthma go hand-in-hand for rural African American children, researchers says

Being poor and African American increases children's risk of developing asthma, regardless of whether they live in a rural or urban area, says a study by the Medical College of Georgia, Robert Preidt reports for Health Day. Researchers, who estimated that 60 to 70 percent of asthma risk is environmental, said the study "challenges the common belief that living in a city boosts the chances of developing the respiratory condition" and "asthma is a disease of poverty and poor housing, where children are exposed to high levels of asthma triggers such as mold, fungi, cockroaches, mice, dust mites and tobacco smoke."

Comparing data of 7,300 students at six public high schools in Detroit with data of 2,500 students in rural Georgia, researchers said results were nearly identical, Preidt writes. In Detroit, 15 percent of students had diagnosed asthma, and 8 percent had undiagnosed asthma, while in rural Georgia, 14 percent had diagnosed asthma, and 7.5 percent undiagnosed asthma. Researchers said that more than 90 percent of the children in Detroit and more than 60 percent of the children in rural Georgia are African American.

The poverty rate in Detroit and rural Georgia is 23 percent, and about 74 percent of students qualified for free or reduced-cost lunches, Preidt writes. Overall, 10 percent of U.S. children have asthma, while 20 percent of African American children suffer from asthma. (Read more)