Detecting Asthma Irritants

By Brittany Sauser

Researchers at Georgia Tech Research Institute (GTRI) in Atlanta have developed a portable sensor system to monitor the air quality for people suffering from asthma. The device is a combination of sensors that measure the level of chemicals in the air thought to cause asthma attacks, such as ozone, volatile organic compounds, and formaldehyde. It is lightweight and small enough to fit into a patient's pocket, so exposure levels can be continuously monitored.

The only way that we are going to understand how environmental factors affect asthma is if we can measure a person's exposures on a day-to-day basis, says Charlene Bayer, the leader of the Environmental Exposures and Analysis Group at GTRI and the sensor system's principal investigator. "To do so, we need a device like this that can hold numerous sensors in a small, portable package.".

An estimated 20 million Americans suffer from asthma, according to the National Institutes of Health (NIH), and identifying the triggers of an attack is currently a guessing game. "There are a few devices on the market that measure one or two chemicals, but they are stationary and the size of a desktop computer," says Mark Jones, the chief executive officer of Keehi Technologies and the lead engineer developing the sensor system.

Currently, the only way to control an asthma attack is with medication, or "trigger avoidance." In 2007, the total health-care costs of asthma in the United States were approximately $19.7 billion, according to the NIH.

"Research has shown that if you can reduce the triggering of an asthma attack, you will reduce the impact of the disease," says Mark Millard, the director of the Baylor Martha Foster Lung Care Center at Baylor University Medical Center in Dallas, TX. The new sensor system, he says, is really trying to answer the question, "What are the triggers for people with asthma?"

The device is about the size of a cell phone and contains a total of five sensors that measure different possible asthma triggers: ozone, nitrogen dioxide, formaldehyde, carbon dioxide, and total volatile organic compounds--the brew of chemicals that are emitted as gases from products such as paints, cleaning supplies, and building materials. The device also includes temperature and humidity sensors and a clock, to put a time stamp on the measurements. The researchers used sensors already on the market and kept the device small by outfitting the sensors on a two-sided circuit board.

Establishing a timeline is important for late-phase reactions, says Millard, since reactions to compounds such as formaldehyde may happen four to six hours after a patient is exposed. "Now we can look at the data and know that a patient was exposed to a lot of those compounds and that could be the trigger."

To measure the air quality, a small motor in the device sucks in air through an intake hose. Before the air passes over the sensors, it encounters a small filter that removes particulates, such as dust and pollen. The mass of the filter is measured before and after a sampling period to determine the total amount of particles. The air is then evenly distributed over the sensors.

"It takes about 30 seconds for the air to pass through the device and the data to be stored, and then it goes to sleep for another minute. In one hour it takes approximately 50 or 60 samples," says Jones.

The device can be worn for up to 24 hours before the particle filter needs to be replaced and the memory on the device is full. The data can be downloaded from the sensor system onto a computer.

Millard says the device is unique and innovative, but that he would like to see its capabilities expanded to measure tobacco smoke. He would also like to be able to separate out the particle measurements so they can be measured in real time--an upgrade that Bayer says will be introduced once the device is commercialized. Bayer would also like to get more specific readings on the different volatile organic compounds.

"We would like to get to the point where we can pop certain sensors in and out so a patient can target it towards their particular needs," says Bayer. "Asthma is a very complicated disease and there are a number of different airborne exposures that can exacerbate an asthma attack. This technology will allow us to find the source of exacerbation and understand the health impacts," she says.

The researchers at GTRI are currently in talks with an undisclosed company to commercialize the device, says Bayer. The initial target users will be asthma patients but the device will be open for use by others who want to study environmental exposures.

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Med diet 'cuts baby asthma risk'

Pregnant women who eat a Mediterranean diet may help protect their children from asthma and other allergies, researchers say.

The Crete team studied 468 mothers and their children from pregnancy to six and a half years after the birth.

They found asthma and allergies were significantly less common in children whose mothers ate lots of vegetables, fruit, nuts and fish during pregnancy.

The Thorax study also found eating high levels of red meat increased the risk.

It made that conclusion in cases where red meat was being eaten more than three to four times a week.

This is of particular significance to mothers in the UK as we have one of the highest rates of childhood asthma worldwide Leanne Male Asthma UK

More than five million people in the UK have asthma, and one in 10 children is affected.

Previous work by the same team, from the University of Crete, found that children who ate a Mediterranean diet appeared to be protected from asthma and allergies.

The latest study suggests that the protective effect of the diet may kick in an even earlier stage.

The researchers found that by the time the children were six-and-a-half years old their diet appeared to have little impact on their risk of asthma and allergy.

However, their mother's diet during pregnancy appeared to be much more important.

Beneficial nutrients

Consumption of vegetables more than eight times a week, of fish more than three times a week, and of legumes more than once a week, seemed to be particularly protective.

The researchers said the Mediterranean diet tended to be well balanced and full of foods which contained beneficial vitamins and minerals.

In particular, the diet was high in antioxidants, which help to keep tissues - including those in the lungs - healthy.

Fatty acids from fish were known to help cut potentially damaging inflammation.

The Thorax study continues: "Further studies are needed to better understand the mechanisms of this protective effect and the most relevant window of exposure."

Leanne Male, assistant director of Research at the charity Asthma UK, said: "This supports our advice to pregnant mothers to eat a healthy, balanced diet.

"It is of particular significance to mothers in the UK as we have one of the highest rates of childhood asthma worldwide, with one in 10 children suffering from the condition."

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