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UCSF study to examine whether probiotics can prevent asthma in children

May 16, 2006

In the first effort of its kind in the United States, researchers at the University of California, San Francisco have launched a study to determine whether giving active probiotic supplements to infants can delay or prevent asthma in children.

The intervention is a novel method for the primary prevention of asthma with enormous potential to have a public health impact, said Michael Cabana, MD, chief of the Department of General Pediatrics at UCSF Children's Hospital and principal investigator for the study. There currently are no known ways to prevent asthma, he said.

"It would be a great thing to be able to prevent asthma," Cabana said. "We believe that using probiotics is a safe and effective way to do that."

Probiotics are defined as micro-organisms administered in adequate amounts to confer beneficial health effects. They typically are chosen from bacteria that normally inhabit the gastrointestinal system and are therefore known to be safe.

Asthma is one of the most common chronic diseases of childhood and the most common cause of school absenteeism. Asthma is an inflammation of the bronchial tubes that causes airway obstruction, chest tightness, coughing and wheezing.

Called the Trial of Infant Probiotic Supplementation to Prevent Asthma, or TIPS, the study is based on the "hygiene hypothesis," which says that little or no exposure to bacteria and viruses during a critical period of infancy can lead to an imbalance in the immune system and result in diseases such as asthma, especially in high-risk groups, like children with parents who have asthma.

The study seeks to determine whether stimulating the immune system by giving an active probiotic supplement, Lactobacillus GG, can prevent or delay the appearance of early signs of asthma, such as wheezing, frequent runny nose, and eczema. Lactobacillus GG is a common bacterium found in yogurt and many other foods and often is given to treat diarrhea.

The three-year study will include about 280 healthy full-term babies with either a mother or a father with asthma, because parents with asthma are more likely to have children with asthma. During the first six months of life, half of the infants will receive a once-daily dose of active Lactobacillus GG and half will receive a placebo.

The babies will be followed for three years, with six follow-up visits at UCSF Children's Hospital or an outpatient center starting at one month old. Researchers will analyze the data from the visits to see if the active supplements prevented or delayed the appearance of the early signs of asthma.

Cabana said a similar study conducted in Finland found that administration of Lactobacillus to infants delayed or prevented the onset of eczema.

According to the American Lung Association, an estimated 4 million children under 18 years old have had an asthma attack in the past 12 months, and many others have "hidden" or undiagnosed asthma.

Other study co-investigators include Joan Hilton, ScD; Cewin Chao, MS, RD, MBA; Homer Boushey, MD; Lawrence Fong, MD, PhD; and Aaron Brandon Caughey, MD, MPP, MPH, all of UCSF.

University of California-San Francisco