|
|
|
2007-8-30 23:00:20 |
|
Babies who received antibiotics in the first year of life may significantly increase their risk of asthma by age 7, according to a new study published in the June 2007 issue of CHEST, the peer-reviewed journal of the American College of Chest Physicians. The study found that the risk for asthma doubled in children receiving antibiotics for non-respiratory infections and children who received multiple courses of antibiotics and who did not live in a house with a dog during the first year. “Antibiotics are prescribed mostly for respiratory tract infections, yet respiratory symptoms can be a sign of future asthma. This may make it difficult to attribute antibiotic use to asthma development,? said Anita Kozyrskyj, PhD, lead study author, from University of Manitoba, Winnipeg, MB. “Our study reported on antibiotic use in children being treated for nonrespiratory tract infections, which distinguishes the effect of the antibiotic.? For the study, Dr. Kozyrskyj and colleagues from the University of Manitoba and McGill University in Montreal used a prescription database of 13,116 children from firth to age 7 to sort out data on children who used antibiotics in the first year of life and presence of asthma by age 7. The subjects were grouped based on the purposes of antibiotic use including lower respiratory tract infection (bronchitis, pneumonia), upper respiratory tract infection (otitis media, sinusitis), and nonrespiratory tract infection (urinary infections, impetigo). Risk and protective factors considered in the study included gender, urban or rural location, neighborhood income, number of siblings at age 7, maternal history of asthma, and pets reported living in the home. The researchers noted that in the study group, 6 percent of children had current asthma at age 7 and 65 percent of children had received at least one course of antibiotics during the first year of life. Among children who received antibiotics, 40 percent received antibiotics for otitis media, 28 percent for other upper respiratory tract infections, 19 percent for lower respiratory tract infections, and 7 percent for non-respiratory tract infections. Results showed use of antibiotic in infants in the first year of life was significantly associated with greater risk of developing asthma at age 7. The risk of asthma increased with the number of antibiotic courses. Those who received more than four courses of antibiotics were 1.5 times more likely to have asthma than those who did not receive antibiotics. Those who received an antibiotic to treat nonrespiratory tract infections were twice as likely to have asthma by age 7 as those who did not receive antibiotics. The history of maternal asthma and presence of a dog in the house where the child lived during the first year of life were both associated with asthma risk. Children who received multiple antibiotic courses and who were born to women without a history of asthma were twice as likely to develop asthma as those who did not receive antibiotics. Similar results were reported in the June 1999 issue of Clinical & Experimental Allergy by Wickens K, Pearce N, Crane J, and Beasley R. from Wellington Asthma Research Group, Wellington School of Medicine, in New Zealand. According to the study, which involved about 650 children age 5 to 10, antibiotic use was significantly associated with 174 percent increased risk of asthma after potential confounders were considered. If antibiotics were used in the first year of life, the risk of asthma would increase by 305 percent. The risk was 64 percent higher among those who used antibiotics after the first year of life, compared to those who did not use antibiotics. The authors found the number of antibiotic courses also had an effect. Those who received one or two courses during the first year were at 127 percent higher risk of asthma, compared to those who did not use antibiotics. Three or four courses increased the risk by 302 percent. However, this study did not consider the purposes of antibiotic use. Because of this, it remains unknown if those who received antibiotics developed asthma because of antibiotic use or the infection treated with the antibiotic or their genetic predisposition. Droste J. H. J. and colleagues reported a similar conclusion in the November 2000 issue of Clinical & Experimental Allergy about the effect of early use of antibiotics on risk of asthma. They found among a population of 7 and 8 year children, the use of antibiotics during the first year of life was associated with 70 percent increased risk of asthma. The current study also found that babies living without a dog in the same house had increased risk of asthma. Babies who lived without a dog in the house during the birth year doubled the asthma risk among children receiving multiple courses of antibiotics. “Dogs bring germs into the home, and it is thought that this exposure is required for the infant's immune system to develop normally. Other research has shown that the presence of a dog in early life protects against the development of asthma,? said Dr. Kozyrskyj. “Exposure to germs is lower in the absence of a dog. The administration of an antibiotic may further reduce this exposure and increase the likelihood of asthma development.? “Antibiotics are frequently prescribed for young children for both respiratory and nonrespiratory infections,? said Mark J. Rosen, MD, FCCP, President of the American College of Chest Physicians. “Understanding the relationship between antibiotic use and asthma can help clinicians make more informed decisions about treatment options for children.? Asthma is a disease of the lung airways. People with asthma have the airways swollen and inflamed. When the inflamed airways react, the airways get narrow, making it hard to breath. Asthma affects about 17 million people in the United States; early five million of them are children. Many asthmatic children outgrow asthma in their teen years, but the disease kills 5000 people in a year, according to a U.S. government agency. |
