Is Exposure to Antibiotics in Early Life Related to Increased Asthma Rates?

In March of 2006, a study was published that analyzed the association between antibiotic exposure in the first year of life and the development of childhood asthma.  Asthma is the most common chronic disease of children, affecting about 12.5% of children in America.  It has increased significantly over the last 30 years and is a major public health concern.  In this article, the health status of over 40,000 children were studied.  The authors discovered that an increase in antibiotic use in children coincides with an increase in physician visits for ear infections, and a high rate of inappropriate prescribing for viral upper respiratory infections and bronchitis.  They also found that the increased asthma risk after antibiotic exposure in the first year of life was 105%.  For each additional course of antibiotics in the first year of life, the risk of developing asthma increased 16%.  This study suggested that exposure to at least one course of antibiotics in the first year of life appears to be a risk factor for the development of childhood asthma.  The reason for this correlation is known as the hygiene hypothesis.  It suggests that growing up in a more hygiene-conscious environment with less microbial exposure may increase atopic immune responses and, thus, the development of asthma.