The Hygenie Hypothesis
While this might seem like an odd relationship, it is consistent with the 'hygiene hypothesis.' The hypothesis initially came from the observations that kids who grew up on farms had fewer allergies than kids who grew up in the city. Similarly, allergies were noted to be more common in children without brothers and sisters compared to kids with brothers and sisters. The thought is that kids from larger families are exposed to more infectious diseases. In scientific terms, antibiotics create a more hygienic environment with less exposure to infectious diseases that may alter a person's immune response and lead to asthma.
Because there was increased antibiotic use in the 1980s and 90s that paralleled increases in asthma, some scientists have thought that antibiotics were responsible for the increased asthma rates.
A study from the March 2, 2009 issue of Pediatrics found that antibiotic use in the first year of life is associated with increased risk of developing asthma.
Dr. Fawziah Marra of the faculty of Pharmaceutical Sciences, University of British Columbia in Vancouver, British Columbia, Canada and colleagues used data from all births in British Columbia, Canada from 1997 to 2003 to determine the relationship of antibiotics prescribed in the first year of life and the development of asthma.
Receiving antibiotics was associated with a small increase (12%) in the development of asthma compared to a baby that did not receive antibiotics and the more times a baby received antibiotics the more likely asthma was to develop. The greatest risk was in babies receiving more than 4 courses of antibiotics in the first year of life (30% increase compared to those not receiving antibiotics).
Dr. Marra concludes, "The results of our analysis show a small but significant association between antibiotic use and the subsequent development of asthma. In addition, we found a positive dose response between the number of courses of antibiotics in the first year of life and the risk of asthma, but we did not find that the increased risk was associated with any particular type or class of antibiotics."
Several other studies have found similar results with antibiotics being associated with small increases in asthma.
However, Celedon and colleagues followed more than 4,000 children enrolled in a HMO from birth to 5 years of age and did not find a relationship which supported the hypothesis that antibiotic use was associated with the development of asthma.
What Should I Take From This
It seems safe to say there is a small, but real increase in asthma among people receiving antibiotics in early life. However, this is not to say you should not take antibiotics. Rather, if your healthcare provider says your child needs antibiotics, then have your child take them as directed. You should not take antibiotics unnecessarily or pressure your provider into giving antibiotics.
Marra F., Marra CF, Richardson K, Lynd LD, Kozyrskyj A, Patrick DM, William RB, and FitzGerald JM. Antibiotic Use in Children Is Associated With Increased Risk of Asthma. Pediatrics 2009; 123:1003-1010.
Sharland M. SACAR Paediatric Subgroup. The use of antibacterials in children: a report of the Specialist Advisory Committee on Antimicrobial Resistance (SACAR) Paediatric Subgroup. J Antimicrob Chemother. 2007;60 (suppl 1):i15 –26
Strachan DP. Hay fever, hygiene and house size. BMJ. 1989;299 (6710):1259 –1260
Cohet C, Cheng S, MacDonald C, et al. Infections, medication use, and the prevalence of symptoms of asthma, rhinitis, and eczema in childhood. J Epidemiol Community Health. 2004;58 (10):852 –857
Celedón JC, Litonjua AA, Ryan L, et al. Lack of association between antibiotic use in the first year of life and asthma, allergic rhinitis, or eczema at age 5 years. Am J Respir Crit Care Med. 2002;166 (1):72 –75