Antibiotics in Infancy Greatly Increase the Risk of Asthma

asthma_antibioticsThe meteoric rise of asthma in children and adults since the 1970s has been blamed on smog, fragrances, processed foods, chemicals such as formaldehyde found in furniture and carpets, dust mites, tobacco smoke and more. But many parents aren’t aware of the connection between antibiotics and asthma.

A number of studies published over the past decade found a link between the use of antibiotics before a child’s first birthday and a four to five times higher risk of developing asthma, but each of the studies had a weakness that made the medical community skeptical about the results. A recent study from Yale School of Public Health should settle the matter. It followed 1400 women from pregnancy through their child’s sixth year, and took into account factors such as genetic predisposition. The researchers found that children who were given antibiotics in the first six months of life had a 66% higher risk of developing asthma after age three.

The currently accepted theory for why antibiotics increase the risk of asthma is that antibiotics interfere with an infant’s developing immune system. Childhood illnesses serve to prime a child’s immunity, which is barely formed at birth, and when antibiotics are used this “priming” isn’t as effective.

Antibiotics save many lives, but are used far too indiscriminately, especially in children.

Dozens of studies have also shown that fragrances can cause or exacerbate asthma and allergies in children and adults. The elimination of fake fragrances in the home and workplace is one of the simplest ways to reduce the incidence of asthma and allergies. Look for laundry soaps, shampoos, conditioners, and cosmetics that say, “free and clear of dyes and perfumes;” throw away the fabric softeners, air fresheners, and scented candles; and be aware of other possible sources of fragrance such as cat litter and dry cleaning, so that you can eliminate them.

Hormonal imbalances and the hormones in birth control pills can increase asthma in teens and women. For details read Asthma and Hormones in Women.


Risnes KR, Belanger K, Murk W, Bracken MB, “Antibiotic Exposure by 6 Months and Asthma and Allergy at 6 Years: Findings in a Cohort of 1,401 US Children,” Am. J. Epidemiol. (2011) 173 (3): 310-318.
Wickens K, “Antibiotic use in early childhood and the development of asthma,” Clinical and Experimental Allergy, 1999;29:766-771.

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