Does antibiotic use affect childhood asthma rates in China?

• Epidemiology
• letters to editor
• prevention

According to a national survey published in The Chinese Journal of Tuberculosis and Respiratory Diseases [1], the prevalence of asthma among Chinese children increased from 0.91% in 1990 to 1.54% in 2000 and finally to 3.02% in 2010 [2]. Increasing air pollution was thought to be the major contributor.

However over that same period, rates of asthma among Hong Kong school children was significantly higher at 10.2–11.2% [3,4]. This is despite Hong Kong generally having better air quality than mainland China. It implies that risk factors other than air pollutants are involved in causing childhood asthma. One risk factor was discussed in a 2013 study [5] which found an important association between antibiotic use and childhood asthma development. This was despite there being no significant associations between the severity of asthma and respiratory viral or atypical bacterial infections. The authors’ recommendation in this instance was to discourage the use of antibiotics in children [5].

The biological explanation for this observation comes from what is known as the hygiene hypothesis. This hypothesis suggests that the lack of early childhood exposure to infectious agents including parasites and symbiotic micro-organisms like gut flora or probiotics increases the risk of developing allergic diseases. In effect, the lack of exposure to environmental antigens prevents children from developing normal immune tolerance [6]. In Crane et al. [7], a further hypothesis was put forward suggesting that antibiotic use in the early childhood years contributes to an increased risk of developing asthma. Hoskin-Parr and coworkers showed that there was a strong dose-dependent correlation between early childhood antibiotic use and the development of asthma later in life [8], although it has also been suggested that genetic variation could play a role [9]. A multi-center European cohort study which examined possible risks factor associated with the development of childhood wheezing found that antibiotic use in the first year of life was associated with an increased risk, even after adjusting for gender, socioeconomic status, breast feeding, tobacco smoke exposure, family history of asthma and respiratory infection (OR = 5.80;95% CI 1.56–21.6) [10].

According to a medication marketing report, Chinese sales of antibiotics have been increasing yearly with sales totaling 3.68 billion Chinese RMB in 2007 and 3.84 billion Chinese RMB in 2008 [11]. Between 2001 and 2010, 80% of children who were admitted to China's pediatric departments were prescribed antibiotics, a rate significantly higher than other departments [12]. Evidence suggests that when children present to health care providers with fever, Chinese parents tend to encourage and even expect antibiotics to be administered. Even more concerning, in China parents can purchase antibiotics for their children at a pharmacy without prescription.

In 2011, to address concerns about the overuse of antibiotics, the Chinese Ministry of Health launched a campaign to improve antibiotic stewardship in the country. Unfortunately, reducing antibiotic use in China has been much more difficult than similar efforts in Western countries. One possible reason is that China’s hospitals, particularly grassroots hospitals, are heavily dependent on medication sales for their income, with antibiotics making up a large percent of those sales. Similar to other countries, pharmaceutical companies incentivized by large financial rewards, aggressively promote their products through campaigns targeted at physicians. Because of these competing forces, even after the Ministry of Health instituted their antibiotic stewardship campaign, outpatient antibiotic prescriptions remained high, averaging about 50.3% from 2000–2012 (95% CI: 47.4–53.1%) [13].

Adding to the myriad of other established concerns regarding antibiotic overuse, this correlation between early childhood antibiotic use and the increased risk of developing asthma provides further evidence for the need for greater antibiotic stewardship in China. China needs new policies and surveillance systems to improve antibiotic management with the goal of ultimately decreasing the high level of antibiotic usage among children.

Declaration of interest

The authors report no conflicts of interest. The authors alone are responsible for the content and writing of this article.