Economic development raises asthma concerns
China has undergone rapid and massive economic development and urbanisation over the past three decades, along with development of severe air pollution. In parallel the prevalence of asthma and allergic diseases has escalated. Even a slight increase in the prevalence rate will translate into millions of people with asthma due to China’s large population. Thus there is urgency to address environmental factors and improve asthma management.
Based on the national epidemiological survey from 2012 to 2015, the overall prevalence of asthma was estimated to be 4.2% in China. There has been an increase in asthma prevalence, especially in the paediatric population, over the past three decades. Using the standardised International Study of Asthma and Allergies in Childhood (ISAAC) questionnaire, the prevalence of current wheeze in 13-14 year old children was documented to rise from 3.4% in 1994 to 4.8% in 2001, and rose further to 6.1% in 2009 in Guangzhou, southern China.
China is a country with marked regional differences in socioeconomic development and environmental exposures. The prevalence of asthma and related atopic disorders varies substantially within the country, with much lower prevalence in rural areas compared with urban regions. For example, Conghua is an agricultural area located only 130 kilometres away from the highly urbanised city of Guangzhou. The prevalence of ever having asthma among secondary schoolchildren in rural Conghua was only half of that in urban Guangzhou (3.4% vs. 6.9%). Exposures related to a traditional rural lifestyle have been recognised as one of the most potent protective factors for asthma.
In contrast growing numbers of motor vehicles in parallel with rapid urbanisation aggravate the problem of traffic related air pollution (TRAP). The largest percentage of paediatric asthma incidence (from the Global Burden of Disease Study 2015) attributable to exposure to nitrogen dioxide (NO2), one of the major components of diesel exhausts, was found in Shanghai, China. Nearly half of the new cases were attributable to NO2 exposure. Driving restrictions in Beijing, with stringent pollution control policy, have shown to improve lung function and reduce asthma-related physician visits.
Challenges create opportunities
Asthma prevention and control remains a significant challenge in China, where under-reporting, underdiagnoses and undertreatment constitute major obstacles to effective delivery of care. A real-world survey has revealed that many of the people with mild asthma in China received only non-steroidal and short-acting medicines and may benefit from treatment intensification. Education programmes and dissemination of control tools such as Asthma Control Test and action plans are critical steps to raise patients’ awareness, to monitor daily control, and to improve treatment adherence. The national health insurance policy was adjusted in 2019, covering most of the important medicines for asthma. Targeted therapies for difficult asthma such as omalizumab which used to be expensive now are becoming affordable as a large part of the cost is covered for eligible patients. At the same time improvements in air pollution need to be prioritised.