Asthma, rhinitis still on rise

Dust mites and pollen are the chief allergens affecting people with asthma and rhinitis in China, according to a national study on the causes of aggravation among sufferers of both conditions.

The study, which was released by the China Alliance of Research on Respiratory Allergic Disease on Friday in Guangzhou, capital of Guangdong province, investigated variations in sensitization among asthma and rhinitis patients between 2008 and 2018.

"The prevalence of allergic rhinitis and asthma increased dramatically in China over the last decade, as tremendous transformations have taken place to work and life, urbanization, and increases in temperature and humidity," said Zhong Nanshan, a leading respiratory expert.

Following the first report in 2008, the study was conducted again in 2018 in 26 cities with 36 medical centers in northern, eastern, central and southern coastal areas of China, targeting 5,532 patients between 5 and 65 years of age.

"Policies need to be adjusted to mitigate human-induced climate change to limit sensitization to dust mites," Zhong said.

As in 2008, the study found that mites were still the main problem in 2018, especially among the youngest sufferers.

It also found that allergen sensitization rates varied by geographic location, with weed pollen, especially that of Artemisia vulgaris (common mugwort) being a major outdoor allergen in northern China.

The study showed an upward trend in A. vulgaris sensitization rates, which has reached 30.3 percent in northern areas of the country, a threefold increase on 2008. In addition, it was found that sensitization to dust mites was at its highest－79.2 percent－in southern areas.

"Changes in climate and the increased planting of Alyssum desertorum (desert madwort) were associated with the upward trend in sensitization to mites and pollen," said Zhong.

The expansion of the plant is due to its use as a windbreak, and as a means of controlling sand displacement in the desert steppes of northwestern China.

Citing the study, which showed a link between the expansion of A.desertorum and sensitization rates, Zhong said that the number of patients with asthma and rhinitis had increased dramatically in northern areas in recent years.

"Many of my students who work as respiratory doctors in Shaanxi province and the Inner Mongolia autonomous region told me that they are treating an increasing number of patients with asthma and rhinitis in recent years, especially during the spring," he said.

Consequently, Zhong has recommended reducing the planting of A. desertorum to prevent further sensitization to weed pollen.

"Fortunately, we have noticed that local governments in northern China have already taken measures to plant other varieties in place of A. desertorum," he said.