More than 70 percent of adults with asthma in China are not aware they have it, highlighting the urgency for improved diagnosis and treatment, new research shows.

Led by the China-Japan Friendship Hospital, the study estimated there are more than 45 million adults with asthma, with a rate of about 4.6 percent for men and 3.7 percent for women. Smokers are more likely to suffer asthma, and among nonsmokers, air pollution both outdoors and indoors can increase their risks of getting the disease.

"Asthma has become a major health problem that requires urgent efforts to be solved, and government health policies should make major respiratory diseases such as asthma a higher priority to improve prevention and control as soon as possible," said Wang Chen, president of the Chinese Academy of Medical Sciences.

The study was based on surveys of more than 50,000 residents in 10 provinces and municipalities. A paper on the research was published in the international medical journal Lancet last week.

Asthma is a common disease, but surveys have shown many hospitals and clinics at the grassroots, especially in rural areas, lack adequate knowledge of it and cannot provide precise and standard treatment, Wang said.

Respiratory doctors at major hospitals should take the lead in promoting knowledge of asthma, he said.

"A tiered diagnosis and treatment system for asthma should be established so patients with common asthma can get diagnosis and treatment at grassroots facilities, while trickier asthma cases should be treated at medical centers," he said.

Zhou Jun, vice-president of the China-Japan Friendship Hospital, said the research will play a significant role in bringing awareness to respiratory diseases and improving the prevention and control of chronic diseases in China.

"It will provide an important scientific basis for the formulation of asthma prevention and treatment policies in China," he said.

Shen Kunling, a professor of pediatrics at Beijing Children's Hospital, said that in addition to the vast number of adult asthma patients, China also has around 10 million minors with the disease who also deserve attention.

National surveys done over the past three decades have shown the incidence of asthma among people under 14 years old in urban areas in China has been increasing by 50 percent every 10 years, she said.

In many cases, respiratory diseases among adults are connected with poor health conditions when they are infants, including premature birth and serious lung infections, so reducing the incidence of asthma among the whole population should start with children, she said.