ATLANTA — The nation’s death rate from asthma has increased by more than 30 percent in seven years, and nearly 10 million Americans are now affected by the disease, federal health officials said Thursday.

A number of factors may contribute to the increase, the national Centers for Disease Control reported. They include exposure to infections and other “triggers” for bronchial constriction, health-care factors and air quality.

Between 1980 and 1987, the death rate from asthma in the United States rose from 1.3 per 100,000 population to 1.7, according to the CDC. The number of actual asthma deaths rose from 2,891 in 1980 to 4,360 in 1987, the latest year for which statistical analysis is available.

More Americans suffer from the chronic disease, characterized by difficulty in breathing. An estimated 9.6 million people in the United States were affected by asthma in 1987, compared with 6.8 million in 1980, the Atlanta-based CDC said in its weekly report.

The nation’s asthma rate increased by 29 percent, from 31.2 cases per 1,000 people to 40.1.

“To reduce morbidity … associated with asthma, health-care personnel and public health officials must promote timely and aggressive medical treatment,” the CDC said.

The death rate for asthma was “consistently higher” for blacks than for whites, the CDC said. For blacks, the asthma fatality rate increased 44 percent from 1980 to 1987 — from 2.5 per 100,000 to 3.6 — while the white fatality rate increased 36 percent, from 1.1 to 1.5.

Death rates were higher for older people, with the highest rate of asthma death — 7.9 per 100,000 in 1987 — among people 65 and older.