When Gloria Reyes’s heat shut off on a freezing night last week, a burning sensation flared in her lungs. Her asthma was acting up.

Ms. Reyes, 51, was one of more than 300 residents of Bushwick, Brooklyn, surveyed last year in a study of the connection between poor housing and the prevalence of asthma attacks. The study, conducted by Wyckoff Heights Medical Center and the community group Make the Road by Walking, reported squalid conditions in the neighborhood: 69% live with cockroaches, 47% with rats or mice, 30% with mold.

Along with cold, these conditions have been found to exacerbate symptoms in asthma sufferers. In the Brooklyn study, those surveyed reported frequent attacks: 41% at least once a month, 28% on a weekly or daily basis.

While hospital visits by asthma sufferers are falling in New York, decreasing by about 10% in 2004, according to city statistics, they remain about twice the nation’s average. Bushwick-Williamsburg, after Harlem, had the highest rate of hospitalization of residents, at 12% in 2004, quadruple the city’s average.

About half of the asthmatics surveyed in the Brooklyn study reported going straight to the emergency room when they had an attack, and 59% reported not using medicine to control their asthma.

The study argued that poor housing conditions and lack of preventive care show the need to improve housing-code enforcement and increase city and state funding for asthma education. It urged the passage of the Healthy Homes Act, introduced by the City Council in 2004, which would reclassify asthma triggers such as mold, mice, and cockroaches as “immediately hazardous” violations required by law to be fixed within 35 days.

The city’s Department of Housing Preservation and Development, which enforces tenant maintenance complaints, could not be reached for comment. In the past, it has maintained that its emergency repair program corrects violations when landlords refuse to or are unable to do so themselves.

The end of last week found Ms. Reyes trying to figure out how to get the city to help her get the heat back on. A call to 311 brought the Fire Department, but they could not get into the basement. Then there are other problems. She said her apartment is rat-infested – one bit her grandson in October – and the roaches are “everywhere.” In her mind, there is no question that the conditions have made her asthma worse. “I feel like I’m going to die because I can’t breathe,” she said in Spanish.