Many Americans living with diabetes, heart disease, or cancer believe their health has been or will be harmed by the economic downturn, a new poll from the Harvard School of Public Health shows.

Almost half of the more than 1,000 people with heart disease and diabetes surveyed said the difficult economic climate has made managing their illnesses more stressful, while more than 35 percent of them believe the poor economy has negatively impacted their health, according to the poll.

The economic downturn has left many chronically ill people in financial trouble, causing them to use up almost all of their life savings, go into credit card debt, neglect non-health bills, or even declare bankruptcy, according to the survey results. Diabetes, heart disease, and cancer often require ongoing, costly treatment.

“We wanted to give a voice to these people living with chronic illnesses,” said Gillian K. SteelFisher, assistant director at the public-health school’s Harvard Opinion Research Program, which conducted the poll along with research company Knowledge Networks. “The fact is, the economic downturn has had a really bad impact on their health, which is important when we think about public health overall.”

Of those surveyed, just under half said they believed their current financial problems would continue to harm them in the future.

“We’re not just looking at bankruptcy,” SteelFisher said, “but a wider set of measures. They suggest that people are vulnerable to these significant financial stresses.”

—Staff writer Helen X. Yang can be reached at hxyang@fas.harvard.edu.