A new Harvard study released last week found that an estimated 45,000 deaths each year are associated with a lack of health insurance coverage—a finding that is likely to bolster the case for health insurance reform currently being debated in Congress this fall.

The study—conducted by researchers at Harvard Medical School and the Cambridge Health Alliance—represents the latest effort to gauge the effects of health insurance on Americans’ health.

“People who don’t have access to [health] care tend to have more serious health outcomes. That is quite intuitive,” said Andrew P. Wilper, lead researcher. “However, our study quantifies the effects of not having health insurance on mortality.”

Steffie Woolhandler, a co-author of the paper and a professor at Harvard Medical School, said that the results suggest that the 45,000 deaths were preventable.

According to Woolhandler, 45 million Americans are currently uninsured. Both Wilper and Woolhandler said they hope that their results will have an impact on health policy makers.

Several plans for health care are being debated in Congress, but according to Woolhandler, even the most liberal of the House bills, called HR3200, leaves 17 million Americans outside of the health care plan.

“As a doctor, I believed that everyone deserves health care,” said Woolhandler. “It’s unacceptable to just leave 17 million people out of the system because the Senate and [House of] Representatives don’t have the backbone to stand up to the health insurance industry.”

Data analyzed in this study was taken from NHANES III, a survey of Americans age 17 to 64 by the National Center for Health Statistics that started in 1988 and ended with a follow-up in 2000.

Researchers adjusted the data for possible confounding factors such as age, gender, income, education, body mass index, and regular alcohol use and smoking.

Even with taking into account for those factors that may affect mortality rate, the study found that uninsured Americans have a 40 percent higher risk of death than their counterparts.

Robert J. Blendon, a professor of health policy and political analysis at the Harvard School of Public Health and Kennedy School of Government, calls the timing of this study “terrific” in aiding the cause for universal health insurance.

“In the world of politics and policy, a study that comes out during the crisis of a debate that makes such a visible point on how people’s lives are lost is highly significant,” Blendon said.

“It will cost billions of dollars to solve this problem, and for many people, we can’t afford to solve it,” he said. “But this study shows that it’s not about the money, it’s about lives. This is an issue we can’t afford not to solve.”

But not everyone is as confident about this study’s potential influence.

According to Amitabh Chandra, a professor of health policy at KSG, this observational study “failed to control for some obvious confounders.”

He points out that not having insurance could be “a mask” for a host of causes of poor health such as living in a hazardous environment and engaging in risky behaviors.

“We need studies that establish the causal effect between health insurance and health effects, and I’m not convinced that this study does that,” Chandra said.

“While I don’t disagree with the study’s basic premise, this particular paper is pure advocacy, in an effort to get the biggest number possible,” he added.

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