BOSTON  When Massachusetts began offering virtually free treatments to help poor residents of the state stop smoking in 2006, proponents hoped the new Medicaid program would someday reap benefits.

But state officials never expected it would happen so soon.

New state data show a steep drop in the smoking rate among poor people. When the program started, about 38 percent of poor Massachusetts residents smoked. By 2008, the smoking rate for poor residents had dropped to about 28 percent, a decrease of about 30,000 people in two and a half years, or one in six smokers, said Lois Keithly, director of the state’s Tobacco Cessation and Prevention Program.

There are also indications that the drop has lowered rates of hospitalization for heart attacks and emergency room visits for asthma attacks, she said.

The data has not yet been peer-reviewed. But the numbers have already grabbed national attention, with several United States senators and antismoking advocates using the data to push for similar new Medicaid coverage for tobacco addiction in the national health care legislation.