About 14 million major medical cases in the United States can be blamed on smoking, according to a study by health officials.

Using surveys, the researchers found that in 2009, roughly 7 million Americans reported a total of almost 11 million cases of major medical conditions caused by smoking. Taking into account ailments that are believed underreported, that number climbs to 14 million such cases.

"That's obviously an immense number," said Brian Rostron, the study's lead author. "It's continuing to be a problem. Even if people are former smokers, they have lasting lung damage."