Vulnerable populations in particular are not getting the help they need to stop smoking, it said, and recommended that doctors and public health officials devote more attention to offering smoking cessation assistance to gay and transgender people, Native Americans, people with mental illness diagnoses and several other groups with high smoking rates.

“The biggest take-home from this report is that far too many people who want to quit aren’t getting access to the cessation treatments that we know work,” Dr. Adams added.

Antismoking groups welcomed the new report. Chris Bostic, deputy director for policy at the Action on Smoking & Health, said, “I believe society has withheld or restricted access to cessation because smokers ‘did it to themselves,’ but nearly all smokers became addicted as children, when they could not have consented to the risk.”

More than 55 years after the first surgeon general’s report warned that smoking causes cancer, it remains the leading cause of preventable death and disease in the United States. According to the Centers for Disease Control and Prevention, the rate of smoking in the United States has declined to an all-time low of 14 percent. More than 3 of every 5 adult Americans who have smoked have quit, the report said. Still, 34 million Americans currently smoke, and an estimated 480,000 die from smoking-related illnesses each year, the agency said.

About 16 million people in the United States now suffer from cancer, heart disease and smoking-related disorders, according to the C.D.C. The financial toll is enormous too, with annual health care spending attributed to smoking exceeding $170 billion, the agency said.