However bad you thought smoking was, it is even worse.

A new study adds at least five diseases and 60,000 deaths a year to the toll taken by tobacco in the United States. Before the study, smoking was already blamed for nearly half a million deaths a year in this country from 21 diseases, including 12 types of cancer.

The new findings are based on health data from nearly a million people who were followed for 10 years. In addition to the well-known hazards of lung cancer, artery disease, heart attacks, chronic lung disease and stroke, the researchers found that smoking was also linked to significantly increased risks of infection, kidney disease, intestinal disease (caused by inadequate blood flow) and heart and lung ailments not previously attributed to tobacco.

Even though people are already barraged with messages about the dangers of smoking, researchers say it is important to let the public know there is yet more bad news.

“The smoking epidemic is still ongoing, and there is a need to evaluate how smoking is hurting us as a society, to support clinicians and policy making in public health,” said Brian D. Carter, an epidemiologist at the American Cancer Society and the first author of an article about the study, which appears in The New England Journal of Medicine. “It’s not a done story.”

In an editorial accompanying the article, Dr. Graham A. Colditz, from Washington University School of Medicine in St. Louis, said the new findings showed that officials in the United States had substantially underestimated the effect smoking had had on public health. He said smokers, particularly those who depended on Medicaid, had not been receiving enough help to quit.

About 42 million Americans smoke – 15 percent of women and 21 percent of men – according to the Centers for Disease Control and Prevention. Research has shown that their death rates are two to three times higher than those of people who never smoked and that on average they die more than a decade before nonsmokers. Smokers are more than 20 times as likely as nonsmokers to die of lung cancer. Poor people and those with less formal education are the most likely to smoke.

The research was paid for by the American Cancer Society, and Carter worked with scientists from four universities and the National Cancer Institute.