New research suggests that smoking's deadly consequences are worse than previously thought, UPI reported.

Researchers found that, in addition to the 21 diseases already linked to smoking, smokers were twice as likely to die from kidney failure, fatal infections and possibly even breast and prostate cancers.  The study, led by American Cancer Society researchers, suggests that cigarette smoking may kill tens of thousands more from diseases that are not currently counted as caused by smoking.

"The number of additional deaths potentially linked to cigarette smoking is substantial," Eric Jacobs, co-author of the study, said in a statement.  "In our study, many excess deaths among smokers were from disease categories that are not currently established as caused by smoking, and we believe there is strong evidence that many of these deaths may have been caused by smoking."
For the study, researchers followed nearly a million people from the years 2000 to 2011, looking at smoking in relation to a "number of deadly diseases and fatal health complications" that haven't before been directly linked to smoking, Time reported.

The analysis, which involved 89,000 current smokers, revealed that smoking increased the risk of deaths from diseases not previously associated with the deadly habit.  

The Surgeon General estimates that each year, smoking kills about 480,000 Americans. 

 "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," Brian D. Carter, head author of the study, told the Time.

The findings are detailed in The New England Journal of Medicine.