Obesity and hepatitis C infections have been identified as risk factors for liver cancer, according to two new studies published in Mayo Clinic Proceedings.

Liver cancer is on the rise, having tripled in the United States in the last three decades. It has just a 10 to 12 percent survival rate when detected in its later stages.

Mayo Clinic researchers analyzed decades of records to find that liver cancer that used to be caused by liver-scarring diseases such as cirrhosis due to alcohol consumption, now tends to occur as a result of hepatitis C infections.

“The liver scarring from hepatitis C can take 20 to 30 years to develop into cancer,” says W. Ray Kim, M.D., a principal investigator of one study and specialist in gastroenterology and hepatology. “We’re now seeing cancer patients in their 50s and 60s who contracted hepatitis C 30 years ago and didn't even know they were infected."

In addition, 11 percent of liver cancer cases were found to be linked to obesity, specifically fatty liver disease.