Obesity may increase your risk of developing liver cancer, according to a new study in Cancer Research.

The study reported that body mass index, waist circumference and type 2 diabetes are all associated with an increased risk for liver cancer. As the sixth most common cancer, liver cancer and its incidence has tripled since the mid-1970s in the United States.

"This study adds to the growing pool of evidence that obesity, specifically visceral obesity, and type II diabetes are independent risk factors for the development of liver cancer.  This is important because we do not currently screen patients with these risk factors for liver cancer," said Dina Halegoua-DeMarzio, professor of medicine and director of the fatty liver center at Thomas Jefferson Hospital.

Researchers accessed data from 14 prospective studies with more than 1.5 million participants who did not initially have liver cancer. After controlling for age, sex, alcohol use, smoking and race, they found that being overweight increased the relative risk for liver cancer by between 21 percent and 142 percent as BMI increased.

For every five-point increase in BMI, there was a 38 percent increase in the risk of liver cancer among men and a 25 percent among women.

With each 2-inch increase in waist circumference, the risk of liver cancer rose by 8 percent, even when controlling for BMI.

People with type 2 diabetes had more than twice the risk of liver cancer, even among those who were not obese. The risk for those with diabetes, which is often associated with obesity, rose with an increase in BMI.

Halegoua-DeMarzio noted that the findings in the study could be due to the "connection between obesity and diabetes in the development of nonalcoholic fatty liver disease (NAFLD) and nonalcoholic steatohepatitis (NASH).

"Approximately, 70% of diabetics have some form of NAFLD which is a known risk factor for liver cancer," she said.  "Further study is needed on whether people with diabetes and obesity should be screened for NAFLD and liver cancer periodically," she said.

Halegoua-DeMarzio also noted some limitations of the study.

"Despite its important findings, this study has some limitations that put the accuracy of its results into question. For example, hepatitis status, which is a known risk factor for liver cancer, was only available for small series of cases," she said.

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