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Obesity, diabetes linked to increased intrahepatic cholangiocarcinoma risk

Results of a pooled analysis and systematic review showed an increased risk for intrahepatic cholangiocarcinoma among patients with obesity and diabetes.

“As rates of [intrahepatic cholangiocarcinoma (ICC)] are increasing in most populations, it is critical to understand the underlying etiology, especially as prevalence of obesity and diabetes is also increasing,” Jessica L. Petrick, PhD, MPH, from the National Cancer Institute in Bethesda, Maryland, and colleagues wrote. “This may help to identify primary prevention measures for ICC.”

According to Petrick and colleagues, the incidence of ICC began rapidly increasing in the U.S. approximately 10 years after the obesity epidemic began in the mid-1980s.

To quantify the correlation between ICC risk and obesity and diabetes, the researchers conducted a pooled analysis of individual-level data from 13 U.S.-based cohort studies and review of 14 published studies.

In the pooled analysis, obesity correlated with a 62% increased risk for ICC (HR = 1.62; 95% CI, 1.24-2.12) compared with normal BMI. The association was minimally attenuated after adjustment for diabetes (HR = 1.54; 95% CI, 1.18-2.02).

Self-reported diabetes correlated with an 81% increased risk for ICC (HR = 1.81; 95% CI, 1.33-2.46) compared with no diabetes, which was minimally attenuated after adjustment for BMI (HR = 1.7; 95% CI, 1.24-2.31). The risk was higher among women; however, the researchers found no evidence of interaction by sex.

According to the systematic review, obesity correlated with a 49% increased risk for ICC (RR = 1.49; 95% CI, 1.32-1.7) with no indication for publication bias or evidence of heterogeneity. The researchers also determined the results to be robust after excluding one study at a time.

A history of diabetes correlated with a 53% increased risk for ICC (RR = 1.53; 95% CI, 1.31-1.78) in prospective studies. While the researchers identified a moderate heterogeneity between studies reporting on diabetes, publication bias was unlikely, and the summary relative risks did not materially chance after they excluded one study at a time.

Petrick and colleagues noted that self-reporting of height and weight presents a significant limitation. Additionally, the researchers were unable to adjust for diabetes medication use. However, the pooled analysis included over 1.54 million individuals, quantified by the associations observed in the systematic review.

“These findings suggest that obesity and diabetes are associated with increased ICC risk, highlighting similar etiologies of hepatocellular carcinoma and intrahepatic cholangiocarcinoma,” the authors wrote. “However, additional prospective studies are needed to verify these associations.” – by Talitha Bennett

Disclosure: The authors report no relevant financial disclosures.