Population-attributable risk of modifiable lifestyle factors to hepatocellular carcinoma: The multi-ethnic cohort

Background and Aims: Lifestyle factors are well associated with risk of hepatocellular carcinoma (HCC). However, the impact of reducing adverse lifestyle behaviours on population-level burden of HCC is uncertain.Methods: We conducted prospective analysis of the population-based multi-ethnic cohort (MEC) with linkage to cancer registries. The association of lifestyle factors (smoking, alcohol, diet quality assessed by alternate Mediterranean diet score, coffee drinking, physical activity and body mass index) with HCC incidence was examined using Cox regression. Population-attributable risk (PAR, %) for the overall, lean and overweight/obese populations was determined.Results: A total of 753 incident cases of HCC were identified in 181,346 participants over median follow-up of 23.1 years. Lifestyle factors associated with elevated HCC risk included former/current smoking, heavy alcohol use, poor diet quality, lower coffee intake and obesity, but not physical activity. The lifestyle factor with highest PAR was lower coffee intake (21.3%; 95% CI: 8.9%-33.0%), followed by current smoking (15.1%; 11.1%-19.0%), obesity (14.5%; 9.2%-19.8%), heavy alcohol use (7.1%; 3.5%-10.6%) and lower diet quality (4.1%; 0.1%-8.1%). The combined PAR of all high-risk lifestyle factors was 51.9% (95% CI: 30.1%-68.6%). A higher combined PAR was observed among lean (65.2%, 26.8%-85.7%) compared to overweight/obese (37.4%, 11.7%-58.3%) participants. Adjusting for viral hepatitis status in a linked MEC-Medicare dataset resulted in similar PAR results.Conclusions; Modifying lifestyle factors, particularly coffee intake, may have a substantial impact on HCC burden in diverse populations, with greater impact among lean adults. Diet and lifestyle counselling should be incorporated into HCC prevention strategies.