Liver cancer is a leading cause of cancer death, with hepatocellular carcinoma (HCC) accounting for 85–90% of all primary liver cancers. In a recent issue of Journal of Hepatology, Dr Baumeister et al. showed that higher total physical activity was associated with a reduced risk of HCC, an effect potentially mediated by obesity.
The European Prospective Investigation into Cancer and Nutrition (EPIC) cohort is a pan-European prospective study designed to investigate the link between diet, lifestyle and environmental factors, and the risk of cancer and chronic diseases. One of the largest cohort studies in the world, over 520,000 men and women aged 25–70 years-old were recruited from 23 European centres between 1992 and 2000. A total of 467,336 participants were included in this analysis of liver cancer risk, of whom 275 were diagnosed with HCC.
Recreational, household, and occupational physical activity were assessed using the EPIC physical activity questionnaire. Recreational physical activity was assessed by calculating the amount of time participants spent, in hours per week, performing physical activities, including cycling, jogging and swimming. Activity levels were split into 4 categories: inactive, moderately inactive, moderately active, and active. Participants reported their level of occupational physical activity as either sedentary, standing, manual work, or heavy manual work. Participants’ total physical activity was then determined by combining measures of recreational and occupational physical activity. Vigorous physical activity was defined as activities that led to an increase in sweating or heartbeat, and patients were categorised based on how many hours per week they dedicated to such exercises.
The mean age of participants was 51.3 years, and 70.2% were women. Median follow-up time was 14.9 years, providing 6,508,182 person-years of data. The risk of HCC was significantly lower for active vs. inactive individuals (adjusted hazard ratio 0.55), and for individuals that performed >2 hours/week of vigorous activity vs. those that performed no vigorous activity (adjusted hazard ratio 0.50). The associations between total physical activity/vigorous physical activity and cancer incidence were not modified by sex, age, waist circumference, body mass index, smoking, or current/lifetime alcohol consumption.
Both waist circumference and body mass index were shown to mediate the associations between total physical activity/vigorous physical activity and HCC. However, diabetes was shown not to mediate these associations.
This study suggests that “physical activity reduces the risk of HCC”. However, further studies that provide details and objective measures of physical activity over multiple time points are required to confirm these findings. This will enable clinicians to establish the optimal dose, type, intensity and timing of physical activity-based interventions for the prevention of HCC.
For more information, visit the EPIC working group website