Population attributable risk for colorectal and breast cancer in England, Wales, Scotland, Northern Ireland, and the United Kingdom

Background: The population attributable risk (PAR) is a statistic commonly used for quantifying preventability of cancer. We report here PAR estimates for the United Kingdom (UK) along with its constituent countries for up-to-date risk factor-attributable colorectal cancer (CRC) and breast cancer (BC), focusing on diet and nutrition related factors and tobacco (CRC) using representative national surveys. Methods: The PAR was calculated using established, modifiable risk factors by the World Cancer Research Fund/American Institute of Cancer Research (WCRF/AICR): physical activity, body mass index (BMI), alcoholic drinks, red meat, processed meat, dietary fiber, dietary calcium, as well as cigarette smoking for CRC, and physical activity, BMI, alcoholic drinks, and fruits and vegetable consumption for BC. National prevalence estimates and relative risks (RRs) for CRC and BC were obtained from meta-analyses or large pooled analyses. Results: Based on eight dietary and lifestyle risk factors, the estimates for attributable cases of CRC for males and females, respectively, were as follows: England: 67% and 60%; Scotland: 68% and 59%, Wales: 66% and 61%; Northern Ireland: 67% and 61%; and UK: 67% and 60%. Excluding smoking, the PAR for the UK was 61% for men and 52% for women. Based on four dietary and lifestyle risk factors, the estimates for BC were as follows: England: 26%, Scotland: 27%; Wales: 25%; Northern Ireland: 26%; and UK: 27%. Conclusion: Up to 67% for CRC and 27% of BC were attributable to modifiable dietary and lifestyle factors in the UK. Moderate differences in PAR are observed between countries due to different prevalence of exposure to risk factors.