The future burden of lung cancer attributable to current modifiable behaviours: a pooled study of seven Australian cohorts

Background: Knowledge of preventable disease and differences in disease burden can inform public health action to improve health and health equity. We quantified the future lung cancer burden preventable by behavioural modifications across Australia. Methods: We pooled seven Australian cohort studies (n = 367 058) and linked them to national registries to identify lung cancers and deaths. We estimated population attributable fractions and their 95% confidence intervals (CIs) for modifiable risk factors, using risk estimates from the cohort data and risk factor exposure distribution from contemporary national health surveys. Results: During the first 10-year follow-up, there were 2025 incident lung cancers and 20 349 deaths. Stopping current smoking could prevent 53.7% (95% CI, 50.0–57.2%) of lung cancers over 40 years and 18.3% (11.0–25.1%) in 10 years. The smoking-attributable burden is highest in males, those who smoke <20 cigarettes per day, are <75 years of age, unmarried, of lower educational attainment, live in remote areas or are healthy weight. Increasing physical activity and fruit consumption, if causal, could prevent 15.6% (6.9–23.4%) and 7.5% (1.3–13.3%) of the lung cancer burden, respectively. Jointly, the three behaviour modifications could prevent up to 63.0% (58.0–67.5%) of lung cancers in 40 years, and 31.2% (20.9–40.1%) or 43 300 cancers in 10 years. The preventable burden is highest among those with multiple risk factors. Conclusions: Smoking remains responsible for the highest burden of lung cancer in Australia. The uneven burden distribution distinguishes subgroups that could benefit the most from activities to control the world’s deadliest cancer.Maarit A Laaksonen, Karen Canfell, Robert MacInnis, Maria E Arriaga ... Tiffany K Gill ... Anne W Taylor ... et al

The Future Colorectal Cancer Burden Attributable to Modifiable Behaviors: A Pooled Cohort Study

Background: Previous estimates of the colorectal cancer (CRC) burden attributed to behaviors have not considered joint effects, competing risk, or population subgroup differences. Methods: We pooled data from seven prospective Australian cohort studies (n ¼ 367 058) and linked them to national registries to identify CRCs and deaths. We estimated the strength of the associations between behaviors and CRC risk using a parametric piecewise constant hazards model, adjusting for age, sex, study, and other behaviors. Exposure prevalence was estimated from contemporary National Health Surveys. We calculated population attributable fractions for CRC preventable by changes to current behaviors, accounting for competing risk of death and risk factor interdependence. Statistical tests were two-sided. Results: During the first 10 years of follow-up, there were 3471 incident CRCs. Overweight or obesity explained 11.1%, ever smoking explained 10.7% (current smoking 3.9%), and drinking more than two compared with two or fewer alcoholic drinks per day explained 5.8% of the CRC burden. Jointly, these factors were responsible for 24.9% (95% confidence interval [CI] ¼ 19.7% to 29.9%) of the burden, higher for men (36.7%) than women (13.2%, Pdifference < .001). The burden attributed to these factors was also higher for those born in Australia (28.7%) than elsewhere (16.8%, Pdifference ¼ .047). We observed modification of the smoking-attributable burden by alcohol consumption and educational attainment, and modification of the obesity-attributable burden by age group and birthplace. Conclusions: We produced up-to-date estimates of the future CRC burden attributed to modifiable behaviors. We revealed novel differences between men and women, and other high–CRC burden subgroups that could potentially benefit most from programs that support behavioral change and early detection.Claire M. Vajdic, Robert J. MacInnis, Karen Canfell, Peter Hull, Maria E. Arriaga, Vasant Hirani, Robert G. Cumming, Paul Mitchell, Julie E. Byles, Graham G. Giles, Emily Banks, Anne W. Taylor, Jonathan E. Shaw, Dianna J. Magliano, Julie Marker, Barbara-Ann Adelstein, Tiffany K. Gill, Maarit A. Laaksone