The effect of modifiable risk factors on pancreatic cancer mortality in populations of the Asia-Pacific region

Background: Pancreatic cancer accounts for about 220,000 deaths each year. Known risk factors are smoking and type 2 diabetes. It remains to be seen whether these risk factors are equally important in Asia and whether other modifiable risk factors have important associations with pancreatic cancer. Methods: An individual participant data analysis of 30 cohort studies was carried out, involving 420,310 Asian participants (33% female) and 99,333 from Australia/New Zealand (45% female). Cox proportional hazard models, stratified by study and sex and adjusted for age, were used to quantify risk factors for death from pancreatic cancer. Results: During 3,558,733 person-years of follow-up, there were 324 deaths from pancreatic cancer (54% Asia and 33% female). Mortality rates (per 100,000 person-years) from pancreatic cancer were 10 for men and 8 for women. The following are age-adjusted hazard ratios (95% confidence interval) for death from pancreatic cancer: for current smoking, 1.61 (1.12-2.32); for diabetes, 1.76 (1.15-2.69); for a 2-cm increase in waist circumference, 1.08 (1.02-1.14). All three relationships remained significant (P < 0.05) after adjustment for other risk factors. There was no evidence of heterogeneity in the strength of these associations between either cohorts from Asia and Australia/New Zealand or between the sexes. In men, the combination of cigarette smoking and diabetes more than doubled the likelihood of pancreatic cancer (2.47; 95% confidence interval, 1.17-5.21) in both regions. Conclusions: Smoking, obesity, and diabetes are important and are potentially modifiable risk factors for pancreatic cancer in populations of the Asia-Pacific region. Activities to prevent them can be expected to lead to a major reduction in the number of deaths from this cancer, particularly in Asia with its enormous population.