Pancreatic cancer risk after loss of a child: a register-based study in Sweden during 1991-2009.

The potential role of psychological stress in pancreatic cancer has rarely been investigated in epidemiologic studies. During 1991-2009, we conducted a nested case-control study based on Swedish national population and health registers to investigate whether severe psychological stress induced by the death of a child was associated with subsequent risk of pancreatic cancer. The study included 16,522 cases and 82,107 controls who were matched to the cases on sex and year of birth. Conditional logistic regression was used to estimate odds ratios and 95% confidence intervals. Overall, loss of a child was associated with an odds ratio of 1.09 for pancreatic cancer (95% confidence interval (CI): 1.02, 1.17). The risk elevation was mainly seen during the first 5 years after the loss (odds ratio (OR) = 1.27, 95% CI: 1.12, 1.45) and for loss of a child due to suicide (OR = 1.23, 95% CI: 1.03, 1.46). The association was statistically significant among women but not among men, and it appeared stronger for early-onset pancreatic cancer. Persons with a history of psychiatric illness had the greatest risk increase after child loss (OR = 1.43, 95% CI: 1.17, 1.76). Although other explanations are possible, our findings provide some evidence that psychological stress may be associated with pancreatic cancer.