Objective: All Campylobacter jejuni species produce a genotoxin, which induce DNA double strand breaks, could lead to an increased risk of cancer especially in the gastro-intestinal tract.
Material and methods: All individuals in Stockholm County who tested positive with C. jejuni between 1989 and 2006 were included. The cohort was followed-up until December 31, 2007 for the occurrence of cancer, overall and site specific. Standard incidence ratios (SIR) with 95% confidence intervals (CI) were calculated by comparisons with the background population.
Results: There were 16,276 individuals who tested positive for C. jejuni generating 124,387 person years. Excluding the first year of follow-up the overall risk for cancer did neither differ from that expected SIR = 0.95 (95% CI 0.82-1.09) nor after 10 years or more of follow-up; SIR = 0.91 (95% CI 0.71-1.16). There was no increased risk for cancer in the gastro-intestinal tract, but there were significantly increased risks for melanomas SIR = 1.84 (95% CI 1.27-2.57) and squamous cell skin cancer SIR = 1.52 (95% CI 1.01-2.19) while a significantly decreased risk of respiratory cancers among males SIR = 0.32 (95% CI 0.12-0.70) was observed.
Conclusions: Our results indicate no excess risks of malignancies following an infection by C. jejuni at least during the first decade. Furthermore, the finding of a decreased risk of respiratory cancers could be of interest, if the results are reproduced in future studies in other populations.