Opium consumption and pancreatic cancer: A meta-analysis.

Pancreatic cancer represents a serious public health problem worldwide. Due to its high mortality, efforts on identifying risk factors are very important since only a few risk-related factors have been well established. The present study aimed to address this knowledge gap by estimating the risk of pancreatic cancer associated with opium use. We performed a thorough literature search of PubMed, Web of Science and Scopus, which yielded 3 case-control and 1 cohort study which were included in the analysis. A meta-analysis was conducted using the DerSimonian and Laird inverse-variance approach as the random effects method. The pooled risk ratio for pancreatic cancer in opium users was significantly increased (RR=1.98, 95 % CI 1.33-2.96, p = 0.0008) compared to never users. Subgroup analyses identified a significantly increased risk for pancreatic cancer in men (RR=1.74, 95 % CI 1.22-2.47, p = 0.002), in persons who consumed both raw teriak and refined shireh opium (RR=4.21, 95 % 1.27-13.93, p = 0.02) and in persons who smoked opium (RR=4.21, 95 % 1.27-13.93, p = 0.02). The findings of this study will help in efforts aimed at prevention of pancreatic cancer. Still, further epidemiological research is necessary.