Cancer incidence near oilfields in the Amazon basin of Ecuador revisited
- 1Risk Management Resources España, Zaragoza, Spain
- 2St Vincent’s Clinical School, Faculty of Medicine, University of New South Wales, Sydney, New South Wales, Australia
- Correspondence to: F M Arellano Risk Management Resources España, SL Zurita 14, 50001 Zaragoza, Spain;
San Sebastian et al1 reported an overall excess for all cancers in San Carlos, Ecuador (standardised incidence ratio (SIR) 2.26; 95% CI 0.97 to 4.46 for males), and an increased mortality due to cancers in males (standardised mortality ratio (SMR) 3.6; 95% CI 1.31 to 7.81). The authors concluded that there was an excess of cancer cases among the villagers linked to environmental pollutants stemming from oil production activities.
Since clusters present many epidemiological biases, the Centers for Disease Control issued a set of guidelines2 in 1990 to investigate clusters. Under those guidelines, we reviewed the cluster of cancer …