Serum superoxide dismutase activity and risk of esophageal cancer in a nested case-control study

Superoxide dismutase (SOD) is an antioxidant enzyme that acts to degrade superoxide, a major causative factor in carcinogenesis. We assessed associations between serum SOD activities and the incidence of esophageal cancer in a case-control study nested in the Japan Collaborative Cohort (JACC) Study.

At baseline, 39 242 subjects donated serum samples. Participants who were diagnosed with esophageal cancer during follow-up were regarded as cases. Conditional logistic regression models were used to evaluate odds ratios (ORs) for esophageal cancer incidence associated with serum SOD activity.

The present study included 27 cases and 80 controls. Serum SOD activity was associated with risk of esophageal cancer (P for trend = .040) and the third tertile of SOD level showed the highest risk compared to the first (OR = 7.41, 95% confidence interval [CI] = 1.14-48.35). Limiting subjects to those followed-up over 3 years, all trends remained unchanged (P for trend = .044), with the third tertile still showing the highest risk compared to the first (OR = 7.63, 95% CI = 1.06-55.23).

Our findings suggest that serum SOD activity may be associated with the risk of esophageal cancer.