- Metformin users were at a lower risk of developing oesophageal squamous cell carcinoma (ESCC) compared with non-metformin users.
Why this matters
- A growing number of observational studies demonstrated that metformin use reduces the risk for overall cancer and a few specific cancer types such as a colon or rectum, breast and stomach.
- Limited existing literatures evaluating the association between metformin use and the risk for oesophageal cancer have shown conflicting results.
- A population-based cohort study included 411,603 metformin users and 4,116,030 age- and sex-matched non-metformin users.
- Funding: The Swedish Research Council and others.
- Metformin users had a lower incidence rate of ESCC compared with vs non-users (3.5 vs 5.3 per 100,000 person-years).
- The risk for ESCC was lower in metformin users compared with non-users (adjusted HR [aHR], 0.68; 95% CI, 0.54-0.85).
- New metformin users were at a reduced risk for ESCC (aHR, 0.44; 95% CI, 0.28-0.64).
- Metformin use was associated with a decreased risk for ESCC in women (aHR, 0.62; 95% CI, 0.39-0.97), men (aHR, 0.70; 95% CI, 0.54-0.90) and participants aged 60-69 years (aHR, 0.45; 95% CI, 0.31-0.66).
- Risk of unmeasured confounding.