High circulating B12 levels tied to increased risk for lung cancer

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Takeaway

  • High concentrations of circulating B12 are tied to an increased risk for lung adenocarcinoma and small-cell carcinoma, but not squamous cell carcinoma (SCC).

Why this matters

  • The findings suggest any chemopreventive effect of B12 is overshadowed by the increased risk for lung cancer.

Study design

  • Case-control study with 5183 lung cancer-control pairs.
  • Mendelian randomization (MR) analysis based on genetic data on 29,266 lung cancer cases and 56,450 control patients.
  • Funding: NIH; others.

Key results

  • High concentrations of circulating B12 were associated with increased overall risk for lung cancer in the case-control pairs (OR, 1.15; 95% CI, 1.06-1.25).
  • By tumor subtype, strong associations with lung adenocarcinoma (OR, 1.14; 95% CI, 1.00-1.30) and small-cell carcinoma (OR, 1.20; 95% CI, 0.91-1.59), but not SCC (OR, 1.00; 95% CI, 0.81-1.23).
  • MR analysis confirmed findings for association between B12 concentrations and increased overall risk for lung cancer (overall OR, 1.08; 95% CI, 1.00-1.16) and in lung adenocarcinoma (OR, 1.23; 95% CI, 1.11-1.37) and small-cell carcinoma (OR, 1.17; 95% CI, 0.96-1.41), but not SCC (OR, 0.97; 95% CI, 0.86-1.10).
  • Results persisted after adjusting for smoking history, sex, geographic region, or time from blood draw.

Limitations

  • Findings may not be generalizable to the general population.