> Risk was further elevated in male smokers taking more than 20 milligrams of B6 or 55 micrograms of B12 a day for 10 years. Male smokers taking B6 at this dose were three times more likely to develop lung cancer. Male smokers taking B12 at such doses were approximately four times more likely to develop the disease compared to non-users.
"Long-Term, High-Dose Vitamin B6/B12 Use Associated With Increased Lung Cancer Risk Among Men" (2023) https://cancer.osu.edu/news/long-term-high-dose-vitamin-b6-b... :
> Risk was further elevated in male smokers taking more than 20 milligrams of B6 or 55 micrograms of B12 a day for 10 years. Male smokers taking B6 at this dose were three times more likely to develop lung cancer. Male smokers taking B12 at such doses were approximately four times more likely to develop the disease compared to non-users.