Led by the International Agency for Research on Cancer (I.A.R.C.) and funded by the World Cancer Research Fund (W.C.R.F.), the European study followed 520,000 participants from 10 countries between 1992 and 2000. Blood samples taken at the start of the study were measured for four B-vitamins (B2, B6, folate (B9) and B12), as well as methionine and homocysteine.
People with above average levels of B6 and methionine had less than half the risk of developing lung cancer than those with below average levels, the study determined. A lower risk was also seen with higher levels of folate consumption. The results were the same for smokers, for people who had never smoked and those who had quit smoking before the start of the study. The lower risk was also observed regardless of time interval since blood collection, indicating the results were not explained by the early stages of the disease.
“The size of this study, and the strong association observed, provide confidence that the association is real,” said Paul Brennan, one of the study’s coordinators. “Whether they are causing the lower risk, or whether they are a marker of the real causal factor, will require further studies.”
For more information, visit www.iarc.fr/.