Modulation of familial risk of lung cancer by dietary folate and vitamin B6 intake in former smokers Hongbing Shen, Qingyi Wei, Patricia C. Pillow, Christopher I. Amos, Waun K. Hong, Margaret R. Spitz. University of Texas M. D. Anderson Cancer Center, Houston, TX. Folate and vitamin B6 play important roles in DNA methylation, synthesis and repair, and low folate and vitamin B6 intake is associated with increased risk of lung cancer. Family history of lung cancer and sub-optimal DNA repair capacity are also associated with elevated risk of lung cancer. Therefore, we hypothesized that dietary folate and vitamin B6 intake may modulate the risk of lung cancer among genetically susceptible individuals (using family history as a surrogate measure). To test this hypothesis, we analyzed data from 470 histopathologically-confirmed incident lung cancer cases and 472 cancer-free controls frequency-matched to the cases on age, sex, and ethnicity. All subjects in this analysis were former smokers to minimize residual confounding bias from current smoking. Dietary intake levels of folate and vitamin B6 were estimated from standard food frequency questionnaires. Unconditional logistic regression analyses were used to estimate risk (OR) of lung cancer associated with family history of lung cancer in first degree relatives stratified by dietary folate and/or vitamin B6 levels, and to evaluate the interactions between low dietary folate and/or vitamin B6 intake and family history of lung cancer. We observed a statistically significant increased risk of lung cancer associated with family history only among those whose dietary intake levels of folate or vitamin B6 were lower than the control median levels (adjusted OR = 3.23, 95% CI, 1.89-5.23 for low dietary folate, and OR = 3.49, 95% CI, 2.04-6.01 for low vitamin B6, respectively), but not among those with high intake levels. This association was especially strong among subjects with both low dietary folate and low vitamin B6 intake (adjusted OR = 4.49, 95% CI, 2.28-8.86). In addition, we observed a statistically significant interaction between low dietary folate or low vitamin B6 and family history (P for the interaction terms = 0.009 and 0.002, respectively). Our results suggest that higher intakes of folate and vitamin B6 may protect against the excess risk of lung cancer associated with a family history of the disease. These data, once validated prospectively, may have important implications for cancer prevention in at-risk populations (Supported by NCI grants CA 55769, CA68437 and CA 86390). AACR Abstract Number: 3990, 2003 Remember we are NOT Doctors and have NO medical training. This site is like an Encylopedia - there are many pages, many links on many topics. Support our work with any size DONATION - see left side of any page - for how to donate. You can help raise awareness of CAM.