Is folic acid associated with lung cancer development? A cross-sectional study in NHANES

The folic acid is used as an adjuvant dietary supplement in cancer treatment, but its potential benefits or adverse effects in lung cancer (LC) management remain unclear. This study aimed to examine the relationship between different forms of folic acid and LC based on a national population-based survey and conduct a thorough analysis of the potential use of folic acid in cancer treatment.

Cross-sectional analysis from the 2007-2018 National Health and Nutrition Examination Survey (NHANES) was assessed. A cohort of 27,631 participants was identified and weighted. Information on folic acid levels and malignancy was determined through laboratory tests and interviews. To address potential confounding variables, a 1:2 propensity score matching (PSM) was employed, and 201 participants were included. This study utilized restricted cubic splines (RCS) to explore the none-linear relationship between various forms of folic acid and the incidence of LC.

Significant associations were observed between clinical characteristics of the participants and LC in both unweighted and weighted analyses. Following PSM, total folate, dietary folate, 5-formyltetrahydrofolate (5-formylTHF) and 5,10-methylenetetrahydrofolate (5,10-methenylTHF) were significantly associated with LC risk (p < 0.05). The RCS analysis suggested that there was a significant non-linear association between 5,10-methenylTHF and the odds of developing LC. Additionally, total folate, folic acid, 5,10-methenylTHF, and RBC folate influenced the likelihood of developing LC in a certain dose range.

The development of LC was associated with total folate, dietary folate, 5-formylTHF and 5,10-methenylTHF levels. Folic acid, total folate, 5,10-methenylTHF, and RBC folate were positively correlated with LC within a certain range.