Red blood cell folate and visceral adipose tissue among young and middle-aged American adults.

BACKGROUND

The relationship between red blood cell (RBC) folate levels and visceral adipose tissue (VAT) accumulation has not been well-explored. This study investigates the association between RBC folate and VAT in young and middle-aged adults in the United States.

METHODS

A cross-sectional analysis was conducted using data from 7,591 individuals aged 20 to 59 years, drawn from the National Health and Nutrition Examination Survey (NHANES) 2011-2018. VAT was measured using dual-energy X-ray absorptiometry (DXA). RBC folate levels were quantified using a multi-step process combining microbiologic assays and liquid chromatography-tandem mass spectrometry (LC-MS/MS). Multivariate linear regression models were applied to assess the relationship between RBC folate and VAT mass.

RESULTS

After adjusting for potential confounders, RBC folate levels were positively associated with VAT mass, with a coefficient (95% CI) of 0.05 (0.03, 0.07). A J-shaped dose-response relationship was observed (nonlinear,  < 0.001), with a threshold effect identified at an RBC folate level of 397.18 ng/mL. Below this threshold, the association was negative [ (95% CI): -0.10 (-0.20, -0.01)], while above the threshold, the association became positive [ (95% CI): 0.06 (0.03, 0.09)].

CONCLUSION

The association between RBC folate and VAT mass in young and middle-aged American adults follows a J-shaped curve, with a threshold effect observed at an RBC folate level of 397.18 ng/mL. Further research is needed to explore the underlying mechanisms of this association.