Association between folic acid levels and sarcopenia in American adults: evidence from NHANES

Abstract Background Sarcopenia is associated with several health problems, and people with type 2 diabetes have a significantly increased risk.Nonetheless，it is unclear whether folic acid levels are associated with sarcopenia in individuals with type 2 diabetes.This study aims to investigate the relationship between serum and red blood cell folate levels and muscle mass，and the incidence of sarcopenia in American adults with diabetes，and to assess the mediating role of heavy metal levels. Methods This study involved 3，371 adult patients with diabetes，based on data gathered from the National Health and Nutrition Examination Survey(NHANES)between 1999 and 2018.Muscle mass was assessed using dual-energy X-ray absorptiometry(DXA)，and participants were grouped according to serum and red blood cell folate levels.Multivariable linear and logistic regression models were used to assess linear associations between folate levels and sarcopenia，while restricted cubic spline regression was used to assess non-linear associations.The role of heavy metals was assessed using mediation effect analysis. Results In diabetic men，higher levels of serum and red blood cell folate were linked to a greater muscle mass index ALMBMI and a lower incidence of sarcopenia.Blood lead levels were a partial mediator of the association between folate levels and sarcopenia.In women，there was no significant association found between folate levels and sarcopenia. Conclusions The study found that in American male diabetic patients, higher serum and red blood cell folate levels are associated with better muscle mass and a lower incidence of sarcopenia, with blood lead levels playing a partial mediating role. This suggests that folate might reduce the risk of sarcopenia by lowering levels of heavy metals, particularly lead, especially in male diabetic patients.Future studies should continue to investigate this correlation and its underlying mechanisms.