The association between altitude and serum folate levels in Tibetan adults on the Tibetan plateau

This study investigated the relationship between residence altitude and serum folate levels in healthy Tibetans living on the Tibetan Plateau. Participants were selected from those who underwent physical examinations at our health center between November 2019 and February 2020. Demographic characteristics and medical histories were collected, and fasting blood was tested for serum folate and other hematological indicators. The relationship between altitude and serum folate levels was analyzed using a multivariable linear regression model. Serum folate levels were associated with altitude (β = − 0.44; 95% confidence interval [CI] − 0.71; − 0.16), hemoglobin (β = − 0.01; 95% CI − 0.03; − 0.00), red blood cells (β = − 0.72; 95% CI − 1.18; − 0.27), hematocrit (β = − 0.07; 95% CI − 0.12; − 0.02), high-density lipoprotein cholesterol (β = 2.67; 95% CI 1.35; 3.98), and sex (β = 0.68; 95% CI 0.12; 1.23). Multivariate linear regression analysis revealed that altitude was negatively associated with serum folate levels. After adjusting for confounding factors, serum folate levels decreased by 0.33 ng/mL per each 500-m increase in altitude (β = − 0.33; 95% CI − 0.6; − 0.05; P = 0.022). Altitude was negatively associated with serum folate levels in Tibetan adults. The relationship between altitude and folate levels should be further explored in populations of different races and disease states. Further large-scale prospective studies should illustrate the causality of this relationship.