Folate status in the red blood cell and related geographical differences among 810 with 65- to 74-year-old population of two counties in Southern and Northern China

Abstract

To assess the red blood cell (RBC) folate status among Chinese elderly population and its geographical differences between Southern and Northern regions, and to evaluate the correlation between RBC and plasma folate. This study was conducted in two counties of Jiangsu and Hebei provinces of China. A total of 810 individuals aged 65-74 years were recruited. RBC folate in blood samples was measured by microbiological assay. Data on RBC folate was log-transformed before analysis. Means of RBC folate concentration were compared by t-test, and the prevalence rates of RBC folate deficiency for different characteristics were compared by χ2 test. The geometric mean of RBC folate concentration was 1083.3 nmol/L (95%CI: 1034.1-1134.8) among the Southerners and 489.1 nmol/L (95%CI: 466.7-512.6) among the Northerners, with the former being 2.2 times of the latter (t=23.684, P<0.001). The prevalence rates of RBC folate deficiency were 1.0% in the South and 28.9% in the North (χ2=124.06, P<0.001). The concentrations of RBC folate were positively correlated with plasma folate (r=0.49, P<0.001). After adjustment for region, sex, age, BMI, education, exposure to tobacco smoking and alcohol consumption, the correlation remained significant (r=0.38, P<0.001). In 810 Chinese elderly population aged 65-74 from the two counties, Southerners had a higher RBC folate concentration and a lower deficiency prevalence than those in the Northerners. The RBC folate concentration was positively associated with plasma folate.