Reduced circulating folate among older adults caused by continuous work: nested cross-sectional study conducted in a country with folic acid fortification program

Population aging is 1 of the biggest challenges facing public health today, and cognitive dysfunction is an important concern. Cognitive impairment may be associated with high folate concentrations and low vitamin B12 concentrations; the latter is a common problem among elderly people. Therefore, we hypothesized there was a high circulating folate concentration among older people living in a country with a mandatory folic acid fortification program. We conducted a cross-sectional study to investigate nutritional status of folate and vitamin B12 among aged people. Three dietary recalls, serum folate (sfolate), erythrocyte (red blood cell) folate (RBC folate), and serum vitamin B12 and homocysteine were collected. Linear regression models were used to investigate factors associated with circulating vitamins. We interviewed 169 participants. Half reported inadequate consumption of folate. However, RBC folate deficiency was observed in 27%, 13% in the serum, and a 10% excess of sfolate. One-quarter reported inadequate consumption of B12, but only 5% had deficiency. Factors negatively associated with circulating folate were continuous work and smoking, and positively associated with polyunsaturated fatty acid. Factor negatively associated with the circulating B12 were use of a dental prosthesis and intake of saturated fatty acid. Permanent investigation of excess of sfolate and B12 deficiency, especially among older adults living in countries exposed to a mandatory folic acid fortification program, is important because of the possible relation to the cognitive function.