Hyperhomocysteinemia Is Associated with Vitamin B-12 Deficiency: A Cross-sectional Study in a Rural, Elderly Population of Shanxi China.

Objectives: To report the association of lifestyle factors and plasma vitamin B-12 with hyperhomocysteinemia in a large sample of men and women living in a region of China where there is an increased risk of NTDs.

Design: Community-based, cross-sectional study of Lvliang City, Shanxi Province, China. Setting: Hyperhomocysteinemia is an independent risk factor for cardiovascular disease (CVD) and a sensitive marker of vitamin B-12 and folate deficiency. Participants: A total of 2355 (1044 men and 1311 women) participants born before 1 January 1958 (≥55 years of age) and living in Lvliang City for at least 2 months a year were included. Measurements: The participants were assessed regarding demographic characteristics, height, weight, as well as having a physical examination and blood sampling for serum cholesterol, total homocysteine (tHcy), folate, and vitamin B12 levels.

Results: The median (25th-75th percentile) tHcy concentration was 21.5 (15.8-33.6) µmol/L in men and 18.0 (13.4-24.8) µmol/L in women. The overall prevalence of hyperhomocysteinemia (tHcy ≥15 µmol/L) was 72.6% (84.3% in men and 63.2% in women), inversely correlated with folate (r=-0.230, P=0.006) and vitamin B-12 (r=-0.540, P<0.001), and positively correlated with uric acid (r=0.054, P<0.001). Vitamin B-12 and folate deficiency, older age, and male gender were associated with elevated tHcy; with vitamin B-12 deficiency being the strongest.

Conclusions: Plasma tHcy concentration and hyperhomocysteinemia were significantly higher in this population than in previously studied populations. Vitamin B-12 and folate supplementation, concomitant lifestyle changes such as smoking cessation, and lipid-lowering treatments may help to decrease plasma tHcy concentrations and reduce the CVD risk in this population.