Distribution and status of vitamin B12 in Chinese adults with hypertension: a comprehensive report across 14 provinces

Background: Vitamin B12 (VB12) is an essential biomarker for population health, and its deficiency status leads to severe health burdens. A comprehensive and updated investigation on the distribution of VB12 levels and status is critically needed to address public health and clinical concerns. Methods: We conducted a cross-sectional analysis using data obtained from the Precision Medical Program, which encompassed 14 provinces in China. Specific criteria based on previously published cutoffs and our study population’s characteristics are adopted to define B12 deficiency. Biochemical B12 deficiency was identified with circulating VB12 levels <148 pmol/L. Metabolic B12 deficiency was determined with circulating VB12 levels ≥148 and ≤258 pmol/L with concomitant elevated plasma total homocysteine (tHcy ≥14 µmol/L). Normal B12 status included VB12 levels >258 pmol/L or VB12 levels ranging from 148 to 258 pmol/L with tHcy levels below 14 µmol/L. VB12 levels and status were analyzed and stratified by age, sex, and geographical region. Results: This study enrolled a total of 2174 hypertensive adults, with a mean age of 63.0 years (±13.4) and 45.8% female. The overall mean VB12 levels were 322.3 (85.0) pmol/L. The prevalence rates of B12 biochemical deficiency, metabolic deficiency, metabolic deficiency with excluded renal dysfunction, and adequate status were 0.7%, 13.3%, 11.5%, and 85.9%, respectively. Females exhibited higher VB12 levels than males, with a β value of 19.72 (95% confidence interval [CI], 10.59–28.84) in the multivariate model. The southern population demonstrated higher VB12 levels than people from the north, with a β value of −18.14 (95% CI, −25.72 to −10.76). Males had a higher prevalence of metabolic VB12 deficiency in comparison to females (15.8% vs. 10.4%). Conclusions: Our study revealed that Chinese hypertensive adults exhibit relatively higher levels of VB12. Additionally, while biochemical B12 deficiency is uncommon, a noteworthy proportion of individuals were affected by metabolic VB12 deficiency. This study has important implications for nutritional counseling and vitamin B supplement strategies.