Associations of Serum Thiamine Levels with Blood Pressure Among Middle-Aged and Elderly Women in Eastern China.

: Although B vitamins are implicated in cardiovascular regulation, the associations between serum thiamine (vitamin B1) and blood pressure (BP) remain unclear, particularly among women who are at high risk for hypertension-related complications. This study aimed to investigate relationships between serum thiamine levels and BP outcomes among middle-aged and elderly women in eastern China. : A community-based cross-sectional study was conducted among 2015 women aged 45-69 years in Zhejiang Province, China. Serum thiamine levels were quantified using liquid chromatography tandem mass spectrometry (LC-MS/MS). Hypertension was defined as measured BP ≥ 140/90 mmHg, or current use of antihypertensive medications. Multivariate logistic and linear regression models were used to assess associations of thiamine with hypertension prevalence and BP levels, respectively. Dose-response relationships were evaluated using restricted cubic splines (RCSs). : Higher thiamine levels were significantly associated with reduced hypertension prevalence (adjusted OR per SD increase: 0.87; 95%CI: 0.77, 0.97), with RCSs confirming linear dose-response (-overall < 0.05, -nonlinearity > 0.05). Compared with the lowest tertile, participants in the highest thiamine tertile had a 25% lower hypertension risk. Thiamine levels also showed negative associations with systolic BP (adjusted coef: -1.51 mmHg per SD; 95% CI: -2.33, -0.68), with the participants in the highest tertile showing a 3.94 mmHg reduction (95%CI: -5.97, -1.92). No significant relationship was found for diastolic BP. : Serum thiamine is inversely associated with both hypertension prevalence and systolic BP in middle-aged and elderly women. This study supports the potential of serum thiamine as a modifiable biomarker in hypertension prevention strategies, particularly among aging women.