LAUSR

BACKGROUND Homocysteine-lowering intervention with folate was recently shown to be able to increase day-night difference of blood pressure (BP) in humans indicating a potential relationship between homocysteine and circadian BP variation. We thus sought to investigate the association between plasma total homocysteine level (tHcy) and circadian BP variation in hypertensive adults. METHODS We enrolled 244 eligible dipping and 249 nondipping BP status adults from 560 adults who were randomly sampled from 5,233 Chinese hypertensive adults who received ambulatory BP monitoring (ABPM). We further enrolled 390 adults with CC/CT genotypes of the methylenetetrahydrofolate reductase (MTHFR) and 79 TT genotype who received ABPM at the same time from 1858 hypertensive adults with MTHFR polymorphisms detection. RESULTS Plasma tHcy in nondippers was significantly higher than dippers (P < 0.001). Simple linear analysis revealed that tHcy significantly correlated with nocturnal systolic BP fall (r = -0.145, P = 0.001) and diastolic BP fall (r = -0.141, P = 0.002). Multivariate logistic regression analysis further identified tHcy as an independent factor correlated with the presence of nondipping BP status in hypertensive adults (odds ratio: 1.873, 95% confidence interval: 1.171-2.996, P = 0.009). The percentage of dipping BP status was 19.49% or 8.86% and the percentage of nondipping BP status was 80.51% or 91.14% in CC/CT or TT genotypes, respectively. The above different between CC/CT and TT genotypes was significant (P = 0.024). CONCLUSIONS These results indicated that high homocysteine levels associate with disturbed circadian BP variation in Chinese hypertensive adults.