Effect of long-term low-dose folic acid supplementation on degree of total homocysteine-lowering: major effect modifiers.

We sought to examine the potential modifiers in the association between long-term low-dose folic acid supplementation and the reduction of serum total homocysteine (tHcy) among hypertensive patients, using data from the China Stroke Primary Prevention Trial (CSPPT). This analysis included 16 867 participants who had complete data on tHcy measurements at both the baseline and exit visit. After a median treatment period of 4·5 years, folic acid treatment significantly reduced the tHcy levels by 1·6 µmol/l (95 % CI 1·4, 1·8). More importantly, after adjustment for baseline tHcy and other important covariates, a greater degree of tHcy reduction was observed in certain subgroups: males, the methylenetetrahydrofolate reductase (MTHFR) 677TT genotype, higher baseline tHcy levels (≥12·5 (median) v. <12·5 µmol/l), lower folate levels (<8·0 (median) v. ≥8·0 ng/ml), estimated glomerular filtration rate (eGFR) <60 ml/min per 1·73 m2 (v. 60-<90 and ≥90 ml/min per 1·73 m2), ever smokers and concomitant use of diuretics (P for all interactions <0·05). The degree of tHcy reduction associated with long-term folic acid supplementation can be significantly affected by sex, MTHFR C677T genotypes, baseline folate, tHcy, eGFR levels and smoking status.

Association of total homocysteine with blood pressure in a general population of Chinese adults: a cross-sectional study in Jiangsu province, China.

OBJECTIVES: We aimed to evaluate the relation of total homocysteine (tHcy) concentrations with systolic blood pressure (SBP) and diastolic blood pressure (DBP) levels, and examine the possible modifiers in the association among a general population of Chinese adults. DESIGN: A cross-sectional study. SETTING: The study was conducted within 21 communities in Lianyungang of Jiangsu province, China. PARTICIPANTS: A total of 26 648 participants aged ≥35 years and with no antihypertensive drug use were included in the final analysis. RESULTS: Overall, there was a positive association between tHcy concentrations and SBP (per 5 µmol/L tHcy increase: adjusted ß=0.45 mm Hg; 95% CI 0.29 to 0.61) or DBP levels (per 5 µmol/L tHcy increase: adjusted ß=0.47 mm Hg; 95% CI 0.35 to 0.59). Compared with participants with tHcy <10 µmol/L, significantly higher SBP levels were found in those with tHcy concentrations of 10 to <15 (adjusted ß=0.80 mm Hg; 95% CI 0.32 to 1.28) and ≥15 µmol/L (adjusted ß=1.79 mm Hg; 95% CI 1.20 to 2.37; p for trend <0.001). Consistently, significantly higher DBP levels were found in participants with tHcy concentrations of 10 to <15 (adjusted ß=0.86 mm Hg; 95% CI 0.49 to 1.22) and ≥15 µmol/L (adjusted ß=2.01 mm Hg; 95% CI 1.57 to 2.46; p for trend <0.001), respectively as compared with those with <10 µmol/L. Furthermore, a stronger association between tHcy and SBP (p for interaction=0.009) or DBP (p for interaction=0.067) was found in current alcohol drinkers. CONCLUSION: Serum tHcy concentrations were positively associated with both SBP and DBP levels in a general Chinese adult population. The association was stronger in current alcohol drinkers.

Association between serum total homocysteine and arterial stiffness in adults: a community-based study.

Both increased arterial stiffness and higher total homocysteine (tHcy) are associated with an elevated risk for cardiovascular disease. However, the relationship between tHcy and arterial stiffness is still inconclusive. The authors aimed to test the relationship of tHcy with carotid-femoral pulse wave velocity (cfPWV) and examine the possible effect modifiers in adults. A study was conducted from July to September 2016 in Jiangsu Province, China. A total of 16 644 participants were enrolled in the final analysis. Increased arterial stiffness is defined as a cfPWV ≥10 m/s. Overall, there was a positive association between tHcy and cfPWV levels (per 5-µmol/L tHcy increase: ß = 0.10; 95% confidence interval [CI], 0.08-0.13) and increased arterial stiffness (per 5-µmol/L tHcy increase: odds ratio, 1.11; 95% CI, 1.07-1.14). Compared with participants with tHcy <10 µmol/L, the significantly higher cfPWV levels were observed in those with tHcy ≥15 µmol/L (ß = 0.37; 95% CI, 0.28-0.47). Accordingly, a higher prevalence of increased arterial stiffness was found in patients with tHcy10 to <15 µmol/L (odds ratio, 1.18; 95% CI, 1.05-1.33) and tHcy ≥15 µmol/L (odds ratio, 1.50; 95% CI, 1.32-1.71) as compared with participants with tHcy <10 µmol/L. Furthermore, the stronger positive association was found in participants who were older (≥60 years, P for interaction = .008), had low body mass index (<25 kg/m2 , P for interaction = .026), high systolic blood pressure levels (≥145 mm Hg [median], P for interaction = .048), or diabetes mellitus (P for interaction = .045). The present study demonstrated that serum tHcy concentrations were positively associated with cfPWV and the prevalence of increased arterial stiffness. These results suggest that the cardiovascular effects of tHcy may partly be mediated through arterial stiffness.