Study Title:

Folic Acid Helps Prevent High Blood Pressure

Study Abstract

BACKGROUND:
Laboratory studies suggest that folate intake may decrease blood pressure (BP) through increasing nitric oxide synthesis in endothelial cells and/or reducing plasma homocysteine concentrations. However, human studies, particularly longitudinal data, are limited.

OBJECTIVE:
Our objective was to investigate whether dietary folate intake is associated with the 20-y incidence of hypertension.

DESIGN:
We prospectively followed 4400 men and women (African Americans and whites aged 18-30 y) without hypertension at baseline (1985) in the Coronary Artery Risk Development in Young Adults study 6 times, in 1987, 1990, 1992, 1995, 2000, and 2005. Diet was assessed by dietary-history questionnaire at baseline and in 1992 and 2005. Incident hypertension was defined as the first occurrence at any follow-up examination of systolic BP ≥140 mm Hg, diastolic BP ≥90 mm Hg, or use of antihypertensive medication.

RESULTS:
A total of 989 incident cases were identified during the 20-y follow-up. After adjustment for potential confounders, participants in the highest quintile of total folate intake had a significantly lower incidence of hypertension (HR: 0.48; 95% CI: 0.38, 0.62; P-trend < 0.01) than did those in the lowest quintile. The multivariable HRs for the same comparison were 0.33 (95% CI: 0.22, 0.51; P-trend < 0.01) in whites and 0.54 (95% CI: 0.40, 0.75; P-trend < 0.01) in African Americans (P-interaction = 0.047). The inverse associations were confirmed in a subset of the cohort (n = 1445) with serum folate measured at baseline and in 1992 and 2000.

CONCLUSIONS:
Higher folate intake in young adulthood was longitudinally associated with a lower incidence of hypertension later in life. This inverse association was more pronounced in whites. Additional studies are warranted to establish the causal inference.

Study Information

Xun P, Liu K, Loria CM, Bujnowski D, Shikany JM, Schreiner PJ, Sidney S, He K.
Folate intake and incidence of hypertension among American young adults: a 20-y follow-up study.
American Journal of Clinical Nutrition
2012 April
Departments of Nutrition and Epidemiology, Gillings School of Global Public Health, University of North Carolina at Chapel Hill, Chapel Hill, NC.

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