Folate Intake and the Risk of Incident Hypertension Among US Women

Abstract

YPERTENSION AFFECTS AN EStimated 65 million individuals in the United States and many more worldwide. 1,2 Because the risk of hypertension increases with age, the prevalence is growing along with the aging population. Hypertension is a potent independent risk factor for cardiovascular disease 3-6 and renal failure. 7-9 Therefore, identifying risk factors for hypertension could lead to specific preventive interventions that may favorably affect public health. Folate may have beneficial effects on blood pressure by increasing nitric oxide synthesis in endothelial cells, 10,11 or by reducing plasma homocysteine, which itself can cause endothelial cell injury. 12-16 Oral folic acid supplementation improves endothelial function in vivo. 17,18 Although there are no published studies on the association between folate intake and risk of incident hypertension, 2 small randomized trials have demonstrated that high-dose folic acid supplementation may lower systolic and diastolic blood pressure. 19,20 Taken together, these data suggest that a higher intake of folate may reduce an individual's risk of hypertension. We prospectively examined the association between folate intake and risk of incident hypertension in 2 large studies of younger and older women who were followed up for 8 years. METHODS Study Populations The younger cohort (Nurses' Health Study II [NHS II]) was assembled in 1989 when 116671 female registered nurses aged 25 to 42 years returned an initial questionnaire. 21 The older cohort (Nurses' Health Study I, [NHS I]) was assembled in 1976 when 121700 female nurses aged 30 to 55 years returned a mailed questionnaire. 22 Subsequent questionnaires have been mailed every 2 years to update information on health-related behavior and medical events. Detailed dietary information was collected every 4 years using a semiquantitative food frequency questionnaire. 23 The assembly of the 2 populations for the purpose of this study is outlined in FIGURE 1. Each cohort was followed up for 8 years (1991 to 1999 in NHS II and 1990 to 1998 in NHS I). The institutional review board at Brigham and Women's Hospital re

Folate Nutritional Genetics and Risk for Hypertension in an Elderly Population Sample

“…This interactive effect occurred only in females, with higher dietary folate intake being associated with decreased blood pressure. This finding in an elderly population is consistent with previous work by Forman et al [16] , although in their much larger study, higher total folate intake was associated with a decreased risk of hypertension in younger women in particular.…”

A causal relationship between antioxidants, minerals and vitamins and metabolic syndrome traits: a Mendelian randomization study

“…The role of folate in hypertension risk has been previously noted. In line with our MR study results, a prospective cohort study involving 93,803 younger women aged 27 to 44 years from the Nurses' Health Study II and 62,260 older women aged 43 to 70 years from the Nurses' Health Study I demonstrated that higher total folate intake was associated with a reduced risk of incident hypertension, especially among younger women [ 52 ]. Mechanistically, folate deficiency can lead to the blockage of insulin synthesis and secretion in cultured β cells due to increased reactive oxygen species production and pro-apoptotic changes [ 53 ].…”

High-dose short-term folate administration modifies ambulatory blood pressure in postmenopausal women. A placebo-controlled study

“…The herein reported capability of folate of decreasing BP agrees with previous data showing that a low intake (Forman et al, 2005) or low level (Kahleová et al, 2002) of folates is associated with hypertension, and that, in individuals at increased cardiovascular risk, folate supplementation reduces daytime office BP of about 4-5 mm Hg (van Dijk et al, 2001;Mangoni et al, 2002;Anderson et al, 2006). In our data, daytime BP did not or only slightly decreased.…”