Serum antioxidant vitamins and blood pressure in the United States population

Serum vitamin C has been inversely associated with blood pressure in several epidemiologic studies, but little is known about effect of other antioxidant vitamins. We examined the relation between serum vitamins A, C, and E, alpha-carotene, and beta-carotene levels and blood pressure among 15 317 men and women greater than or equal to20 years of age who participated in the Third National Health and Nutrition Examination Survey. Blood pressure was characterized as the average of 6 measurements obtained over 2 visits by trained observers and hypertension was defined as blood pressure greater than or equal to140/90 mm Hg and/or taking antihypertensive medications. In multivariate models, a 1 SD difference in vitamin A (16.2 mug/dL) and vitamin E (20.4 mug/dL) was associated with a 43% (OR, 1.43; 95% CI, 1.34 to 1.53) and 18% (OR, 1.18; 95% CI, 1.09 to 1.27) higher odds of hypertension, respectively. A 1 SD difference in alpha-carotene (0.47 mug/dL) and beta-carotene (496 mug/dL) was associated with a 16% (OR, 0.84; 95% CI, 0.76 to 0.94) and 11% (OR, 0.89; 95% CI, 0.82 to 0.97) lower odds of hypertension, respectively. In addition, serum vitamins A and E were positively and significantly associated with both systolic and diastolic blood pressure, whereas a-carotene and beta-carotene were inversely and significantly associated with systolic and vitamin C associated with diastolic blood pressure in multivariate linear regression analyses. These findings indicate that antioxidant vitamins may be important in the underlying cause and prevention of hypertension. Further studies in this important area are warranted.