Association Between Plasma Vitamin C Concentrations and Blood Pressure in the European Prospective Investigation Into Cancer-Norfolk Population-Based Study
The effect of fruit and vegetable consumption and blood pressure is unclear. A population-based cross-sectional study was conducted in 20 926 men and women aged 40 to 79 years participating in the European Prospective Investigation Into Cancer-Norfolk who completed a health questionnaire and attended a clinic from 1993 to 1997. The relationship between plasma vitamin C concentrations, as an indicator of fruit and vegetable intake, and systolic BP was examined. The magnitude of their association was assessed using dichotomized values of high (≥140 mm Hg) and low (<140 mm Hg) systolic blood pressure. A total of 20 926 participants (46% men; mean [SD] 58.5 years [9.2 years]) were included after excluding participants with any missing data for variables of interest. People with high vitamin C concentrations had lower clinic blood pressure. The likelihood of having high blood pressure was 22% lower (odds ratio: 0.78 [95% CI: 0.71 to 0.86]) for those who were in the top quartiles of plasma vitamin C levels compared with the bottom quartiles after adjusting for age, sex, body mass index, cholesterol, prevalent medical conditions, smoking, physical activity, alcohol consumption, social class, education, use of vitamin C–containing supplement, and antihypertensive medication. Sex-specific analysis, as well as repeated analysis after exclusion of people who used vitamin C–containing supplements or who were taking antihypertensive medication, did not alter the results. There appears to be a strong association between vitamin C concentrations, an indicator of fruit and vegetable consumption, and a lower level of blood pressure. This may provide further evidence for health benefits of dietary patterns with higher fruit and vegetable consumption.