| This is a study of the relation between protein intake and blood pressure in middle-aged adults based on data derived from a prospective population-based study of four US communities: the Atherosclerosis Risk in Communities (ARIC) study. It is comprised of a series of analyses of both cross-sectional and longitudinal relations and focusing on the contexts of both single nutrient and broader eating patterns.;The first part of the analysis describes the cross-sectional race and gender-specific associations between protein intakes and blood pressure. Data from 15,139 adults, aged 44--66, who participated in the baseline of the ARIC study from 1987 to 1989 were used in the analysis. The second part of the analysis examines whether the association persists throughout the six-year follow-up course for the study cohort. Of the study cohort, 92% (N = 13,935) completed at least one of the two follow-up examinations in 1989 to 1992 and 1992 to 1995, and were included in this longitudinal analysis. Analyses were conducted stratified by race, gender, and use of anti-hypertensive medication. Dietary intakes were only available at baseline and were assessed by an interviewer-administered, semiquantitative food frequency questionnaire. Protein intakes were adjusted for total energy, using the residual approach. The cross-sectional associations of total, animal, or plant protein intakes relating to systolic (SBP) or diastolic blood pressure (DBP) were examined by multiple regression models with adjustment for age, center, education level, body mass index (BMI), energy intake, smoking status, alcohol consumption, and Keys score.;Based on the baseline data of the ARIC study, intakes of both total and animal protein were inversely associated with blood pressure, after adjustment for potentially confounding factors, and regardless of hypertension medication use. No statistically significant association was found relating plant protein intake and blood pressure. These results were further confirmed by longitudinal analysis which indicated that intakes of both total and animal protein at baseline were inversely associated with average DBP at three examinations over a six-year period after adjustment for potentially confounding factors, and regardless of hypertension medication use.;In the third part of this study, the relation of protein intake and blood pressure is analyzed from a extended view of diet to examine how differences in eating patterns influenced the relation of interest. Using factor analysis, eight, seven, six, and six eating patterns were characterized for African-American men, African-American women, white men and white women, respectively, from the baseline food consumption frequency data. The measures of identified eating patterns were then related to levels of protein intake as well as to SBP and DBP. Five race-gender specific factors were identified as significantly, inversely related to blood pressure. All of these five favorable eating patterns for BP were associated with higher protein intakes.;Results from the present study support the hypothesis that higher protein intakes are related to lower blood pressure. This relation persists over time and is consistently demonstrated among men and women, African-Americans and whites, and subjects with or without anti-hypertensive medication. The results also indicate that the observed relation of protein intake with BP is parallel to what is observed for animal protein but not for plant protein. Furthermore, the present study provides insight into paths by which protein is consumed in this population and how this relates to protein intake and blood pressure. (Abstract shortened by UMI.). |
