Objectives: It is not yet clear whether dietary protein could help maintaining a healthy blood pressure (BP). We investigated the association between total protein intake, estimated from 24-h urinary urea excretion, and incident hypertension in Dutch men and women.
Methods: We analyzed data of 3997 men and women (aged 28-75 years) who participated in the Prevention of Renal and Vascular Endstage Disease (PREVEND) study, a prospective cohort study. Urea excretion was assessed in two consecutive 24-h urine collections at baseline and approximately 4 years later, from which total protein intake was estimated using the Maroni method. Participants were followed for 9 years for hypertension incidence, defined as BP at least 140/90 mmHg or initiation of antihypertensive medication. Hazard ratios (HR) were obtained in sex-specific quintiles of protein intake using time-dependent Cox regression, adjusted for age, sex, BMI, smoking, alcohol use, and 24-h urinary excretions of sodium and potassium.
Results: Baseline BP was on average 119/70 mmHg and 976 participants developed hypertension during follow-up. Mean protein intake (in g/kg ideal body weight) was 1.18 ± 0.26 for men and 1.12 ± 0.25 for women. Estimated protein intake was nonlinearly inversely associated with incident hypertension in the fully adjusted model, with nonsignificant HR of 0.77, 0.75, 0.82, and 0.83 in consecutive quintiles compared with the lowest quintile (P-trend: 0.52).
Conclusion: Protein intake, as assessed by urinary urea excretion, was not significantly associated with 9-year hypertension incidence in Dutch men and women.