Determinants of the Magnitude of Blood Pressure in Essential Hypertension

Park, Jeong Bae; Shin, Hyun Ho

Abstract

BACKGROUND
The cause of blood pressure (BP) variation is difficult to identify because genes and environment interact to produce the BP phenotype. Different genetic background and culture in a population make different gene frequency and environment for hypertension. Therefore, we studied the determinants of BP with reference to genes, metabolic factors and environmental factors in Korean population.
METHODS
A study was carried out in two hundred fifty- eight patients (mean age 49, females 74%) with newly detected hypertension. Twenty-four hour ambulatory blood pressure monitoring (Accutracter II, Suntecr) was performed as an index of the magnitude of BP. The contributory factors studied were angiotensin-converting enzyme (ACE), angiotensinogen (AGT ; T174M and M235T) gene as a genetic factor, alcohol and smoking habitus, exercise, sodium intake as an environmental factor, and body mass index (BMI), insulin, lipid, renin, and aldosterone as a intermediate phenotype.
RESULTS
1) Genetic factors : There were no significant associations between ACE and AGT polymorphisms and the magnitude of BP. 2) Environmental factors : Alcohol and weight were significantly correlated with daytime systolic BP (r=.13, p=.04 and r=.15, p=.02), diastolic BP (r=.17, p=.01 and r=.12, p=.05), and nighttime diastolic BP (r=.15, p=.02 and r=.11, p=.01). Sodium intake, as assessed by fasting spot urine Na/K ratio in the morning, was not related to the magnitude of BP. 3) Intermediate phenotype : Plasma aldosterone level was significantly correlated to daytime diastolic BP (r=.16, p=.03), nighttime systolic BP (r=.17, p=.03), and nighttime diastolic BP (r=.16, p=.04). In women, plasma aldosterone was reversely correlated to urine Na/K ratio (r=-.42, p=.001).
CONCLUSIONS
The magnitude of blood pressure in essential hypertension seems to be mainly determined by weight, alcohol intake, and plasma aldosterone level.