What is the clinical evidence from this study?

Study design: Cross-Sectional. Population: Hypertension (n=802). Intervention: AT1 A/C1166 gene polymorphism (C allele) vs. AA genotype. Primary outcome: Adjusted daytime systolic blood pressure (p=0.32).

January 1, 2003Open Access

A/C1166 Gene Polymorphism of the Angiotensin II Type 1 Receptor (AT1) and Ambulatory Blood Pressure: The Ohasama Study.

MKMasahiro KikuyaPreventive Cardiology KSKen SugimotoGeneral / Preventive / Lipids TKTomohiro KatsuyaGeneral / Preventive / Lipids

Key Result

The presence of the AT1 C1166 allele was not significantly associated with adjusted daytime systolic blood pressure (129.1 vs 127.9 mmHg, p=0.32) or other clinical parameters of hypertension.

Study Design

Type

Cross-Sectional (n=802)

Multicenter

Structured PICO

Does the AT1 A/C1166 gene polymorphism affect ambulatory blood pressure and cardiovascular disease prevalence in a general Japanese population?

Population

802 Japanese adults aged 40 and older from the general population who underwent ambulatory blood pressure monitoring and genetic analysis.

Exposure

Presence of the AT1 C1166 allele (AC or CC genotype)

Comparator

Absence of the AT1 C1166 allele (AA genotype)

Outcome

Ambulatory blood pressure (daytime, nighttime, and 24-hour)surrogate

The AT1 A/C1166 gene polymorphism is not significantly associated with ambulatory blood pressure levels or cardiovascular disease prevalence in the general Japanese population.

Main Result

Absolute Event Rate: 129.1% vs 127.9%

p-value: p=0.32

Limitations

Low frequency of the C1166 allele in the Japanese population may limit statistical power
Limited number of subjects with ambulatory blood pressure monitoring
Analysis of cardiovascular events included all vascular events together
Conducted in a rural area, which may differ from urban populations

Abstract

We previously investigated the relation between hypertension and each of three major genetic polymorphisms in the renin-angiotensin (AGT)-aldosterone system (R-A-A), AGT M235T, angiotensin convert enzyme (ACE) I/D, and CYP11B2 -344C/T, by means of ambulatory blood pressure (ABP) monitoring in a general Japanese population (the Ohasama Study). A/C1166 gene polymorphism in the 3' untranslated region of the angiotensin II type 1 receptor (AT1) gene is the final remaining major target in R-A-A to be examined in the Ohasama Study population. In the present study, the AT1 A/C1166 polymorphism was genotyped by the TaqMan polymerase chain reaction (PCR) method or restriction fragment length polymorphism (RFLP) in 802 Japanese subjects aged 40 and over, who were previously genotyped for the AGT M235T, ACE D/I, CYP11B2 -344C/T polymorphisms. The AA genotype, AC genotype, and CC genotype were present in 678 (84.5%), 121 (15.1%), and 3 (0.4%) of subjects, respectively. Since the frequency of the C allele was quite low (0.079), the genotypes were classified according to the presence or absence of the C allele. Although daytime blood pressure (BP) was higher in subjects with the C allele, the difference was not statistically significant after adjusting for age, gender, body mass index, and smoking status. No significant difference was noted in the prevalence of cardiovascular diseases or nocturnal BP decline between the two groups. These results indicated that AT1 A/C1166 polymorphism was not associated with any clinical parameters associated with hypertension or atherosclerosis in the Japanese population.

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