2 the eGFR (15 to 59 mL/min per 1.73 m2) and proteinuria on the central hemodynamics and PWV in middle-aged healthy Japanese men who were not receiving any medications for cardiovascular disease or the cardiovascular risk factors. 2. Methods 2.1. Study Cohort. The study protocol has been described in detail in a previous report [11, 12]. The study sub- jects were all employees of a construction company who underwent annual health checkup plus the measurements of the brachial-ankle PWV and of the radial augmentation index (radial AI) in 2008. The annual health checkup was conducted in the morning hours after the subjects had fasted overnight and included physical examinations, blood pressure measurement (2 times), blood and urine examinations, electrocardiography, chest roentgenography, upper gastrointestinal roentgenography, audiometry, and vision testing. In addition, measurements of the brachial- ankle PWV and radial augmentation index (radial AI) were also conducted during this series of examinations. The following subjects were excluded from the study: (1) subjects with conditions in which the reliability of the brachial-ankle PWV measurement is considered to be questionable [11, 12] (atrial ﬁbrillation; ankle/brachial systolic blood pressure index of less than 0.95; undergoing regular hemodialysis); (2) subjects in whom the standard deviation of the radial AI, calculated from ten radial pressure waveforms, was over 6%; (3) subjects with serum C-reactive protein levels ≥10 mg/L; (4) subjects receiving medications for heart disease, stroke, or risk factors for cardiovascular disease (i.e., hyperten- sion, hypercholesterolemia, and/or diabetes mellitus). Verbal informed consent was obtained from all of the participants prior to the measurements. The study was conducted with the approval of the Ethics Guidelines Committee of Tokyo Medical University. 2.2. Measurements. Subjects were randomly allocated to measurement of the brachial-ankle PWV ﬁrst, followed by that of the radial AI, or to measurement of the radial AI ﬁrst, followed by that of the brachial-ankle PWV. The procedural details of both measurements are described elsewhere. 2.2.1. Augmentation Index. The measurements of the blood pressure and radial AI were conducted after the subjects had rested for 5 minutes in the sitting position, in an air- conditioned room (24–26◦C) earmarked exclusively for this purpose. The blood pressure was measured in the right upper arm by the oscillometric method (HEM-907; Omron Healthcare Co., Ltd., Kyoto, Japan). Immediately after this measurement, the left radial arterial waveform was recorded using an arterial applanation tonometry probe equipped with an array of 40 micropiezoresistive transducers (HEM- 9000AI; Omron Healthcare Co., Ltd. Kyoto, Japan) [12, 13]. The HEM-9000AI device is programmed to automatically determine the pressure against the radial artery to yield the optimal radial arterial waveforms, and 10 radial arterial pressure waveforms were recorded. Then, the ﬁrst and International Journal of Nephrology second peaks of the peripheral systolic pressure (SBP1 and SBP2) and radial diastolic pressure (DBP) were automatically detected, and the radial AI was calculated using the equation (SBP2 − DBP)/(SBP1 − DBP) × 100(%). The waveform data were conﬁrmed by well-trained technicians, and the data of subjects with a standard deviation of the radial AI of over 6% were excluded from the analysis. The radial AI values were adjusted to a heart rate of 75 beats/minute (radial AI75). 2.3. Pulse Wave Velocity. The brachial-ankle PWV was measured using a volume-plethysmographic apparatus (Form/ABI, OMRON Colin Co. Ltd., Kyoto, Japan) [11, 12]. In brief, electrocardiographic electrodes were placed on both wrists, and a microphone for the phonocardiogram was ﬁxed to the left chest. Occlusion cuﬀs, which were connected to both the plethysmographic and oscillometric sensors, were tied around both upper arms and both ankles, with the subjects lying supine. The brachial and posttibial arterial pressures were measured using the oscillometric sensor. The brachial and posttibial arterial pressure waveforms determined by the plethysmographic sensor and recorded for 10 seconds were stored. The measurements were conducted after the subjects had rested for at least 5 minutes in the supine position in an air-conditioned room (24–26◦C) designated exclusively for this purpose. 2.4. Laboratory Measurements. The serum levels of total cholesterol (TC), high-density lipoprotein cholesterol (HDL), and triglycerides (TG) and the fasting plasma glucose (FPG) were measured enzymatically (FALCO Biosystems Co. Ltd, Tokyo, Japan). The serum CRP level was determined by the latex-aggregation method (Eiken Co., Tokyo, Japan), which is a high-sensitivity assay method with a detection threshold of <0.1 mg/L. All the blood and urine samples were obtained in the morning after the patients had fasted overnight. The severity of the renal function impairment was determined based on measurement of the eGFRcr using the Modiﬁcation of Diet in Renal Disease (MDRD) equation for Japanese subjects [3]: eGFRcr = 194 × Crnn−1.094× Age−0.287 (in females, ×0.739). A urinary dipstick test result for proteinuria of >1+ (urinary protein concentration ≥30 mg/dl) was deﬁned as proteinuria [2, 3, 12]. 2.5. Statistical Analysis. The data were represented as mean ± SD. The basic covariates used for the adjustments were the age, height, waist circumference, smoking status (non- or past smoker: 0, present smoker: 1), alcohol intake status (nondrinker: 0, light-to-moderate drinker (ethanol consumption, 1–29 g/day): 1, and heavy drinker (ethanol consumption, over 30 g/day): 2) TC, HDL, TG, and FPG. For assessment of the diﬀerences in each variable among the groups, an unpaired t-test for continuous variables and the chi-squared test for categorical variables were applied. Furthermore, for assessment of the diﬀerences in the brachial-ankle PWV, radial AI, and SBP2 among the groups, a general linear model (GLM) analysis with adjustments was