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Background and ObjectivesWe estimated the prevalence of hypertension and hypertension subtypes in a large semi-urban city in Korea, using 24-hour ambulatory blood pressure monitoring (ABPM) in a randomly selected sample population.Subjects and MethodsA random sample (aged 20-65 years) from a city with an adult population of approximately 600000 was selected by using a list-assisted random digit dialing method. The 24-hour ABPM and conventional blood pressure measurement (CBPM) of these individuals were obtained.ResultsAmong the 496 participants, valid 24-hour ABPM and CBPM were obtained from 462 (93%) individuals. The estimated prevalence of hypertension in Goyang was 17.54% by CBPM and 32.70% by 24-hour ABPM (p<0.01). In the age stratified analysis, both CBPM and 24-hour ABPM showed increased prevalence of hypertension with age. The estimated prevalence of masked hypertension was 16.22% and that of white-coat hypertension was 1.08%. Men had a higher prevalence of masked hypertension than women (20.79% vs. 11.86%, p=0.0295). The estimated prevalence of masked hypertension was 17.5%, 20.58%, 24.34%, and 13.29% in the age categories of 30s, 40s, 50s, and 60s, respectively. The estimated prevalence of masked uncontrolled hypertension was 26.79% in patients with hypertension who were taking antihypertensive medications.ConclusionThe estimated prevalence of hypertension by 24-hour ABPM was higher than that by CBPM, revealing high prevalence of masked hypertension. The high prevalence of masked hypertension supports the adoption of ABPM in the national population survey and clinical practice to improve public health and reduce health care costs.

Background/Aims: Ascertaining the prevalence of isolated nocturnal hypertension (INHT) in the general population and identifying the characteristics of patients with INHT may be important to determine patients who should receive 24- hour ambulatory blood pressure (BP) measurements. This study aimed to evaluate the prevalence and characteristics of INHT in the general population.Methods: Of 1,128 participants (aged 20 to 70 years), we analyzed 823 who had valid 24-hour ambulatory BP measurements and were not on antihypertensive drug treatment.Results: The prevalence of INHT in the study was 22.8%. Individuals with INHT had a higher office, 24-hour, and daytime and nighttime ambulatory systolic and diastolic BPs compared to individuals with sustained day-night normotension. INHT was more prevalent in individuals with masked hypertension (MH) than in those with sustained hypertension (59.8% vs. 15.6%, p < 0.001). Among individuals with INHT, 92.6% had MH. Among individuals with office BP-based prehypertension, 34.5% had both INHT and MH. The prevalence of INHT was highest in individuals with office BP-based prehypertension. INHT was an independent determinant of MH after adjustment for age, sex, body mass index, diabetes, low-density-lipoprotein cholesterol, 24-hour systolic and diastolic BP, systolic and diastolic BP dipping, and systolic and diastolic BP non-dipping.Conclusions: The present study showed that INHT is not uncommon and is a major determinant of MH. Our findings strongly suggest the use of 24-hour ambulatory BP measurement for individuals within the prehypertension range of office BP owing to the high prevalence of INHT and MH in this population.

The authors developed an equation to estimate 24-hour urine sodium (24HUNa) using the average of three spot urine (SU) samples (morning-first, morning, and evening) from 74 individuals and validated this equation using the average of three SU samples (morning-first, daytime, and evening) from 174 additional individuals. Compared with previously published equations using a single SU sample, the currently developed equation using the average of three SU samples showed much lower bias from measured 24HUNa (À2.9 vs >10 mmol/ 24 h). The intraclass and concordance correlation coefficients of the proposed equation using the average of three SU samples were 0.909 and 0.832, respectively. The limits of agreement were À64.1-58.3 mmol/24 h and approximately 100 mmol/24 h for the currently developed and previously published equations, respectively. All equations showed a tendency to overestimate or underestimate 24HUNa in a manner dependent on the level of 24HUNa but irrespective of the number of SU samples considered. Nonetheless, among the currently tested equations, our equation using the average of three SU samples provided the best estimation of 24HUNa at a population level.

When the energy performance of concrete is substantially higher than that of normal type concrete, such concrete is regarded as energy efficient concrete (WBSCSD 2009). An experimental study was conducted to investigate mechanical properties of energy efficient concrete with binary, ternary and quaternary admixture at different curing ages. Slump test for workability and air content test were performed on fresh concretes. Compressive strength, splitting tensile strength were made on hardened concrete specimens. The mechanical properties of concrete were compared with predicted values by ACI 363R-84 Code, NZS 3101-95 Code, CSA A23.3-94 Code, CEB-FIP Model, EN 1991, EC 2-02, AIJ Code, JSCE Code, and KCI Code. The use of silica fume increased the compressive strengths, splitting tensile strengths, modulus of elasticities and Poisson's ratios. On the other hand, the compressive strength and splitting tensile strength decreased with increasing fly ash.