Measurement Errors on Normotensive Subjects in Screening Test / 한국역학회지

BACKGROUND: Blood pressure measurements with a mercury sphygmomanometer serve as the screening test to establish the clinical diagnosis of primary hypertension. But one of the problems of hypertension screening is the variability of blood pressure measurements. METHODS: In order to identify the measurement error of blood pressure through the biennial health screening program of Korea Insurance Medical Corporation, we compared the blood pressure of screening test with true value which defined as the mean of blood pressures taken from the direct contact and twice check-up among normotensive Seoul Cohort participants. RESULTS: Three hundred forty-nine participants had both data of screening measurement and survey of direct contact. The means of difference in systolic and diastolic blood pressure between both data were 8.47 mmHg and 6.54 mmHg, respectively. These results showed statistical significance with paired t-test (p=0.001). CONCLUSION: Our findings indicated that screening measurement of blood pressure had false negative. And if a epidemiologic study about blood pressure used the data of screening test, it should adjust value of systolic and diastolic blood pressure with adding 8 and 7 mmHg, respectively.

A Nested Case-Control Study on the High Normal Blood Pressure as a Risk Factor of Hypertension in Korean Middle-aged Men / 예방의학회지

OBJECTIVES: 'High-normal blood pressure' is a factor influencing decision to initiate targeted intensive intervention strategy in westernized populations. JNC-VI offered the vigorous lifestyle modification for persons with 'high-normal blood pressure', who could be early detected. As a hypertension seems to be the result of multiple genetic factors operating in concert with associated environmental factors, it will be necessary to identify the high-normal blood pressure as a risk factor of hypertension for applying primary prevention strategy in Korean people. METHODS: Although cohort study design might be adequate to recruit incidence cases, to keep time sequence of events, and to prevent information bias, nested case-control study was chosen for avoiding measurement errors because hypertension is a benign disease. Source population was the 'Seoul Cohort' participants and follow-up was done by using Korea Medical Insurance Corporation's database on the utilization of health services from 1Jan93 to 30Jun97. Incidence cases were ascertained through the chart review, telephone contacts, and direct blood pressure measurements. Controls included the pairing of 4 individuals to each case on the basis of age. RESULTS: As 75 % of 247 incident cases had high-normal blood pressure, the crude odds ratio for hypertension was 2.04 (95% CI 1.47-2.83). Another statistically significant risk factors of hypertension were body mass index, dietary fiber, alcohol consumption, weekly activity and history of quitting smoking. The multivariate odds ratio of high-normal blood pressure adjusted for all risk factors was 1.84 (95 % CI 1.31-2.56). Among high-normal blood pressure group, body mass index, weekly ethanol amounts, weekly physical activity, and dietary fiber except history of quitting smoking were still risk factors of hypertension. CONCLUSION: 'High-normal blood pressure' is a risk factor for hypertension in Korean middle-aged men, which represents that the vigorous lifestyle modification for persons with 'high-normal blood pressure' is need.

A Distribution of Waist-hip Ratio Associated with the Blood Pressure in Middle-aged Men / 예방의학회지

BACKGROUND: Excess abdominal fat, expressed as an increased ratio of waist to hip circumferences (WHR), is independently associated with higher levels of blood pressure. Although a WHR greater than 1.0 in men has been shown to predict complications from obesity, the WHR has not been evaluated in all ethnic groups. METHODS: In order to ascertain the association between WHR and classification of blood pressure and to investigate the critical value of WHR as a predictive factor of hypertension in Korean middle-aged men, we compared the mean of WHRs according to the classification of blood pressure in Seoul Cohort participants. RESULTS: Through a survey of direct measurement of waist and hip girth, 452 subjects were recruited from the cohort. The mean of WHR was 0.88 and its standard deviation was 0.04. The mean of WHRs was higher in the systolic blood pressure group (above 140 mmHg), diastolic blood pressure group (above 90 mmHg), and hypertension group than in the systolic blood pressure group (below 140 mmHg), diastolic blood pressure group (below 90 mmHg), and normotensive group, respectively. And WHR of above 0.89 was associated with hypertension (z-value =6.66). CONCLUSIONS: It is necessary for Korean males with WHR greater than 0.89 to recommend the primary prevention and early detection of hypertension.

Association of Liver Dysfunction with Self-Medication History in Korean Healthy Male Adults / 예방의학회지

BACKGROUND: Korean people could abuse healthy foods as well as medications, which might cause serious side effects. The aim of this study was elucidating liver dysfunction due to the self-medications of hepatotonics, healthy foods and herb medications by nested case-control study. METHODS: Study subjects were drawn from male members of seoul Cohort Study who were recruited by self-administered structured questionnaire survey through mailing to the healthy men between the age of 40 and 59 years through the program of biennial health check-up offered by Korea Medical Insurance Corporation(KMIC). The liver dysfunction was defined as the level of serum AST and ALT above 40 IU/L and increased in more than one hundred per-cent during the 2 year follow-up period. To estimate the odds ratio between self-medication and liver dysfunction after controlling for potential confounders, logistic regression was performed. RESULTS: During the follow-up period, 30 members were identified to fit into case criteria and 2,625 members were selected as control. In logistic regression analyses, history of healthy foods intake, age under 45 years, obesity, and habit of regular exercise were significantly associated with liver dysfunction. The following factors exhibited no statistical significance: intake of hepatotonics, of herb medicine; history of disease in family, of operation, and of radiologic examination; smoking habits and drinking amounts. CONCLUSION: The significant association between the intake of healthy foods and the liver dysfunction illustrates that chronically optional overuse of healthy foods might bring to hazards to health. As the increasing trend of the size of purchasing healthy foods in Korea, pharmacoepidemiologic studies evaluating the safety and efficacy of the widely used healthy foods should be performed in the near future.