So-Yeon Ryu

Rapid increase of scrub typhus, South Korea, 2001-2006.

To the Editor: Scrub typhus, or tsutsugamushi disease, is a febrile illness caused by the rickettsial bacteria Orientia tsutsugamushi. Scrub typhus is endemic to a geographically distinct region, the so-called tsutsugamushi triangle, which includes Japan, Taiwan, China, and South Korea (1,2). Scrub typhus is a public health issue in Asia, where 1 billion persons may be at risk for the disease (3). In South Korea, scrub typhus is the most common rickettsial disease, and public health authorities are concerned about its increased incidence. Scrub typhus has been a reportable disease in South Korea since 1994. Physicians who diagnose suspected or confirmed cases must report these cases to their local health bureau and the Korea Centers for Disease Control and Prevention (KCDC) through the National Notifiable Disease Surveillance System (NNDSS). For a patient’s illness to meet the case definition for scrub typhus, the clinical signs (acute febrile illness and skin eschar) must be present or there must be laboratory confirmation (4-fold rise in antibody titer, antigen detected in blood, or genetic material detected by PCR). We analyzed NNDSS data confirmed by KCDC and classified all reported cases into 2 groups according to residential area. Cases with rural administrative address codes “eup” or “myun” were defined as rural cases, whereas cases with a city administrative address code of “dong” were defined as urban cases. All case-patients were classified by occupation as farmer or nonfarmer; all agricultural, fishery, and forest workers from rural areas were defined as farmers. In total, 23,929 cases, including 16,199 (67.7%) serologically confirmed cases, were reported between 2001 and 2006, of which 35.5% were male patients and 64.5% female patients. The greatest number of cases was in the age group 50–69 years, in both male (47.2%) and female (51.7%) patients; however, there were 167 boys (2.0%) and 119 girls (0.8%) <10 years of age. The number of cases peaked in 2005, with 2,331 and 4,449 cases in male and female patients, respectively. In 2006, a total of 6,480 cases (2,364 and 4,116 in males and females patients), which is 2.5× the number reported in 2001, were reported. The autumn epidemic period was from October through November; 96.2% of all cases were reported during this period (Figure). The proportion of cases identified in farmers decreased from 2001 (44.4%) to 2006 (36.4%); the number of cases in nonfarmers reached 4,121 (63.6%) in 2006. The number and proportion of patients living in urban areas increased from 1,059 (40.2%) in 2001 to 3,230 (49.9%) in 2006. This trend was observed in both farmers and nonfarmers. The number of cases among farmers living in urban areas increased from 150 (12.8%) to 443 (18.8%), while the corresponding number of cases in nonfarmers went from 909 (62.0%) to 2,787 (67.6%). In addition, we identified different features of scrub typhus epidemicity, compared with those reported in previous studies (4–7). Many of the values reported in this study (64.5% of cases in female patients, 59.5% in nonfarmers, and 96.2% occurring in autumn) are higher than the values reported previously in Japan (4), Taiwan (5), and China (6). The higher incidence in female workers may be associated with conventional South Korean working behavior. Female workers typically work in a squatting position, with bare hands, and usually in dry fields, whereas male workers tend to work in a standing position, with tools, and in rice fields. Therefore, female workers are more likely to be exposed to infected mites. Figure Monthly occurrence of scrub typhus cases in South Korea, 2001–2006. Previously, farmers were considered a high-risk group, but our results imply that the same or even more attention should be given to nonfarmers. Leptotrombidium pallidum, a common mite in Korea, first appears in September. Its population then peaks in October and November and to a lesser degree in April and May (7). In autumn, especially around Chusok (Korean Thanksgiving), nonfarmers and urban residents also take part in agricultural activities, such as the chestnut harvest, mowing around graves, and assisting their farmer relatives. A sharp peak in the number of cases occurred during October–November, which is inconsistent with a previous report on vector density showing a secondary peak during April–May (7). This finding suggests that many cases are misreported, especially in spring. Unfortunately, there are still no reports on the comprehensiveness of the scrub typhus surveillance system in South Korea. We cannot exclude other modes of exposure such as golf, climbing, and other outdoor leisure activities. A 5-day work week was introduced in 2004, and, as a result, more leisure time has been available to urban residents. In addition, improved surveillance and diagnostic methods as well as changes in atmospheric temperature (8) may have contributed to the increase. We report the rapid increase of scrub typhus and the proportion of infected persons living in urban areas in South Korea. This information will be used to establish strategies for prevention, surveillance, and management in South Korea and in other countries where scrub typhus is endemic.

Cohort Profile: The Namwon Study and the Dong-gu Study

These two cohorts were designed to examine the increasing burden of chronic diseases among Korean populations. The studies investigated determinants for stroke, osteoporosis, dementia and cancer among middle-aged and elderly Korean populations. The Namwon Study baseline survey was performed between 2004 and 2007 (n = 10 667), and followed up 4 years later (n = 8157, follow-up rate = 76.5%). The baseline survey of the Dong-gu Study was administered over 2007-2010 (n = 9260), and will be followed up between 2014 and 2015. Questionnaires included assessment of cognitive function, psychiatric health and lifestyle factors. Clinical examinations, biochemical tests and genotyping focused on evaluating the determinants of target diseases and their intermediate phenotypes. Potential collaborators will be invited to contact the chief investigators.

Association between levels of physical activity and poor self-rated health in Korean adults: The Third Korea National Health and Nutrition Examination Survey (KNHANES), 2005

OBJECTIVE To investigate the association between level of physical activity and poor self-rated health in Korean adults. STUDY DESIGN A cross-sectional study was conducted on 7,800 adults aged > or =19 years who completed the Health Interview and the Health Behavior Surveys, issued during the Third National Health and Nutrition Examination Survey (2005). METHODS The association between self-rated health and physical activity was tested using Chi-squared test. Multiple logistic regression analysis was used to calculate the odds ratios of poor self-rated health for different levels of physical activity after adjusting for physical and chronic medical conditions. RESULTS The prevalence of poor self-rated health was significantly lower as the level of physical activity increased, and odds ratios for poor self-rated health were significantly lower for higher levels of physical activity after adjusting for age, marital status, educational status, smoking, alcohol consumption, and the number of physical impairments and chronic medical conditions. The association was similar in different age groups and among healthy respondents and respondents with physical impairments or chronic medical conditions. CONCLUSIONS Physical activity was positively associated with self-rated health in Koreans. The independent association between a lower level of physical activity and poor self-rated health supports public health programmes that encourage regular physical activity.

Distribution of the Ankle-Brachial Index and Associated Cardiovascular Risk Factors in a Population of Middle-Aged and Elderly Koreans

The Doppler ankle-brachial pressure index (ABI) is an objective and efficient tool that can be used to determine the presence and severity of peripheral arterial disease in the lower extremities. The ABI value is inversely associated with other cardiovascular risk factors. To date, there have been no studies of the distribution of ABI in Korea. We performed a cross-sectional study of 1,943 subjects (681 men and 1,262 women; 45-74 yr old) in Namwon, Korea. The prevalence of a low ABI (<0.90) was 2.2% in men and 1.8% in women, and a high ABI (≥1.30) was prevalent in 3.1% of men and 0.8% of women. Age, smoking habits, waist circumference, hypertension, and blood pressure were associated with ABI values in both sexes. The presence of carotid plaques was associated with ABI values only in men, whereas pulse pressure was associated with ABI values only in women (p<0.05). Although the prevalence of a low ABI in the present study was lower than those reported previously for Western populations and Japanese men, our results suggest that the ABI might be used as an indicator of cardiovascular risk factors in adult Koreans.

eGFR is associated with subclinical atherosclerosis independent of albuminuria: The Dong-gu Study

OBJECTIVES This study evaluated the relationships between estimated glomerular filtration rate (eGFR) and carotid atherosclerosis, peripheral arterial disease (PAD), arterial stiffness, and left ventricular hypertrophy, independent of albuminuria. METHODS The study population consisted of 6694 people aged 50 years and older who participated in the baseline survey of the Dong-gu Study conducted in Korea between 2007 and 2009. The common carotid artery intima-media thickness (CCA-IMT), carotid plaque, ankle-brachial index (ABI), brachial-ankle pulse wave velocity (baPWV), and left ventricular mass index (LVMI) of each subjects was assessed. RESULTS After adjustment for risk factors and albumin-creatinine ratio (ACR), kidney dysfunction (eGFR=30-44 ml/min per 1.73 m2) was significantly associated with carotid plaque presence (odds ratio [OR], 1.75; 95% confidence interval [CI], 1.21-2.53) and PAD (OR, 2.64; 95% CI, 1.51-4.62) compared to normal kidney function (eGFR≥60 ml/min per 1.73 m2). Similarly, mean LVMI and baPWV differed significantly according to eGFR after adjustment for other risk factors and ACR; in contrast, no significant difference was observed for CCA-IMT. CONCLUSIONS Independent of albuminuria, eGFR is associated with carotid plaque, PAD, baPWV, and LVMI but not with CCA-IMT in Koreans aged 50 years and older.

Cumulative smoking exposure, duration of smoking cessation, and peripheral arterial disease in middle-aged and older Korean men.

BackgroundWe investigated the association of cumulative smoking exposure and duration of smoking cessation with peripheral arterial disease (PAD).MethodsThe study population consisted of 2517 community-dwelling Korean men aged 50 years and older. Information on smoking characteristics such as smoking status, pack-years of smoking, and years since quitting smoking was collected using a standardized questionnaire. PAD was defined as an ankle-brachial index (ABI) less than 0.90 in either leg.ResultsThe odds ratio (OR, 95% confidence interval) of PAD was 2.31 (1.20-4.42) for former smokers and 4.30 (2.13-8.66) for current smokers, after adjusting for other cardiovascular risk factors. There was a significant dose-response relationship between pack-years of smoking and PAD. Compared with those who had never smoked, the multivariate-adjusted ORs of PAD for smokers of 0.1-20.0, 20.1-40.0, and >40.0 pack-years were 2.15 (1.06-4.38), 2.24 (1.08-4.65), and 2.93 (1.41-6.09), respectively. There was a significant decrease in PAD risk as the years since quitting smoking increased. The multivariate-adjusted ORs of PAD for 11-20 and ≥21 years smoking cessation were 0.41 (0.19-0.86) and 0.49 (0.24-0.98), compared with current smokers.ConclusionsCumulative smoking exposure and duration of smoking cessation were significantly associated with PAD in middle aged and older Korean men.

Preliminary report: A serious link between adiponectin levels and metabolic syndrome in a Korean nondiabetic population

This large-scale cross-sectional investigation highlights the relationships between adiponectin levels and a number of metabolic syndrome components in a nondiabetic Korean population (N = 6634). In a multivariate logistic regression model, after adjustment for age, homeostasis model assessment of insulin resistance, body mass index, smoking history, C-reactive protein, and low-density lipoprotein cholesterol, adiponectin levels were inversely related with metabolic syndrome in men and women (P < .05). Adiponectin level was found to be a significant contributor to metabolic syndrome. Our findings suggest that adiponectin is an important biomarker even in a nondiabetic population at high risk of metabolic syndrome.

Alcohol consumption and carotid artery structure in Korean adults aged 50 years and older

BackgroundEpidemiologic studies of the association between alcohol consumption and carotid artery structure have reported conflicting results. We investigated the association between alcohol consumption and carotid atherosclerosis by evaluating the effects of alcohol intake on carotid artery enlargement.MethodsThe study population consisted of 4302 community-dwelling Koreans (1577 men and 2725 women) aged 50 years and over. All the subjects had participated in the baseline survey of the Dong-gu Study conducted between 2007 and 2008. Daily alcohol consumption was determined by the number and frequency of alcoholic beverages consumed. We measured common carotid artery intima-media thickness (CCA-IMT), common carotid and bulb IMT (CB-IMT), carotid plaques, and the diameter of the common carotid artery (CCA-diameter) using high-resolution B-mode ultrasonography. We used analysis of covariance and multiple logistic regressions to determine the relationship between alcohol consumption and carotid artery parameters.ResultsCCA-IMT and CB-IMT were negatively correlated with alcohol consumption after controlling for cardiovascular risk factors in men (p for linear trend = 0.009 and = 0.038, respectively). The multivariate-adjusted odds ratio (OR) for carotid plaques was significantly higher in men who consumed >40.0 g/d (OR = 1.81, 95% CI = 1.13-2.91), although a significant positive correlation was observed between alcohol consumption and carotid plaques (p for linear trend = 0.027). Neither carotid IMT nor carotid plaques were correlated with alcohol intake in women. Alcohol intake was positively correlated with CCA-diameter adjusted for carotid IMT and plaques in the multivariate-adjusted model in both sexes (p for linear trend <0.001 for men and 0.020 for women).ConclusionThe results of our study indicate that alcohol consumption is inversely related to carotid IMT and positively related to carotid plaques in men, but not women. However, alcohol intake is positively associated with CCA-diameter in both men and women. Additional large population-based prospective studies are needed to confirm the effects of alcohol consumption on carotid artery structure.

The Association Between the Socioeconomic Status and Thyroid Cancer Prevalence; Based on the Korean National Health and Nutrition Examination Survey 2010-2011

The incidence of thyroid cancer has recently increased in most industrialized countries, including Korea. To date, few studies have examined the association between thyroid cancer and socioeconomic status (SES). The current study was based on data collected from a total of 12,276 subjects (5,277 men and 6,999 women) by the Korean National Health and Nutrition Examination Survey (KNHANES) between 2010 and 2011. Univariate and multivariate logistic regression analysis revealed that older age (odds ration [OR], 1.03; 95% confidence interval [CI], 1.00-1.05), being female (OR, 8.16; 95%CI, 2.99-22.24), being overweight (OR, 1.04; 95%CI, 1.01-1.06), monthly household income (OR, 3.27; 95%CI, 1.16-9.20 for medium-highest household income vs lowest household income; OR, 3.30; 95%CI, 1.16-9.34 for highest household income vs lowest household income), educational level (OR, 2.74; 95%CI, 1.16-6.46 for 10-12 yr vs < 7 yr) and alcohol consumption (OR, 1.89; 95%CI 1.08-3.32) were significant risk factors for thyroid cancer. Our results indicate that the recent increase in thyroid cancer is attributable to better early detection rather than to any increase in actual prevalence.

Influence of Organizational Culture and Health Promotion Life Style on Job Satisfaction in General Hospitals Nurses

Purpose: The effects of the organizational culture and health promotion life style on job satisfaction of nurses in general hospitals have been studied in an effort to provide basic information that will be helpful in effective management of the organization and enhancement of nursing. Method: The 341 samples used in the study were selected randomly from general hospitals having more than 250 beds in Gwangju province and Yosu province. Data collected were analyzed for frequency, percentage, ANOVA, t-test, Pearson`s correlation analysis, and Multiple regression analysis using SPSS, a program package for statistical analysis. Result: Factors affecting job satisfaction included work years, position, monthly income, stress management, which is a substructure of health promotion life style, innovation-oriented culture, relation-oriented culture, and task-oriented culture in organizational culture. Results showed an influence of 64.2%. Ed - highlight: Please review. Conclusion: The organizational culture, such as an innovation-oriented culture, relation-oriented culture, or task-oriented culture, has a positive influence on job satisfaction.