Yoosik Youm

Social network effects on the transmission of sexually transmitted diseases

Background Only a limited number of studies have examined the effects of social networks on sexually transmitted diseases (STDs), although the findings of such studies would be helpful in designing more effective prevention strategies. Goal This study attempts (1) to determine whether there are any social network effects on STD transmission after controlling for other risk factors and (2) to explore the possible mechanisms by which social networks exert their effects. Study Design Logistic regressions examine the effects of friendship networks on STD transmission using data drawn from the Chicago Health and Social Life Survey (CHSLS). Additional logistic regressions probe the possible mechanisms (social control versus information and dyadic versus third party) that account for how the observed effects of networks might arise. Results and Conclusion Among people who had fewer than 13 lifetime sex partners, those with no social friends were only 0.4 times as likely to be infected as those with one or more social friends. Among people who had 13 or more lifetime partners, those with many friends (5 or 6) but weak ties to them (talking less than once a day with them) were only 0.2 times as likely to be infected as those with either fewer friends or stronger ties to their friends. Additional regressions suggest that network effects resting on dyadic control prevail among those with fewer than 13 lifetime sex partners. In contrast, network effects resting on information exchange among third parties prevail among those with 13 or more lifetime partners.

Association between skeletal muscle mass and radial augmentation index in an elderly Korean population

Increasing evidence supports the importance of maintaining skeletal muscle mass for cardiovascular health. However, there is limited data on the relationship between skeletal muscle mass and arterial stiffness targeting an elderly population. Thus, we investigated the association between skeletal muscle mass and arterial stiffness in an elderly Korean population. This study used data from the Korean Social Life, Health and Aging Project which started in 2011. In this cross-sectional study, 180 men (mean age 71.7) and 247 women (mean age 70.9) were included. Arm and leg muscle masses were measured by bioelectrical impedance analysis. Radial augmentation index, a noninvasive measure of arterial stiffness, was assessed by radial pulse wave analysis. The relationship between skeletal muscle mass and augmentation index was investigated by multiple linear regression analysis. In men, limb muscle mass was significantly and inversely associated with augmentation index (β=-1.07% per 1 kg muscle mass, p<0.001) when adjusted for age. This inverse association remained after additional adjustment for body mass index, systolic blood pressure, total cholesterol, high-density lipoprotein-cholesterol, fasting glucose, insulin, smoking and alcohol intake (β=-0.69%, p=0.019). In women, the inverse association between limb muscle mass and augmentation index was less prominent (β=-0.59%, p=0.030), and the association disappeared when fully adjusted (β=-0.32%, p=0.304). However, limb muscle mass was not associated with resting blood pressure either in men or women. Our results suggest that decreased skeletal muscle mass may affect arterial wall elasticity.

Socioeconomic burden of influenza in the Republic of Korea, 2007-2010.

Background Although the socioeconomic burden of 2009 pandemic influenza A (H1N1) was considerable, no reliable estimates have been reported. Our aim was to compared medical costs and socioeconomic burden resulting from pandemic influenza A (H1N1) 2009 with that of previous seasonal influenza. Methods We estimated the medical costs and socioeconomic burden of influenza from May 2007 to April 2010. We used representative national data sources(data from the Health Insurance Review Agency, the National Health Insurance Corporation, the Korea Centers for Disease Control and Prevention, and the Korean National Statistics Office) including medical utilization, prescription of antivirals, and vaccination. Uncertainty of data was explored through sensitivity analysis using Monte Carlo simulation. Results Compared with the seasonal influenza, total medical costs (US

Social Network Characteristics and Body Mass Index in an Elderly Korean Population

291.7 million) associated with pandemic (H1N1) 2009 increased more than 37-fold. Compared with the 2007–2008 season, outpatient diagnostic costs (US

Association between C reactive protein level and depressive symptoms in an elderly Korean population: Korean Social Life, Health and Aging Project

135.3 million) were 773 times higher in the 2009–2010 season, and the mean diagnostic cost per outpatient visit was 58.8 times higher. Total socioeconomic burden of pandemic (H1N1) 2009 was estimated at US

A sociological interpretation of emerging properties in STI transmission dynamics: walk-betweenness of sexual networks

1581.3 million (10%–90%: US

Gender differences in hypertension control Among Older Korean Adults: Korean social life, health, and aging project

1436.0–1808.3 million) and those of seasonal influenza was estimated at US

The Korean social life, health and aging project-health examination cohort

44.7 million (10%–90%: US

Social Network Effects on Post-Traumatic Stress Disorder (PTSD) in Female North Korean Immigrants

32.4–57.9 million) in 2007–2008 season and US

Sex-specific effects of social networks on the prevalence, awareness, and control of hypertension among older Korean adults

42.3 million (10%–90%: US