Won Joon Lee

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.

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

Objectives Research has shown that obesity appears to spread through social ties. However, the association between other characteristics of social networks and obesity is unclear. This study aimed to identify the association between social network characteristics and body mass index (BMI, kg/m2) in an elderly Korean population. Methods This cross-sectional study analyzed data from 657 Koreans (273 men, 384 women) aged 60 years or older who participated in the Korean Social Life, Health, and Aging Project. Network size is a count of the number of friends. Density of communication network is the number of connections in the social network reported as a fraction of the total links possible in the personal (ego-centric) network. Average frequency of communication (or meeting) measures how often network members communicate (or meet) each other. The association of each social network measure with BMI was investigated by multiple linear regression analysis. Results After adjusting for potential confounders, the men with lower density (<0.71) and higher network size (4-6) had the higher BMI (β=1.089, p=0.037) compared to the men with higher density (>0.83) and lower size (1-2), but not in the women (p=0.393). The lowest tertile of communication frequency was associated with higher BMI in the women (β=0.885, p=0.049), but not in the men (p=0.140). Conclusions Our study suggests that social network structure (network size and density) and activation (communication frequency and meeting frequency) are associated with obesity among the elderly. There may also be gender differences in this association.

Serum 25-Hydroxyvitamin D and Insulin Resistance in Apparently Healthy Adolescents

Purpose Vitamin D deficiency is a common condition that is associated with diabetes and insulin resistance. However, the association between vitamin D and insulin resistance has not been fully studied, especially in the general adolescent population. Therefore, we assessed the association between serum 25-hydroxyvitamin D [25(OH)D] level and insulin resistance among apparently healthy Korean adolescents. Methods A total of 260 (135 male and 125 female) adolescents in a rural high school were assessed for serum 25(OH)D, fasting plasma glucose, and insulin. All of the participants were aged 15 to 16 years old, and without known hypertension or diabetes. Serum 25(OH)D was analyzed both as a continuous and categorical variable in association with insulin resistance. Insulin resistance was estimated by homeostasis model assessment (HOMA-IR). Increased insulin resistance was operationally defined as a HOMA-IR value higher than the sex-specific 75th percentile. Results In male adolescents, every 10 ng/ml decrease in 25(OH)D level was associated with a 0.25 unit increase in HOMA-IR (p = 0.003) after adjusting for age and BMI. Compared to those in the highest quartile, male adolescents in the lowest 25(OH)D quartile were at significantly higher risk for insulin resistance: unadjusted odds ratio 4.06 (95% CI, 1.26 to 13.07); age and BMI adjusted odds ratio 3.59 (95% CI, 1.03 to 12.57). However, 25(OH)D level, either in continuous or categorical measure, was not significantly associated with insulin resistance among female adolescents. Conclusions This study suggests that serum 25(OH)D level may be inversely associated with insulin resistance in healthy male adolescents.

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

Objectives: Controlling blood pressure is a key step in reducing cardiovascular mortality in older adults. Gender differences in patients’ attitudes after disease diagnosis and their management of the disease have been identified. However, it is unclear whether gender differences exist in hypertension management among older adults. We hypothesized that gender differences would exist among factors associated with hypertension diagnosis and control among community-dwelling, older adults. Methods: This cross-sectional study analyzed data from 653 Koreans aged ≥60 years who participated in the Korean Social Life, Health, and Aging Project. Multiple logistic regression was used to compare several variables between undiagnosed and diagnosed hypertension, and between uncontrolled and controlled hypertension. Results: Diabetes was more prevalent in men and women who had uncontrolled hypertension than those with controlled hypertension or undiagnosed hypertension. High body mass index was significantly associated with uncontrolled hypertension only in men. Multiple logistic regression analysis indicated that in women, awareness of one’s blood pressure level (odds ratio [OR], 2.86; p=0.003) and the number of blood pressure checkups over the previous year (OR, 1.06; p=0.011) might influence the likelihood of being diagnosed with hypertension. More highly educated women were more likely to have controlled hypertension than non-educated women (OR, 5.23; p=0.013). Conclusions: This study suggests that gender differences exist among factors associated with hypertension diagnosis and control in the study population of community-dwelling, older adults. Education-based health promotion strategies for hypertension control might be more effective in elderly women than in elderly men. Gender-specific approaches may be required to effectively control hypertension among older adults.

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

The Korean Social Life, Health, and Aging Project (KSHAP) is a population-based longitudinal study of health determinants among elderly Koreans. The target population of the KSHAP are people aged 60 years or older and their spouses living in a rural community of Korea. A complete enumeration survey was conducted in the first wave of the KSHAP on 94.7% (814 of 860) of the target population between December 2011 and July 2012. The KSHAP-Health Examination (KSHAP-HE) cohort consists of 698 people who completed additional health examinations at a public health center (n=533) or at their home (n=165). Face-to-face questionnaires were used to interview participants on their demographics, social network characteristics, medical history, health behaviors, cognitive function, and depression symptoms. Health center examinations included anthropometric measures, body impedance analysis, resting blood pressure measurement, radial artery tonometry, bone densitometry, the timed up-and-go test, and fasting blood analysis. However, only anthropometric measures, blood pressure measurement, and non-fasting blood analysis were available for home health examinations. Collaboration is encouraged and access to the KSHAP baseline data will be available via the website of the Korean Social Science Data Archive (http://www.kossda.or.kr).

Factors Associated with a Low-sodium Diet: The Fourth Korean National Health and Nutrition Examination Survey

OBJECTIVES The low-sodium diet is a known preventive factor for hypertension and cardiovascular disease. Factors associated with low-sodium diets should be identified to reduce sodium intake effectively. This study was conducted to identify factors correlated with a low-sodium diet. METHODS This cross-sectional study analyzed data from a total of 14,539 Koreans aged 20 years or older, who participated in the Fourth (2007-2009) Korean National Health and Nutrition Examination Survey. A low-sodium diet was defined as having ≤2,000 mg/day based on 24-hour recalls. Multiple logistic regression models were used to assess sex, age, education, number of family members, household income, occupation, alcohol drinking, total energy intake, frequency of eating out, and hypertension management status for their associations with low-sodium diets. RESULTS Among all participants, only 13.9% (n=2,016) had low-sodium diets. In the multivariate analysis, 40-49 years of age, clerical work jobs, higher total energy intake, and frequent eating out were inversely associated with low-sodium diets. And female sex and living-alone were associated with low-sodium diets. Lower frequency of eating out was significantly associated with low-sodium diets, even after adjusting for total energy intake and other potential confounders. Adjusted odds ratios (95% confidence interval) for a low-sodium diet were 1.97 (1.49-2.61), 1.47 (1.13-1.91), 1.24 (0.96-1.61), and 1.00 (reference) in people who eat out <1 time/month, 1-3 times/month, 1-6 times/week, and ≥1 time/day, respectively. CONCLUSIONS Our study suggests that sex, age, number of family members, occupation, total energy intake, and lower frequency of eating out were associated with a low-sodium diet in Korean adults.

Impaired insula functional connectivity associated with persistent pain perception in patients with complex regional pain syndrome.

Given that the insula plays a contributory role in the perception of chronic pain, we examined the resting-state functional connectivity between the insular cortex and other brain regions to investigate neural underpinnings of persisting perception of background pain in patients with complex regional pain syndrome (CRPS). A total of 25 patients with CRPS and 25 matched healthy controls underwent functional magnetic resonance imaging at rest. With the anterior and posterior insular cortices as seed regions, we compared the strength of the resting-state functional connectivity between the two groups. Functional connectivity between the anterior and posterior insular cortices and the postcentral and inferior frontal gyri, cingulate cortices was reduced in patients with CRPS compared with controls. Additionally, greater reductions in functional connectivity between the anterior insula and right postcentral gyrus were associated with more severe sensory pain in patients with CRPS (short-form McGill Pain Questionnaire sensory subscores, r = -.517, P = .023). The present results imply a possible role of the insula in aberrant processing of pain information in patients with CRPS. The findings suggest that a functional derangement of the connection between one of the somatosensory cortical functions of perception and one of the insular functions of awareness can play a significant role in the persistent experience of regional pain that is not confined to a specific nerve territory.

Different patterns in mental rotation of facial expressions in complex regional pain syndrome patients

Abstract Although facial pain expressions are considered to be the most visible pain behaviors, it is known that the association between pain intensity and facial pain expression is weak for chronic pain. The authors hypothesized that the facial pain expressiveness was altered in chronic pain and investigated it with a mental rotation task using various facial expression, which seems to be associated with actual facial movements. As a task stimulus, 4 types of facial expression stimuli consisted of upper (tightening of eye and furrowed brows) and lower (raising upper lip) pain-specific facial expressions, and upper (eyeball deviation) and lower (tongue protrusion) facial movements not using facial muscles were used. Participants were asked to judge whether a stimulus presented at various rotation angles was left- or right-sided. The authors tested 40 patients with complex regional pain syndrome (CRPS) (12 women, age range 21–60) and 35 healthy controls (15 women, age range 26–64). In an analysis of reaction time (RT) using a linear mixed model, patients were slower to react to all types of stimuli (P = .001) and a significant interaction between group (patient or control) and type of facial expression was observed (P = .01). In the post hoc analysis only patients showed longer RTs to raising upper lip than other types of facial expressions. This reflects a deficit in mental rotation tasks especially for lower facial region pain expressions in CRPS, which may be related to the psychosocial aspects of pain. However, comprehensive intra- and interpersonal influences should be further investigated.