Korea Nurses' Health Study and the health of reproductive-aged women: a cohort profile.

The Korea Nurses' Health Study (KNHS) is an ongoing, large-scale, prospective cohort study of female nurses, focusing on the effects of occupational, environmental, and lifestyle factors on the health of women. The first KNHS survey was performed in 2013-2014 (n=20,613). As of December 2023, 11 follow-up surveys have been conducted. Participants who were pregnant were asked to participate in the early pregnancy survey (n=2,179) and postpartum survey after giving birth (n=2,790). The main variables included sociodemographic, work-related, lifestyle, physical, mental, and women's health factors. Blood, urine, and toenail samples were collected from a participant subgroup of the first survey (n=1,983). The subgroups of the second survey completed a food frequency questionnaire in 2019 (n=300) and 2021 (n=871). In 2020, a subgroup of the first survey answered a coronavirus disease 2019 (COVID-19)-related survey (n=975). To examine various health-related factors in young adults, new participants were added to the KNHS cohort in the 11th (n=1,000) and 12th (n=1,002) surveys. The KNHS cohort will help identify health and illness determinants in Korean women. Data can be accessed at https://coda.nih.go.kr/frt/index.do.

Folate, vitamin B12, and homocysteine status in the Korean population: data from the 2013-2015 Korea National Health and Nutrition Examination Survey.

OBJECTIVES: We aimed to assess the serum folate, vitamin B12, and homocysteine status in Korean adolescents and adults using national data. METHODS: Blood samples were collected from participants aged ≥10 years in the Korea National Health and Nutrition Examination Survey 2013-2015. The stored serum samples were used to measure folate, vitamin B12, and homocysteine concentrations. A total of 8,016 participants were included in this analysis. Unweighted descriptive statistics and adjusted geometric means of the B vitamins and homocysteine concentrations were estimated. RESULTS: Females had higher serum folate and vitamin B12 concentrations and lower serum homocysteine concentrations than males. Folate deficiency (<6.8 nmol/L) and hyperhomocysteinemia (>15 µmol/L) were found in 8.6% and 11.8% of males, respectively. Approximately 3% of males had low or marginally low vitamin B12 status (≤221 pmol/L). Folate and vitamin B12 deficiencies and hyperhomocysteinemia were found in <2% of females. Suboptimal folate status was prevalent among adolescents and young adults, while suboptimal vitamin B12 status and hyperhomocysteinemia were relatively higher in older adults. Adjusted mean homocysteine concentrations were sharply decreased from the first to second decile of serum folate in males. CONCLUSIONS: In the Korean population, the proportion of males who achieved desirable folate and homocysteine concentrations were lower than those of females. Although most Koreans have adequate vitamin B12, a suboptimal folate status is common, particularly among adolescents and young adults. These findings could establish a foundation for public health initiatives aimed at improving folate levels in the Korean population.

Risk of uterine leiomyomata with menstrual and reproductive factors in premenopausal women: Korea nurses' health study.

BACKGROUND: Uterine leiomyomata (UL) are benign smooth muscle tumors that may cause significant morbidity in women of reproductive age. This study aimed to investigate the relationship of menstrual and reproductive factors with the risk of UL in premenopausal women. METHODS: This prospective study included 7,360 premenopausal women aged 22-48 years who were part of the Korea Nurses' Health Study. Information on the menstrual cycle and reproductive history was assessed between 2014 and 2016, and self-reported cases of UL were obtained through 2021. Cox proportional hazards models were used to estimate the hazard ratios (HRs) and 95% confidence intervals (CIs). RESULTS: During 32,072 person-years of follow-up, 447 incident cases of UL were reported. After adjusting for other risk factors, women with late age at menarche had a lower incidence of UL (≥ 16 vs. 12-13 years: HR 0.68; 95% CI 0.47-0.99; p for trend = 0.026). The risk of UL was inversely associated with current menstrual cycle length (≥ 40 or too irregular to estimate vs. 26-31 days: HR 0.40; 95% CI 0.24-0.66) and cycle length at ages 18-22 years (HR 0.45; 95% CI 0.31-0.67; p for trend < 0.001, each). Parous women had lower risk of UL than nulliparous women (HR 0.40; 95% CI 0.30-0.53) and women who were aged 29-30 years at first birth had a lower risk of UL than those who were aged ≤ 28 years at first birth (HR 0.58; 95% CI 0.34-0.98). There was no significant association of the number of births or breastfeeding with the risk of UL among parous women. Neither a history of infertility nor oral contraceptive use was associated with the risk of UL. CONCLUSIONS: Our results suggest that age at menarche, menstrual cycle length, parity, and age at first birth are inversely associated with the risk of UL in premenopausal Korean women. Future studies are warranted to confirm the long-term effects of menstrual and reproductive factors on women's health.

Weight Changes and Unhealthy Weight Control Behaviors Are Associated With Dysmenorrhea in Young Women.

BACKGROUND: This study aimed to evaluate the prevalence of dysmenorrhea and to investigate the effect of weight changes or unhealthy weight control behaviors on dysmenorrhea in young Korean women. METHODS: We used large-scale data of women, aged 14 to 44 years, who participated in the Korean Study of Women's Health-Related Issues. Dysmenorrhea was measured using a visual analog scale and was categorized as none, mild, moderate, and severe according to the severity. Weight changes and unhealthy weight control behaviors (any of the behaviors, fasting/meal skipping, drugs, the use of unapproved dietary supplements, and one-food diets) over the past year were self-reported. We used multinomial logistic regression to investigate the association between weight changes or unhealthy weight control behaviors and dysmenorrhea. RESULTS: Of the 5,829 young women participating in the study, 5,245 (90.0%) participants experienced dysmenorrhea [2,184 (37.5%) had moderate and 1,358 (23.3%) had severe]. After adjusting for confounders, the odds ratios for moderate and severe dysmenorrhea in participants with weight changes ≥ 3 kg (vs. < 3 kg) were 1.19 (95% confidence interval: 1.05-1.35) and 1.25 (95% confidence interval: 1.08-1.45), respectively. The odds ratios in participants with any unhealthy weight control behaviors were 1.22 (95% confidence interval: 1.04-1.42) and 1.41 (95% confidence interval: 1.19-1.67) for those with moderate and severe dysmenorrhea, respectively. CONCLUSION: Weight changes (≥ 3 kg) or unhealthy weight control behaviors are common among young women, which may adversely affect dysmenorrhea. Therefore, attention needs to be paid to excessive weight changes and unhealthy weight control behaviors to improve dysmenorrhea in young women.

Associations of Serum Folate and Homocysteine Concentrations with All-Cause, Cardiovascular Disease, and Cancer Mortality in Men and Women in Korea: the Cardiovascular Disease Association Study.

BACKGROUND: Evidence on the association of serum folate and homocysteine concentrations with risk of mortality in the general population is unclear. OBJECTIVES: This study aimed to examine the associations of serum folate and homocysteine concentrations with all-cause, CVD, and cancer mortality risk in Korean men and women aged ≥40 y. METHODS: In this population-based prospective cohort study, serum folate and homocysteine concentrations were measured in a subset of participants enrolled between 2005 and 2012. A total of 21,260 participants were linked to mortality data from the survey date to 31 December 2019. Cox proportional hazards models and restricted cubic splines were used to identify the associations of serum folate and homocysteine concentrations with mortality. RESULTS: During a median follow-up of 12.3 y, 2501, 549, and 842 deaths were attributed to all-cause, CVD, and cancer, respectively. The prevalence of folate deficiency and hyperhomocysteinemia were higher in men than in women. In men, a nonlinear inverse association was observed between serum folate concentrations and all-cause mortality. Men in the third quartile of serum folate concentrations exhibited a lower risk of all-cause mortality (HR: 0.85; 95% CI: 0.73, 0.99) than those in the lowest quartile. Serum homocysteine concentration was positively associated with all-cause and CVD mortality. Men and women in the highest compared with those in the lowest serum homocysteine quartile showed a higher risk of CVD mortality (HR: 1.60; 95% CI: 1.07, 2.39; and HR: 1.79; 95% CI: 1.11, 2.89, respectively). Hyperhomocysteinemia combined with folate deficiency was associated with increased all-cause, CVD, and cancer-related mortality rates. CONCLUSIONS: Higher serum homocysteine and lower serum folate concentrations were associated with an increased risk of all-cause, CVD, and cancer-related mortality in Korean adults. The finding of a nonlinear inverse relationship between serum folate concentration and mortality in men warrants further investigation.

Association between haemoglobin A1c and all-cause and cause-specific mortality in middle-aged and older Koreans: a prospective cohort study.

BACKGROUND: This study aimed to examine associations between haemoglobin A1c (HbA1c) levels over time and all-cause and cause-specific mortality in middle-aged and older Koreans. METHODS: Using 16 years of follow-up data from the Korean Genome and Epidemiology Study, we analysed 9294 individuals aged 40-69 years with no history of cardiovascular disease (CVD) or cancer. Participants were divided into a known diabetes group and five groups categorized by HbA1c levels (< 5.0%, 5.0-5.4%, 5.5-5.9%, 6.0-6.4%, and ≥ 6.5%). Hazard ratios (HRs) for all-cause and cause-specific mortality associated with HbA1c levels were calculated using a conventional and a time-dependent Cox proportional hazards model. Restricted cubic spline models were fitted to investigate the relationship between continuous HbA1c levels and mortality among people without known diabetes. Subgroup analyses were performed for age, sex, smoking, hypertension, liver diseases, and red blood cell counts. RESULTS: During a median follow-up period of 15.7 years, there were 944 deaths, including 185 deaths from CVD, 359 from cancer, and 125 from all external causes. Compared with participants with HbA1c levels of 5.5-5.9%, multivariate-adjusted HRs and 95% confidence intervals for all-cause death of participants with levels < 5.0%, 5.0-5.4%, 6.0-6.4%, and ≥ 6.5% and participants with known diabetes were 1.84 (1.35-2.51), 1.13 (0.95-1.34), 1.30 (1.04-1.62), 1.37 (0.97-1.93), and 2.03 (1.70-2.44), respectively. The risk of cancer mortality was significantly increased in HbA1c < 5.0% (HR, 2.21; 95% CI 1.42-3.44) and known diabetes (HR, 1.60; 95% CI 1.18-2.15). When we performed diverse subgroup analyses, low HbA1c levels at baseline were strongly associated with mortality in participants with liver diseases. CONCLUSIONS: We found U-shaped associations between HbA1c levels at baseline and over time and all-cause mortality in middle-aged and older Koreans. Additionally, the risk of cancer mortality increased both in low and high HbA1c groups, but CVD mortality increased only in high HbA1c group. In particular, people with liver diseases and low HbA1c levels had a high risk of all-cause mortality. Therefore, more careful management of these groups is suggested to identify any deteriorating health conditions.

Associations between age and dyslipidemia are differed by education level: The Cardiovascular and Metabolic Diseases Etiology Research Center (CMERC) cohort.

BACKGROUND: Dyslipidemia is a multifactorial disorder, which arises from complex interactions among genetic and environmental risk factors. Previous studies have established the deteriorating effect of aging on lipid profiles. However, little is known about the role of education level, a stable marker of socioeconomic status, which reflect modifiability of lifestyle risk factors. Therefore, we examined the association between age and individual dyslipidemia parameter across education level among healthy, middle-aged Korean women. METHODS: From 2049 middle-aged women, education attainment was classified into completion of elementary school or below, middle school, high school, college or above. Dyslipidemia was assessed in adherence to the 2018 Korean Dyslipidemia Treatment Guideline. Multivariable logistic regression and generalized linear model tested for associations between age and dyslipidemia parameter across education level and other known risk factors, including menopause, obesity, and current drinking and smoking. RESULTS: In this cross-sectional analysis, the prevalence of each dyslipidemia parameter was significantly different by age and education level. The odds ratio (OR) for dyslipidemia was higher among participants who were older and had received higher education (OR = 2.31, p for interaction = 0.008) than younger and low education counterpart. The interaction between age and education level remained significant for hypercholesterolemia (p for interaction = 0.003) and hyper-LDL-cholesterolemia (p for interaction = 0.002). CONCLUSIONS: Separate examination of individual dyslipidemia parameter indicated varying degree of interaction with age and education level. Such results imply that each type of lipid abnormality may arise from and be exacerbated by heterogeneous composition of biological and lifestyle risk factors, which may be reflected by education level.

Cohort Profile: The Cardiovascular and Metabolic Diseases Etiology Research Center Cohort in Korea.

Mortalities from cardiovascular disease in Korea have decreased markedly over the past three decades. The major cardiovascular and metabolic risk factors, however, remain prevalent, and their burden on health is large. The Cardiovascular and Metabolic Diseases Etiology Research Center (CMERC) planned a cohort study in order to identify novel risk factors and to develop evidence-based prevention strategies of cardiovascular and metabolic diseases. The CMERC deliberately designed two prospective cohorts, a community-based general population cohort (the CMERC cohort) and its sister cohort (a hospital-based high-risk patient cohort), covering a broad spectrum of cardiovascular and metabolic diseases. This paper describes the CMERC cohort study of community-dwelling adults aged 30 to 64 years. A total of 8097 adults completed baseline measurement between 2013 and 2018. Baseline measurements assessed socio-demographic factors, medical history, health-related behaviors, psychological health, social network and support, anthropometry, body composition, and resting blood pressure and comprised electrocardiography, carotid artery ultrasonography, fasting blood analysis, and urinalysis. Both active follow-up through an annual telephone survey and a 5-year on-site health examination survey and passive follow-up through secondary data linkage with national databases, such as national death records, have been applied. Researchers interested in collaborative research may contact the corresponding author.

Comparison between Right and Left Upper Arms in Detection of Hypertension.

BACKGROUND AND OBJECTIVES: This study aimed to investigate the right-left arm difference in detection of hypertension in the general Korean population. METHODS: This study analyzed data from the Cardiovascular and Metabolic Disease Etiology Research Center cohort. Study population was 2,103 people who were aged 30 to 64 years old, without history of major cardiovascular diseases, and did not use antihypertensive medication. Brachial blood pressures (BPs) were measured for both arms using an automated oscillometric device equipped with 2 cuffs for simultaneous double-arm measurements. Systolic and diastolic blood pressures (SBP and DBP) were measured 3 times, and the average value was used in the analysis. Overall hypertension was defined as elevated blood pressure (SBP/DBP ≥140/90 mmHg) at the arm with higher value, while right-arm or left-arm hypertension was defined as elevated BP at each arm. Sensitivity was calculated as the number of each-arm hypertension divided by the number of overall hypertension. RESULTS: Overall 8.6% of the population had hypertension at either arm, while 7.8% had right-arm hypertension, 7.2% had left-arm hypertension, and 6.4% had both arms hypertension. The sensitivity for the detection of hypertension was 90.6% when BP was measured only at right arm, and 83.4% when measured only at left arm. Corresponding sensitivity were 87.9% and 87.1% in men, and 95.4% and 76.9% in women. CONCLUSIONS: Single-arm measurements, compared to double-arm measurements, may underestimate the prevalence of hypertension. However, if double-arm measurements are unavailable, right arm is preferred for measurement of BP, especially in women.

Association of appendicular skeletal muscle mass with carotid intima-media thickness according to body mass index in Korean adults.

OBJECTIVES: The combined effects of obesity and appendicular skeletal muscle (ASM) on atherosclerosis, especially in middleaged populations, remain poorly understood. This cross-sectional study investigated the effects of ASM on carotid intima-media thickness (IMT) according to body mass index (BMI) in middle-aged Korean adults. METHODS: Herein, 595 men and 1,274 women aged 30-64 years completed questionnaires and underwent health examinations as part of the Cardiovascular and Metabolic Disease Etiology Research Center cohort. ASM was measured via bioelectrical impedance analysis and adjusted for weight (ASM/Wt). IMT was assessed using B-mode ultrasonography; highest quartile of IMT was defined as gender-specific top quartile of the IMT values. Higher BMIs was defined as a BMI over 25.0 kg/m2 . RESULTS: Compared to the highest ASM/Wt quartile, the lowest ASM/Wt quartile was significantly associated with highest quartile of IMT in men with lower BMIs (adjusted odds ratio [aOR], 2.78; 95% confidence interval [CI], 1.09 to 7.13), but not in those with higher BMIs (aOR, 0.59; 95% CI, 0.24 to 1.91). In women, there was no significant association of low skeletal muscle mass with highest quartile of IMT, regardless of BMI. CONCLUSIONS: Low appendicular skeletal muscle mass is associated with carotid arterial wall thickening in men with lower BMIs, but not in men with higher BMIs. Our findings suggest that the risk of atherosclerosis may be low in middle-aged Korean men with appropriate body weight and skeletal muscle mass maintenance.

Aminotransferase levels, body mass index, and the risk of diabetes: a prospective cohort study.

PURPOSE: To investigate whether the relationship between body mass index (BMI) and incident diabetes is modified by different alanine or aspartate aminotransferases (ALT or AST) levels. METHODS: We carried out an analysis of 6484 participants aged 40 years or older using data from the Korean Genome Epidemiology Study. The serum aminotransferase levels were stratified into low and high groups according to the median values and classified into three groups: both low, either high, and both high. To assess the association between BMI and incident diabetes according to the serum aminotransferase levels, multiple logistic regression models were used. RESULTS: In participants with high levels of both ALT and AST, compared with the first BMI quartile, the adjusted odds ratios for incident diabetes of the second, third, and fourth BMI quartiles were 1.72 (95% confidence interval, 0.84-3.55), 2.19 (1.11-4.33), and 3.08 (1.60-5.90), respectively (P trend < .001). In participants with either high ALT or AST, the adjusted odds ratios were 3.58 (1.23-10.41), 2.65 (0.90-7.76), and 5.28 (1.86-15.02), respectively (P trend = .005). However, in participants with both low ALT and AST levels, high BMI was not independently associated with the risk of incident diabetes. CONCLUSIONS: There was a strong association between BMI and incident diabetes among individuals with high aminotransferase levels, whereas no association was observed among those with low aminotransferase levels.

Association between appendicular skeletal muscle mass and depressive symptoms: Review of the cardiovascular and metabolic diseases etiology research center cohort.

BACKGROUND: The effects of skeletal muscle mass on depressive symptoms remain poorly understood, especially in the middle-aged population. We examined the relationship between skeletal muscle mass and depressive symptoms according to sex and menopausal status in the middle-aged Korean population. METHODS: Herein, 1,151 men and 2,176 women aged 30-64 years completed questionnaires and underwent health examinations in the Cardiovascular and Metabolic Disease Etiology Research Center study. Appendicular skeletal muscle mass (ASM) was measured via bioelectrical impedance analysis and adjusted for height squared (ASM/Ht2). Both continuous values and tertile groups of ASM/Ht2 were used for analysis. Depressive symptoms were assessed using the Beck Depressive Inventory-II (BDI), and the prevalence of depressive symptoms was determined as a BDI score ≥ 20. RESULTS: Multiple logistic regression analysis using a fully adjusted model showed that depressive symptoms were more frequently observed among men in the lower ASM/Ht2 tertile and middle ASM/Ht2 tertile than among those in the higher ASM/Ht2 tertile. Each 1-kg/m2 decrease in ASM/Ht2 was significantly associated with the presence of depressive symptoms in men. Such significant association was not observed among premenopausal and postmenopausal women. LIMITATIONS: The cross-sectional nature of the study design, measurement of skeletal muscle mass and depressive symptoms only once, estimation of skeletal muscle mass using bioelectrical impedance analysis, assessing depressive symptoms by self-reported questionnaire, and potential unknown confounding variables constitute the limitations of our study. CONCLUSIONS: The independent association between low skeletal muscle mass and depressive symptoms was observed in men but not in women.

Toward a Mechanistic Understanding of Color Vision in Insects.

Many visual animals exploit spectral information for seeking food and mates, for identifying preys and predators, and for navigation. Animals use chromatic information in two ways. "True color vision," the ability to discriminate visual stimuli on the basis of their spectral content independent of brightness, is thought to play an important role in object identification. In contrast, "wavelength-specific behavior," which is strongly dependent on brightness, often associates with foraging, navigation, and other species-specific needs. Among animals capable of chromatic vision, insects, with their diverse habitats, stereotyped behaviors, well-characterized anatomy and powerful genetic tools, are attractive systems for studying chromatic information processing. In this review, we first discuss insect photoreceptors and the relationship between their spectral sensitivity and animals' color vision and ecology. Second, we review recent studies that dissect chromatic circuits and explore neural mechanisms of chromatic information processing. Finally, we review insect behaviors involving "true color vision" and "wavelength-specific behaviors," especially in bees, butterflies, and flies. We include examples of high-order color vision, such as color contrast and constancy, which are shared by vertebrates. We focus on Drosophila studies that identified neuronal correlates of color vision and innate spectral preferences. We also discuss the electrophysiological studies in bees that reveal color encoding. Despite structural differences between insects' and vertebrates' visual systems, their chromatic vision appears to employ the same processing principles, such as color opponency, suggesting convergent solutions of neural computation to common problems.

Comparison of self-reported and accelerometer-assessed measurements of physical activity according to socio-demographic characteristics in Korean adults.

OBJECTIVES: Previous studies have shown relatively low correlations between self-reported and accelerometer-assessed physical activity (PA). However, this association differs by socio-demographic factors, and this relationship has not been fully investigated in the general population. Thus, we investigated the correlation between self-reported and accelerometer-assessed PA and whether it differed by demographic and socioeconomic factors among the Korean general population. METHODS: This cross-sectional study included 623 participants (203 men and 420 women) aged 30 to 64 years, who completed a PA questionnaire and wore a wrist-worn accelerometer on the non-dominant wrist for 7 days. We examined the agreement for metabolic equivalent task minutes per week (MET-min/wk) between the 2 measures and calculated Spearman correlation coefficients according to demographic and socioeconomic factors. RESULTS: The kappa coefficient between tertiles of self-reported and accelerometer-assessed total MET-min/wk was 0.16 in the total population, suggesting overall poor agreement. The correlation coefficient between the 2 measurements was 0.26 (p<0.001) in the total population, and the correlation tended to decrease with increasing age (p for trend <0.001) and depression scores (p for trend <0.001). CONCLUSIONS: We found a low correlation between self-reported and accelerometer-assessed PA among healthy Korean adults, and the correlation decreased with age and depression score. When studying PA using accelerometers and/or questionnaires, age and depression need to be considered, as should differences between self-reported and accelerometer-assessed PA.

Cardiovascular and Metabolic Diseases Etiology Research Center (CMERC) cohort: study protocol and results of the first 3 years of enrollment.

Although the etiologies of cardiovascular disease (CVD) are widely understood, the goal of finding a globally effective solution for preventing CVD is unrealistic. Therefore, we aimed to conduct a community-based prospective study on the prevention and management of CVD in Korean adults. This study was designed to recruit 8,000 healthy adults over the course of 5 years. The baseline assessment includes a wide range of established CVD risk factors, including demographic characteristics, medical history, health behaviors, psychological conditions, body size and composition, blood pressure, the augmentation index, carotid ultrasonography, an electrocardiogram, and biochemical indicators, as well as some novel factors, such as social network characteristics, exposure to environmental pollutants, inflammatory markers, hemostatic markers, and immunosenescence markers. Annual telephone interviews and follow-up health examinations at 5-year intervals after the baseline assessment are planned to collect information on changes in health status and its determinants. Additionally, indirect follow-up using secondary data sources will be conducted to obtain information on health services utilization and death. So far, more than 6,000 adults have been enrolled during the first three and a half years, and almost all participants have been tracked by annual telephone follow-up surveys. The data have been uploaded to iCReaT, the clinical research information management system of the Korea National Institute of Health.

Association between HbA1c and carotid atherosclerosis among elderly Koreans with normal fasting glucose.

AIM: We examined whether glycated haemoglobin (HbA1c) is associated to carotid atherosclerosis in an elderly Korean population with normal fasting glucose. METHODS: Using data from the Korean Urban Rural Elderly study, we conducted a cross-sectional analysis of 1,133 participants (335 men and 798 women) with a mean age of 71.8 years. All participants had fasting blood glucose less than 100mg/dL (5.6 mmol/L) and HbA1c level below 6.5% (48 mmol/mol). They were also free from a history of cardiovascular disease, known type 2 diabetes mellitus or use of anti-diabetes medications. Carotid atherosclerosis was assessed by intima-media thickness (IMT) using ultrasonography. The association between HbA1c and carotid IMT was investigated using multivariable linear regression analysis. RESULTS: HbA1c levels were independently and positively associated with carotid IMT (ß = 0.020, p = 0.045) after adjusting for sex, age, body mass index, systolic blood pressure, diastolic blood pressure, triglyceride, LDL cholesterol, smoking and alcohol intake. However, fasting insulin and glucose levels were not associated with carotid IMT. CONCLUSION: HbA1c levels were positively associated with carotid atherosclerosis, as assessed by carotid IMT, in an elderly population with normoglycemia. Our study suggested that higher HbA1c level is an effective and informative marker of carotid atherosclerosis in an elderly population.

Association of metabolic syndrome and 25-hydroxyvitamin D with cognitive impairment among elderly Koreans.

AIM: Metabolic syndrome and vitamin D deficiency are prevalent in older adults, and are considered risk factors for cognitive impairment. We investigated the combined effects of MetS and serum 25-hydroxyvitamin D (25[OH]D) levels on cognitive function in older adults. METHODS: We studied 2940 participants aged ≥65 years from the Korean Urban Rural Elderly cohort study. Metabolic syndrome was defined according to the updated Adult Treatment Panel III criteria. Serum 25(OH)D levels were categorized into four groups: <25, 25-49, 50-74 and ≥75 nmol/L. Cognitive function was assessed using the Mini-Mental State Examination. RESULTS: Participants with cognitive impairment had higher metabolic syndrome prevalence and lower serum 25(OH)D levels than those without cognitive impairment. In univariate analysis, both metabolic syndrome and low 25(OH)D levels were associated with cognitive impairment. These associations remained unchanged after adjusting for potential confounders including age, sex, season and education. In addition, participants with metabolic syndrome and low 25(OH)D had significantly increased odds for cognitive impairment (odds ratio 3.06, 95% CI 1.61-5.80) when compared with those with no metabolic syndrome and high 25(OH)D. CONCLUSIONS: Metabolic syndrome was associated with cognitive impairment, and this risk was synergistically increased when metabolic syndrome was combined with low 25(OH)D. A focus on individuals with metabolic syndrome and low 25(OH)D might be helpful to identify older adults who are at risk of cognitive impairment. Geriatr Gerontol Int 2017; 17: 1069-1075.

Occupational exposure to crystalline silica and gastric cancer: a systematic review and meta-analysis.

Crystalline silica is a widely used industrial material that is readily available worldwide, and is one of the most common types of particulate mineral pollutants. It has been classified as a group 1 human carcinogen of the respiratory system; however, whether it is linked to gastric cancer remains uncertain. We conducted a systemic review and meta-analyses to search for evidence of the relationship between gastric cancer and occupational exposure to crystalline silica. We searched for articles on occupations involving silica exposure and gastric cancer studies up to December 2014. Pooled-risk estimates of the association between occupational crystalline silica exposure and risk of gastric cancer were calculated by a random effects model. Metaregression analyses of industry type and histological confirmation status, study design and industrial subgroup analyses were performed. 29 articles, including 9 case-control and 20 cohort studies, were analysed. The overall summary effects size was 1.25 (95% CI 1.18 to 1.34) for the association of occupational silica exposure with gastric cancer. Both heterogeneity and publication bias were partially attenuated after subgroup analyses. Heterogeneity of studies was attenuated after metaregression by industry. Higher overall effects were observed in the mining and foundry industries. We found a significant relationship between occupational crystalline silica exposure and gastric cancer. Our results were strengthened by various subgroup analyses and, considering the biological plausibility of our premise, further studies are required to better understand this association.

Inter-Arm Difference in Brachial Blood Pressure in the General Population of Koreans.

BACKGROUND AND OBJECTIVES: We investigated the inter-arm difference in blood pressure of the general Korean population to identify associated factors. SUBJECTS AND METHODS: A total of 806 participants aged 30 to 64 years without history of major cardiovascular disease were analyzed in this cross-sectional study. They participated in the Cardiovascular and Metabolic Disease Etiology Research Center cohort study that began in 2013. Brachial blood pressure was measured simultaneously for both arms using an automated oscillometric device equipped with two cuffs in seated position. After five minutes of rest, systolic blood pressure (SBP) and diastolic blood pressure (DBP) were measured three times. The average of the three measurements was used for analysis. Multivariate logistic regression models were used to identify factors associated with inter-arm differences in blood pressure. RESULTS: The mean inter-arm difference was 3.3 mmHg for SBP and 2.0 mmHg for DBP. Large inter-arm differences (≥10 mmHg) in SBP and in DBP were found in 3.7% and 0.9% of subjects, respectively. A large inter-arm difference in SBP was associated with mean SBP (p=0.002) and C-reactive protein (p=0.014) while a large inter-arm different in DBP was only associated with body mass index (p=0.015). Sex, age, and anti-hypertensive medication use were not associated with differences in inter-arm blood pressure. CONCLUSION: Large inter-arm difference in blood pressure is only present in a small portion of healthy Korean adults. Our findings suggest that high SBP, chronic inflammation, and obesity may be associated with larger difference in inter-arm blood pressure.

Serum uric acid concentration and metabolic syndrome among elderly Koreans: The Korean Urban Rural Elderly (KURE) study.

BACKGROUND: Epidemiologic studies have demonstrated that elevated serum uric acid concentration is an independent risk factor for metabolic syndrome. However, few studies have focused on elderly populations. Thus, we investigated the association of serum uric acid concentration with metabolic syndrome in community-dwelling elderly Koreans. METHODS: This cross-sectional analysis included 2940 participants (986 men and 1954 women) aged 65 years or older who participated in a baseline health assessment for the Korean Urban Rural Elderly cohort study from 2012 to 2014. Serum uric acid concentration was analyzed using both continuous and dichotomous variables. Hyperuricemia was defined as a uric acid concentration ≥7.0 mg/dL in men and ≥6.0 mg/dL in women. Metabolic syndrome was defined according to the 2009 harmonizing definition. Multiple logistic regression models were used to investigate independent association between serum uric acid and metabolic syndrome, after adjusting for age, body mass index, LDL cholesterol, glycated hemoglobin, blood urea nitrogen, estimated glomerular filtration rate health behaviors, and medications. RESULTS: Prevalence of metabolic syndrome and its components increased significantly according to uric acid concentration in both sexes. The adjusted odds ratios for having metabolic syndrome per 1.0mg/dL higher uric acid concentration were 1.16 (95% CI: 1.03-1.31) in men and 1.27 (95% CI: 1.13-1.42) in women. Hyperuricemia was also associated with metabolic syndrome, with adjusted odds ratios of 1.71 (95% CI: 1.11-2.63) in men and 1.55 (95% CI: 1.05-2.29) in women. CONCLUSIONS: Elevated serum uric acid concentration was independently associated with an increased prevalence of metabolic syndrome in community-dwelling elderly Koreans.