Interactions between physical activity and psychological factors in the association with the risk of lean type 2 diabetes mellitus

Background: The extent to which physical activity and psychological factors may affect the risk of diabetes mellitus among lean individuals remains unclear.Purpose: This study aimed to investigate the associations of total physical activity (TPA) and psychological factors with lean type 2 diabetes mellitus (T2DM) risk.Research Design: A prospective cohort study.Study Sample: The study population included 1,945 Korean adults who maintained a body mass index <23 kg/m2.Data Collection and Analysis: Baseline data on TPA and psychological factors were collected and T2DM incidence was assessed for 10 years. For analysis, a multivariable Cox proportional hazards regression model was used.Results: TPA was inversely associated with T2DM risk and this association was more pronounced in participants who were depressed or distressed; the top TPA quartile exhibited significant reductions in T2DM risk of 66% (95% confidence interval [CI]: 0.15, 0.78) and 65% (95% CI: 0.14, 0.88) among participants who reported depressed mood and those who perceived high distress, respectively, compared with the bottom TPA quartile.Conclusions: The current study demonstrated the preventive effects of physical activity on T2DM in lean adults through its interaction with psychological factors.

Association of insomnia and daytime napping with metabolic syndrome and its components in a Korean population: an analysis of data from the Korean Genome and Epidemiology Study

OBJECTIVES

We investigated the association between metabolic syndrome (MetS) and the coexistence of insomnia and daytime napping, because limited data have been reported regarding this association.

METHODS

The study population was 8,440 participants aged 40-65 years, who were from the Korean Genome and Epidemiology Study. Self-reported information on insomnia symptoms and nap duration was used to define exposure variables. Data on waist circumference (WC), blood pressure (BP), and fasting blood glucose (FBG), triglyceride (TG), and high-density lipoprotein cholesterol levels in blood were used to define MetS. Multivariate logistic regression analysis was performed to obtain odds ratio (OR) and 95% confidence interval (CI).

RESULTS

In multivariate logistic regression analysis, the coexistence of insomnia and napping was not significantly associated with MetS. However, the insomnia and non-napping group showed higher ORs of high TG (OR, 1.19; 95% CI, 1.02 to 1.39) and high BP (OR, 1.28; 95% CI, 1.10 to 1.49) than the non-insomnia and non-napping group. The combination of non-insomnia and napping and that of insomnia and napping showed higher ORs of high TG (OR, 1.13; 95% CI, 1.00 to 1.29) and high FBG (OR, 1.59; 95% CI, 1.14 to 2.21), respectively. In analyses of insomnia symptoms, only the combination of difficulty in maintaining sleep (DMS) and non-napping showed a higher OR for MetS (OR, 1.25; 95% CI, 1.03 to 1.52) than the non-DMS and non-napping group.

CONCLUSIONS

Individuals with insomnia, particularly those who do not take naps, were disproportionately likely to have MetS components, especially TG or BP. Information on these variables may help predict individuals' vulnerability to specific MetS components.

Associations of Serum Vitamin D Concentration with Cardiovascular Risk Factors and the Healthy Lifestyle Score

Vitamin D status is reportedly associated with risk factors for cardiovascular disease (CVD), although conflicting data have been generated. The healthy lifestyle score (HLS) was formulated as a primary approach toward preventing CVD; however, data on the association between the HLS and vitamin D status remain insufficient. This study aimed to investigate the associations of CVD risk factors and the HLS with serum 25-hydroxyvitamin D concentration in adults who participated in a national survey. HLS components, including body mass index, smoking status, alcohol consumption, physical activity, and dietary pattern, as well as other risk factors, including diabetes mellitus (DM), hypertension (HTN), and dyslipidemia (DL), were fitted in multiple linear regression models to determine their association with vitamin D status. DM, HTN, and DL were inversely associated whereas a balanced dietary pattern, alcohol consumption, and physical activity were positively associated with serum vitamin D concentration (p < 0.01). Furthermore, a strong association was observed between the total HLS and serum vitamin D concentration (p for trend <0.01); the regression coefficient estimate (95% confidence interval) for the highest score was 1.41 (0.65, 2.17) (p < 0.01) compared with that for the lowest. These findings suggest that CVD risk factors and the HLS may reflect vitamin D status.

Associations of dietary vitamin A and C intake with asthma, allergic rhinitis, and allergic respiratory diseases

BACKGROUND/OBJECTIVES

Asthma and allergic rhinitis (AR) are closely related and considered as allergic respiratory diseases (ARD), and their prevalence has recently increased. Data on the association of dietary antioxidant vitamin intake with asthma and AR in adults are limited. The present study aimed to investigate the associations of vitamin A and C intake with asthma, AR, and all cases of both diseases in young adults who participated in a cross-sectional national survey, with the use of high-sensitivity C-reactive protein (hs-CRP) level as an effect modifier.

SUBJECTS/METHODS

This study included 6,293 male and female adults aged 20-49 years from the Korea National Health and Nutrition Examination Survey (KNHANES) conducted between 2016 and 2018. The questionnaire-based reports on asthma and AR diagnosis were used to determine outcome variables. Further, 24-h recall data on dietary vitamin A and C, carotene, and retinol intake were acquired. Logistic regression analysis was performed to calculate odds ratios (ORs) and 95% confidence interval (CI).

RESULTS

Dietary vitamin C intake was inversely associated with asthma prevalence among participants with hs-CRP levels (≥ 1 mg/L); the OR of asthma prevalence was 0.27 (95% CI, 0.08-0.84) for participants with vitamin C consumption ≥ 75 mg/day compared with those consuming < 20 mg/day. Similar association analyses limiting to non-users of dietary supplements were performed to rule out the potential effects of supplement intake on the outcomes; results showed a stronger association. However, the association between vitamin C and asthma was not significant in participants with hs-CRP levels < 1 mg/L; the OR of asthma was 1.44 (95% CI, 0.66-3.16) for participants with vitamin C consumption ≥ 75 mg/day compared with those consuming < 20 mg/day. Vitamin C intake was not associated with AR. Moreover, there was no association between vitamin A intake and neither asthma nor AR.

CONCLUSIONS

These findings suggest that higher vitamin C intake may play a potential role in reducing asthma prevalence. Nevertheless, further studies should be conducted to evaluate whether this association is causal.

Association of blood pressure measurements in sitting, supine, and standing positions with the 10-year risk of mortality in Korean adults

OBJECTIVES

This prospective cohort study investigated the association between blood pressure (BP) as measured in different body postures and all-cause and cardiovascular (CV) mortality risk.

METHODS

This population-based investigation included 8,901 Korean adults in 2001 and 2002. Systolic blood pressure (SBP) and diastolic blood pressure (DBP) were measured sequentially in the sitting, supine, and standing positions and classified into 4 categories: 1) normal, SBP <120 mmHg and DBP <80 mmHg; 2) high normal/prehypertension, SBP 120-129 mmHg and DBP <80 mmHg/SBP 130-139 mmHg or DBP 80-89 mmHg; 3) grade 1 hypertension (HTN), with SBP 140-159 mmHg or DBP 90-99 mmHg; and 4) grade 2 HTN, SBP ≥160 mmHg or DBP ≥100 mmHg. The date and cause of individual deaths were confirmed in the death record data compiled until 2013. Data were analyzed using Cox proportional hazard regression.

RESULTS

Significant associations were found between the BP categories and all-cause mortality, but only when BPs were measured in the supine position. The multivariate hazard ratios (95% confidence intervals) were 1.36 (1.06-1.75) and 1.59 (1.06-2.39) for grade 1 and grade 2 HTN, respectively, compared with the normal category. The associations between the BP categories and CV mortality were significant regardless of body posture among participants ≥65 years, whereas they were significant for supine BP measurements only in those <65 years.

CONCLUSIONS

BP measured in the supine position predicted all-cause mortality and CV mortality better than BP measured in other postures.

Bacterial Extracellular Vesicle Composition in Human Urine and the 10-Year Risk of Abdominal Obesity

Objective: We aimed to evaluate a causal relationship between commensal bacteria and abdominal obesity. Methods: A prospective study, including 2222 adults who provided urine samples at baseline, was performed. These samples were used for assays of genomic DNA from bacterial extracellular vesicles (EVs). During the 10-year period, the incidence rates of obesity (measured as body mass index) and abdominal obesity (measured as waist circumference) were ascertained as outcomes. To evaluate associations of bacterial composition at the phylum and genus levels with the outcomes, the hazard ratio (HR) and its confidence interval (95% CI) were estimated. Results: No significant association was observed for the risk of obesity, whereas the risk of abdominal obesity was inversely associated with the composition of Proteobacteria and positively associated with that of Firmicutes (adjusted P value <0.05). In joint analysis for the combination groups of Proteobacteria and Firmicutes composition tertiles, the group with top tertiles of both Proteobacteria and Firmicutes showed a significant HR of 2.59 (95% CI: 1.33 - 5.01) compared with the reference with lower tertiles (adjusted P value <0.05). Some genera of these phyla were associated with the risk of abdominal obesity. Conclusions: These findings suggest that bacterial composition in urinary EV samples can predict the 10-year risk of abdominal obesity.

Oral Administration of Human-Gut-Derived Prevotella histicola Improves Sleep Architecture in Rats

(1) Background: The human gut microbiome may regulate sleep through the gut-brain axis. However, the sleep-promoting effects of gut microbiota remain unclear. (2) Methods: We obtained sleep-wake profiles from 25 rats receiving P. histicola (P. histicola group), 5 rats receiving P. stercorea (P. stercorea group), 4 rats not receiving bacteria (No administration group), and 8 rats receiving P. histicola extracellular vesicles (EV) (EV group) during the baseline, administration, and withdrawal periods. (3) Results: The P. histicola group showed increased total sleep, rapid eye movement (REM) sleep, and non-rapid eye movement (NREM) sleep time during the administration and withdrawal periods; on the last day of administration, we found significant increases of 52 min for total sleep (p < 0.01), 13 min for REM sleep (p < 0.05), and 39 min for NREM sleep (p < 0.01) over the baseline. EV administration also increased NREM sleep time on Day 3 of administration (p = 0.05). We observed a linear trend in the dose-response relationship for total sleep and NREM sleep in the P. histicola group. However, neither the no-administration group nor the P. stercorea group showed significant findings. (4) Conclusions: Oral administration of probiotic P. histicola may improve sleep and could be a potential sleep aid. Further rigorous evaluations for the safety and efficacy of P. histicola supplementation are warranted.

Potential Antiaging and Hepatoprotective Effects of Acanthopanax senticosus Extracts in Adult Rat Models

Data regarding plant extracts with antiaging properties, particularly through the biological process involving telomeres and telomerase, are limited. Thus, this study aimed to investigate the effects of Acanthopanax senticosus extract (ASE) supplementation on leukocyte telomere length (LTL), telomerase, and inflammatory and metabolic markers in adult animal models. A freeze-dried product of ethanol extracts was prepared using a mixture product of stem and root ASE. In a 24-week experiment that included 24-week-old Sprague Dawley male rats, experimental rats (n = 10) were administrated with 7 mg/day of ASE dissolved in saline and control rats (n = 10) with saline. All rats had access to chow and tap water ad libitum. Their LTL and plasma levels of telomerase and inflammatory and metabolic markers were assayed and compared between the two groups. The experimental rats showed significantly longer LTL (p < 0.05) and lower plasma levels of alanine aminotransferase (p < 0.05) and aspartate aminotransferase (p = 0.08) compared with the control. In addition, LTL was correlated with the aforementioned biochemical parameters of liver function test among experimental rats only. No significant differences in plasma levels of telomerase and inflammatory and metabolic markers were observed. These findings indicate that ASE supplementation may attenuate LTL shortening and reduce liver biochemical parameters, indicating its potential antiaging and hepatoprotective effects without any adverse metabolic response.

Region-specific COVID-19 risk scores and nutritional status of a high-risk population based on individual vulnerability assessment in the national survey data

BACKGROUND & AIMS

Coronavirus disease 2019 (COVID-19) is an ongoing pandemic outbreak leading to more than 1 million deaths worldwide as reported in 2020. Several risk assessment tools, including individual vulnerability to COVID-19, have been developed. The present study aimed to characterize a high-risk population using such a tool and examine risk factors and nutritional status in the national survey data and estimate the region-specific population size.

METHODS

The study included 17,540 Korean adults who participated in the Korea National Health and Nutrition Examination Survey (KNHANES). The risk scores for individual vulnerability to COVID-19 were calculated based on age, sex, smoking status, and comorbidities, and a high-risk population was defined as having risk scores ≥11. Nutritional status was compared between the high-risk population and the remaining participants in the KNHANES data. The region-specific population size was estimated using national statistics.

RESULTS

The proportion of the high-risk population was estimated to be 10.5%, which corresponds to approximately 4.6 million adults in South Korea. About 20% of them had inadequate intake of all of vitamins A, B1, B2, B3, and C below the estimated average requirement. The high-risk population showed 1.65 [95% confidence interval: 1.39, 1.96] higher odds of inadequate intake of multiple vitamins than the remaining participants. In the ecological analysis, the region-specific numbers of the high-risk population correlated significantly with the actual numbers of deaths due to COVID-19 (P value = 0.013).

CONCLUSIONS

These results suggest that individuals vulnerable to COVID-19, in particular those are living in densely populated regions, should pay particular attention to the protection against this pandemic and have adequate nutritional status, which may support optimal immune function.

Association between body temperature and leukocyte telomere length in Korean middle-aged and older adults

OBJECTIVES

Data on associations between body temperature (BT) and leukocyte telomere length (LTL), which has been widely used as a biomarker of cellular senescence in recent epidemiological studies, are limited. Therefore, this study aimed to explore the associations between a normal BT range (35.0-37.5°C) and LTL via 6-year longitudinal observations of 2,004 male and female adults aged 50 or older.

METHODS

BT was obtained by measuring the tympanic temperature, and relative LTL was determined by real-time polymerase chain reaction. Robust regression analysis was used to evaluate the association between the baseline and follow-up LTL values and their differences.

RESULTS

A significant inverse association was found between BT and LTL at baseline. The regression coefficient estimate was -0.03 (95% confidence interval, -0.07 to -0.001; p<0.05). This association was stronger in participants with a body mass index >25 kg/m² and males (p<0.01). However, there were no associations between BT and LTL at follow-up or BT and 6-year longitudinal differences in LTL.

CONCLUSIONS

These findings suggest that having a high BT between 35°C and 37.5°C (95°F and 99°F) may be detrimental for obese individuals in terms of biological aging.

Effects of poly-gamma-glutamic acid and vitamin B6 supplements on sleep status: a randomized intervention study

BACKGROUD/OBJECTIVES

Data regarding the effects of poly-γ-glutamic acid (γ-PGA) on sleep status are limited. This study aimed to test whether γ-PGA and vitamin B₆ (VitB6) supplements improve sleep duration and quality.

SUBJECTS/METHODS

A factorial randomized, double-blinded, placebo-controlled crossover study included 47 adults (25 men and 22 women) who were free of chronic disease. Stratified randomized allocation considered age and gender for three interventions, group A (supplementation with γ-PGA 600 mg; n = 16), group B (supplementation with VitB6 100 mg; n = 14), and group C (dual supplementation of both γ-PGA 600 mg and VitB6 100 mg; n = 17). Participants underwent a 1-mon intervention period, followed by a 1-mon washout period, and then a second 1-mon intervention period. Differences (mean ± SD) in nighttime sleep status before and after supplementation were compared between the placebo and intervention groups using nonparametric tests.

RESULTS

Significant changes in sleep duration (0.27 ± 0.98 h, P < 0.05) and the Pittsburgh Sleep Quality Index global score (−0.52 ± 1.58, P < 0.05) indicating improved sleep status were observed in the intervention compared with the placebo of group C while no significant changes were observed in groups A and B. No statistical significance was detected between the intervention and the placebo; however, there was a greater increase in the group C intervention (4.59 ± 38.5 ng/mL) in serum serotonin concentrations than the groups A and B interventions. No side effects were observed.

CONCLUSIONS

On the basis of these findings, the dual supplementation of γ-PGA and VitB6 may be effective as functional food components to improve nighttime sleep status.

Trial Registration

Clinical Research Information Service Identifier: KCT0005083

Associations of alcohol consumption and physical activity with lean type 2 diabetes mellitus among Korean adults: A prospective cohort study

Data on the association between alcohol consumption and the risk of type 2 diabetes mellitus (T2DM) have accumulated, but little has been reported about this association in terms of lean T2DM. The present study analyzed 10-year longitudinal data to investigate the association between alcohol consumption and T2DM risk among lean individuals. This prospective study included 2,366 male and female Koreans aged 40–69 years who were free of DM and had a body mass index (BMI) <23 kg/m² during the baseline period between 2001 and 2012. Information on alcohol consumption, BMI, and incident cases of T2DM were identified by interviews and health examinations. To analyze the association between alcohol consumption and T2DM risk, Cox proportional hazard regression analysis was used. Alcohol drinkers consuming at least 16 g/day of alcohol (2 units/day) who maintained a BMI <23 kg/m² over 10 years had a significantly higher T2DM risk even after controlling for BMI and potential risk factors. Compared with lifetime abstainers, multivariate hazard ratios (HR) [95% confidence interval] of T2DM were 1.74 [1.02, 2.95] for 16–30 g/day, 2.09 [1.16, 3.77] for 31–60 g/day, and 1.94 [1.07, 3.51] for >60g/day among alcohol drinkers. No protective effect of moderate alcohol consumption <16 g/day on T2DM risk was observed. Age, parental history of DM, and physical inactivity were also significant risk factors for lean T2DM. Alcohol consumption of at least 2 units/day increased T2DM risk among lean individuals. Abstaining from alcohol and physical activity may be beneficial for the prevention of lean T2DM.

Dietary and modifiable factors contributing to hyper-LDL-cholesterolemia prevalence in nationwide time series data and the implications for primary prevention strategies

BACKGROUND/OBJECTIVES

A number of studies examined secular trends in blood lipid profiles using time series data of national surveys whereas few studies investigated individual-level factors contributing to such trends. The present study aimed to examine secular trends in dietary and modifiable factors and hyper-LDL-cholesterolemia (HC) prevalence and evaluate their associations using time series data of nationwide surveys.

SUBJECTS/METHODS

The study included 41,073 Korean adults aged ≥ 30 years from the 2005, 2007–2009, 2010–2012, 2013–2015, and 2016 Korea National Health and Nutrition Examination Surveys. Stepwise logistic regression analysis was performed to select significant factors associated with HC, which was defined as serum LDL cholesterol levels ≥130 mg/dL.

RESULTS

The following factors showed a positive association with HC (P < 0.05): for men having higher body mass index (BMI), being married, having an office job, and consuming higher dairy and vegetable oil products; for women having higher age or BMI, having no job or a non-office job, not in a low-income household, and consuming higher dairy products. In the given model, the 2016 survey data showed that a 2 kg/m² reduction in BMI of obese persons resulted in a decreased HC prevalence from 30.8% to 29.3% among men and from 33.6% to 32.5% among women.

CONCLUSIONS

Based on these findings, it is suggested that primary prevention programs should advocate having proper BMI for Korean adults with a high-risk of HC. However, whether discouraging consumption of dairy and vegetable oil products can reduce HC prevalence warrants further studies with a prospective longitudinal design.

Projection of Diabetes Prevalence in Korean Adults for the Year 2030 Using Risk Factors Identified from National Data

BACKGROUND

A number of studies have reported future prevalence estimates for diabetes mellitus (DM), but these studies have been limited for the Korean population. The present study aimed to construct a forecasting model that includes risk factors for type 2 DM using individual- and national-level data for Korean adults to produce prevalence estimates for the year 2030.

METHODS

Time series data from the Korea National Health and Nutrition Examination Survey and national statistics from 2005 to 2013 were used. The study subjects were 13,908 male and 18,697 female adults aged 30 years or older who were free of liver cirrhosis. Stepwise logistic regression analysis was used to select significant factors associated with DM prevalence.

RESULTS

The results showed that survey year, age, sex, marital, educational, or occupational status, the presence of obesity or hypertension, smoking status, alcohol consumption, sleep duration, psychological distress or depression, and fertility rate significantly contributed to the 8-year trend in DM prevalence (P<0.05). Based on sex-specific forecasting models that included the above factors, DM prevalence for the year 2030 was predicted to be 29.2% (95% confidence interval [CI], 27.6% to 30.8%) in men and 19.7% (95% CI, 18.2% to 21.2%) in women.

CONCLUSION

The present study projected a two-fold increase in the prevalence of DM in 2030 compared with that for the years 2013 and 2014 in Korean adults. Modifiable factors contributing to this increase in DM prevalence, such as obesity, smoking, and psychological factors, may require attention in order to reduce national and individual costs associated with DM.

Obstructive sleep apnea, low transferrin saturation levels, and male-pattern baldness

BACKGROUND

There are limited data on the association between obstructive sleep apnea (OSA), which is characterized by intermittent hypoxia, and male-pattern baldness (MPB). Low blood iron levels are reportedly associated with hypoxia and hair loss. This study explored a possible link among OSA, iron status, and MPB.

METHODS

Polysomnography (PSG) and hair assessments were conducted in a cross-sectional study including 932 men aged 46-76 years. OSA was defined as an apnea-hypopnea index ≥5 by PSG evaluation and MPB as scales from IV to VII according to the Norwood-Hamilton scale classification. Serum transferrin saturation (TSA) levels were assessed.

RESULTS

A total of 224 men (24%) were identified as MPB cases and 495 men (53%) as having OSA. After considering potential risk factors, OSA and other sleep-related variables were not associated with MPB. In joint analysis of OSA and family history of hair loss, men with these two factors showed a sevenfold higher multivariate odds ratio (95% confidence interval: 3.70, 12.56) for MPB than those without both of them (P < 0.05 for the interaction between OSA and family history of hair loss). TSA levels were significantly associated with MPB and OSA. OSA cases without MPB as well as MPB cases showed lower TSA levels than those with neither OSA nor MPB (P < 0.05).

CONCLUSIONS

These findings suggest that OSA may be a risk factor for MPB in men who have a family history of hair loss and that low serum TSA levels associated with hypoxia may be involved in a pathway linking OSA and MPB.

Forecasting obesity prevalence in Korean adults for the years 2020 and 2030 by the analysis of contributing factors

BACKGROUND/OBJECTIVES

There are few studies that forecast the future prevalence of obesity based on the predicted prevalence model including contributing factors. The present study aimed to identify factors associated with obesity and construct forecasting models including significant contributing factors to estimate the 2020 and 2030 prevalence of obesity and abdominal obesity.

SUBJECTS/METHODS

Panel data from the Korea National Health and Nutrition Examination Survey and national statistics from the Korean Statistical Information Service were used for the analysis. The study subjects were 17,685 male and 24,899 female adults aged 19 years or older. The outcome variables were the prevalence of obesity (body mass index ≥ 25 kg/m²) and abdominal obesity (waist circumference ≥ 90 cm for men and ≥ 85 cm for women). Stepwise logistic regression analysis was used to select significant variables from potential exposures.

RESULTS

The survey year, age, marital status, job status, income status, smoking, alcohol consumption, sleep duration, psychological factors, dietary intake, and fertility rate were found to contribute to the prevalence of obesity and abdominal obesity. Based on the forecasting models including these variables, the 2020 and 2030 estimates for obesity prevalence were 47% and 62% for men and 32% and 37% for women, respectively.

CONCLUSIONS

The present study suggested an increased prevalence of obesity and abdominal obesity in 2020 and 2030. Lifestyle factors were found to be significantly associated with the increasing trend in obesity prevalence and, therefore, they may require modification to prevent the rising trend.

Eating patterns of children's favorite foods and its related factors among elementary, middle, and high school students in Korea

BACKGROUND/OBJECTIVES

There are limited studies investigating the eating patterns of children's favorite foods. The present study aimed to evaluate a wide range of children's favorite foods, derive its eating patterns, and identify factors related to the patterns.

SUBJECTS/METHODS

A nationwide cross-sectional study included 5,458 students in elementary, middle, and high schools. The survey was conducted at each school to evaluate children's favorite food intake, including the intake frequency of 31 food items or food groups, and its related factors, such as demographic, economic, and environmental characteristics and awareness of policies on children's favorite foods. Factor analysis using varimax rotation method and logistic regression analysis were conducted.

RESULTS

Two factors were derived as major eating patterns from data of children's favorite foods: the ‘unhealthy eating pattern’ which mainly involves confectionery, chocolate, ramen, fried food, etc.; and the ‘healthy eating pattern’ which mainly involves soybean milk, vegetables, fruit juice, and nuts. A stepwise selection procedure through the regression analysis revealed that allowance, use of screen media, less awareness of policies on children's favorite foods, and less interest in health were positively related to the tendency of unhealthy or less-healthy eating patterns (P < 0.05).

CONCLUSIONS

This study examined that the eating patterns of children's favorite foods were associated with certain environmental characteristics and awareness about the related policies. These findings suggest that a nutrition education program regarding children's favorite foods needs to be conducted according to the characteristics of students to develop their healthy eating habits and proper choice of favorite foods.

The FTO rs9939609 polymorphism is associated with short leukocyte telomere length in nonobese individuals

The fat mass and obesity-associated (FTO) rs9939609 polymorphism have been associated with the increased metabolic risk and mortality, irrespective of obesity. The mechanism underlying this association is not known. We aimed to evaluate whether the FTO rs9939609 risk variant is independently associated with metabolic risk factors and/or leukocyte telomere length (LTL). We further aimed to investigate whether this relationship is modified by obesity status.A total of 2133 participants were recruited from the Korean Genome and Epidemiology Study. LTL was measured using the real-time quantitative polymerase chain reaction methodology. The FTO rs9939609 polymorphism was genotyped using DNA samples collected at baseline.The proportions of the TT, TA, and AA genotypes were 76.7%, 21.5%, and 1.8%, respectively, and obese subjects comprised 44.5% of the total subjects. Among the 1184 nonobese subjects, body mass index, waist circumference, and visceral fat area were higher in subjects with the FTO risk allele than in noncarriers. In contrast, only high-sensitive C-reactive protein level was associated with the FTO risk allele in the obese subjects. LTL was significantly shorter in carriers of the FTO risk allele compared with noncarriers after controlling for several confounding factors (P < .01). Of particular note, this significant association between the FTO risk allele and LTL appeared only in nonobese subjects (P = .03). Multivariate linear regression analyses identified older age, low high-density lipoprotein cholesterol level, and the presence of the FTO risk allele as independent risk factors affecting LTL. This finding was evident only in nonobese subjects.The FTO rs9939609 polymorphism is an independent risk factor for obesity and also for biological aging in the nonobese population.

Associations of alcohol consumption and alcohol flush reaction with leukocyte telomere length in Korean adults

BACKGROUND/OBJECTIVES

Telomere length is a useful biomarker for determining general aging status. Some studies have reported an association between alcohol consumption and telomere length in a general population; however, it is unclear whether the alcohol flush reaction, which is an alcohol-related trait predominantly due to acetaldehyde dehydrogenase deficiency, is associated with telomere length. This cross-sectional study aimed to evaluate the associations of alcohol consumption and alcohol flush reaction with leukocyte telomere length (LTL).

SUBJECTS/METHODS

The study included 1,803 Korean adults. Participants provided blood specimens for LTL measurement assay and reported their alcohol drinking status and the presence of an alcohol flush reaction via a questionnaire-based interview. Relative LTL was determined by using a quantitative polymerase chain reaction. Statistical analysis used multiple linear regression models stratified by sex and age groups, and potential confounding factors were considered.

RESULTS

Age-specific analyses showed that heavy alcohol consumption (> 30 g/day) was strongly associated with a reduced LTL in participants aged ≥ 65 years (P < 0.001) but not in younger participants. Similarly, the alcohol flush reaction was associated with a reduced LTL only in older participants who consumed > 15 g/day of alcohol (P < 0.01). No significant alcohol consumption or alcohol flush reaction associations with LTL were observed in the sex-specific analyses.

CONCLUSIONS

The results suggest that older alcohol drinkers, particularly those with the alcohol flush reaction, may have an accelerated aging process.

Carbohydrate Composition Associated with the 2-Year Incidence of Metabolic Syndrome in Korean Adults

The aim of this study was to investigate the association between macronutrient composition and metabolic syndrome (MetS) incidence in Korean adults. Data were obtained from a cohort of 10,030 members aged 40 to 69 years who were enrolled from the 2 cities (Ansung and Ansan) between 2001 and 2002 to participate in the Korean Genome Epidemiology Study. Of these members, 5,565 participants, who were free of MetS and reported no diagnosis of cardiovascular disease at baseline, were included in this study. MetS was defined using the criteria of the National Cholesterol Education Program-Adult Treatment Panel III and Asia-Pacific criteria for waist circumference. MetS incidence rate were identified during a 2-year follow-up period. Baseline dietary information was obtained using a semi-quantitative food frequency questionnaire. Multivariate logistic regression analysis was used to evaluate the association between the quartiles of percentages of total calorie from macronutrients consumed and MetS incidence. In analyses, baseline information, including age, sex, body mass index, income status, educational status, smoking status, alcohol drinking status, and physical activity level was considered as confounding variables. Participants with the second quartile of the percentages of carbohydrate calorie (67%–70%) had a 23% reduced odds ratio (95% confidence interval, 0.61–0.97) for MetS incidence compared with those with the fourth quartile after adjusting for confounding variables. The findings suggest that middle aged or elderly Korean adults who consume approximately 67%–70% of calorie from carbohydrate have a reduced risk of MetS.

Subclinical left ventricular diastolic dysfunction and incident type 2 diabetes risk: the Korean Genome and Epidemiology Study

Background

Subclinical left ventricular (LV) diastolic dysfunction in type 2 diabetes (T2D) is a common finding and represents an early sign of diabetic cardiomyopathy. However, the relationship between LV diastolic dysfunction and the incident T2D has not been previously studied.

Methods

A total of 1817 non-diabetic participants (mean age, 54 years; 48% men) from the Korean Genome and Epidemiology Study who were free of cardiovascular disease were studied. LV structure and function were assessed by conventional echocardiography and tissue Doppler imaging. Subclinical LV diastolic dysfunction was defined using age-specific cutoff limits for early diastolic (Em) velocity, mitral E/Em ratio, and left atrial volume index.

Results

During the 6-year follow-up period, 273 participants (15%) developed T2D. Participants with incident T2D had greater LV mass index (86.7 ± 16.4 vs. 91.2 ± 17.0 g/m²), worse diastolic function, reflected by lower Em velocity (7.67 ± 1.80 vs. 7.47 ± 1.70) and higher E/Em ratio (9.19 ± 2.55 vs. 10.23 ± 3.00), and higher prevalence of LV diastolic dysfunction (34.6 vs. 54.2%), compared with those who did not develop T2D (all P < 0.001). In a multivariate logistic regression model, lower Em velocity (odd ratio [OR], 0.867; 95% confidence interval [CI] 0.786–0.957) and the presence of LV diastolic dysfunction (OR, 1.617; 95% CI 1.191–2.196) were associated with the development of T2D, after adjusting for potential confounding factors.

Conclusions

In a community-based cohort, the presence of subclinical LV diastolic dysfunction was a predictor of the progression to T2D. These data suggest that the echocardiographic assessment of LV diastolic function may be helpful in identifying non-diabetic subjects at risk of incident T2D.

Associations of Caffeinated Beverage Consumption and Screen Time with Excessive Daytime Sleepiness in Korean High School Students

The present study investigated caffeinated beverage consumption and screen time in the association with excessive daytime sleepiness (EDS) and sleep duration. We conducted a cross-sectional study including 249 Korean male high school students. These participants responded to a questionnaire inquiring the information on lifestyle factors, consumption of caffeinated beverages, time spent for screen media, and sleep duration as well as to the Epworth Sleepiness Scale (ESS) questionnaire. EDS was defined as ESS scores of 9 or greater. Students with EDS consumed greater amount of chocolate/cocoa drinks and spent longer time for a TV and a mobile phone than those without EDS (p < 0.05). In addition, students with short sleep (≤ 6 hours) consumed greater amount of coffee than others whereas students with long sleep (> 8 hours) consumed greater amount of chocolate/cocoa drinks than others (p < 0.05). Screen time did not differ according to the categories of sleep duration. Although these findings do not support causal relationships, they suggest that screen time is associated with EDS, but not with sleep duration, and that consumption of certain types of caffeinated beverages is associated with EDS and sleep duration. Adolescents may need to reduce screen time and caffeine consumption to improve sleep quality and avoid daytime sleepiness.

Associations between Lifestyle Factors and Iron Overload in Korean Adults

It has been suggested that iron overload, which indicates the accumulation of iron, generates cellular reactive oxygens and causes peroxide damages to the body. Such oxidative stresses, in a broader context, are also caused by lifestyles such as alcohol consumption and smoking. However, there are limited data on the association between these lifestyle factors and internal iron overload. In present study, we evaluated associations between lifestyle factors, such as smoking status, alcohol consumption, and physical activity, and serum markers of iron overload. In a population-based cross-sectional study including 2,347 Korean men and women aged 49–79 years, we assessed serum transferrin saturation (TSAT) levels and defined iron overload as TSAT levels > 50% for men and > 45% for women. After excluding persons with chronic diseases and iron deficiency, multivariate odds ratio (OR) and its 95% confidence interval (CI) were estimated to evaluate associations between lifestyle factors and iron overload in 1,973 participants. In all participants, we examined a significantly positive association between heavy alcohol consumption (> 30 g/day) and iron overload; heavy drinkers showed 1.6-fold higher OR (95% CI, 1.11–2.36) than non-drinkers. Stratified analysis by sex showed that this association was significant only among men. In addition, we observed a potential association between heavy smoking > 10 cigarettes/day and iron overload (p = 0.07). In stratified analysis by sex, we examined a significant association between smoking and iron overload only among women; former or current smokers had 1.9-fold higher OR (95% CI, 1.01–3.63) than never-smoker. Our findings suggest that heavy alcohol consumption and smoking may worsen iron accumulation in the body.

Interaction between Obstructive Sleep Apnea and Shortened Telomere Length on Brain White Matter Abnormality

STUDY OBJECTIVES

Age-related brain white matter changes (WMC) have been associated separately with obstructive sleep apnea (OSA) and short telomere length (TL). No studies have examined their interaction effect on WMC.

METHODS

This is a cross-sectional study with a community-based sample of 420 participants (mean age, 61.3 ± 7.2) from the Korean Genome and Epidemiology Study during 2011-2012. An overnight fasted blood sample was taken to determine glucose and blood lipid levels at the sleep laboratory of Korea University Ansan Hospital. The status of brain WMC was determined using structural magnetic resonance imaging at 1.5 Tesla. Overnight polysomnography was performed, and leukocyte TL was measured. OSA was determined based on apnea-hypopnea index, and short TL was defined as the lowest quartile of the study participants.

RESULTS

Adjusting for age, sex, BMI, smoking, drinking, snoring, and hypertension, odds ratio (OR) of brain WMC was estimated using multivariate logistic regression. The odds ratio was significant for cardiovascular disease (OR, 4.5; 95% CI, 1.2-16.3) and OSA (OR, 4.0; 95% CI, 1.0-15.2) among those with short TL; and for diabetes (OR, 3.0; 95% CI, 1.3-13.0) and age (OR, 1.1; 95% CI, 1.0-1.1) among those with longer TL. Interaction effect of OSA and short TL (OR, 4.3; 95% CI, 1.4-13.8) was significant, compared to those with neither OSA nor short TL.

CONCLUSIONS

This study provides a first evidence of mediated interaction of short TL with OSA on brain WMC in a community-based sample. The results generate new hypotheses regarding mechanisms of impaired brain health in sleep apnea.

Association between Snoring and Leukocyte Telomere Length

STUDY OBJECTIVES

Data on the association between snoring and telomere length, an indicator of biological aging, are very limited. Moreover, no polysomnography (PSG) studies on this association in a general population have been conducted. Our study aimed to evaluate the association between snoring and leukocyte telomere length (LTL) using PSG and a questionnaire.

METHODS

A cross-sectional PSG study embedded in a population-based cohort from the Korean Genome Epidemiology Study was conducted in 2010-2013. During the same period, questionnaire-based interviews, blood collection, and relative LTL assays were conducted. A total of 887 Korean men and women aged 50-79 y with an apnea-hypopnea index (AHI) < 15 determined in the PSG study were included in the study.

RESULTS

We observed that the percentage of time spent snoring during sleep (% time spent snoring) assessed by PSG was inversely associated with LTL even after adjusting for potential risk factors and AHI. In the linear regression association between tertiles of percentage of time spent snoring and log-transformed LTL, coefficient estimates (P value) were -0.076 (< 0.05) for the second tertile and -0.084 (< 0.01) for the third tertile compared with the bottom tertile. When LTL was compared according to snoring status determined using PSG and questionnaire information, both primary snorers and those with mild sleep apnea (5 ≤ AHI < 15) had shorter LTL than nonsnorers.

CONCLUSIONS

Our findings suggest that snoring may influence telomere attrition independent of sleep apnea.

Associations Between Alcohol Consumption and Leukocyte Telomere Length Modified by a Common Polymorphism of ALDH2

BACKGROUND

Data on the association between alcohol consumption and telomere length, a marker of biological aging, are inconsistent. Moreover, the genetic modification of this association has been reported only rarely. To evaluate the association between alcohol consumption and leukocyte telomere length (LTL), and the effect modification of this association by a common polymorphism of the aldehyde dehydrogenase 2 (ALDH2) gene, we conducted a cross-sectional study in a general population including 1,771 middle-aged and elderly Koreans, aged 49 to 79 years.

METHODS

Study participants provided blood samples between 2011 and 2012 for the LTL assay, and between 2001 and 2002 for genomewide genotyping. Between 2011 and 2012, they also completed a questionnaire-based interview regarding their alcohol consumption. We examined effect modification by rs2074356, a surrogate marker of the ALDH2 polymorphism.

RESULTS

Heavy alcohol consumption (average daily alcohol consumption of >30 g) was inversely associated with LTL only among carriers of the mutant alleles (CT and TT) of rs2074356 (p < 0.01). Among these subjects, elderly drinkers in particular showed the strongest association (p < 0.001). Light-to-moderate alcohol consumption on an almost daily basis was positively associated with LTL (p < 0.001), and this association was significant among carriers of the wild-type allele (CC) of rs2074356 (p < 0.01) but not among those with the mutant alleles.

CONCLUSIONS

Our findings suggest that the potential benefit of light-to-moderate alcohol consumption and the detriment of heavy alcohol consumption on biological aging may depend on ALDH2 polymorphism.

Leukocyte Telomere Length is Associated With Serum Vitamin B12 and Homocysteine Levels in Older Adults With the Presence of Systemic Inflammation

Folate, vitamin B₁₂, and homocysteine (HCY) are involved in the metabolism of nucleic acid precursors and it has been hypothesized that they also influence telomere length, a biomarker of aging. However, previous studies have reported inconsistent findings, and data for older adults are limited. Our study aimed to evaluate associations between leukocyte telomere length (LTL) and serum folate, vitamin B₁₂, and HCY levels among adults aged 55 years and over. In a cross-sectional study in 798 men and women aged 55-79 years, serum folate, vitamin B₁₂, and HCY levels were measured using chemiluminescent immunometric assays, and relative LTL was assessed using quantitative real-time polymerase chain reaction. To evaluate associations between LTL and serum folate, vitamin B₁₂, and HCY levels, multiple linear regression models were used. In multiple models adjusted for age, sex, serum high sensitive C-reactive protein (hs-CRP) levels, and other potential confounding factors, we found no association between LTL and serum folate, vitamin B₁₂, and HCY levels. However, we did find a significant inverse association between HCY levels and LTL in participants with serum hs-CRP levels of ≥ 2 mg/L (p < 0.05). Moreover, there was a trend toward an association between HCY and vitamin B₁₂ levels in these individuals (p = 0.08). In those with serum hs-CRP levels of < 2 mg/L, HCY was inversely associated with vitamin B₁₂ levels (p < 0.001) and had no association with LTL. Our findings suggest that increased serum HCY levels, when combined with the presence of systemic inflammation, may play a role in accelerating biological aging.

Sex-Specific Association between Longitudinal Changes in Adiposity, FTO rs9939609 Polymorphism, and Leukocyte Telomere Length

OBJECTIVE

A longitudinal study was conducted to examine sex-specific associations between changes in adiposity over a 10-year period, the FTO rs9939609 polymorphism, and leukocyte telomere length (LTL).

METHODS

A population-based cohort including 2128 middle-aged and older Korean men (n = 1087) and women (n = 1041) participated in a prospective study. Anthropometric measurements of weight, height, and waist and hip circumference were taken at baseline (from 2001 to 2003) and at the 10-year follow-up period (from 2011 to 2012). The FTO rs9939609 polymorphism was genotyped using DNA samples collected at baseline and LTL was assessed at the 10-year follow-up period. Multiple linear regression analysis was used with adjustments for age, baseline body mass index, and other potential confounders.

RESULTS

Presence of the FTO rs9939609 polymorphism risk allele was inversely associated with LTL (p < 0.01) in all participants, with a significant association seen only in women when the genders were modeled separately. Conversely, a significant inverse association between changes in waist circumference and LTL was found in men (p < 0.001) but not in women. No significant interaction between adiposity measures and the FTO polymorphism in association with LTL was identified for either sex.

CONCLUSIONS

These data suggest that biological aging in men may be accelerated by increasing waist circumference, whereas in women, aging may be affected by genetic variations in FTO regardless of adiposity changes over time.

Sodium Excretion and Cardiovascular Structure and Function in the Nonhypertensive Population: The Korean Genome and Epidemiology Study

BACKGROUND

The effect of sodium intake on the cardiovascular system remains controversial. The purpose of this study is to investigate the relation between sodium intake and cardiovascular structure and function in the nonhypertensive population.

METHODS

We performed a cross-sectional analysis in 1,586 nonhypertensive subjects who participated in the Korean Genome Epidemiology Study (2007-2008). Sodium intake was assessed by estimating the 24-hour urinary sodium excretion from a spot urine sample. Changes in cardiovascular structure and function were assessed by using tissue Doppler echocardiography, the carotid intima-media thickness (CIMT), and the brachial-ankle pulse wave velocity (baPWV).

RESULTS

Systolic and diastolic blood pressures increased with increasing tertiles of estimated 24-hour urinary sodium excretion. In multivariate analyses adjusting for covariates, there were stepwise decreases in the baPWV (P = 0.003) and CIMT (P = 0.001) values as the estimated 24-hour urinary sodium excretion increased, whereas no significant differences in left ventricular (LV) structural and functional parameters were observed across the tertiles of estimated 24-hour urinary sodium excretion. Multiple linear regression analyses revealed that the estimated 24-hour urinary sodium excretion was independently and inversely associated with baPWV (P < 0.001) and CIMT (P = 0.001), but not with LV parameters.

CONCLUSIONS

In the nonhypertensive population, urinary sodium excretion was inversely related to baPWV and CIMT. However, there were no associations between urinary sodium excretion and LV structure or function.

Associations of Sleep Apnea, NRG1 Polymorphisms, Alcohol Consumption, and Cerebral White Matter Hyperintensities: Analysis with Genome-Wide Association Data

STUDY OBJECTIVE

There are few studies on gene-environment interactions with obstructive sleep apnea (OSA). Our study aimed to explore genetic polymorphisms associated with OSA using genome-wide association (GWA) data and evaluate the effects of relevant polymorphisms on the association between risk factors, including obesity and alcohol consumption, and OSA. We also investigated on these associations in relation to cerebral white matter hyperintensities (WMH) on magnetic resonance images.

DESIGN

A cross-sectional design.

SETTING

A polysomnography study embedded in a population-based cohort from the Korean Genome Epidemiology Study was conducted in 2011-2013.

PARTICIPANTS

1,763 participants aged 48-78 years.

RESULTS

251 individuals were identified to have OSA with an apnea-hypopnea index ≥ 15. A common polymorphism of neuregulin-1 gene (NRG1), rs10097555, was selected as the most suggestive locus associated with OSA (P value < 10(-5)) based on the results of GWA analysis in a matched case-control subsample (n = 470). Among 1,763 participants, we found that the presence of the NRG1 polymorphism is inversely associated with OSA (P value < 0.01) even after taking into account potential risk factors; the multivariate odds ratio (95% confidence interval) for the mutant alleles was 0.57 (0.39-0.82) compared with the wild-type. We observed that this association is modified by alcohol consumption (P < 0.05), not by obesity. We also observed that WMH are positively associated with OSA independent of the NRG1 polymorphism and alcohol consumption (P < 0.05).

CONCLUSIONS

These findings suggest that the neuregulin-1 gene (NRG1) may be involved in the etiological mechanisms of obstructive sleep apnea (OSA) and that carriers of a particular NRG1 mutation may be less likely to have OSA if they do not drink alcoholic beverages.

Sex-specific differences in the association of a common aldehyde dehydrogenase 2 gene polymorphism and alcohol consumption with stroke risk in a Korean population: a prospective cohort study

BACKGROUND/OBJECTIVES

It is well-known that alcohol consumption is associated with stroke risk as well as with aldehyde dehydrogenase 2 gene (ALDH2) polymorphisms. However, it is unclear whether ALDH2 polymorphisms are associated with stroke risk independent of alcohol consumption and whether such association is modified by sex. We evaluated sex-specific associations of a common ALDH2 polymorphism and alcohol consumption with stroke risk in a Korean population.

SUBJECTS/METHODS

We conducted a prospective cohort study involving 8,465 men and women, aged 40-69 years and free of stroke between June, 2001 and January, 2003, and followed for the development of stroke. We identified new cases of stroke, which were self-reported or ascertained from vital registration data. Based on genome-wide association data, we selected a single-nucleotide polymorphism (rs2074356), which shows high linkage disequilibrium with the functional polymorphism of ALDH2. We conducted Cox proportional hazards regression analysis considering potential risk factors collected from a baseline questionnaire.

RESULTS

Over the median follow-up of 8 years, 121 cases of stroke were identified. Carrying the wild-type allele of the ALDH2 polymorphism increased stroke risk among men. The multivariate hazard ratio [95% confidence interval] of stroke was 2.02 [1.03-3.99] for the wild-type allele compared with the mutant alleles, but the association was attenuated after controlling for alcohol consumption. Combinations of the wild-type allele and other risk factors of stroke, such as old age, diabetes mellitus, and habitual snoring, synergistically increased the risk among men. Among women, however, the ALDH2 polymorphism was not associated with stroke risk.

CONCLUSIONS

The prospective cohort study showed a significant association between a common ALDH2 polymorphism and stroke risk in Korean men, but not in Korean women, and also demonstrated that men with genetic disadvantages gain more risk when having risk factors of stroke. Thus, these men may need to make more concerted efforts to control modifiable risk factors of stroke.

Visceral adiposity and skeletal muscle mass are independently and synergistically associated with left ventricular structure and function: the Korean Genome and Epidemiology Study

BACKGROUND

Obesity and low muscle mass may coexist as age-related changes in body composition. We aimed to investigate the effect of visceral adiposity and skeletal muscle mass on left ventricular (LV) structure and function in the general population.

METHODS

A total of 1941 participants without known cardiovascular disease were enrolled from the Korean Genome and Epidemiology Study. Visceral fat area (VFA) was assessed by computed tomography. Appendicular skeletal muscle mass (ASM) was estimated by dual-energy X-ray absorptiometry and was used as a percentage of body weight (ASM/Wt). LV structure and function were assessed by tissue Doppler imaging (TDI) echocardiography.

RESULTS

Across VFA tertiles, ASM increased, but ASM/Wt decreased (all P<0.001). In multivariate models adjusted for conventional cardiovascular risk factors, LV mass index and LV diastolic parameters, such as left atrial dimension, TDI Ea velocity, and E/Ea ratio, were significantly impaired as VFA increased. On the other hand, an increase in ASM/Wt was associated with a decrease in LV mass index and improvement of LV diastolic parameters. With regard to LV mass index and TDI Ea velocity, VFA and ASM/Wt showed synergistic effects (all P interaction<0.05). When both VFA and ASM/Wt were simultaneously included in the same model, both remained independent predictors of LV mass index and TDI Ea velocity.

CONCLUSIONS

More visceral fat and less muscle mass are independently and synergistically associated with an increase in LV mass index and impairment of LV diastolic parameters. Further research is needed to explore the complex mechanisms underlying these associations.

Non-alcoholic fatty liver disease, metabolic syndrome and subclinical cardiovascular changes in the general population

OBJECTIVE

The effect of non-alcoholic fatty liver disease (NAFLD) on cardiovascular system remains controversial. We investigated the independent contribution of NAFLD to cardiovascular structure and function in the general population.

METHODS

A total of 1886 participants without known cardiovascular disease were enrolled from the Korean Genome Epidemiology Study. The participants were divided into four groups, based on the presence of NAFLD, metabolic syndrome (MetS), neither or both. NAFLD was diagnosed by CT. Changes in cardiovascular structure and function were assessed by tissue Doppler imaging (TDI) echocardiography, carotid ultrasound and brachial-ankle pulse wave velocity (baPWV).

RESULTS

In multivariate analyses, subjects with both NAFLD and MetS had a higher E/Ea ratio and baPWV, as well as a lower TDI Ea velocity (all p<0.001) than those with neither NAFLD nor MetS. Subjects with either NAFLD or MetS also showed significant differences in TDI Ea velocity and baPWV (all p<0.05). However, no significant differences of carotid intima-media thickness (CIMT) values were seen among the four groups. Multivariate linear regression revealed that both NAFLD and MetS were independent predictors of TDI Ea velocity and baPWV (all p<0.001). Both MetS and NAFLD were not a determinant of CIMT.

CONCLUSIONS

NAFLD was associated with early alterations of cardiovascular system, independent of established cardiovascular risk factors and MetS.

A lipoprotein lipase gene polymorphism interacts with consumption of alcohol and unsaturated fat to modulate serum HDL-cholesterol concentrations

There are limited data from prospective studies regarding interactions between lipoprotein lipase gene (LPL) and lifestyle factors in association with HDL-cholesterol (HDL-C) concentrations, a biomarker of coronary heart disease risk. Our prospective cohort study investigated the interactive effects of a common LPL polymorphism and lifestyle factors, including obesity, smoking, alcohol consumption, physical activity, and dietary intake, on follow-up measurements of HDL-C and triglyceride (TG) concentrations. A total of 5314 Korean men and women aged 40-69 y participated in the study. Serum HDL-C and TG concentrations were measured in all participants at baseline and 6-y follow-up examinations. On the basis of genome-wide association data for HDL-C and TG concentrations, we selected the most significant polymorphism (rs10503669), which was in high linkage disequilibrium with the serine 447 stop (S447×) mutation (D' = 0.99) of LPL. We found that carrying the T allele reflecting the LPL ×447 allele was positively associated with follow-up measurement of HDL-C concentrations (P < 0.001). In the linear regression model adjusted for baseline HDL-C concentration and potential risk factors, we observed interactive effects of the polymorphism and consumption of alcohol (P-interaction < 0.01) and unsaturated fat (P-interaction < 0.05) on follow-up measurement of HDL-C concentrations. We also observed interactive effects of the polymorphism and body mass index (P-interaction < 0.01) on follow-up measurement of TG concentrations after adjusting for the baseline level and potential risk factors. Our findings suggest that carriers of the LPL ×447 allele benefit from moderate alcohol consumption and a diet high in unsaturated fat to minimize reduction of blood HDL-C concentrations and that obese persons who do not carry the LPL ×447 allele need to control body weight to prevent hypertriglyceridemia.

Associations between dietary patterns and screen time among Korean adolescents

Data are limited on the association between dietary patterns and screen time among Korean adolescents. The present study identified dietary patterns of 691 adolescents, aged 13-18 years, who had participated in the Third Korean National Health and Nutrition Examination Survey (KNHANES III) and analyzed their associations with screen time. Screen time was defined as the time spent watching TV, using a computer, or playing video games was calculated as a sum of all these times. Dietary patterns and their factor scores were derived from a food frequency questionnaire using the factor analysis method. To analyze the association between dietary patterns and screen time, we conducted multiple linear regression analysis. We also performed multiple logistic regression analysis to estimate odds ratios (OR) of excessive screen time (2 hours or longer per day) and 95% confidence intervals (CI). We identified 2 dietary patterns labeled "the Korean healthy dietary pattern" and "the Western diet and fast foods pattern". The former included mixed grains, legumes, potatoes, red meat, eggs, fish, dairy products, fruits, vegetables, seaweeds, and mushrooms, whereas the latter included noodles, bread, red meat, poultry, fast foods, snack, and soft drinks. After controlling for potential confounding factors, factor scores for the Korean healthy dietary pattern were inversely associated (P-value for trend < 0.01) and those for the Western diet and fast foods pattern were positively associated with the screen time (P-value for trend < 0.01). Adolescents in the top tertile of the scores for the Korean healthy dietary pattern had a multivariable-adjusted OR [95% CI] of 0.44 (0.25-0.75) for excessive screen time compared with those in the lowest tertile. On the basis of these findings, adolescents who have excessive screen time may need to be encouraged to consume a more healthy diet.

A healthy dietary pattern consisting of a variety of food choices is inversely associated with the development of metabolic syndrome

There are limited data on healthy dietary patterns protective against metabolic syndrome (MetSyn) development. We identified dietary patterns among middle-aged and older adults and investigated the associations with the incidence of MetSyn. A population-based prospective cohort study included 5,251 male and female Koreans aged 40-69 years. At baseline, all individuals were free of MetSyn, other major metabolic diseases, and known cardiovascular disease or cancer. Cases of MetSyn were ascertained over a 6-year of follow-up. Dietary patterns and their factor scores were generated by factor analysis using the data of a food frequency questionnaire. We performed pooled logistic regression analysis to estimate multivariable-adjusted relative risk (RR) and 95% confidence interval (CI) for associations between factor scores and MetSyn risk. Two dietary patterns were identified; (1) a healthy dietary pattern, which included a variety of foods such as fish, seafood, vegetables, seaweed, protein foods, fruits, dairy products, and grains; and (2) an unhealthy dietary pattern, which included a limited number of food items. After controlling for confounding factors, factor scores for the healthy dietary pattern were inversely associated with MetSyn risk (P-value for trend < 0.05) while those for the unhealthy dietary pattern had no association. Individuals in the top quintile of the healthy diet scores showed a multivariable-adjusted RR [95% CI] of 0.76 [0.60-0.97] for MetSyn risk compared with those in the bottom quintile. The beneficial effects were derived from inverse associations with abdominal obesity, low HDL-cholesterol levels, and high fasting glucose levels. Our findings suggest that a variety of healthy food choices is recommended to prevent MetSyn.

Interaction Effects of Lipoprotein Lipase Polymorphisms with Lifestyle on Lipid Levels in a Korean Population: A Cross-sectional Study

Lipoprotein lipase (LPL) plays an essential role in the regulation of high-density lipoprotein cholesterol (HDLC) and triglyceride levels, which have been closely associated with cardiovascular diseases. Genetic studies in European have shown that LPL single-nucleotide polymorphisms (SNPs) are strongly associated with lipid levels. However, studies about the influence of interactions between LPL SNPs and lifestyle factors have not been sufficiently performed. Here, we examine if LPL polymorphisms, as well as their interaction with lifestyle factors, influence lipid concentrations in a Korean population. A two-stage association study was performed using genotype data for SNPs on the LPL gene, including the 3' flanking region from 7,536 (stage 1) and 3,703 (stage 2) individuals. The association study showed that 15 SNPs and 4 haplotypes were strongly associated with HDLC (lowest p = 2.86 × 10^-22) and triglyceride levels (lowest p = 3.0 × 10^-15). Interactions between LPL polymorphisms and lifestyle factors (lowest p = 9.6 × 10^-4) were also observed on lipid concentrations. These findings suggest that there are interaction effects of LPL polymorphisms with lifestyle variables, including energy intake, fat intake, smoking, and alcohol consumption, as well as effects of LPL polymorphisms themselves, on lipid concentrations in a Korean population.

Interactions between the FTO rs9939609 polymorphism, body mass index, and lifestyle-related factors on metabolic syndrome risk

Whether the FTO polymorphisms interact with environmental factors has not yet been evaluated in associations with metabolic syndrome (MS) risk. The present study investigated the association of the FTO rs9939609 genotypes, body mass index (BMI), and lifestyle-related factors including smoking, alcohol drinking, physical activity, and diet with MS incidence. A population-based prospective cohort study comprised 3,504 male and female Koreans aged 40 to 69 years. At the beginning of the study, all individuals were free of MS and known cardiovascular disease. Incident cases of MS were identified by biennial health examinations during a follow-up period from April 17, 2003 to April 15, 2009. Pooled logistic regression analysis was applied to obtain relative odds (RO) of MS with its 95% confidence interval (CI). After controlling for potential MS risk factors, we observed no association between the rs9939609 genotypes and MS incidence. In analysis stratified by BMI, however, carriers with the FTO risk allele whose BMI is 29 kg/m² or greater showed an approximately 6-fold higher RO (95% CI: 3.82 to 9.30) compared with non-carriers with BMI less than 25 kg/m². In particular, the association between the rs9939609 variants and MS risk was significantly modified by high BMI (P-value for interaction < 0.05). Such significant interaction appeared in associations with central obesity and high blood pressure among the MS components. Because carriers of the FTO risk alleles who had BMI of 29 kg/m² or greater are considered a high risk population, we suggest that they may need intensive weight loss regimens to prevent MS development.

Genome-wide association studies identify genetic loci related to alcohol consumption in Korean men

BACKGROUND

Genome-wide association (GWA) studies regarding the quantitative trait of alcohol consumption are limited.

OBJECTIVE

The objective of the study was to explore genetic loci associated with the amount of alcohol consumed.

DESIGN

We conducted a GWA study with discovery data on single nucleotide polymorphisms (SNPs) for 1721 Korean male drinkers aged 40-69 y who were included in an urban population-based cohort. Another sample that comprised 1113 male drinkers who were from an independent cohort enrolled in a rural area served as a resource for replication. At baseline (18 June 2001 through 29 January 2003), members of both cohorts provided information on average daily alcohol consumptions, and their DNA samples were collected for genotyping.

RESULTS

We tested 315,914 SNPs of discovery data by using multivariate linear regression analysis adjusted for age and smoking, and 12 SNPs on chromosome 12q24 had genome-wide significant associations with alcohol consumption; adjusted P values by using Bonferroni correction were 1.6 × 10(-5) through 5.8 × 10(-46). We observed most SNPs in intronic regions and showed that the genes that harbor SNPs were C12orf51, CCDC63, MYL2, OAS3, CUX2, and RPH3A. In particular, signals in or near C12orf51, CCDC63, and MYL2 were successfully replicated in the test for 317,951 SNPs; rs2074356 in C12orf51 was in high linkage disequilibrium with SNPs in ALDH2, but other SNPs were not.

CONCLUSIONS

In a GWA study, we identified loci and alleles highly associated with alcohol consumption. The findings suggest the need for further investigations on the genetic propensity for drinking excessive amounts of alcohol.

Adiponectin concentrations: a genome-wide association study

Adiponectin is associated with obesity and insulin resistance. To date, there has been no genome-wide association study (GWAS) of adiponectin levels in Asians. Here we present a GWAS of a cohort of Korean volunteers. A total of 4,001 subjects were genotyped by using a genome-wide marker panel in a two-stage design (979 subjects initially and 3,022 in a second stage). Another 2,304 subjects were used for follow-up replication studies with selected markers. In the discovery phase, the top SNP associated with mean log adiponectin was rs3865188 in CDH13 on chromosome 16 (p = 1.69 × 10(-15) in the initial sample, p = 6.58 × 10(-39) in the second genome-wide sample, and p = 2.12 × 10(-32) in the replication sample). The meta-analysis p value for rs3865188 in all 6,305 individuals was 2.82 × 10(-83). The association of rs3865188 with high-molecular-weight adiponectin (p = 7.36 × 10(-58)) was even stronger in the third sample. A reporter assay that evaluated the effects of a CDH13 promoter SNP in complete linkage disequilibrium with rs3865188 revealed that the major allele increased expression 2.2-fold. This study clearly shows that genetic variants in CDH13 influence adiponectin levels in Korean adults.

Association of coronary artery calcification with obstructive sleep apnea and obesity in middle-aged men

BACKGROUND AND AIMS

Obstructive sleep apnea (OSA) and obesity are closely associated, and both have been reported to increase the risk of coronary heart disease. Although obesity is known to be associated with coronary artery calcification (CAC), there is limited information on whether OSA is associated with CAC independent of obesity.

METHODS AND RESULTS

A cross-sectional study examined the association between OSA and CAC among 258 healthy men, ages 40-49 years old, randomly selected from a population-based cohort. All individuals underwent overnight polysomnography and electron-beam computed tomography to measure their apnea-hypopnea index (AHI) and degree of CAC. A logistic regression model including potential cardiovascular risk factors excluding body mass index (BMI) showed that the presence of CAC was significantly greater in the fourth quartile versus the first quartile of AHI severity (odds ratio [OR] 2.21, 95% confidence interval [CI] 1.01-4.86). A multivariate linear regression model excluding BMI also showed that AHI was significantly associated with CAC (P = 0.004). However, this association was no longer significant after adjusting for BMI.

CONCLUSIONS

In our cross-sectional study, even though both OSA and obesity were positively associated with the presence and extent of CAC, only obesity remained a significant independent contributor after an adjustment for potential cardiovascular risk factors, irrespective of OSA.