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.

Transferrin saturation concentrations associated with telomeric ageing: a population-based study.

There are limited data on the association between Fe overload and leucocyte telomere length (LTL), known as a useful biomarker of the replicative ageing of cells. The aim of the study was to evaluate associations between Fe-status biomarkers and LTL. A cross-sectional study included 1174 men and women aged 50-79 years who provided blood samples for assays of Fe-status biomarkers including ferritin, transferrin saturation (TSAT), total Fe-binding capacity (TIBC) and relative LTL. They were free of hepatitis, potential infection or Fe deficiency. In multiple linear regression analysis adjusted for potential confounding variables, log-transformed LTL was positively associated with TIBC (adjusted coefficient estimate for its highest quartile: 0·17 (se 0·03), P45 %) but also with high-normal concentrations (35-45 %) of TSAT had shorter LTL compared with those with low-normal concentrations (<30 %) (P<0·05). We also observed that less-active or obese persons with high TSAT concentrations had shorter LTL than others. Our findings that cellular ageing is influenced not only by Fe overload but also by high-normal concentrations of TSAT support the hypothesis regarding the detrimental effects of labile Fe, which has a potent pro-oxidant activity in the body.

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.

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.

The association between leukocyte telomere lengths and sleep instability based on cardiopulmonary coupling analysis.

PURPOSE: The purpose of the study is to examine the objective association between sleep stability and leukocyte telomere lengths (LTL) using cardiopulmonary coupling (CPC) analysis, which is an electrocardiogram (ECG)-based technique to quantify physiologic sleep stability. METHODS: Three hundred eighty-one healthy subjects were recruited from a community-based cohort study from the Korean Genome and Epidemiology Study (KoGES), and the associations between LTL and total quantities of different frequency coupling bands were examined using generalized linear model (GLM) with adjustment of significant covariates. RESULTS: LTL showed a significant association with elevated narrow-band low frequency coupling (e-LFCNB, a CPC marker of periodic breathing or sleep fragmentation due to pathological respiratory chemoreflex activation) by interacting with obstructive sleep apnea (OSA) severity (p value of <0.0001). Especially, sleep stability significantly reduced with shortened LTL in OSA patients (Apnea-Hypopnea Index (AHI) ≥15) based on increased e-LFCNB which had a negative correlation with high-frequency coupling band (HFC), a marker of stable sleep. CONCLUSION: The present study suggested that shorter LTL might contribute to reduced sleep stability by interacting with OSA severity due to the stress of chronic sleep fragmentation or invariant sympathetic activity by respiratory chemoreflex activation.

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.

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.

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.

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.

Associations of green tea, coffee, and soft drink consumption with longitudinal changes in leukocyte telomere length.

Whether beverage consumption is associated with longitudinal observation of telomere length remains unclear. We evaluated the association of green tea, coffee, and soft drink consumption with 6-year changes in leukocyte telomere length (LTL). The study included 1952 participants who provided whole blood samples for LTL assays during the baseline (year 2011-2012) and follow-up (year 2017-2018) periods and reported baseline information on consumption of green tea, coffee, and soft drinks. Robust regression analysis was used to analyze the association adjusted for potential confounding variables. In the results, an inverse association between green tea consumption and LTL changes from baseline, which indicate telomere shortening, was found; regression coefficient [95% confidence interval] was - 0.097 [- 0.164, - 0.029] for participants who daily consumed at least 1 cup of green tea compared with non-consumers (p value = 0.006). This association was stronger among women (versus men) and younger participants aged 50-64 years (versus older). However, a positive association between soft drink consumption and LTL shortening was observed among women (p value < 0.05). Coffee consumption was not associated with LTL changes. These findings suggested that green tea consumption may be protective against telomere shortening reflecting biological aging whereas coffee and soft drink consumption may not.

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.

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.

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.

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.

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.

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.

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.

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.