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.
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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.
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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.
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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.
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