Validation and reproducibility of food frequency questionnaire for Korean genome epidemiologic study

Life’s Simple 7 Cardiovascular Health Metrics and Progression of Coronary Artery Calcium in a Low-Risk Population

Objective—

We examined the association of cardiovascular health (CVH) metrics with the development and progression of coronary artery calcium (CAC) among apparently healthy adults.

Approach and Results—

This cohort study included 65 494 men and women 30 years of age and older free of cardiovascular disease at baseline who underwent a comprehensive exam including CAC scoring. CVH metrics were defined according to the American Heart Association Life’s Simple 7 metrics based on smoking, diet, physical activity, body mass index, blood pressure, total cholesterol, and fasting glucose. CVH scores range from 0 (all metrics considered unhealthy) to 7 (all metrics considered healthy). Participants were followed-up for a maximum of 6.6 years. Compared with participants with ideal CVH scores 0–1, the multivariable-adjusted difference in the change in geometric means of CAC scores over 5 years of follow-up were −0.40 (−0.62 to −0.19), −0.83 (−1.03 to −0.63), −1.06 (−1.25 to −0.86), −1.22 (−1.42 to −1.03), and −1.05 (−1.42 to −0.69) in participants with ideal CVH scores 2, 3, 4, 5, and 6–7, respectively. The inverse association between CVH scores and progression of CAC was observed both in participants with no CAC and in those with CAC detectable at baseline.

Conclusions—

A higher ideal CVH metrics score was strongly associated with a lower prevalence of CAC and with lower progression of CAC in males and females in a large cohort of healthy adults. Our findings suggest that maintaining a healthy life habits could help reduce the development and progression of subclinical atherosclerosis and ultimately prevent clinically cardiovascular event.

Changes in Brain Volume Associated With Vegetable Intake in a General Population

Objective: Although brain atrophy is a natural process of healthy aging, diet may play a role in delaying the process across age. We sought to investigate how food groups associate brain region-specific volume changes over 4 years in a general population. Methods: We obtained data from the Korean Genome and Epidemiology Study on 848 community-dwelling individuals. The participants completed a dietary examination using a food frequency questionnaire between 2005 and 2006 to determine habitual usual intakes of food consumption and two brain magnetic resonance imaging (MRI) scans between 2011 and 2014 and between 2015 and 2017, respectively. The 106 food items in the questionnaire were regrouped into 18 food groups. A multivariable generalized linear model was used with the adjustment of potential confounding variables. Results: The average age at baseline was 53.5 years. The average follow-up year of brain MRI was 4.13 ± 0.33 years. With considering a corrected p value due to multiple comparisons, vegetable intake indicated a statistically significant inverse association with gray matter volume change (β = -2.28, p = 0.006), after adjusting for potential confounding variables. Particularly, the temporal region showed a significant inverse association with vegetable intake (β= -0.63, p = 0.002). Conclusions: In a longitudinal study among 848 cognitively healthy participants from a general population, we found significant inverse associations between vegetable intake and brain gray matter volume change, particularly the change of temporal region.

Self-rated health and the risk of incident type 2 diabetes mellitus: A cohort study

We aimed to evaluate the association between self-rated health (SRH) and the risk of incident type 2 diabetes mellitus (T2D). This cohort study consisted of 250,805 Korean men and women without T2D at baseline. SRH was assessed at baseline with a self-administered structured questionnaire. Incident T2D was defined as fasting serum glucose ≥126 mg/dL, HbA1C ≥6.5%, or use of medication for T2D during follow-up. After adjustment for possible confounders including age, center, year of screening exam, smoking status, alcohol intake, physical activity, education level, total calorie intake, body mass index, sleep duration, depressive symptoms, family history of diabetes, history of hypertension, and history of cardiovascular disease, the multivariable-adjusted hazard ratios (95% confidence intervals) for incident T2D comparing good, fair, and poor or very poor SRH to very good SRH were 1.20 (0.98-1.48), 1.63 (1.33-1.98), and 1.83 (1.47-2.27), respectively. These associations were consistently observed in clinically relevant subgroups. Fair or poorer SRH was independently and positively associated with the development of T2D in a large-scale cohort study of apparently healthy Korean adults, indicating that SRH is a predictor of metabolic health. Physicians involved in diabetes screening and management should routinely consider SRH when evaluating T2D risk as well as overall health.

Dietary Lutein Plus Zeaxanthin Intake and DICER1 rs3742330 A > G Polymorphism Relative to Colorectal Cancer Risk

It is unclear whether dietary lutein/zeaxanthin intake in colorectal cancer is associated with microRNA processing involved in DICER1 cleavage for messenger RNA translation. We investigated whether dietary lutein/zeaxanthin intake affects colorectal cancer risk in patients with a DICER1 rs3742330 polymorphism. In this hospital-based case-control study, we recruited 923 colorectal cancer patients and 1,846 controls based on eligibility criteria, a semiquantitative food frequency questionnaire and the DICER1 rs3742330 genotype. Odds ratios (ORs) and 95% confidence intervals (CIs) were calculated by unconditional logistic regression adjusted for confounders. The highest quartile of lutein/zeaxanthin consumption was inversely associated with a reduced colorectal cancer risk (OR, 95% CI = 0.25, 0.18-0.36). Carrying G allele (AG + GG) showed a significantly reduced colorectal cancer incidence compared with that of AA carriers (OR, 95% CI = 0.71, 0.55-0.91). Those carrying the G allele (AG + GG) along with high lutein/zeaxanthin consumption were markedly associated with a decreased colorectal cancer risk (OR, 95% CI = 0.32, 0.22-0.46, P for interaction = 0.018), particularly for rectal cancer (OR, 95% CI = 0.24, 0.15-0.39, P for interaction = 0.004), compared with that of AA carriers with low lutein/zeaxanthin intakes. In conclusion, colorectal cancer risk was related to an interactive effect between dietary lutein/zeaxanthin intake and the DICER1 rs3742330 polymorphism.

The Prevalence of Hyperuricemia Sharply Increases from the Late Menopausal Transition Stage in Middle-Aged Women

The impact of menopausal transition on change of serum uric acid level remains unknown. The present study evaluated the relationship of menopausal stages with prevalent hyperuricemia in middle-aged women. This cross-sectional study included 58,870 middle-aged Korean women, aged ≥40, who participated in a health examination from 2014 to 2016. Menopausal stages were obtained with a standardized, self-administered questionnaire and were categorized according to the criteria of the Stages of Reproductive Aging Workshop (STRAW+10). Hyperuricemia was defined as a serum uric acid level of ≥6 mg/dL. The prevalence of hyperuricemia increased as menopausal stage increased. The multivariable-adjusted odds ratios (95% confidence intervals) for prevalent hyperuricemia comparing early transition, late transition, and post-menopause to pre-menopause were 1.19 (0.80–1.77), 2.13 (1.35–3.36), and 1.65 (1.33–2.04), respectively. This association was stronger among non-obese compared to obese participants and in those with low high-sensitivity C-reactive protein (hsCRP) levels (<1.0 mg/L) compared to those with elevated hsCRP levels of ≥1.0 mg/L (p for interaction = 0.01). In this large sample of middle-aged women, the prevalence of hyperuricemia significantly increased from the menopausal stage of late transition, independent of potential confounders. Appropriate preventive strategies for reducing hyperuricemia and its related consequences should be initiated prior to menopause.

Weight change after smoking cessation and incident metabolic syndrome in middle-aged Korean men: an observational study

We aimed to examine the effect of weight change attributable to cessation of cigarette smoking on newly diagnosed metabolic syndrome (MetS). We prospectively followed 5,809 men aged between 40 to 69 years without MetS at baseline in the Health Examinees-Gem (HEXA-G) study up to 4 years. The participants were grouped into continual smokers, quitters with weight gain, quitters without weight change, quitters with weight loss, and never smokers. We constructed multivariable logistic regression models adjusted for sociodemographic factors, health status, and health conditions to estimate the odds of newly diagnosed MetS. During the follow-up, there were 609 cases of newly diagnosed MetS in 5,809 men of the HEXA-G study. After adjustment for potential confounders, the odd ratios (OR) and 95% confidence intervals (95% CI) for MetS were 1.90 (95% CI: 1.43-2.52) in quitters with weight gain, 0.77 (95% CI: 0.60-1.00) in quitters without weight change, and 0.40 (95% CI: 0.28-0.57) in quitters with weight loss compared with continual smokers. Never smokers also had lower odds of MetS (OR = 0.54; 95% CI: 0.42-0.71) compared to continual smokers. Weight management program following smoking cessation may be necessary in clinical practice to reduce worsening of cardiometabolic risk factors related to post-cessation weight gain.

Noodle consumption is positively associated with incident hypertension in middle-aged and older Korean women

BACKGROUND/OBJECTIVES

This study examined the association between refined grain consumption by subtype and the incidence of hypertension from the Korean Genome and Epidemiology Study data.

SUBJECTS/METHODS

In total, 5,018 participants (2,439 men and 2,579 women) from 40 to 69 years without hypertension were recruited at the beginning (2001–2002). Blood pressure and antihypertensive medication use were assessed biennially for the incidence of hypertension during the 8-year follow-up period (2009–2010). Hypertension was diagnosed as systolic blood pressure ≥ 140 mmHg or diastolic blood pressure ≥ 90 mmHg or antihypertensive medication use. Dietary intake including refined grains was assessed by a food frequency questionnaire at baseline and the follow-up (2005–2006). A multivariate Cox proportional hazard model was used to examine hazard ratios (HRs) and 95% confidence intervals (CIs) for incident hypertension according to refined-grain consumption.

RESULTS

A total of 1,377 cases of hypertension (710 men and 667 women) were newly ascertained. Frequent noodle consumers (≥ 5 servings/week) among the women had a 2.3-fold higher risk of hypertension than infrequent noodle consumers after adjustment for potential confounders (HR = 2.31, 95% CI = 1.33–4.01, P for trend = 0.0001). However, no significant association was found among the men. The intake of other refined grain products such as white rice and breads was not associated with the incidence of hypertension.

CONCLUSIONS

Frequent noodle consumption was positively associated with a risk of incident hypertension in South Korean women.

Association between Total Diet Quality and Metabolic Syndrome Incidence Risk in a Prospective Cohort of Korean Adults

The purpose of this study was to prospectively investigate the relation between total diet quality and metabolic syndrome in Korean adults. A community-based cohort of the Korean Genome and Epidemiology Study (KoGES) provided basis for this study. During the total follow-up period of 38,171 person-years of 5,549 subjects, a total of 1,891 metabolic syndrome incident cases were identified. Metabolic syndrome was defined by the criteria of the National Cholesterol Education Program Adult Treatment Panel. Mediterranean Diet Score (MDS), Dietary Approaches to Stop Hypertension diet, and Recommended Food Score (RFS) were used to assess total diet quality. Cox proportional hazards regression was used to estimate hazard ratios (HRs) for metabolic syndrome associated with total diet quality. In men, the incidence of metabolic syndrome in the 5th MDS quintile group decreased by approximately 25% compared to the 1st quintile group (p for trend < 0.01) after adjusting for age and energy intake. In women, significant decreasing trend of metabolic syndrome incidence risk was observed across the quintiles of RFS in an age and energy intake-adjusted model (HR [95% CI] of Q5 vs. Q1; 0.662 [0.521-0.842], p for trend < 0.01). However, such associations did not reach at a significance level when additional covariates were included. In this first study looking at prospective relation of metabolic syndrome with total diet quality in a Korean population, study findings suggest some protective role of better diet quality in preventing future metabolic syndrome. But no convincing evidence was observed in this study.

Association of Dietary Potassium Intake with the Development of Chronic Kidney Disease and Renal Function in Patients with Mildly Decreased Kidney Function: The Korean Multi-Rural Communities Cohort Study

Background

Dietary potassium has negative outcomes in patients with mildly impaired kidney function, while having positive outcomes in patients with hypertension. The association of dietary potassium intake with chronic kidney disease (CKD) development, with presence of hypertension, was studied in the Korean rural population with mildly impaired kidney function.

Material/Methods

From 3 rural areas of Korea, 5064 participants age ≥40 with CKD stage 2 at baseline were recruited. Patients were classified according to the quartile of dietary potassium intake. Newly developed CKD, defined as estimated glomerular filtration rate (eGFR) of <60 mL/min/1.73 m² at the time of follow-up, and eGFR decline, defined as eGFR decrease >15% at follow-up, were studied. The effect of dietary potassium on CKD development and eGFR decline were studied by Cox proportional hazard models. The association of potassium with blood pressures and C-reactive protein was also studied to examine the underlying mechanisms.

Results

Compared to 8.6% in normotensives, 15.7% of hypertensives developed CKD. The hazard ratio (HR) (95% confidence interval) of CKD was lower in high potassium diet only in hypertensives, with 0.60 (0.37–0.99) in the highest quartile. The eGFR decline was also lower in patients with higher potassium diet, with 0.70 (0.50–0.98) in Q3 and 0.54 (0.34–0.85) in Q4. Potassium intake has also been shown to decrease high diastolic blood pressure development (>90 mmHg) in hypertensives at 0.45 (0.25–0.83).

Conclusions

Dietary potassium was associated with lower risk of CKD development and eGFR decline, and this association was observed only in hypertensives.

A Diabetes-Related Dietary Pattern Is Associated with Incident Diabetes in Obese Men in the Korean Genome Epidemiology Study

BACKGROUND

Diet plays an important role in both the development and management of diabetes.

OBJECTIVE

Using data from the Korean Genome Epidemiology Study, we assessed dietary patterns associated with the clinical indicators of diabetes.

METHODS

This study included 7255 subjects aged 40-69 y. Individuals with chronic diseases were excluded. The daily intakes of specific food items were assessed using a dish-based semiquantitative food-frequency questionnaire comprising 103 items; the food items were then grouped into 26 food groups. Dietary patterns were analyzed by the reduced rank regression method using glycated hemoglobin, the homeostasis model of insulin resistance, and fasting glucose concentrations as dependent variables. We investigated the associations between dietary patterns and incident diabetes using the Cox proportional hazards model.

RESULTS

During an 11.5-y follow-up, the incidence of diabetes was 11.8/1000 person-years. The dietary pattern related to selected biomarkers of diabetes was characterized by a relatively high intake of kimchi, beef, other meat, fish, and coffee in men and a high intake of rice, kimchi, and fruit in women. In men, the association of dietary patterns with incident diabetes was significant only in the obese group, and those in the top quartile of the dietary pattern score had a 1.72 times (95% CI: 1.15, 2.56 times) greater risk of incident diabetes than those in the bottom quartile. Conversely, dietary patterns in women were not associated with incident diabetes.

CONCLUSION

Using reduced rank regression, we identified dietary patterns related to selected biomarkers of diabetes in a long-term study with follow-up data in Korea.

Inadequate fat or carbohydrate intake was associated with an increased incidence of type 2 diabetes mellitus in Korean adults: A 12-year community-based prospective cohort study

AIMS

Few studies have focused on the relationship between long-term fat intake and type 2 diabetes mellitus (T2D) risk in Asia where fat intake is relatively lower than the Western countries. We examined association of dietary fat and carbohydrate intake with incidence of T2D among Korean adults.

METHODS

Based on the data from the Korean Genome and Epidemiology Study, a total of 5595 adults aged 40-69 years without diabetes, cardiovascular diseases or any cancer at baseline were included. Dietary intake was measured by the validated semi-quantitative food frequency questionnaire. Cox proportional hazards regression analysis was used to calculate multivariable-adjusted relative risks (RRs) and 95% confidence intervals (CIs).

RESULTS

During a median follow-up of 138-months, 1010 cases of T2D were newly determined. The proportion of participants with fat intake less than 15% of total energy and with carbohydrate intake more than 65% of total energy was 59.0% and 88.9%, respectively. After adjusting for confounders, a very-low-fat intake was associated with an increased risk of T2D (RR of Quartile 1 vs Quartile 4, 1.74; 95% CI, 1.18-2.57; p for trend = 0.0058) in women. A very-high-carbohydrate intake was associated with an increased risk of T2D in men (RR of Quartile 4 vs Quartile 1, 1.54; 95% CI, 1.03-2.30; p for trend = 0.0124) and women (RR of Quartile 4 vs Quartile 1, 1.69; 95% CI, 1.08-2.67; p for trend = 0.0376).

CONCLUSIONS

A very-low-fat or very-high-carbohydrate intake may increase the T2D risk and might be associated with lower intake of various nutrients and unbalanced macronutrient composition.

Body Mass Index and Risk of Intestinal Metaplasia: A Cohort Study

BACKGROUND

We examined the association between body mass index (BMI) and development of endoscopic intestinal metaplasia.

METHODS

This retrospective cohort study included 142,832 Korean adults free of endoscopic intestinal metaplasia and atrophic gastritis who underwent upper endoscopy at baseline and subsequent visits and were followed for up to 5 years. A parametric proportional hazards model was used to estimate the adjusted HR with 95% confidence interval (CI) for incident intestinal metaplasia.

RESULTS

In more than 444,719.1 person-years of follow-up, 2,281 participants developed endoscopic intestinal metaplasia (incidence rate, 5.1 per 1,000 person-years). Increased BMI categories were associated with increased risk of new-onset intestinal metaplasia in a dose-response manner. After adjustment for age, sex, center, year of screening exam, smoking status, alcohol intake, exercise, total calorie intake, history of diabetes and hypertension, and history of Helicobacter pylori infection, the multivariable adjusted HRs (95% CIs) for incident intestinal metaplasia comparing BMIs of <18.5, 23-24.9, 25.0-29.9, and >30 kg/m² with a BMI of 18.5-22.9 kg/m² were 0.84 (0.64-1.09), 1.03 (0.93-1.16), 1.07 (0.96-1.20), and 1.48 (1.20-1.83), respectively. These associations did not differ by clinically relevant subgroups. Risk of endoscopic atrophic gastritis also increased as the baseline BMI category increased.

CONCLUSIONS

In a large cohort of Korean men and women, obesity was independently associated with increased incidence of endoscopic atrophic gastritis and intestinal metaplasia.

IMPACT

Excessive adiposity appears to play a role in development of stomach precursor lesions of stomach cancer, requiring further studies to determine whether strategies to reduce obesity will also help reduce precancerous lesions and, in turn, gastric cancer.

The association between genetic variants of angiopoietin-like 3 and risk of diabetes mellitus is modified by dietary factors in Koreans

The role of angiopoietin-like 3 (ANGPTL3) in blood lipid levels, cardiovascular disease risk, and glucose metabolism has received wide attention. This study aimed to examine whether rs11207997 in ANGPTL3 is associated with a 10-year risk of diabetes mellitus (DM) and if the association is modified by the consumption of certain food groups or nutrients. A prospective cohort study was designed using the Ansan-Ansung data of the Korean Genome and Epidemiology Study (n = 7,358; age ≥40 years at baseline). Participants with the T allele of rs11207997, particularly TT homozygotes, had lower triglyceride (TG) and total cholesterol levels than those with CC. There was no association with fasting blood glucose or other biochemical parameters. ANGPTL3 mRNA was positively associated with circulating TG levels and blood pressure (all p < 0.05). Cox proportional hazard models showed that the rs11207997 T allele is associated with a lower risk of DM after adjusting for covariates (hazard ratio: 0.90, 95% confidence interval: 0.812-0.998, p = 0.046). Furthermore, the association between rs11207997 and the risk of DM was modified by dietary factors. These associations were no longer statistically significant when additionally adjusted for baseline TG, a potential mediator. Our data suggest that genetic variation of rs11207997 in the ANGPTL3 gene is associated with risk of DM, possibly through contributing to a lifelong set point of TG.

Impact of Self-Rated Health on Progression to a Metabolically Unhealthy Phenotype in Metabolically Healthy Obese and Non-Obese Individuals

We examined the association between self-rated health (SRH), a subjective measure of an individual’s health status, and the incidence of metabolic abnormalities, as well as the effect of obesity on this association in metabolically healthy individuals. The cohort study included 85,377 metabolically healthy men and women who were followed annually or biennially for a median of 3.0 years (interquartile range, 1.9–4.1 years). A parametric proportional hazard model was used to assess hazard ratios (HRs) and 95% confidence intervals (CIs) for the association between SRH and the incidence of metabolic abnormalities. During 258,689.03 person-years, 40,858 participants developed metabolic abnormalities. Poorer SRH was significantly associated with increased risk of developing any metabolic abnormality including hypertriglyceridemia, high homeostasis model assessment of insulin resistance (HOMA-IR), and fatty liver in a dose-dependent manner (p for trend <0.05). The association between SRH and progression to metabolically unhealthy status was much stronger in individuals with obesity than those without, especially in relation to any metabolic abnormality, fatty liver, and high C-reactive protein (all p for interaction by obesity <0.05). The multivariable-adjusted HR (95% CI) for any metabolic abnormality comparing the “poor or very poor” vs. the “very good” self-rated health category was 0.97 (0.90–1.05) among non-obese subjects, whereas the corresponding HR (95% CI) among obese subjects was 1.25 (1.02–1.52). Low SRH, as assessed by a single question, was independently associated with increased risk of progression to metabolically unhealthy status in metabolically healthy individuals, especially metabolically healthy individuals with obesity. SRH may help identify individuals at high risk for progression to metabolically unhealthy status.

High genetic risk scores of SLIT3, PLEKHA5 and PPP2R2C variants increased insulin resistance and interacted with coffee and caffeine consumption in middle-aged adults

BACKGROUNDS AND AIMS

Insulin resistance is a common feature of metabolic syndrome that may be influenced by genetic risk factors. We hypothesized that genetic risk scores (GRS) of SNPs that influence insulin resistance and signaling interact with lifestyles to modulate insulin resistance in Korean adults.

METHODS AND RESULTS

Genome-wide association studies (GWAS) of subjects aged 40-65 years who participated in the Ansung/Ansan cohorts (8842 adults) in Korea revealed 52 genetic variants that influence insulin resistance. The best gene-gene interaction model was explored using the generalized multifactor dimensionality reduction (GMDR) method. GRS from the best model were calculated and the GRS were divided into low, medium and high groups. The best model for representing insulin resistance included SLIT3_rs2974430, PLEKHA5_rs1077044, and PPP2R2C_rs16838853. The odds ratios for insulin resistance were increased by 150% in the High-GRS group compared to the Low-GRS group. However, ORs for insulin secretion capacity, measured by HOMA-B, were not associated with GRS. Coffee and caffeine intake and GRS had an interaction with insulin resistance: In subjects with high coffee (≥10 cups/week) or caffeine intake (≥220 mg caffeine/day), insulin resistance was significantly elevated in the High-GRS group, but not in the Low-GRS. However, alcohol intake, smoking and physical activity did not have an interaction with GRS. Insulin secretion capacity was not significantly influenced by GRS when evaluating the adjusted odds ratios.

CONCLUSIONS

Subjects with High-GRS may be susceptible to increased insulin resistance by 50% and its risk may be exacerbated by consuming more than 10 cups coffee/week or 220 mg caffeine/day.

Higher serum uric acid is associated with higher lumbar spine bone mineral density in male health-screening examinees: a cross-sectional study

Bone health has been associated with oxidative stress and antioxidants have received interest to this end. Serum uric acid (SUA), an end product of purine metabolism in humans, has recently shown antioxidant properties regarding bone health, but there are conflicting results. The aim of this study was to investigate the relationship between SUA levels and lumbar spine bone mineral density (BMD) in clinically apparently healthy males aged 40-60 years. We performed a cross-sectional study of 6588 Korean males who completed a health-screening program from January 2011 to December 2014. Of the study participants, the mean age was 48.2 ± 10.7 years. Multiple regression analyses resulted in a significant positive association with lumbar spine BMD across SUA quintiles in a dose-response manner after adjusting for various confounding factors (p = 0.013); for each 1 mg/dl increase of SUA, BMD rose by 0.0054 g/cm² (p = 0.004). Stratified analyses revealed that this association between SUA and lumbar spine BMD was consistently observed across all clinically relevant subgroups. The present study demonstrated a positive association in males between SUA and lumbar spine BMD, suggesting that SUA could have a profitable effect on bone metabolism.

Effects of Consuming Calcium-Rich Foods on the Incidence of Type 2 Diabetes Mellitus

The effect of calcium consumption in the prevention of type 2 diabetes mellitus (T2DM) remains controversial, and depends on food calcium sources. This prospective study aimed to evaluate the association between calcium-rich food consumption and T2DM incidence among Korean adults. We analyzed the data of 8574 adults aged 40⁻69 years, without a history of T2DM, cardiovascular disease, and cancer at the baseline from the Korean Genome and Epidemiology Study. The consumption of calcium-rich foods was assessed using a validated semi-quantitative food frequency questionnaire. T2DM-related data were collected using biennial questionnaires, health examinations, and clinical tests. Hazard ratios (HRs) and 95% confidence intervals (CIs) were calculated using Cox proportional hazards regression models. In the multivariate-adjusted model, yogurt intake was inversely associated with T2DM risk (HR: 0.73; 95% CI: 0.61⁻0.88 in the fourth quartile as compared to the first quartile). However, the intakes of other calcium-rich foods, including milk and anchovies, were not significantly associated with T2DM risk. Yogurt may provide protective effects against T2DM in Korean adults, owing to the beneficial effects of probiotics. Further prospective large-scale cohort studies should be conducted to validate these findings.

Dietary Patterns Related to Triglyceride and High-Density Lipoprotein Cholesterol and the Incidence of Type 2 Diabetes in Korean Men and Women

We aimed to examine whether dietary patterns that explain the variation of triglyceride (TG) to high-density lipoprotein cholesterol (HDL-C) ratio were associated with the incidence of type 2 diabetes in Korean adults. We included a total of 5097 adults without diabetes at baseline with a mean follow-up of 11.54 years. Usual diet was assessed by a validated food frequency questionnaire, and serum levels of TG and HDL-C were measured at baseline. We derived dietary pattern scores using 41 food groups as predictors and the TG/HDL-C ratio as a response variable in a stepwise linear regression. We calculated the odds ratio (OR) with the 95% confidence interval (CI) of type 2 diabetes according to pattern scores using multivariate logistic regression. A total of 1069 incident cases of type 2 diabetes were identified. A list of foods characterizing the dietary pattern differed by sex. Higher dietary pattern scores were associated with an increased risk of type 2 diabetes; ORs (95% CIs) comparing extreme quintiles were 1.53 (1.12–2.09; p for trend = 0.008) for men and 1.33 (0.95–1.86; p for trend = 0.011) for women. Our study suggests the evidence that dietary patterns associated with low levels of TG/HDL-C ratio may have the potential to reduce the burden of type 2 diabetes.

Dietary Patterns Related to Appendicular Skeletal Muscle Mass: The Korea National Health and Nutrition Examination Survey 2008-2011

OBJECTIVE

Muscle mass plays an important role in healthy aging among elderly adults. We investigated the association between dietary patterns and appendicular skeletal muscle mass (ASM) among 3,488 adults ages 60 years or older.

METHODS

The Korea National Health and Nutrition Examination Survey (KNHANES) data for 2008-2011 were analyzed. Dietary information from a food frequency questionnaire was utilized. To identify dietary patterns, factor analysis was performed. Dual-energy x-ray absorptiometry was used to ascertain ASM. To examine the association between dietary patterns and ASM, a multivariable regression model was used after adjusting for potential confounding factors.

RESULTS

Two dietary patterns were identified: Healthy and Western dietary patterns. The Healthy dietary pattern was characterized as high frequencies of intake in vegetables, fish, fruits, seaweeds, legumes, mushrooms, whole grains, potatoes, eggs, dairy products, and red meat. In contrast, the Western dietary pattern was characterized by high intake of red meat, bread, noodles, fast food, rice cake, poultry, and soft drinks. Men showed a significant association between the Healthy dietary pattern and higher ASM, even after adjusting for covariates (p value =0.034).

CONCLUSION

In this cross-sectional study, we observed that men ages 60 years and older with the Healthy dietary pattern had higher muscle mass.

Smoking and Urinary Cotinine Levels Are Predictors of Increased Risk for Gastric Intestinal Metaplasia

Studies on a longitudinal relationship between smoking status and intestinal metaplasia (IM), a premalignant lesion of stomach cancer, are limited. Here we examined the association of smoking status and urinary cotinine levels, an objective measure of smoking, with the development of endoscopic IM. This cohort study included 199,235 Korean adults free of endoscopic IM who underwent upper endoscopy at baseline and subsequent visits and who were followed for up to 6.8 years (median, 3.7 years). Former and current smoking status and pack-years based on self-reports were associated with an increased risk of new-onset IM in men but not in women. However, urinary cotinine levels were positively associated with incident IM in a dose-response manner in both men and women. For men, the multivariable-adjusted HR [95% confidence interval (CI)] for incident IM comparing the urinary cotinine levels of 50 to 99 ng/mL, 100 to 499 ng/mL, and ≥500 ng/mL with <50 ng/mL were 1.20 (0.94-1.55), 1.26 (1.14-1.40), and 1.54 (1.44-1.64), respectively, whereas for women, corresponding HR (95% CI) were 0.75 (0.19-2.99), 1.86 (1.20-2.88), and 1.57 (1.07-2.30), respectively. These associations were observed when changes in smoking status and other confounders were updated during follow-up as time-varying covariates. In this large cohort of young and middle-aged men and women, urinary cotinine levels were independently associated with an increased incidence of endoscopic IM in a dose-response manner. Collectively, these data confirm smoking as an independent risk factor for the development of gastric IM, a precursor lesion of stomach cancer. SIGNIFICANCE: A large-scale cohort study of nearly 200,000 adults associates smoking with increased risk for gastric intestinal metaplasia, a precursor lesion of stomach cancer.

Positive Association between Dietary Inflammatory Index and the Risk of Osteoporosis: Results from the KoGES_Health Examinee (HEXA) Cohort Study

Previous studies have found that diet’s inflammatory potential is related to various diseases. However, little is known about its relationship with osteoporosis. The aim of this study was to investigate the association between the dietary inflammatory index (DII^®) and osteoporosis risk in a large-scale prospective cohort study in Korea. This prospective cohort study included 159,846 participants (men 57,740; women 102,106) from South Korea with a mean follow-up of 7.9 years. The DII was calculated through a validated semi-quantitative FFQ (SQFFQ), and information on osteoporosis was self-reported by the participants. Analyses were performed by using a multivariable Cox proportional hazard model. Higher DII scores were associated with higher osteoporosis risk (HR 1.33; 95% CI 1.12–1.58). In women, a higher DII score indicated a higher risk of osteoporosis (HR 1.33; 95% CI 1.11–1.59). However, a hazards ratio of similar magnitude in men was not significant (HR 1.32; 95% CI 0.64–2.71). Post-menopausal women had higher risks of osteoporosis for higher DII scores (HR 1.33; 95% CI 1.09–1.63), whereas among pre-menopausal women, the relationship was not statistically significant (HR 1.39; 95% CI 0.87–2.21). Also, there was an increase in osteoporosis risk when the DII increased among women participants with irregular physical activity (HR 1.53; 95% CI 1.17–2.01); however, there was no statistically significant increase in osteoporosis risk among women participants with regular physical activity (HR 1.19; 95% CI 0.93–1.52). A more pro-inflammatory diet was significantly associated with higher osteoporosis risk in women. Given the similar magnitude of the hazards ratio, studies with sufficient numbers of men are warranted.

Dietary intake of pantothenic acid is associated with cerebral amyloid burden in patients with cognitive impairment

Alzheimer’s disease (AD) is a neurodegenerative disease characterized by the deposition of amyloid-β peptide (Aβ) in diffuse and neuritic plaques. Previous research has suggested that certain vitamins may prevent this process. In the present study, we evaluated the relationship between vitamin intake and cerebral Aβ burden in patients with cognitive impairment. This study included 19 patients with subjective cognitive impairment and 30 patients with mild cognitive impairment. All patients underwent brain MRI and ¹⁸F-florbetaben positron emission tomography. The Food Frequency Questionnaire was used to evaluate dietary intake of the 15 vitamins. Intake of vitamin B6 (p = 0.027), vitamin K (p = 0.042), vitamin A (p = 0.063), riboflavin (p = 0.063), β-carotene (p = 0.081), pantothenic acid (p = 0.092), and niacin (p = 0.097) was higher in the Aβ-positive group than in the Aβ-negative group. Multivariate linear regression analysis revealed that pantothenic acid intake was an independent determinant of cerebral Aβ burden (β = 0.287, p = 0.029). No significant correlations were observed between cerebral Aβ burden and the intake of other vitamins. Our findings demonstrated that pantothenic acid intake may be associated with increased cerebral Aβ burden in patients with cognitive impairment. These results may offer insight into potential strategies for AD prevention.

Effects of Coffee Intake on Incident Chronic Kidney Disease: A Community-Based Prospective Cohort Study

BACKGROUND

Drinking coffee can raise public health problems, but the association between coffee and kidney disease is unknown. We studied whether coffee intake can affect the development of chronic kidney disease in the general population.

METHODS

We analyzed 8717 subjects with normal renal function recruited from the Korean Genome and Epidemiology Study (KoGES) cohort. Based on a food frequency questionnaire, coffee consumption was categorized into 5 groups: 0 per week, <1 cup per week, 1-6 cups per week, 1 cup per day, and ≥2 cups per day. The primary outcome was incident chronic kidney disease, defined as an estimated glomerular filtration rate <60 mL/min/1.73 m².

RESULTS

The mean age (standard deviation) of study subjects was 52.0 (8.8) years, and 47.8% were male. Among the subjects, 52.8% were daily coffee consumers. During a mean follow-up of 11.3 (range, 5.9-11.5) years, 9.5% of participants developed chronic kidney disease. The incident chronic kidney disease occurred less in daily coffee consumers. Unadjusted hazard ratios (HRs) was significantly lower in daily coffee consumers. In multivariable Cox model even after adjustment of blood pressure, hypertension, cardiovascular disease, diabetes, and amount of daily intake for caffeine-containing foods such as tea and chocolate, coffee consumers with 1 cup per day (HR, 0.76; 95% confidence interval, 0.63-0.92) and ≥2 cups per day (HR, 0.80; 95% confidence interval, 0.65-0.98) were associated with a lower risk of chronic kidney disease development than nondrinkers. Time-averaged and time-varying Cox models yielded similar results. The rates of decline in glomerular filtration were lower in daily coffee consumers.

CONCLUSIONS

Our findings suggest that daily coffee intake is associated with decreased risk of the development of chronic kidney disease.

Association between dietary cadmium intake and early gastric cancer risk in a Korean population: a case-control study

PURPOSE

Foods such as grains and vegetables are the dominant sources of exposure to cadmium, which has been classified as a carcinogen by various public health agencies. Cadmium exposure is a growing concern due to its associations with numerous harmful health effects, including gastric cancer risk. The objective of this study was to investigate the association of dietary cadmium intake and the consumption of cadmium-contributing foods with early gastric cancer risk.

METHODS

A case-control study including 1245 subjects (cases, 415; controls, 830) was conducted in Korea. The dietary cadmium intake and the consumption of cadmium-contributing foods were assessed using a semi-quantitative food frequency questionnaire.

RESULTS

After adjustment for covariates, the gastric cancer risk was increased for participants in the highest tertile of cadmium intake [odds ratios (ORs) 1.33, 95% confidence intervals (95% CIs) 0.94-1.88], but there was no significance. Both female (ORs 2.71, 95% CIs 1.37-5.36) and male (ORs 1.63, 95% CIs 1.07-2.50) participants in the highest tertile of rice consumption had a higher gastric cancer risk than did those in the lowest tertile. Men in the highest tertile of crab consumption had a gastric cancer risk 2.23 times greater than that of men in the lowest tertile (ORs 2.23, 95% CIs 1.21-4.13), but a difference was not seen in women.

CONCLUSIONS

Future studies examining the causal effects of dietary cadmium intake and the consumption of cadmium-contributing foods on early gastric cancer risk in large-scale prospective cohorts are recommended.

Prolonged sitting increases the risk of gallstone disease regardless of physical activity: a cohort study

OBJECTIVES

We aimed to examine the relationship between sitting time and the development of ultrasonography-diagnosed gallstone disease (GSD) in young and middle-aged Korean men and women.

MATERIAL AND METHODS

We conducted a cohort study of 147,237 participants without GSD at baseline who underwent a health checkup examination between 2011 and 2015 and were followed annually or biennially until December 2016. Sitting time and physical activity were measured using the validated Korean version of the international physical activity questionnaire short form. GSD was defined as either having had a cholecystectomy or having gallstones based on ultrasound.

RESULTS

During 486,376 person-years of follow-up, 2382 incident GSD cases were identified. Both prolonged sitting time and inactive physical activity had a significant independent association with the increased risk of GSD. The multivariate-adjusted hazard ratios (95% confidence interval for GSD comparing sitting times of 5-9 and ≥10 h/day with the sitting time of <5 h/day were 1.08 (0.97-1.21) and 1.15 (1.02-1.29), respectively (p for trend = .023). The multivariate-adjusted hazard ratios (95% CIs) for GSD in both the inactive and the minimally active groups compared with HEPA group were 1.22 (1.08-1.38) and 1.13 (0.99-1.28, respectively (p for trend = .001).

CONCLUSION

This study demonstrated that sitting time may be associated with GSD risk regardless of physical activity. The findings of this study suggest that both increasing participation in physical activity and reducing sitting time may be independently important in reducing the risk of GSD.

Association between Genetic Variant of Apolipoprotein C3 and Incident Hypertension Stratified by Obesity and Physical Activity in Korea

Apolipoprotein C3 (APOC3) is an important regulator of lipoprotein metabolism, and has been shown to be strongly associated with hypertriglyceridemia. We tested whether triglyceride-influencing genetic variants at APOC3 (T-455C, C-482T, C1100T, and SstI) are associated with the onset of hypertension (HTN) among Korean adults stratified by lifestyle-related factors in the Ansung–Ansan cohort within the Korean Genome and Epidemiology Study. After excluding participants with preexisting cancer, cardiovascular diseases, diabetes, and HTN, a total of 5239 men and women were included at baseline (2001–2002), and followed up for a median of 9.8 years. Carriers of the C allele of C1100T with body mass index <25 kg/m² showed a significantly lower HTN risk (hazard ratio (HR) than non-carriers: 0.87, 95% confidence interval (CI): 0.77–0.98) after adjusting for covariates. In addition, carriers of the C allele of T-455C and the T allele of C-482T with low physical activity had lower incident HTN than non-carriers (HR: 1.14, 95% CI: 1.03–1.26; HR: 1.13, 95% CI: 1.02–1.25). Our results suggest that genotype effects in APOC3 on HTN risk have been shown in lean carriers of the C allele of C1100T and in less active people having the C allele of T-455C and T allele of C-482T in a large sample of the Korean population.

Genetic Risk Score, Combined Lifestyle Factors and Risk of Colorectal Cancer

Purpose

Both genetic and lifestyle factors contribute to the risk of colorectal cancer, but each individual factor has a limited effect. Therefore, we investigated the association between colorectal cancer and the combined effects of genetic factors or/and lifestyle risk factors.

Materials and Methods

In a case-control study of 632 colorectal cancer patients and 1,295 healthy controls, we quantified the genetic risk score for colorectal cancer using 13 polymorphisms. Furthermore, we determined a combined lifestyle risk score including obesity, physical activity, smoking, alcohol consumption, and dietary inflammatory index. The associations between colorectal cancer and risk score using these factors were examined using a logistic regression model.

Results

Higher genetic risk scores were associated with an increased risk of colorectal cancer (odds ratio [OR], 2.57; 95% confidence interval [CI], 1.89 to 3.49 for the highest tertile vs. lowest tertile). Among the modifiable factors, previous body mass index, physical inactivity, heavy alcohol consumption, and a high inflammatory diet were associated with an increased risk of colorectal cancer. A higher lifestyle risk score was associated with an increased risk of colorectal cancer (OR, 5.82; 95% CI, 4.02 to 8.44 for the highest tertile vs. lowest tertile). This association was similar in each genetic risk category.

Conclusion

Adherence to a healthy lifestyle is associated with a substantially reduced risk of colorectal cancer regardless of individuals’ genetic risk.

An association of urinary sodium-potassium ratio with insulin resistance among Korean adults

BACKGROUND/OBJECTIVES

This study was conducted to investigate the effects of sodium-potassium ratio on insulin resistance and sensitivity in Korean adults.

SUBJECTS/METHODS

Subjects were 3,722 adults (1,632 men and 2,090 women) aged 40-69 years participating in the Korean genome and epidemiology study_Ansan and Ansung study. Insulin resistance was assessed using homeostasis model assessment of insulin resistance (HoMA-IR) and fasting insulin, and insulin sensitivity was assessed by using the quantitative insulin sensitivity check index (QUICKI). The 24-h urinary sodium and potassium excretion were estimated from spot urinary samples using the Tanaka formula. The generalized linear model was applied to determine the association between urinary sodium-potassium ratio and insulin resistance.

RESULTS

HoMA-IR (P-value = 0.029, P-trend = 0.008) and fasting insulin (P-value = 0.017, P-trend = 0.005) levels were positively associated with 24-h estimated urinary sodium-potassium ratio in the multivariable model. QUICKI was inversely associated with 24-h estimated urinary sodium-potassium ratio in all models (P-value = 0.0002, P-trend < 0.0001 in the multivariate model).

CONCLUSION

The present study suggests that high sodium-potassium ratio is related to high insulin resistance and low insulin sensitivity. Decreasing sodium intake and increasing potassium intake are important for maintaining insulin sensitivity. Further studies are needed to confirm these findings in longitudinal studies.

Physical Activity and Gastric Cancer Risk in Patients with and without Helicobacter pylori Infection in A Korean Population: A Hospital-Based Case-Control Study

Although physical activity (PA) is beneficial for prolonging lifespan, evidence for the protective role of PA against the development of gastric cancer (GC) is not yet well established. This study assessed the association between PA and GC risk in patients with and without Helicobacter pylori (H. pylori) infection in a Korean population. In total, 415 GC patients and 830 controls were enrolled at the National Cancer Center, Korea. The International Physical Activity Questionnaire-Short Form was used to collect PA data. The odds ratios (ORs) and 95% confidence intervals (CIs) were estimated using unconditional logistic regression models. In the H. pylori-positive group, subjects who engaged in regular exercise showed a significantly reduced risk of GC in the entire population (OR = 0.52, 95% CI = 0.38⁻0.70) and in females (OR = 0.60, 95% CI = 0.21⁻0.64). Subjects who engaged in a high level of total PA showed a significantly reduced risk of GC relative to subjects in the lowest tertile in the fully adjusted model (OR = 0.46, 95% CI = 0.32⁻0.65, p-trend < 0.001). There was an inverse association between PA and GC risk in the entire population, and in the H. pylori-positive subgroup. Our data indicate the need for the promotion of all domains of PA, especially for Korean populations.

High dairy products intake reduces osteoporosis risk in Korean postmenopausal women: A 4 year follow-up study

BACKGROUND/OBJECTIVES

The aim of this study was to identify the effect of dairy products, milk and yogurt on osteoporosis incidence among Korean postmenopausal women using prospective cohort data.

MATERIALS/METHODS

Between 2001 and 2003, 10,038 participants were recruited in rural and urban areas for a baseline examination of a community-based cohort study. Of those, 1,573 postmenopausal women (aged 40–69 years at baseline) were eligible for the present study. Intakes of dairy products, milk, and yogurt were assessed using a validated semi-quantitative food frequency questionnaire. The speed of sound at the radius and tibia were measured using a quantitative ultrasound device and osteoporosis was defined based on the WHO criteria (T-score ≤ −2.5).

RESULTS

During the 4-years follow-up study, the cumulative incidence of osteoporosis was 18.4% (273 cases) in the radius and 33.6% (407 cases) in the tibia. The subjects with higher frequency of dairy product consumption showed a decreased risk of radius osteoporosis after adjusting for potential confounders [hazard ratio (HR) = 0.51, 95% confidence interval (CI): 0.33–0.80 for >1 time/day vs. non consumer; P for trend = 0.0027]. Similarly, high frequency of milk and yogurt consumption had a protective effect on radius osteoporosis risk [milk: HR = 0.60, 95% CI: 0.42–0.87 for > 5–6 times/week vs. non consumer (P for trend = 0.0130), yogurt: HR = 0.51, 95% CI: 0.30–0.85 for > 5–6 times/week vs. non consumer (P for trend = 0.0167)]. However, high dairy products consumption was not related with tibia osteoporosis.

CONCLUSIONS

This study suggests that daily intake of dairy products could potentially reduce radius osteoporosis incidence among Korean postmenopausal women.

Habitual consumption of soy protein and isoflavones and risk of metabolic syndrome in adults ≥ 40 years old: a prospective analysis of the Korean Multi-Rural Communities Cohort Study (MRCohort)

PURPOSE

Although considerable attention has been paid to the potential benefits of soy protein and isoflavones for preventing metabolic syndrome (MetS) and its components, findings linking habitual consumption of these factors to MetS are limited. This study aimed to evaluate the association of MetS incidence with habitual intake of soy protein/isoflavones among Korean men and women aged ≥ 40 years old who did not have MetS at baseline (n = 5509; 2204 men and 3305 women).

METHODS

Dietary intake of soy protein/isoflavones at baseline and average consumption during follow-up were used.

RESULTS

A significant inverse association between dietary intake and incidence of MetS was found in women (incidence rate ratios, IRR = 0.60, 95% CI = 0.46-0.78, P for trend = 0.0094 for the highest quintile of average soy protein intake compared with the lowest quintile; IRR = 0.57, 95% CI = 0.44-0.74, P for trend = 0.0048 for the highest quintile of average isoflavones intake compared with the lowest quintile). A tendency towards an inverse association was also found in men, although it was not significant for the highest quintile (IRR = 0.80, 95% CI = 0.58-1.11, P for trend = 0.9759, comparing the lowest to the highest quintile of average soy protein intake; IRR = 0.73, 95% CI = 0.53-1.01, P for trend = 0.8956, comparing the lowest to the highest quintile of average isoflavones intake). In terms of individual abnormalities, a significant inverse association was found between soy protein and isoflavones and the incidence of low-high-density lipoprotein cholesterol in both men and women. Abdominal obesity and elevated blood pressure were inversely related to soy protein/isoflavones only in women, and an inverse association of elevated triglyceride appeared only in men.

CONCLUSION

Our findings suggest that habitual intake of soy protein and isoflavones is inversely associated with the risk of MetS and its components. There is likely to be a reverse J-shaped association of average intake with MetS.

Relationship between skeletal muscle mass and lung function in Korean adults without clinically apparent lung disease

Previous studies have demonstrated that low skeletal muscle mass is related to decreased lung function in patients with chronic obstructive pulmonary disease. However, there is little information about the relationship between skeletal muscle mass and lung function in asymptomatic adults without clinically apparent lung disease.This was a cross-sectional study of 240,562 Korean adults without known lung disease. All subjects underwent both pulmonary function test (PFT) and bioelectrical impedance analysis in the health checkup program at Kangbuk Samsung Hospital. Skeletal muscle mass index (SMI) was estimated as skeletal muscle mass/weight×100. We analyzed the relationship between SMI and PFT using multivariate logistic regression models.Of the 240,562 study subjects, values for forced vital capacity (FVC), forced expiratory volume in 1 second (FEV1), and peak expiratory flow (PEF) were decreased across quartiles (Qs) of decreasing SMI. After adjustments for various confounders including demographic and health behavior-related factors, odds ratios (ORs; 95% confidence interval) for subjects with FVC% <80% for Q1-Q3 compared with Q4 (reference) were 2.97 (2.74-3.17), 2.11 (1.99-2.27), and 1.66 (1.52-1.83), respectively. ORs for subjects with FEV1% <80% for Q1-Q3 compared with Q4 were 2.64 (2.43-2.83), 1.96 (1.83-2.09), and 1.51 (1.43-1.62), respectively. Lastly, OR for subjects with PEF% <80% for Q1-Q3 compared with Q4 were 1.73 (1.58-1.89), 1.35 (1.26-1.45), and 1.23 (1.15-1.30), individually. Subgroup analyses for gender and all age groups showed the associations of decreasing SMI Qs with lower FVC%, FEV1%, and PEF% remained significant.Decreased SMI was independently associated with decline in lung function in apparently healthy adults. This association was sustained in subgroup analyses by gender and all age groups.

Physical activity and impaired left ventricular relaxation in middle aged adults

The aim of this study was to examine the relationship between physical activity level and impaired left ventricular (LV) relaxation in a large sample of apparently healthy men and women. We conducted a cross-sectional study in 57,449 adults who underwent echocardiography as part of a comprehensive health examination between March 2011 and December 2014. Physical activity level was assessed using the Korean version of the International Physical Activity Questionnaire Short Form. The presence of impaired LV relaxation was determined based on echocardiographic findings. Physical activity levels were inversely associated with the prevalence of impaired LV relaxation. The multivariable-adjusted odds ratios (95% confidence interval) for impaired LV relaxation comparing minimally active and health-enhancing physically active groups to the inactive group were 0.84 (0.77–0.91) and 0.64 (0.58–0.72), respectively (P for trend < 0.001). These associations were modified by sex (p for interaction <0.001), with the inverse association observed in men, but not in women. This study demonstrated an inverse linear association between physical activity level and impaired LV relaxation in a large sample of middle-aged Koreans independent of potential confounders. Our findings suggest that increasing physical activity may be independently important in reducing the risk of impaired LV relaxation.

Diet-Related Risk Factors for Incident Hypertension During an 11-Year Follow-Up: The Korean Genome Epidemiology Study

Using long-term follow-up cohort data from the Korean Genome Epidemiology Study, we assessed the dietary risk factors for incident hypertension (HTN). In total, 6792 subjects (3300 males and 3492 females) aged 40⁻69 years were included in the study. Physician-diagnosed HTN self-reported by the participants was used as the outcome. Daily intake of 20 food groups was assessed while using a dish-based semi-quantitative food-frequency questionnaire. After controlling for known risk factors, the food groups that were most closely associated with HTN were identified by forward stepwise selection while using the Cox proportional hazards model. The median follow-up period was 11.5 years (interquartile range, 6.0⁻11.7 years) and the incidence of HTN was 20 per 1000 person-years. Older age, obesity, lower education level, high alcohol intake, and having at least one parent with HTN were associated with the risk for HTN. In addition, a high intake of salted seafood and a low intake of eggs and meat were independently associated with the incidence of HTN after controlling for the known risk factors. Those in the top quartile of salted seafood intake had a 28% greater risk for incident HTN than those in the bottom quartile. The population-attributable fraction of three dietary factors accounted for 29.0% of the incidence of HTN. A high intake of salted seafood and a low intake of eggs and meat were associated with a greater risk for HTN.

Dietary Carotenoids Intake and the Risk of Gastric Cancer: A Case-Control Study in Korea

Although the incidence of gastric cancer (GC) has declined, it remains the second most common cancer in Korea. As a class of phytochemicals, carotenoids are fat-soluble pigments that are abundant in fruits and vegetables and have health-promoting properties, including cancer prevention effects. This case-control study investigated the effects of total dietary carotenoids, dietary carotenoid subclasses (α-carotene, β-carotene, β-cryptoxanthin, lutein/zeaxanthin, and lycopene), and foods contributing to the dietary intake of each carotenoid on the risk of GC. Four hundred and fifteen cases and 830 controls were recruited from the National Cancer Center Hospital in Korea between March 2011 and December 2014. A significant inverse association between total dietary carotenoids and GC risk was observed among women (odds ratio (OR) 0.56, 95% confidence interval (CI) 0.32⁻0.99). A higher intake of dietary lycopene was inversely associated with GC risk overall in the subjects (OR 0.60, 95% CI 0.42⁻0.85, p for trend = 0.012), men (OR 0.60, 95% CI 0.39⁻0.93), and women (OR 0.54, 95% CI 0.30⁻0.96, p for trend = 0.039). This significant association between dietary lycopene intake and GC risk was also observed in the subgroups of Helicobacter pylori (H. pylori)-positive subjects and those who had ever smoked. Among the major contributing foods of dietary lycopene, consumption of tomatoes and tomato ketchup was inversely associated with GC risk in the overall subjects, men, and women. Based on our findings, a higher intake of dietary lycopene and contributing foods of lycopene (tomatoes and tomato ketchup) may be inversely associated with the risk of GC.

Genome-wide profiling of normal gastric mucosa identifies Helicobacter pylori- and cancer-associated DNA methylome changes

The large geographic variations in the incidence of gastric cancer (GC) are likely due to differential environmental exposures, in particular to Helicobacter pylori (H. pylori) infection. We aimed to investigate the impact of H. pylori on the epigenome in normal gastric mucosa and methylation changes associated with cancer risk independent of H. pylori. A discovery set of normal gastric mucosa from GC cases (n = 42) and controls (n = 42), nested in a large case-control study and stratified by H. pylori status, were subjected to genome-wide methylation profiling. Single-nucleotide polymorphism arrays from peripheral blood leukocytes were used to conduct methylation quantitative trait loci (mQTL) analysis. A validation set of gastric mucosa samples (n = 180) was used in the replication phase. We found 1,924 differentially methylated positions (DMPs) and 438 differentially methylated regions (DMRs) associated with H. pylori infection, most of which were hypermethylated. Significant methylation alterations identified in the initial set were successfully replicated. Furthermore, the H. pylori-associated DMP/Rs showed marked stability ('epigenetic memory') after H. pylori clearance. Interestingly, we found 152 DMRs associated with cancer risk independent of the H. pylori status in normal gastric mucosa. The methylation score derived from three biomarkers was a strong predictor of GC. Finally, the mQTL analysis indicated that the H. pylori- and cancer-specific methylation signatures were minimally affected by genetic variation. The comprehensively characterized methylome changes associated with H. pylori infection and GC risk in our study might serve as potential biomarkers for early cancer progression in tumour-free gastric mucosa.

Effects of processed red meat consumption on the risk of type 2 diabetes and cardiovascular diseases among Korean adults: the Korean Genome and Epidemiology Study

PURPOSE

Few studies have evaluated the effects of processed red meat (PRM) consumption on chronic disease risk, especially among low average PRM consumption populations. This study examined association between PRM intake and type 2 diabetes mellitus (T2DM) and cardiovascular disease (CVD) incidences in Korea.

METHODS

Participants (n = 10,030; aged 40-69 years) were recruited from the Ansan-Ansung cohort study, a subset of Korean Genome Epidemiology Study. Validated 103-item semi-quantitative food frequency questionnaire was used to assess dietary information, at baseline (2001-2002) and at second follow-up (2005-2006). T2DM and CVD incidences were identified using biennial questionnaire-based interview during a 10-year follow-up period. Cox proportional hazards regression analysis was used to calculate multivariable-adjusted hazard ratios (HRs) and 95% confidence intervals (CIs).

RESULTS

Over the 10-year follow-up period, 668 and 493 incident cases of T2DM (62,130 person-years) and CVD (63,150 person-years), respectively, were documented. In crude models, comparing the highest and lowest levels of PRM intake, no significant association occurred with incident T2DM [HR, 95% CI (0.94, 0.76-1.17)], while significant association occurred with incident CVD (0.67, 0.51-0.88). However, in adjusted models, this association was no longer significant, showing HRs (95% CI) of PRM intake for T2DM and CVD of 1.07 (0.85-1.35) and 1.14 (0.85-1.55), respectively.

CONCLUSIONS

PRM intake did not affect T2DM and CVD incidences among Korean middle-aged adults, although extremely low average consumption of PRM may explain the finding. Therefore, limiting PRM intake may not be a top priority for the prevention of chronic diseases in Korean population.

Egg consumption is associated with a lower risk of type 2 diabetes in middle-aged and older men

BACKGROUND/OBJECTIVES

This prospective study examined gender-specific associations between egg intake and the risk of developing type 2 diabetes using data from a large-scale cohort study.

SUBJECTS/METHODS

A total of 7,002 Korean adults (40–69 years) without type 2 diabetes at baseline were analyzed. Dietary intake was evaluated by a food frequency questionnaire administered at baseline (2001–2002) and the second follow-up examination (2005–2006). Type 2 diabetes was diagnosed as a fasting glucose concentration ≥ 126 mg/dL or current use of glucose-lowering medications or insulin injection. Multivariate Cox proportional hazard models were used to calculate hazard ratios (HRs) with 95% confidence intervals (CIs) for incident type 2 diabetes according to egg consumption or cholesterol intake.

RESULTS

During a 14-year follow up period, 857 subjects developed type 2 diabetes. In men, frequent egg intake (2- < 4 servings/week) was associated with a 40% lower risk of developing type 2 diabetes than infrequent egg intake (0- < 1 serving/week) (HR = 0.60, 95% CI: 0.37–0.97), whereas no association between egg intake and incidence of type 2 diabetes was observed in women (HR = 0.61, 95% CI: 0.27–1.37). There was no association between cholesterol intake and risk of incident type 2 diabetes in either men or women.

CONCLUSIONS

Egg consumption was inversely related to the risk of incident type 2 diabetes in men, but not in women, suggesting gender differences in the relationship between diet and disease risk.

Risk of Metabolic Syndrome among Middle-Aged Koreans from Rural and Urban Areas

Metabolic syndrome (MetS) is a common global health problem. This study aims to assess nutrient intake and risk of MetS in middle-aged Koreans based in residential areas. Participants were 161,326 (142,137 in urban and 19,189 in rural) subjects enrolled in the Korea Genome and Epidemiology Study. The prevalence of MetS was much higher in rural (39.8%) than that in urban (22.5%) subjects (p < 0.001). The rural residents showed significantly higher blood pressure (p < 0.001), serum triglyceride levels (p < 0.001), and LDL (Low density lipoprotein)-cholesterol level (p < 0.001), as well as the odds ratio (OR) for MetS (OR = 1.65, 95% CI: 1.59⁻1.71), compared to urban residents. The rural subjects showed a higher consumption of carbohydrate and sodium compared to the urban subjects (p < 0.001). After adjusting for potential confounders, subjects in the highest quartile of carbohydrate intake had higher OR for MetS (OR = 1.23, 95% CI: 1.15⁻1.32) and those in the highest quartile of sodium intake had a higher chance of having MetS (OR = 1.11, 95% CI: 1.07⁻1.16) than did those in the lowest quartiles. Our results suggested that the higher consumption of carbohydrate and sodium in rural residents might be associated with the increased risk of MetS in this population.

Inflammatory Dietary Pattern, IL-17F Genetic Variant, and the Risk of Colorectal Cancer

A proinflammatory diet may increase the risk of colorectal cancer, but its role may differ according to individuals’ genetic variants. We aimed to examine whether a specific dietary pattern reflecting inflammation was associated with a risk of colorectal cancer and whether IL-17F genetic variant altered this association. In a study of 695 colorectal cancer cases and 1846 controls, we derived a reduced rank regression dietary pattern using 32 food groups as predictors and the plasma C-reactive protein (CRP) concentration as the response. High CRP levels were associated with a high risk of colorectal cancer (OR (95% CI) = 3.58 (2.65–4.82) for the highest quartile vs. lowest quartile). After adjusting for potential confounding factors, high pattern scores were associated with a high risk of colorectal cancer (OR (95% CI) = 9.98 (6.81–14.62) for the highest quartile vs. lowest quartile). When stratified by the IL-17F rs763780 genotype, this association was stronger for individuals carrying the C allele (p for interaction = 0.034), particularly for individuals with rectal cancer (p for interaction = 0.011). In conclusion, a dietary pattern reflecting inflammation was significantly associated with colorectal cancer risk. Moreover, this association could be modified according to the IL-17F rs763780 genotype and anatomic site.

An association between diet quality index for Koreans (DQI-K) and total mortality in Health Examinees Gem (HEXA-G) study

BACKGROUND/OBJECTIVES

Diet quality scores or indices, based on dietary guidelines, are used to summarize dietary intake into a single numeric variable. The aim of this study was to examine the association between the modified diet quality index for Koreans (DQI-K) and mortality among Health Examinees-Gem (HEXA-G) study participants.

SUBJECTS/METHODS

The DQI-K was modified from the original diet quality index. A total of 134,547 participants (45,207 men and 89,340 women) from the HEXA-G study (2004 and 2013) were included. The DQI-K is based on eight components: 1) daily protein intake, 2) percent of energy from fat, 3) percent of energy from saturated fat, 4) daily cholesterol intake, 5) daily whole-grain intake, 6) daily fruit intake, 7) daily vegetable intake, and 8) daily sodium intake. The association between all-cause mortality and the DQI-K was examined using Cox proportional hazard regression models. Hazard ratios and confidence intervals were estimated after adjusting for age, gender, income, smoking status, alcohol drinking, body mass index, and total energy intake.

RESULTS

The total DQI-K score was calculated by summing the scores of the eight components (range 0–9). In the multivariable adjusted models, with good diet quality (score 0–4) as a reference, poor diet quality (score 5–9) was associated with an increased risk of all-cause mortality (hazard ratios = 1.23, 95% confidence intervals = 1.06–1.43). Moreover, a one-unit increase in DQI-K score resulted in a 6% higher mortality risk.

CONCLUSIONS

A poor diet quality DQI-K score was associated with an increased risk of mortality. The DQI-K in the present study may be used to assess the diet quality of Korean adults.

Serum metabolite profile associated with incident type 2 diabetes in Koreans: findings from the Korean Genome and Epidemiology Study

The identification of metabolic alterations in type 2 diabetes (T2D) is useful for elucidating the pathophysiology of the disease and in classifying high-risk individuals. In this study, we prospectively examined the associations between serum metabolites and T2D risk in a Korean community-based cohort (the Ansan-Ansung cohort). Data were obtained from 1,939 participants with available metabolic profiles and without diabetes, cardiovascular disease, or cancer at baseline. The acylcarnitine, amino acid, amine, and phospholipid levels in fasting serum samples were analyzed by targeted metabolomics. During the 8-year follow-up period, we identified 282 cases of incident T2D. Of all metabolites measured, 22 were significantly associated with T2D risk. Specifically, serum levels of alanine, arginine, isoleucine, proline, tyrosine, valine, hexose and five phosphatidylcholine diacyls were positively associated with T2D risk, whereas lyso-phosphatidylcholine acyl C17:0 and C18:2 and other glycerophospholipids were negatively associated with T2D risk. The associated metabolites were further correlated with T2D-relevant risk factors such as insulin resistance and triglyceride indices. In addition, a healthier diet (as measured by the modified recommended food score) was independently associated with T2D risk. Alterations of metabolites such as amino acids and choline-containing phospholipids appear to be associated with T2D risk in Korean adults.

Association between Dietary Mineral Intake and Chronic Kidney Disease: The Health Examinees (HEXA) Study

Few studies have explored the association between mineral intake and chronic kidney disease (CKD). A cross-sectional analysis investigated the association between mineral intake (calcium, phosphorus, sodium, potassium, iron, and zinc) and CKD using the Health Examinee (HEXA) cohort of the Korean Genome and Epidemiologic Study (KoGES). For 159,711 participants, mineral intake was assessed by a food frequency questionnaire. CKD was defined as an estimated glomerular filtration rate (eGFR) of less than 60 mL/min/1.73 m². Dietary intake of each mineral was divided into quartiles and the quartile including recommended dietary allowance (RDA) or adequate intake (AI) of each mineral was used as a reference. We assessed the association between the quartile of mineral intakes and CKD using polytomous logistic regression models. The lowest quartiles of phosphorus (≤663.68 mg/day, odds ratio [OR] = 1.64, 95% confidence interval [CI]: 1.25–2.15), potassium (≤1567.53 mg/day, OR = 1.87, 95% CI: 1.27–2.75), iron (≤6.93 mg/day, OR = 1.53, 95% CI: 1.17–2.01), and zinc (≤5.86 mg/day, OR = 1.52, 95% CI: 1.02–2.26) were associated with higher odds for advanced CKD compared with the references. The present study suggests that an inadequate intake of some minerals may be associated with CKD occurrence in the general population. Due to the reverse causation issue in this cross-sectional study design, further longitudinal prospective studies are needed in order to prove the results.

Carrying minor allele of FADS1 and haplotype of FADS1 and FADS2 increased the risk of metabolic syndrome and moderate but not low fat diets lowered the risk in two Korean cohorts

PURPOSE

Delta-5-desaturase (fatty acid desaturase-1, FADS1) and delta-6 desaturase (fatty acid desaturase-2, FADS2), rate-limiting enzymes in the biosynthesis of long-chain polyunsaturated fatty acids, may be associated with the risk of metabolic syndrome (MetS). We investigated how FADS1 rs174547 and FADS2 rs2845573 variants modify the prevalence of MetS and whether the risk is modulated by interactions with dietary fat.

METHODS

Genetic, anthropometric, biochemical, and dietary data were collected from the Ansan/Ansung (8842 adults) and City-Rural (5512 adults) cohorts in Korea. The association between FADS1 rs174547(C/T) and FADS2 rs2845573(C/T) variants and MetS was analyzed, as was the interaction of genotypes and fatty acid intake and the risk of MetS after adjusting for MetS-related confounders.

RESULTS

Carriers of FADS1 rs174547 and FADS2 rs2845573 minor alleles had lower serum HDL-cholesterol and glucose levels and higher triglyceride levels than those with major alleles. Ansan/Ansung cohort individuals with FADS1 minor alleles or haplotypes of FADS1 and FADS2 minor alleles had increased risk of MetS, including lower serum HDL-cholesterol and triglyceride levels and blood pressure after adjusting for MetS-related confounders. The City-Rural cohort showed similar results. Total fat intake showed interactions with FADS1 and haplotype variants on MetS risk: MetS frequency was reduced in people consuming moderate fat diets as compared to low fat diets in FADS1 and haplotype of FADS1 and FADS2 major alleles.

CONCLUSION

Korean carriers of the FADS1 rs174547 and FADS2 rs2845573 minor alleles have a greater susceptibility to MetS and moderate fat intake protected against the risk of MetS in carriers of the FADS1 major alleles.

High sodium intake and sodium to potassium ratio may be linked to subsequent increase in vascular damage in adults aged 40 years and older: the Korean multi-rural communities cohort (MRCohort)

PURPOSE

Subclinical vascular damage is a chronic intermediate process in cardiovascular disease (CVD) and high sodium (Na) has been regarded as an adverse factor in subclinical vascular health; however, the longitudinal relationship between Na intake and subclinical vascular damage has not been studied. We aimed to evaluate the longitudinal relationship of dietary Na intake and sodium to potassium ratio (Na:K) with brachial-ankle pulse wave velocity (baPWV) and carotid intima media thickness (cIMT) in healthy adults aged 40 years and older in Korea.

METHODS

The present study was based on participants (n = 2145 for baPWV analysis and n = 2494 for cIMT analysis) who visited three times during 2005-2013 (median 5.3 years of follow-up). We used both dietary Na intake and Na:K at baseline and its average (baseline, 2nd, 3rd), which was obtained from food frequency questionnaire (FFQ) as exposure at every visit. baPWV and cIMT levels at the third visit and change from baseline to the third visit were used to represent the level of subclinical vascular damage.

RESULTS

After adjustment for potential confounders, significant positive relationships between dietary Na intake and both baPWV_3rd and cIMT_3rd were observed (baPWV: p for trend ≤ 0.0001 for Na_average; cIMT: p for trend = 0.013 for Na_average). Compared with Na:Ks less than 1.0, the levels of both baPWV and cIMT were higher for participants with Na:Ks over 1.0 (baPWV: p for trend = 0.0002 for Na:K_average; cIMT: p for trend = 0.005 for Na:K_average). Similar significant trends were shown in relationships between dietary Na intake and Na:K and changes in baPWV and cIMT levels.

CONCLUSIONS

In conclusion, dietary Na intake and Na:K may be positively linked to subsequent baPWV and cIMT levels in adults aged 40 years and older in Korea. Our findings may provide informative evidence on subclinical vascular damage, particularly for populations with relatively high dietary Na intake and low dietary K intake.

Prevalence of Fructose Malabsorption in Patients With Irritable Bowel Syndrome After Excluding Small Intestinal Bacterial Overgrowth

Background/Aims

Fructose malabsorption (FM) mimics symptoms of irritable bowel syndrome (IBS), and its prevalence has increased. Diagnosing FM in IBS is challenging because of its overlap with small intestinal bacterial overgrowth (SIBO). We assessed the prevalence of FM by comparing patients with IBS with asymptomatic control individuals after excluding SIBO using the glucose hydrogen breath test (HBT).

Methods

Patients diagnosed with IBS and asymptomatic control individuals were enrolled prospectively. Dietary habits were assessed with the Food Frequency Questionnaire. After excluding SIBO, participants underwent HBTs with both 15 g and 25 g of fructose.

Results

Thirty-five patients with IBS and 35 age- and sex-matched asymptomatic control individuals were enrolled. The 15-g fructose HBT yielded positive results in 7 of the 35 (20.0%) patients with IBS and in 2 of 35 (5.7%) controls (P = 0.070). The 25-g fructose HBT was positive in 16 of the 35 (45.7%) patients with IBS and in 8 of the 35 (22.9%) controls (P = 0.040). Analysis of the Food Frequency Questionnaire responses showed no significant differences between the 2 groups in dietary intake, although patients with IBS showed a significantly higher mean fiber intake than controls (21.24 ± 11.35 g vs 15.87 ± 7.07 g, respectively, P = 0.040).

Conclusions

The 25-g fructose HBT identified FM in a significantly higher percentage of SIBO-negative patients with IBS than in asymptomatic control individuals, suggesting that FM may correlate with IBS. Education regarding dietary control of foods containing fructose may be useful for the management of patients with IBS.