Cohort Profile: The Namwon Study and the Dong-gu Study

Association between reproductive factors with lung cancer incidence and mortality: A pooled analysis of over 308,000 females in the Asia cohort consortium

Previous studies have investigated the association between reproductive factors and lung cancer risk; however, findings have been inconsistent. In order to assess this association among Asian women, a total of 308,949 female participants from 11 prospective cohorts and four Asian countries (Japan, Korea, China, and Singapore) were included. Cox proportional hazards regression models were used to estimate the hazard ratios (HR) and 95% confidence intervals (CIs). A total of 3,119 primary lung cancer cases and 2247 lung cancer deaths were identified with a mean follow-up of 16.4 years. Parous women had a lower risk of lung cancer incidence and mortality as compared with nulliparous women, with HRs of 0.82 (95% CI = 0.70-0.96) and 0.78 (95% CI = 0.65-0.94). The protective association of parity and lung cancer incidence was greater among ever-smokers (HR = 0.66, 95% CI = 0.49-0.87) than in never-smokers (HR = 0.90, 95% CI = 0.74-1.09) (P-interaction = 0.029). Compared with age at first delivery ≤20 years, older age at first delivery (21-25, ≥26 years) was associated with a lower risk of lung cancer incidence and mortality. Women who ever used hormone replacements had a higher likelihood of developing non-small cell lung cancer (HR = 1.31, 95% CI = 1.02-1.68), compared to those who never used hormone replacements. Future studies are needed to assess the underlying mechanisms, the relationships within these female reproductive factors, and the potential changes in smoking habits over time.

Increased alcohol intake is associated with radiographic severity of knee and hand osteoarthritis in men

Observational studies have shown controversial associations between alcohol intake and radiographic osteoarthritis (OA). This study investigated whether this association was causal using a Mendelian randomization (MR) study in a population-based cohort in Korean. The study enrolled 2429 subjects (1058 men, 1371 women) from the Dong-gu Study. X-rays of the hand and knee joints were scored using a semi-quantitative grading system to calculate the total score of the hand and knee joints. ALDH2 rs671 genotyping was performed by high-resolution melting analysis. MR instrumental variable analysis and observational multivariable regression analysis were used to estimate the association between genetically predicted alcohol intake and the radiographic severity of OA. Subjects with the G/G genotype had a higher current alcohol intake than those with the G/A and A/A genotypes in both men and women (all P < 0.001). Men with the G/G genotype had higher total knee (P < 0.001) and hand scores (P = 0.042) compared to those with the G/A and A/A genotypes after adjusting for age and body mass index, but not in women. In the observational multivariable regression analysis, each alcohol drink per day in men was associated with increased knee (P = 0.001) and hand joint scores (P = 0.013) after adjustment, but not in women. In our MR analysis, utilizing ALDH2 rs671 genotypes as instrumental variables for alcohol consumption, has shown a significant link between each additional daily alcohol drink and increased radiographic joint severity in men.

Obesity is associated with biliary tract cancer mortality and incidence: A pooled analysis of 21 cohort studies in the Asia Cohort Consortium

Body fatness is considered a probable risk factor for biliary tract cancer (BTC), whereas cholelithiasis is an established factor. Nevertheless, although obesity is an established risk factor for cholelithiasis, previous studies of the association of body mass index (BMI) and BTC did not take the effect of cholelithiasis fully into account. To better understand the effect of BMI on BTC, we conducted a pooled analysis using population-based cohort studies in Asians. In total, 905 530 subjects from 21 cohort studies participating in the Asia Cohort Consortium were included. BMI was categorized into four groups: underweight (<18.5 kg/m2 ); normal (18.5-22.9 kg/m2 ); overweight (23-24.9 kg/m2 ); and obese (25+ kg/m2 ). The association between BMI and BTC incidence and mortality was assessed using hazard ratios (HR) and 95% confidence intervals (CIs) by Cox regression models with shared frailty. Mediation analysis was used to decompose the association into a direct and an indirect (mediated) effect. Compared to normal BMI, high BMI was associated with BTC mortality (HR 1.19 [CI 1.02-1.38] for males, HR 1.30 [1.14-1.49] for females). Cholelithiasis had significant interaction with BMI on BTC risk. BMI was associated with BTC risk directly and through cholelithiasis in females, whereas the association was unclear in males. When cholelithiasis was present, BMI was not associated with BTC death in either males or females. BMI was associated with BTC death among females without cholelithiasis. This study suggests BMI is associated with BTC mortality in Asians. Cholelithiasis appears to contribute to the association; and moreover, obesity appears to increase BTC risk without cholelithiasis.

Differential patterns of reproductive and lifestyle risk factors for breast cancer according to birth cohorts among women in China, Japan and Korea

BACKGROUND

The birth cohort effect has been suggested to influence the rate of breast cancer incidence and the trends of associated reproductive and lifestyle factors. We conducted a cohort study to determine whether a differential pattern of associations exists between certain factors and breast cancer risk based on birth cohorts.

METHODS

This was a cohort study using pooled data from 12 cohort studies. We analysed associations between reproductive (menarche age, menopause age, parity and age at first delivery) and lifestyle (smoking and alcohol consumption) factors and breast cancer risk. We obtained hazard ratios (HRs) with 95% confidence intervals (CIs) using the Cox proportional hazard regression analysis on the 1920s, 1930s, 1940s and 1950s birth cohorts.

RESULTS

Parity was found to lower the risk of breast cancer in the older but not in the younger birth cohort, whereas lifestyle factors showed associations with breast cancer risk only among the participants born in the 1950s. In the younger birth cohort group, the effect size was lower for parous women compared to the other cohort groups (HR [95% CI] 0.86 [0.66-1.13] compared to 0.60 [0.49-0.73], 0.46 [0.38-0.56] and 0.62 [0.51-0.77]). Meanwhile, a higher effect size was found for smoking (1.45 [1.14-1.84] compared to 1.25 [0.99-1.58], 1.06 [0.85-1.32] and 0.86 [0.69-1.08]) and alcohol consumption (1.22 [1.01-1.48] compared to 1.10 [0.90-1.33], 1.15 [0.96-1.38], and 1.07 [0.91-1.26]).

CONCLUSION

We observed different associations of parity, smoking and alcohol consumption with breast cancer risk across various birth cohorts.

Association Between Plasma Homocysteine Level and Mortality: A Mendelian Randomization Study

BACKGROUND AND OBJECTIVES

In previous studies, high homocysteine levels were associated with high cardiovascular mortality. However, these results were inconsistent with those of randomized controlled trials. We aimed to evaluate the causal role of homocysteine on all-cause and cardiovascular mortality using Mendelian randomization (MR) analysis.

METHODS

This study included the 10,005 participants in the Namwon Study. In conventional observational analysis, age, sex, survey years, lifestyles, body mass index, comorbidities, and serum folate level were adjusted using multivariate Cox proportional regression. MR using 2-stage least squares regression was used to evaluate the association between genetically predicted plasma homocysteine levels and mortality. Age, sex, and survey years were adjusted for each stage. The methylenetetrahydrofolate reductase (MTHFR) polymorphism was used as an instrumental variable for predicting plasma homocysteine levels.

RESULTS

Observed homocysteine levels were positively associated with all-cause (hazard ratio [HR], 1.40; 95% confidence interval [CI], 1.26-1.54) and cardiovascular (HR, 1.62; 95% CI, 1.28-2.06) mortality when plasma homocysteine levels doubled. However, these associations were not significant in MR analysis. The HRs of doubling genetically predicted plasma homocysteine levels for all-cause and cardiovascular mortality were 0.99 (95% CI, 0.62-1.57) and 1.76 (95% CI, 0.54-5.77), respectively.

CONCLUSIONS

This MR analysis did not support a causal role for elevated plasma homocysteine concentrations in premature deaths.

Reproductive Factors and Endometrial Cancer Risk Among Women

Importance

Despite evidence of an association between reproductive factors and endometrial cancer risk, prospective studies have been conducted mainly in non-Asian countries.

Objective

To assess the association between reproductive factors, such as number of deliveries, age at menarche, or menopause, and endometrial cancer risk.

Design, Setting, and Participants

This cohort study used pooled individual data from 13 prospective cohort studies conducted between 1963 and 2014 in the Asia Cohort Consortium. Participants were Asian women. Data analysis was conducted from September 2019 to April 2023.

Exposures

Reproductive factors were assessed using a questionnaire in each cohort.

Main Outcomes and Measures

The main outcome was time to incidence of endometrial cancer. A Cox proportional hazards model was used to calculate hazard ratios (HRs) and 95% CIs.

Results

A total of 1005 endometrial cancer cases were detected among 332 625 women (mean [SD] age, 54.3 [10.4] years) during a mean (SD) of 16.5 (6.4) years of follow-up. Increasing number of deliveries was associated with a decreased endometrial cancer risk in a dose-response manner (≥5 deliveries vs nulliparous [reference]: HR, 0.37; 95% CI, 0.26-0.53; P for trend < .001). Compared with menarche at younger than 13 years, menarche at 17 years or older had an HR of 0.64 (95% CI, 0.48-0.86; P for trend < .001). Late menopause (age ≥55 years) showed an HR of 2.84 (95% CI, 1.78-4.55; P for trend < .001) compared with the youngest age category for menopause (<45 years). Age at first delivery, hormone therapy, and breastfeeding were not associated with endometrial cancer risk.

Conclusions and Relevance

This large pooled study of individual participant data found that late menarche, early menopause, and a higher number of deliveries were significantly associated with a lower risk of endometrial cancer. These convincing results from Asian prospective studies add to the growing body of evidence for the association between reproductive factors and endometrial cancer.

Association Between Serum Bilirubin and Atrial Fibrillation: A Mendelian Randomization Study

BACKGROUND AND OBJECTIVES

The association between bilirubin and atrial fibrillation (AF) has been evaluated previously in observational studies but with contradictory results. This study evaluated the causal association between serum bilirubin level and AF using Mendelian randomization (MR) analysis.

METHODS

This cross-sectional study includes 8,977 participants from the Dong-gu Study. In the observational analysis, multivariate logistic regression was performed to evaluate the association between bilirubin and prevalent AF. To evaluate the causal association between bilirubin and AF, MR analysis was conducted by using the UGT1A1 rs11891311 and rs4148323 polymorphisms as instrumental variables.

RESULTS

Elevated serum bilirubin levels were associated with an increased risk for AF in observational analysis (total bilirubin: odds ratio [OR], 1.31; 95% confidence interval [95% CI], 1.15-1.48 per 1 standard deviation [SD]; direct bilirubin: OR, 1.31; 95% CI, 1.18-1.46 per 1 SD), whereas the genetically predicted serum bilirubin levels in MR analysis did not show this association (total bilirubin: OR, 1.02; 95% CI, 0.67-1.53 per 1 SD; direct bilirubin: OR, 1.03; 95% CI, 0.61-1.73 per 1 SD).

CONCLUSIONS

Genetically predicted bilirubin levels were not associated with prevalent AF. Thus, the observational association between serum bilirubin levels and AF may be non-causal and affected by reverse causality or unmeasured confounding.

Effect Modification of Kidney Function on the Non-linear Association Between Serum Calcium Levels and Cardiovascular Mortality in Korean Adults

OBJECTIVES

This study aimed to evaluate the potential interaction between kidney function and the non-linear association between serum calcium levels and cardiovascular disease (CVD) mortality.

METHODS

This study included 8927 participants enrolled in the Dong-gu Study. Albumin-corrected calcium levels were used and categorized into 6 percentile categories: <2.5th, 2.5-25.0th, 25.0-50.0th, 50.0-75.0th, 75.0-97.5th, and >97.5th. Restricted cubic spline analysis was used to examine the non-linear association between calcium levels and CVD mortality. Cox proportional hazard regression was used to estimate hazard ratios (HRs) for CVD mortality according to serum calcium categories. All survival analyses were stratified by the estimated glomerular filtration rate.

RESULTS

Over a follow-up period of 11.9±2.8 years, 1757 participants died, of whom 219 died from CVD. A U-shaped association between serum calcium and CVD mortality was found, and the association was more evident in the low kidney function group. Compared to the 25.0-50.0th percentile group for serum calcium levels, both low and high serum calcium tended to be associated with CVD mortality (<2.5th: HR, 6.23; 95% confidence interval [CI], 1.16 to 33.56; >97.5th: HR, 2.56; 95% CI, 0.76 to 8.66) in the low kidney function group. In the normal kidney function group, a similar association was found between serum calcium levels and CVD mortality (<2.5th: HR, 1.37; 95% CI, 0.58 to 3.27; >97.5th: HR, 1.65; 95% CI, 0.70 to 3.93).

CONCLUSIONS

We found a non-linear association between serum calcium levels and CVD mortality, suggesting that calcium dyshomeostasis may contribute to CVD mortality, and kidney function may modify the association.

Association of liver fibrosis biomarkers with overall and CVD mortality in the Korean population: The Dong-gu study

This study evaluated the associations of liver fibrosis biomarkers [non-alcoholic fatty liver disease fibrosis score (NFS), fibrosis-4 (FIB-4), aspartate aminotransferase/platelet ratio index (APRI), and BARD score] with mortality in Korean adults aged ≥50 years. We analyzed 7,702 subjects who participated in Dong-gu Study. The associations of liber fibrosis biomarkers with mortality were investigated using Cox proportional hazards models. Overall mortality increased with increasing NFS level [adjusted hazard ratio (aHR) 4.3, 95% confidence interval (CI) 3.3-5.5 for high risk vs. low risk], increasing FIB-4 level (aHR 3.5, 95% CI 2.9-4.4 for high risk vs. low risk), and increasing APRI level (aHR 3.5, 95% CI 2.1-5.8 for high risk vs. low risk) but not with BARD score. The Harrell's concordance index for overall mortality for the NFS and FIB-4 was greater than that for the APRI and BARD score. In conclusion, NFS, FIB-4, and APRI showed a significant relationship with the overall mortality, and NFS and FIB-4 showed a significant relationship with the CVD mortality after adjustment for covariates. In addition, the NFS and FIB-4 were more predictive of overall mortality than the APRI and BARD score in Korean adults aged ≥50 years.

Association between alcohol and bone mineral density in a Mendelian randomization study: the Dong-gu study

INTRODUCTION

Many previous studies have reported a positive relationship between alcohol and bone mineral density (BMD). However, the causality between alcohol and BMD has not been fully evaluated.

MATERIALS AND METHODS

This study enrolled 8892 participants from the Dong-gu study. Mendelian randomization (MR) using two-stage least-squared regression was used to evaluate the association between the genetically predicted amount of alcohol consumption per day and BMD. The aldehyde dehydrogenase 2 (ALDH2) rs671 polymorphism was used as instrumental variables for alcohol consumption. Age, smoking history, and BMI were adjusted in the multivariate model.

RESULTS

Self-reported alcohol consumption was positively related to total hip and lumbar spine BMD in both sexes. In multivariate Mendelian randomization analysis, the genetically predicted amount of alcohol consumption was positively associated with both total hip and lumbar spine BMD in men. Total hip BMD and lumbar spine BMD increased by 0.004 g/cm² (95% confidence interval [CI] 0.002-0.007) and 0.007 g/cm² (95% CI 0.004-0.011) with doubling of alcohol consumption. However, in women, genetically predicted alcohol consumption was not significantly associated with BMD.

CONCLUSION

In our MR study, genetically predicted alcohol consumption was positively associated with BMD in men. This result suggests that the association between alcohol consumption and BMD is causal.

Causal Association Between Alcohol Consumption and Atrial Fibrillation: A Mendelian Randomization Study

Previous observational studies presented a positive association between alcohol and atrial fibrillation (AF). However, previous studies using genetic polymorphisms on the causal relationship between alcohol consumption and AF have reported conflicting results. This study evaluated the causality between alcohol consumption and AF using the aldehyde dehydrogenase 2 (ALDH2) rs671 polymorphism. In 8,964 cohort participants, genetic analysis and Mendelian randomization analysis using the ALDH2 genotypes showed a significant causal association between alcohol consumption and AF in men.

Background and Objectives

Previous observational studies presented a positive association between alcohol and atrial fibrillation (AF). However, previous studies using genetic polymorphisms on the causal relationship between alcohol consumption and AF have reported conflicting results. This study aimed to evaluate the causality between alcohol consumption and AF using the aldehyde dehydrogenase 2 (ALDH2) rs671 polymorphism, which is the genetic variant with the most potent effect on drinking behavior.

Methods

A total of 8,964 participants from the Dong-gu Study were included in the present study. The causal association between alcohol consumption and AF was evaluated through a Mendelian randomization (MR) analysis using the ALDH2 rs671 polymorphism as an instrumental variable.

Results

No significant relationship between alcohol consumption and AF was found in the observational analysis. However, the genetic analysis using the ALDH2 polymorphism showed a significant association in men. In the MR analysis, genetically predicted daily alcohol consumption was positively related to AF.

Conclusions

MR analysis revealed a significant association between the amount of alcohol consumption and AF, which suggests that the association may be causal.

Elevated resting heart rate is associated with increased radiographic severity of knee but not hand joints

Although the resting heart rate (RHR) predicts the clinical outcomes of cardiovascular disease, chronic obstructive lung disease, diabetes mellitus, and the risk of cancer, its role in patients with musculoskeletal diseases, such as osteoarthritis (OA), remains unclear. We explored the association of the RHR with the extents of radiographic changes in the knees and hands of 2369 subjects from the Dong-gu Study. The radiographic hand and knee joint findings were graded semi-quantitatively; we calculated total hand and knee joint scores. Multiple linear regression was performed to examine the associations between the RHR and the radiographic characteristics of these joints. For the knee joints, the RHR was associated positively with the total (p < 0.01), osteophyte (p < 0.01), joint space narrowing (JSN; p < 0.01), and tibial attrition (p = 0.02) scores after adjustment for age, sex, body mass index, smoking status, alcohol consumption, educational and physical activity levels, and comorbidities. For the hand joints, the RHR was associated positively with the JSN (p = 0.01) and subchondral cyst (p < 0.01) scores after such adjustment. The RHR was not associated with the total, osteophyte, sclerosis, erosion, or malalignment score for the hand joints. This study is the first to reveal an association between the RHR and the radiographic severity of knee, but not hand, OA.

Association between Albumin, Total Bilirubin, and Uric Acid Serum Levels and the Risk of Cancer: A Prospective Study in a Korean Population

PURPOSE

In this prospective study, we evaluated the association between the serum levels of antioxidants uric acid (UA), albumin, and total bilirubin and the risk of cancer in a Korean population.

MATERIALS AND METHODS

A total of 15882 subjects were followed up for cancer development and cancer-related death. During the follow-up period, 1619 cancer diagnoses and 617 cancer-related deaths were recorded. Cox proportional regression was performed to calculate the hazard ratio (HR) per standard deviation (SD) increment and 95% confidence interval (CI). The model was adjusted for covariates such as the age, sex, smoking, alcohol consumption, physical activity, education level, body mass index, and family history. Sensitivity analyses using the study subjects with physiological serum levels of each indicator were also performed.

RESULTS

UA levels were positively correlated with cancer risk (HR per SD increment 1.04; 95% CI, 1.01-1.09), and albumin levels were inversely associated with the overall cancer risk (HR, 0.92; 95% CI, 0.88-0.96) and cancer-related death (HR, 0.86; 95% CI, 0.80-0.93). Total bilirubin levels were negatively correlated with the risk of cancer-related death (HR, 0.91; 95% CI, 0.83-0.99). By cancer type, UA was positively associated with prostate cancer, total bilirubin was positively associated with liver cancer, and albumin was inversely associated with lung cancer.

CONCLUSION

The findings of this study support the role of antioxidants in carcinogenesis. Future large-cohort studies are needed to confirm the predictive value of albumin, UA, and total bilirubin levels in each type of cancer.

Association between Alcohol Consumption and Serum Cortisol Levels: a Mendelian Randomization Study

BACKGROUND

Several studies have reported conflicting results regarding the relationship between alcohol consumption and cortisol levels. However, the causality between alcohol consumption and cortisol levels has not been evaluated.

METHODS

This study examined 8,922 participants from the Dong-gu Study. The aldehyde dehydrogenase 2 (ALDH2) rs671 polymorphism was used as an instrumental variable for alcohol consumption. The association between the genetically predicted alcohol consumption and cortisol level was evaluated with Mendelian randomization (MR) using two-stage least squares regression.

RESULTS

Alcohol consumption was positively associated with the serum cortisol level in both sexes in the observational analysis. In the MR analysis, the genetically predicted alcohol consumption was positively related to the cortisol level in men, with cortisol levels increasing by 0.18 μg/dL per drink per day. However, there was no relationship in women in the MR analysis.

CONCLUSION

The predicted alcohol consumption according to the ALDH2 rs671 polymorphism was positively related to the cortisol levels, suggesting a causal relationship between alcohol consumption and cortisol levels.

Association between ALDH2 polymorphism and esophageal cancer risk in South Koreans: a case-control study

Background

Alcohol consumption is a major risk factor for esophageal cancer; however, a high incidence of esophageal cancer is observed particularly among Eastern Asians, although they consume relatively less alcohol, presumably due to the high frequency of aldehyde dehydrogenase 2 (ALDH2) rs671 polymorphisms. Nevertheless, the association between ALDH2 polymorphisms and esophageal cancer remains under debate. In the present study, we evaluated the association between ALDH2 rs671 polymorphisms and the risk of esophageal cancer in the South Korean population.

Methods

This study included 783 hospital based-cases and 8732 population-based controls. Information on smoking history and alcohol consumption was obtained from the medical records or interview questionnaires. Age-adjusted logistic regression analysis was performed to assess the association between ALDH2 rs671 polymorphisms and esophageal cancer.

Results

Odds ratios (ORs) for esophageal cancer in men with GA and AA genotypes were 2.75 (95% confidence interval [CI]: 2.34–3.23) and 0.08 (95% CI: 0.00–0.35), respectively; whereas, in women, these ratios were 2.99 (95% CI: 1.43–6.34) and 6.18 (95% CI: 1.40–19.62), respectively, taking subjects with the ALDH2 GG genotype as a reference. In men, the association between ALDH2 polymorphisms and esophageal cancer was modified by alcohol consumption.

Conclusion

In Eastern Asians, ALDH2 rs671 polymorphisms are associated with esophageal cancer, which may be linked to acetaldehyde accumulation.

Increased adiponectin levels are associated with higher radiographic scores in the knee joint, but not in the hand joint

Several studies have evaluated the association between serum adiponectin levels and knee and hand osteoarthritis (OA); mixed results have been reported. We investigated the relationship between OA and serum adiponectin levels according to the radiographic features of knee and hand OA. A total of 2402 subjects was recruited from the Dong-gu Study. Baseline characteristics were collected via a questionnaire, and X-rays of knee and hand joints were scored using a semi-quantitative grading system. The relationship between serum adiponectin levels and radiographic severity was evaluated by linear and logistic regression analysis. Subjects in the higher serum adiponectin levels tertiles were older and had a lower body mass index (BMI) than those in the lower tertiles. Regarding knee joint scores, serum adiponectin levels was positively associated with the total (P < 0.001), osteophyte (P = 0.003), and joint space narrowing (JSN) scores (P < 0.001) after adjustment for age, sex, BMI, smoking, alcohol consumption, education, and physical activity. In terms of hand joint scores, no association was found between serum adiponectin levels and the total, osteophyte, JSN, subchondral cyst, sclerosis, erosion, or malalignment score after the above-mentioned adjustments. Similarly, subjects with serum adiponectin levels above the median had higher total radiographic scores in the knee joints, but not in the hand joints, after adjustment. An increased serum adiponectin levels was associated with a higher radiographic score in the knee joint, but not in the hand joint, suggesting the involvement of different pathophysiologic mechanisms in the development of OA between those joints.

Low serum 25-hydroxyvitamin D levels, tooth loss, and the prevalence of severe periodontitis in Koreans aged 50 years and older

PURPOSE

Vitamin D deficiency may cause bone loss and increased inflammation, which are well-known symptoms of periodontal disease. This study investigated whether serum 25-hydroxyvitamin D (25(OH)D) levels are associated with periodontal disease status and tooth loss.

METHODS

Cross-sectional data from 5,405 individuals aged ≥50 years (2,253 males and 3,152 females) were obtained from the 2008-2010 Dong-gu study, a prospective cohort study of risk factors for chronic diseases. Periodontal examinations were conducted to evaluate the number of remaining teeth, the periodontal probing depth (PPD), the clinical attachment level (CAL), and bleeding on probing. The percentages of sites with PPD ≥4 mm and CAL ≥4 mm were recorded for each participant. The severity of periodontitis was classified using the Centers for Disease Control and Prevention and the American Academy of Periodontology case definitions. Serum 25(OH)D levels were classified as reflecting severe deficiency, deficiency, insufficiency, or sufficiency. Multivariate linear regression analysis was performed to assess the associations of serum 25(OH)D levels with periodontal parameters and the number of remaining teeth after adjusting for confounders including age, smoking status, alcohol consumption status, month of blood collection, and physical activity. Multivariate logistic regression was used to evaluate the association between serum vitamin D levels and severe periodontitis. An overall statistical analysis and a stratified analysis by sex were performed.

RESULTS

Overall, the rates of severe deficiency, deficiency, insufficiency, and sufficiency were 6.5%, 67.9%, 22.4%, and 3.2%, respectively. After adjustment for confounders, vitamin D levels were directly associated with the number of remaining teeth, an association that was significant in males, but not in females. Sufficient serum 25(OH)D was associated with a low frequency of severe periodontitis.

CONCLUSIONS

This population-based cross-sectional study indicates that low serum 25(OH)D is significantly associated with tooth loss and severe periodontitis in Koreans aged 50 years and older.

Cystatin C-based estimated GFR and albuminuria are independently associated with all-cause and CVD mortality in Korean population: The Dong-gu Study

OBJECTIVE

To assess the associations among the estimated glomerular filtration rate (eGFR), albumin to creatinine ratio (ACR), and all-cause and CVD mortality rate and to compare the performances of eGFR_MDRD, eGFR_CKD-EPI, and eGFR_cys using receiver operating characteristic (ROC) analysis in Korean adults aged ≥ 50 years.

METHODS

Of the 9,260 subjects who participated in the baseline survey of a prospective longitudinal study conducted in Korea, 9,009 (men: 3,574 (39.7%); women: 5,435 (60.3%)) were included in this analysis after the exclusion of 217 subjects with missing eGFR and 34 subjects with missing ACR data.

MAIN OUTCOME MEASURE

The associations of eGFR and ACR with all-cause and CVD mortality were investigated using Cox proportional hazards models that included sex, age, waist circumference, smoking, alcohol intake, degree of physical activity, hypertension, diabetes, systolic blood pressure, log-HbA_1c, total cholesterol, log-triglyceride, log-HDL and log-ACR or eGFR.

RESULTS

After adjustment for covariates, independent associations were found between all-cause mortality and the eGFR_cys (mL/min per 1.73 m²) [HR 1.23, 95% confidence interval (CI) 1.05-1.43 for 60-89 vs. ≥ 90; HR 1.87, 95% CI 1.49-2.34 for 45-59 vs. ≥ 90; HR 2.38, 95% CI 1.77-3.20 for 30-44 vs. ≥ 90; HR 2.82, 95% CI 1.89-4.23 for <30 vs. ≥ 90] and ACR (μg/mg creatinine) [HR 1.09, 95% CI 0.88-1.34 for Q2 vs. Q1; HR 1.34, 95% CI 1.10-1.63 for Q3 vs. Q1; HR 1.49, 95% CI 1.22-1.81 for Q4 vs. Q1]. In addition, independent associations of CVD mortality with the eGFR_cys and ACR were significant. In the comparison of eGFR performance, the ROC-plot AUC for all-cause mortality was significantly greater for the eGFR_cys than for the eGFR_MDRD and eGFR_CKD-EPI.

CONCLUSION

The eGFR_cys and ACR were associated independently with all-cause and CVD mortality after adjustment for covariates, including the eGFR_cys and ACR. In addition, the ROC-plot AUC for all-cause mortality was greater for the eGFR_cys than for the eGFR_MDRD and eGFR_CKD-EPI in Korean adults aged ≥ 50 years.

Association between ALDH2 Polymorphism and Gastric Cancer Risk in a Korean Population

The association between alcohol and gastric cancer is stronger in East Asians than in other ethnic groups, presumably due to an aldehyde dehydrogenase 2 (ALDH2) polymorphism. Therefore, we investigated the relationship between the ALDH2 rs671 polymorphism and gastric cancer in a Korean population. This case-control study included 3,245 hospital patients newly diagnosed with gastric cancer and 8,732 population controls. The ALDH2 rs671 genotype was classified as inactive ALDH2 (GG) or active ALDH2 (GA/AA). The risk of gastric cancer was higher in men with the inactive ALDH2 than in those with active ALDH2 (odds ratio [OR], 1.25; 95% confidence interval [CI], 1.09-1.39), whereas no significant association was found between ALDH2 genotype and gastric cancer in women (OR, 1.00; 95% CI, 0.99-1.02). In men, the association between ALDH2 genotype and gastric cancer was stronger in current drinkers. Our findings support the previously reported association between inactive ALDH2 and high risk of gastric cancer.

Effect Modification of Acetaldehyde Dehydrogenase 2 rs671 Polymorphism on the Association between Alcohol Intake and Blood Pressure: the Dong-gu Study

BACKGROUND

Elevated blood pressure is a major preventable cause of cardiovascular diseases. Alcohol consumption is a well-known risk factor of elevated blood pressure. The aldehyde dehydrogenase 2 (ALDH2) polymorphism is common in Eastern Asians, and inactive ALDH2 genotypes are associated with both avoiding alcohol consumption and aldehyde accumulation. Therefore, this study assessed the associations between alcohol consumption and hypertension and blood pressure according to the ALDH2 genotypes.

METHODS

This study consists of 8,526 participants in the Dong-gu Study. Multivariate logistic regression was used to calculate the odds ratio (OR) according to alcohol consumption after stratifying by gender and ALDH2 genotypes. Multivariate linear regression was performed to estimate the systolic blood pressure (SBP) and diastolic blood pressure (DBP) according to the amount of alcohol consumed.

RESULTS

In men, alcohol consumption was positively associated with both SBP and DBP in active ALDH2 carriers, but not in inactive ALDH2 carriers. In active ALDH2 carriers, compared to non-drinkers, the OR of hypertension was 1.16 (95% confidence interval [CI], 0.91-1.49) for < 1 drink/day, and 1.44 (95% CI, 1.15-1.80) for ≥ 1 drink/day in men. With each 1 drink/day increase, SBP and DBP increased by 3 and 1 mmHg in men, respectively. There was no significant association between ALDH2 genotypes and hypertension and blood pressure in women.

CONCLUSION

ALDH2 genotype modified the association between alcohol consumption and blood pressure in men. There was a positive relationship between alcohol consumption and blood pressure in active ALDH2 carriers, but no significant relationship in inactive ALDH2 carriers.

The Association between the Apolipoprotein E Gene Polymorphism and All-cause Mortality in the Korean Population

BACKGROUND

Apolipoprotein E (APOE) gene polymorphism is associated with neurodegenerative and cardiovascular diseases. Although the effects of the gene differ by ethnic group, few studies have examined Asians. Therefore, the association between APOE polymorphism and mortality in Koreans was evaluated in this study.

METHODS

This study population included participants from the Dong-gu and Namwon Studies. APOE genotypes were categorized as E2 (E2/E2 and E2/E3), E3 (E3/E3), and E4 (E3/E4 and E4/E4). Multivariate Cox proportional hazard models were constructed using the E3 allele as a reference.

RESULTS

In the model adjusting for study site, age, gender, and lifestyle, the hazard ratio (HR) of mortality for those with the E4 allele was 1.08 (95% confidence interval [CI], 0.97-1.20), while that for those with the E2 allele was 0.84 (95% CI, 0.74-0.96). After adjusting for blood lipids to evaluate their mediating effects, the HRs of mortality for those with E4 and E2 alleles were 1.08 (95% CI, 0.97-1.20) and 0.80 (95% CI, 0.70-0.92), respectively. These associations were more evident in younger groups, with HRs of 0.70 (95% CI, 0.52-0.92) for the E2 allele and 1.25 (95% CI, 1.03-1.53) for the E4 allele.

CONCLUSION

In two large population-based cohort studies, the E2 allele was associated with a lower risk of mortality compared with the E3 allele, whereas the E4 genotype was not associated with mortality in Koreans.

Serum level vitamin D and parathyroid hormone, and mortality, with or without chronic kidney disease

Levels of vitamin D and parathyroid hormone (PTH) are closely associated with renal function. We evaluated the associations among 25-hydroxyvitamin D (25OHD) levels, PTH levels, and mortality, and whether these associations varied by renal function. We used data from the Dong-gu Study, a population-based cohort in Korean adults. We analyzed the associations among intact PTH, 25OHD levels and mortality in 8580 participants. Hazard ratios (HRs) for mortality were calculated using Cox proportional hazards regression after adjusting for age, sex, month of sampling, lifestyle, and comorbidities. We also evaluated the effects of chronic kidney disease (CKD). A total of 860 deaths occurred during the follow-up period of 7.6 years. Compared to the first 25OHD quartile, the HRs of the second, third, and fourth quartiles were 0.96 [95% confidence interval (CI) 0.79-1.16], 0.84 (95% CI 0.68-1.02), and 0.71 (95% CI 0.57-0.89), respectively. The association between intact PTH levels and mortality varied by renal function, and was both nonlinear and significant only in subjects with CKD. Compared to the second intact PTH quartile in such subjects, the HRs for the first, third, and fourth quartiles were 1.61 (95% CI 0.92-2.81), 1.97 (95% CI 1.17-3.31), and 2.19 (95% CI 1.33-3.59), respectively. In conclusion, we demonstrated that low serum levels of 25OHD are associated with an increased risk of mortality. Serum levels of intact PTH are nonlinearly associated with mortality only in subjects with CKD, with the lowest risk for mortality being evident in the second quartile.

Association of Falls and Fear of Falling with Mortality in Korean Adults: The Dong-gu Study

This study evaluated the association between falls and the fear of falling (FOF) with the risk of all-cause mortality in Korean adults. The study enrolled 4,386 subjects aged 50 years and over who participated in the Dong-gu Study. Falls in the past year were categorized as yes or no. Injurious falls were defined as falls that resulted in fractures, head injuries, sprains or strains, bruising or bleeding, or other unspecified injuries. FOF was classified as low or high. The associations of falls and fall-related characteristics with mortality were assessed using Cox proportional hazards models. The average follow-up was 7.8 years. During this period, 255 men and 146 women died. In a fully adjusted model, falls in the past year were not associated with an increased risk of all-cause mortality (hazard ratio [HR] 1.16, 95% confidence interval [CI] 0.85–1.58), but a history of injurious falls was associated with an increased risk of mortality (HR 1.36, 95% CI 1.04–1.79). Compared with subjects without a FOF, subjects who were moderately or very afraid of falling had a higher mortality rate (HR 1.26, 95% CI 0.97–1.63). In conclusion, injurious falls and a high FOF increased the risk of all-cause mortality in Koreans. This study suggests that injurious falls and FOF can predict mortality in the general population.

Association of Plasma Pentraxin-3 Level with Lipid Levels and Cardiovascular Risk Factors in People with No History of Lipid-Lowering Medication: the Dong-gu Study

Aim: To elucidate the role of pentraxin-3 (PTX3) in atherosclerosis, we evaluated lipid and cardiovascular risk profiles according to the plasma PTX3 levels in subjects from the general population.

Methods: A sub-cohort of 2,000 subjects was randomly sampled from a Korean community-based cohort study. After excluding those with a medication history for dyslipidemia, 1,747 subjects (902 men and 845 women) were included in the final analyses. Linear and logistic regressions with adjustment for appropriate variables were performed.

Results: The PTX3 level was positively associated with the high-density lipoprotein cholesterol (HDL-C) level and negatively associated with the log-transformed triglyceride (TG) level, total cholesterol/HDL-C ratio, and low-density lipoprotein cholesterol (LDL-C)/HDL-C ratio (p<0.05). Subjects with the highest PTX3 levels (≥ 1.17 ng/dl) exhibited a lower risk of metabolic syndrome (odds ratio [OR] 0.73, 95% confidence interval [CI] 0.57–0.94), overweight/obesity (OR 0.65, 95% CI 0.50–0.83), increased TG level (OR 0.66, 95% CI 0.51–0.86), and increased HDL-C level (OR 0.67, 95% CI 0.51–0.88) compared to those with the lowest PTX3 level (<0.7 ng/dl).

Conclusion: The circulating PTX3 level was inversely associated with metabolic syndrome, overweight/obesity, and parameters of dyslipidemia, suggesting a cardioprotective role of PTX3 in atherosclerosis.

25-Hydroxyvitamin D Is Associated with Kidney Function: The Dong-gu Study

Although the kidneys play a leading part in the biosynthesis of vitamin D, there is no consensus regarding the relationship of the vitamin D concentration with kidney function. Thus, we aimed to estimate the correlation among 25-hydroxyvitamin D (25(OH)D), estimated glomerular filtration rate (eGFR), and albumin/creatinine ratio (ACR) in participants aged ≥50 y in Korea. This study consisted of 9,166 people who participated in a basic survey of the Dong-gu Study. Following an overnight fast, the blood and urine sample were assessed. The serum 25(OH)D, eGFR, ACR of each subject were measured. When adjusting for covariates and log-transformed ACR (Model III), the lower eGFR value was significantly associated with increasing 25(OH)D levels (<10.0: 71.5[70.5-72.4]; 10.0-14.9: 70.0 [69.5-70.4]; 15.0-19.9: 68.7 [68.3-69.2]; ≥20.0: 67.4 [66.8-67.9] mL/min/1.73 m², p<0.001). When adjusted for the same covariates and log-transformed eGFR (Model III), the lower ACR value was significantly associated with increasing 25(OH)D levels (<10.0: 57.4 [48.0-66.9]; 10.0-14.9: 40.8 [36.5-45.2]; 15.0-19.9: 34.0 [29.5-38.5]; ≥20.0: 34.3 [28.8-39.8] μg/mg creatinine, p<0.001). In conclusion, the mean values of eGFR were significantly decreased with increasing 25(OH)D levels independent of ACR. In additon, the mean values of ACR were significantly decreased with increasing 25(OH)D levels independent of eGFR in participants aged ≥50 y in Korea.

Association between hand-grip strength and erectile dysfunction in older men

OBJECTIVES

To evaluate the association between handgrip strength and erectile dysfunction (ED) in community-dwelling older men.

METHODS

This cross-sectional study included 1771 participants of the Dong-gu Study. Handgrip strength was measured with a handheld dynamometer. ED was assessed with the Korean version of the International Index of Erectile Function (IIEF). ED was categorized as none to mild (IIEF-EF scores of 13-30) and moderate to severe (IIEF-EF scores of 0-12). Multivariable logistic regression was conducted with adjustment for potential confounders.

RESULTS

The proportion of men with moderate to severe ED was 48.8%. The age-adjusted ED score increased with increasing quartile of handgrip strength (11.0, 12.4, 13.4, and 14.0 in the lowest, second, third, and highest quartiles, respectively). After adjustment for potential confounders, greater handgrip strength was associated with a lower risk of ED (odds ratio (OR): 0.82 per 5 kg; 95% confidence interval (CI): 0.74-0.90). In addition, a high level of moderate to vigorous physical activity was associated with a lower risk of ED (OR: 0.75; 95% CI: 0.61-0.93).

CONCLUSION

In this study, aging men with greater handgrip strength had a lower risk of ED. This result suggests that reduced physical functioning may contribute to ED.

Nonlinear association between bone mineral density and all-cause mortality: the Dong-gu study

There was a U-shaped association between hip BMD and all-cause mortality, with the lowest mortality in the 90th percentile in males. However, there was an inverse linear relationship in females. In contrast, the association between lumbar spine BMD and mortality was less evident in males, with no association in females.

INTRODUCTION

Bone mineral density (BMD) is reported inversely associated with mortality. Although some previous studies provided evidence for nonlinear associations, these were not adequately assessed in most previous works.

METHODS

We evaluated the nonlinear relationship between BMD and mortality in Asians. Our study involved 8629 participants in the Dong-gu study from 2007 to 2010. Cox proportional hazard regression was used to calculate hazard ratios (HRs) according to BMD categories after adjusting for potential confounders. During a follow-up of 6.7 ± 1.4 years, 712 participants died.

RESULTS

There was a U-shaped association between hip BMD and all-cause mortality, with the lowest mortality in the 90th percentile in males. However, there was an inverse linear relationship in females. In males, compared with the 75th to 95th percentile group, the < 2.5th percentile group had a 3.89 (95% CI 2.41-6.28)-fold higher risk and the 2.5th to 5th percentile group had a 2.51 (95% CI 1.25-5.04)-fold higher risk. The HR was 2.51 (95% CI 1.25, 5.04) in the > 97.5th percentile group. In females, compared with that in the 75th to 95th percentile group, the HR was 2.33 (95% CI 1.24, 4.39) in the < 2.5th percentile group. In contrast, the association between lumbar spine BMD and mortality was less evident in males, with no association in females.

CONCLUSION

In conclusion, this study shows that the association between BMD and mortality varies by gender and that high and low BMD are predictors of all-cause mortality in males.

Association between Plasma Pentraxin 3 Levels and Bone Mineral Density in Elderly Koreans: the Dong-gu Study

BACKGROUND

We investigated the association between pentraxin 3 (PTX3), a novel inflammatory marker, and bone mineral density (BMD) in the general Korean population.

METHODS

We selected a sub-cohort of 1,440 subjects (757 men and 683 women) from participants in the community-based Dong-gu Study. The mean age was 66.0 ± 8.1 years for men and 63.7 ± 7.9 years for women. The plasma PTX3 levels were measured using an enzyme-linked immunosorbent assay, and BMD was measured in the femoral neck and lumbar spine using dual-energy X-ray absorptiometry. Linear regression analyses were used to evaluate the association between the plasma PTX3 levels and BMD.

RESULTS

PTX3 was inversely associated with the BMD of the lumbar spine (P = 0.010) and femoral neck (P < 0.001) in men but not in women. For men, the association with the BMD of the femoral neck remained after adjustment for multiple comparison (P = 0.020).

CONCLUSION

This study suggests that PTX3 levels might be inversely associated with BMD in elderly men.

Comparison of screening strategies for prevalent vertebral fractures in South Korea: vertebral fracture assessment vs. spine radiography

BACKGROUND

Vertebral Fracture Assessment (VFA) is a useful tool to detect the vertebral fracture (VF) with low cost and radiation exposure. We aimed to compare screening strategies including VFA and spine radiography (X-ray) for detecting VF in terms of clinical effectiveness, cost and radiation exposure.

METHODS

Three screening strategies: 1) X-ray following VFA, 2) VFA only, and 3) X-ray only were compared using a Markov model based on administrative data from South Korea in a population aged ≥50 years. We compared the incidence of new VFs, cost-effectiveness of reducing new VFs and radiation exposure in each strategy.

RESULTS

The incidence of new VFs was reduced in all screening strategies compared to no screening: 29.4% for women and 12.5% for men in both X-ray following the VFA and VFA only strategies and 35% for women and 17.5% for men in the X-ray only strategy. The X-ray following VFA strategy had the lowest cost, followed by the X-ray only, and VFA only strategies. The radiation doses for X-ray only were 2,647-2,989 μSv and 3,253-3,398 μSv higher than in the X-ray following VFA and VFA only strategies. The new VF prevention effect was greater in women, and more prominent in older people (women ≥ 70, men ≥ 80) than people ≥ 50 years.

CONCLUSIONS

The X-ray following VFA strategy is a cost-effective option for screening prevalent VF to prevent new VF in people aged ≥50 years due to its high effectiveness, lowest cost, and least radiation exposure.

Detection of Familial Hypercholesterolemia Using Next Generation Sequencing in Two Population-Based Cohorts

We aimed to evaluate the prevalence of familial hypercholesterolaemia (FH) in a subject with hypercholesterolaemia from two population-based cohorts in South Korea. A total of 283 subjects with total cholesterol levels of 290 mg/dL (7.5 mmol/L) or higher were selected from the Namwon and Dong-gu Studies. We used next generation sequencing (NGS) to detect mutations in low-density lipoprotein receptors (LDLR), apolipoprotein B (APOB) and proprotein convertase subtilisin/kexin type 9 (PCSK9) genes. We have confirmed 17 different mutations of the LDLR, APOB and PCSK9 in 23 subjects (8.1%). Eleven LDLR variants and one APOB variant have been previously reported. One LDLR and two PCSK9 rare variants were identified in the variants database, but not in the FH mutation database. Two novel LDLR variants were found, p.Leu680Val, and p.Thr734Phe. No LDLR, APOB or PCSK9 deletions nor insertions were found. When the subjects were restricted to 110 subjects with a total cholesterol ≥310 mg/dL, only 10 variants were found in the 10 subjects (9.1%). These results suggest that given the low prevalence of FH mutations in subjects with high total cholesterol levels, NGS-based testing for a population-based approach to FH detection may not be cost-effective.

Effect of Family History of Diabetes on Hemoglobin A1c Levels among Individuals with and without Diabetes: The Dong-gu Study

PURPOSE

We investigated associations between family history of diabetes (FHD) and hemoglobin A1c (HbA1c) level, among people with and without diabetes.

MATERIALS AND METHODS

In total, 7031 people without diabetes and 1918 people with diabetes who participated in the Dong-gu Study were included. Data on FHD in first-degree relatives (father, mother, and siblings) were obtained. Elevated HbA1c levels in people without diabetes and high HbA1c levels in people with diabetes were defined as the highest quintiles of HbA1c ≥5.9% and ≥7.9%, respectively.

RESULTS

In people without diabetes, the odds of elevated HbA1c levels [odds ratio (OR) 1.34, 95% confidence interval (CI) 1.13-1.59] were significantly greater in people with any FHD than in those without. Specifically, the odds of elevated HbA1c levels in people without diabetes with an FHD involving siblings were greater than in those without an FHD involving siblings. Additionally, in people with diabetes, the odds of high HbA1c levels (OR 1.33, 95% CI 1.02-1.72) were greater in people with any FHD than in those without such history. Moreover, people with diabetes with maternal FHD had increased odds of high HbA1c levels.

CONCLUSION

FHD was associated not only with high HbA1c levels in people with diabetes, but also with elevated HbA1c levels in people without diabetes.

Association between Serum Parathyroid Hormone Levels and the Prevalence of Atrial Fibrillation: the Dong-gu Study

Background and Objectives

We aimed to investigate the association between serum parathyroid hormone (PTH) levels and the prevalence of atrial fibrillation (AF) in a population based study.

Methods

This study included a total of 9,007 community-dwelling Koreans aged 50 years and over who were enrolled in the Dong-gu study from 2007 to 2010. Electrocardiograms were recorded from the subjects using the HP-PageWriter 200 M1771A. All potential cases of AF were determined by 2 cardiologists. PTH concentration was measured by a chemiluminescent microparticle immunoassay. Multiple logistic regression analysis was used to evaluate the relationship between the quartiles of PTH and AF, adjusting for potential confounders.

Results

The prevalence of AF was 2.41% in males and 0.9% in females and increased with advanced age in both genders. The median and interquartile range (IQR) of serum PTH was 39.5 pg/mL (IQR, 30.6–50.8), which was significantly higher in patients with AF than in patients without AF (p<0.001). The prevalence of AF increased with increasing PTH quartile (0.8%, 0.9%, 1.6%, and 2.8% in the lowest, second, third, and highest PTH quartiles, respectively; p<0.001). Multivariable logistic analysis adjusted for cardiovascular risk factors showed the highest quartile of serum PTH levels was associated with a higher prevalence of AF than the lowest quartile (odds ratio, 3.34; 95% confidence interval, 1.93–5.78).

Conclusions

Higher levels of serum PTH were associated with higher prevalence of AF. Further studies are needed to determine whether this association is present in other populations and in a prospective study setting.

Association between grip strength and hand and knee radiographic osteoarthritis in Korean adults: Data from the Dong-gu study

Objectives

We assessed whether grip strength was related to various types of radiographic damage in Korean adults with osteoarthritis (OA).

Methods

Data from 2,251 subjects enrolled in the Dong-gu study, who had no hand joint pain, were analyzed to investigate the relationship between grip strength and OA. Hand grip strength was measured using a hand-held dynamometer, and radiographs of the hand and knee were scored according to a semi-quantitative grading system. Multiple linear regressions were used to explore associations between grip strength and radiographic features of OA.

Results

Grip strength in men and women was negatively related to hand (both p < 0.001) and knee (men, p < 0.001; women, p = 0.010) OA after adjusting for confounders. Hand (men, p < 0.001; women, p = 0.001) and knee (both p < 0.001) joint space narrowing (JSN) showed the strongest associations with low grip strength, regardless of gender. Moreover, the severity of hand osteophytes in women (p = 0.001), and subchondral cysts (men, p < 0.001) was correlated with low grip strength in both genders.

Conclusions

Among subjects without hand joint pain, low grip strength was associated significantly with hand and knee radiographic OA, regardless of gender. Among all types of OA radiographic damage, low grip strength showed the strongest association with JSN.

The value of high-sensitivity C-reactive protein in hand and knee radiographic osteoarthritis: data from the Dong-gu Study

Due to the inconsistent association between high-sensitivity C-reactive protein (hs-CRP) and osteoarthritis (OA), we evaluated the relationship between hs-CRP and various radiographic findings in older adults with OA. This cross-sectional study recruited 2376 participants from the population-based Dong-gu cohort. The scores of radiographic features in OA on X-rays of the knees and hands were computed using a semi-quantitative grading system. The hs-CRP levels were measured using a particle-enhanced immunonephelometry assay. Correlations showing the relationship between hs-CRP and OA were calculated using multiple linear correlation analysis. The hs-CRP levels were significantly higher in older subjects (p < 0.001), those with a higher body mass index (BMI) (p < 0.001), current smokers (p < 0.001), current alcohol drinkers (p = 0.011), those who were less physically active (p = 0.002), and those with a lower level of education (p = 0.043). After adjusting for BMI and other confounders, the total OA scores (knee, p = 0.022; hand, p = 0.029) and sclerosis score (knee, p = 0.007; hand, p = 0.030) in the knees and hands were all significantly positively correlated with hs-CRP. A significant association was also observed between hs-CRP and hand erosion score (p = 0.045), hand malalignment score (p = 0.015), and tibial attrition score (p = 0.039). In this large cross-sectional study, a higher hs-CRP level was significantly associated with radiographic OA severity. Of the various types of radiographic damage, all of sclerosis, erosion, and malalignment were significantly associated with hs-CRP levels.

A Gender-Specific Association between Self-Reported Snoring and Hemoglobin A1c Levels in a General Population without Type 2 Diabetes Mellitus

PURPOSE

We explored whether a gender difference was evident in terms of the associations of snoring with hemoglobin A1c (HbA1c) and homeostatic model assessment-insulin resistance (HOMA-IR) levels in a healthy population without type 2 diabetes mellitus (DM).

MATERIALS AND METHODS

We analyzed 2706 males and 4080 females who participated in the baseline survey of the Namwon Study. In terms of self-reported snoring frequency, participants were classified as non-snorers or occasional (1-3 days/week), frequent (4-6 days/week), or constant (7 days/week) snorers. Participants with DM, defined as a fasting blood glucose level ≥126 mg/dL and/or use of insulin or hypoglycemic medication, were excluded from the analysis.

RESULTS

In females, the fully adjusted mean (95% confidence interval) HbA1c levels in non-snorers and in occasional, frequent, and constant snorers were 5.53% (5.47-5.59%), 5.53% (5.47-5.59%), 5.57% (5.49-5.64%), and 5.57% (5.51-5.64%), respectively, reflecting a dose-response relationship (p trend=0.004). Compared with female non-snorers, the risk of an elevated HbA1c level (top quintile, ≥5.9%) in constant snorers remained significant (odds ratio 1.30, 95% confidence interval 1.02-1.66) after full adjustment. In addition, in females, a significant linear trend in HbA1c level odds ratio by increased snoring frequency was apparent (p trend=0.019 in model 3). In contrast, no significant association between snoring frequency and HbA1c level was identified in males. No significant association between snoring frequency and HOMA-IR was detected in either gender.

CONCLUSION

We discovered a gender-specific association between snoring and HbA1c level in a healthy, community-dwelling population free of DM.

Association of serum vitamin D and parathyroid hormone with subclinical atherosclerotic phenotypes: The Dong-gu Study

Background

Although previous studies reported an association between serum vitamin D and parathyroid hormone (PTH) with carotid atherosclerosis or arterial stiffness, these were inconsistent. We examined the independent association between serum vitamin D and PTH with multiple subclinical markers of atherosclerosis.

Methods

A total of 8,217 subjects who participated in the Dong-gu Study in Korea were included in the final analysis. The carotid artery structure, including intima-media thickness (IMT), plaques, and luminal diameter, was evaluated using a high-resolution B-mode ultrasound. The brachial-ankle pulse wave velocity (baPWV) was determined using an automatic waveform analysis device, and the mean of the left and right baPWV was used.

Results

The PTH concentration was positively associated with carotid luminal diameter and baPWV, but not with carotid IMT and plaques. The mean carotid luminal diameter of individuals with PTH levels in the second, third, and fourth quartiles was significantly larger compared with those in the first quartile (P-trend < 0.01). The mean baPWV of individuals with PTH levels in the fourth quartile was significantly greater than those with PTH levels in the first quartile (P-trend = 0.01). However, there was no significant association between vitamin D and any atherosclerotic phenotypes, including carotid IMT, plaques, luminal diameter, and baPWV.

Conclusion

This suggests that PTH might affect the development of atherosclerosis by altering vascular compliance.

Relationship between plasma pentraxin 3 level and risk of chronic kidney disease in the Korean elderly: the Dong-gu study

Purpose This study investigated the cross-sectional association between chronic kidney disease (CKD) and plasma pentraxin 3 (PTX3) levels in a Korean population, in a community-based cohort study.

METHODS

A total of 1816 (891 men, 925 women) subjects were randomly selected from the cohort of participants for the final analyses. Plasma PTX3 concentration was determined using enzyme-linked immunosorbent assays. The participants were divided into four quartiles according to the PTX3 levels. Multivariate logistic regression was performed to evaluate the association between plasma PTX3 level and CKD. Covariates inserted into the multivariate model included smoking status, systolic blood pressure, body mass index, waist circumference, high-density lipoprotein, low-density lipoprotein uric acid, white blood cell count, and carotid intima-media thickness.

RESULTS

Compared to the lowest PTX3 group (Q1), a significantly higher risk of CKD was found in the highest group (Q4), with an odds ratio of 1.58 and 95% confidence interval of 1.18-2.11 (P for trend <0.001).

CONCLUSIONS

This study showed that higher plasma PTX3 levels are significantly associated with CKD risk. The biological mechanism remains unclear; therefore, further molecular investigation of association between CKD and PTX3 is needed.

Carotid plaque rather than intima-media thickness as a predictor of recurrent vascular events in patients with acute ischemic stroke

Background

To investigate the impacts of carotid plaque and intima-media thickness (IMT) on future vascular events (VEs) in the patients with acute ischemic stroke.

Methods

A total of 479 consecutive Korean patients with acute ischemic stroke were divided into 2 groups according to development of VEs; VE group (65.4 ± 10.9 years) vs no VE group (62.8 ± 13.2 years). VEs were defined as the development of recurrent stroke, coronary events, peripheral arterial disease, and death. Clinical, laboratory, and imaging findings were compared between the groups.

Results

During 105.5 ± 29.0 months of follow up, VEs were developed in 142 patients (29.6%). In univariate analysis, VEs were significantly associated with age, gender, diabetes, renal function, lipid levels, left ventricular function, carotid plaque or IMT. In multivariate analysis, the presence of carotid plaque, diabetes, renal function and male gender were independent predictors of future VEs in the patients with ischemic stroke, but carotid IMT was not a predictor of future VEs. Event free survival was significantly lower in patients with carotid plaque than without carotid plaque on Kaplan-Meier analysis (log rank p < 0.001).

Conclusion

The present study demonstrated that diabetes, impaired renal function, male gender, and the presence of carotid plaque rather than IMT were independent predictors of future VEs in Korean patients with acute ischemic stroke. Active medical management and careful monitoring for the development of recurrent VEs are strongly recommended in patients with acute ischemic stroke and carotid plaque.

Carotid Atherosclerosis and Electrocardiographic Left Ventricular Hypertrophy in the General Population: The Namwon Study

This study aimed to investigate the relationship between carotid atherosclerosis and left ventricular hypertrophy on electrocardiogram (ECG-LVH) on adults living in the community. A total of 9,266 adults who participated in the Namwon Study were included in this analysis. Carotid atherosclerosis, including intima-media thickness (IMT) and plaques, were assessed using high-resolution B-mode ultrasound. ECG-LVH was determined using the Sokolow-Lyon voltage (SokV) and Cornell voltage (CorV) criteria. The prevalence of ECG-LVH was 12.7% using the SokV criteria and 9.7% using the CorV criteria. After full adjustment, compared to the lowest quartile of common carotid artery IMT (CCA-IMT), the odds ratios and 95% confidence intervals for ECG-LVH of the carotid IMT quartiles 2, 3, and 4 increased linearly as follows: 1.54 (1.24-1.90), 1.62 (1.31-2.02), and 1.91 (1.54-2.38), respectively, for the SokV criteria (p<0.001); and 1.33 (1.05-1.68), 1.41 (1.11-1.78), and 1.48 (1.16-1.88), respectively, for the CorV criteria (p=0.003). Positive associations between the carotid bulb IMT (CB-IMT) quartiles and the ECG-LVH were also observed, although the magnitudes of association between CB-IMT and ECG-LVH were slightly lower than those of CCA-IMT. However, no significant association between carotid plaques and ECG-LVH as defined by the SokV or CorV criteria was found. The present study demonstrated that increased carotid IMT, but not carotid plaques, is significantly associated with LVH defined by various ECG criteria in a large population.

Association between Serum 25-hydroxyvitamin D Levels and Type 2 Diabetes in Korean Adults

Previous studies have suggested that a vitamin D deficiency increases the risk of type 2 diabetes. This study evaluated the association between serum vitamin D levels and type 2 diabetes in Korean adults. This study included 9,014 subjects (3,600 males and 5,414 females) aged ≥50 years who participated in the Dong-gu Study. The subjects were divided into groups in whom the serum vitamin D level was severely deficient (<10 ng/mL), deficient (10 to <20 ng/mL), insufficient (20 to <30 ng/mL) and sufficient (≥30 ng/mL). Type 2 diabetes was defined by a fasting blood glucose level of ≥126 mg/dL and/or an HbA1c proportion of ≥6.5% and/or self-reported current use of diabetes medication. Multiple logistic regression was performed to evaluate the association between vitamin D status and type 2 diabetes. The age- and sex-adjusted prevalence of type 2 diabetes was 22.6%, 22.5% and 18.4% and 12.7% for severely deficient, deficient, insufficient, and sufficient, respectively. Multivariate modeling revealed that subjects with insufficient or sufficient vitamin D levels were at a lower risk of type 2 diabetes than were subjects with deficient vitamin D levels [odds ratio (OR), 0.82; 95% confidence interval (CI), 0.71-0.94 and OR, 0.51; 95% CI, 0.35-0.74, respectively]. Higher serum vitamin D levels were associated with a reduced risk of diabetes in Korean adults, suggesting that vitamin D may play a role in the pathogenesis of diabetes.

Association between Vitamin D Status and Risk of Peripheral Arterial Disease: The Dong-gu Study

Low levels of vitamin D have been associated with increased cardiovascular disease risk. However, few studies have evaluated the association between vitamin D status and peripheral arterial disease (PAD). We therefore aimed to investigate whether low 25-hydroxyvitamin D (25(OH)D) levels were associated with increased risk of PAD in the Korean population. This cross-sectional study was conducted among 8,960 subjects aged 50 years or older without known myocardial infarction or stroke. PAD was defined by an ankle brachial blood pressure index <0.9. Multivariate logistic regression was used to evaluate the association between serum 25(OH)D levels and risk of PAD. Of the 8,960 subjects, 3.0% had PAD and the age and sex adjusted prevalence of PAD decreased with the increasing 25(OH)D quartile. After adjusting for potential confounders and parathyroid hormones, serum 25(OH)D levels were associated with a significantly decreased risk of PAD (OR for one SD increase, 0.98; 95% CI, 0.95-1.0, P for trend=0.040). Compared with the first 25(OH)D quartile, the odds of PAD were 0.86 (95% CI, 0.62-1.21), 0.67 (95% CI, 0.46-0.97), and 0.71 (95% CI, 0.49-1.04) for the second, third, and fourth quartiles, respectively. In this cross-sectional study, we found that low serum 25(OH)D levels were associated with an increased risk of PAD, independent of traditional cardiovascular risk factors and parathyroid hormone. Our findings suggest that low vitamin D levels may contribute to PAD in the Korean population.

The association between vitamin D and parathyroid hormone and bone mineral density: the Dong-gu Study

The primary objective of the present study was to investigate the relationship between 25-hydroxyvitamin D (25[OH]D) and areal bone mineral density (aBMD) in Korean subjects from the general population aged ≥50 years. This study included 8,857 individuals who completed the baseline survey of the Dong-gu study, which was conducted in Korea from 2007-2010. The participants who fulfilled the detailed inclusion criteria underwent assessment of the femoral neck and lumbar spine aBMD as well as measurement of serum 25(OH)D and parathyroid hormone (PTH) levels. After adjusting for other covariates and log-PTH values, the mean aBMD of the femoral neck exhibited a significant increase with increasing 25(OH)D levels in both males (p < 0.001) and females (p = 0.005). Additionally, the mean aBMD of the lumbar spine exhibited a significant increase with increasing 25(OH)D levels in males (p = 0.011) but not females (p = 0.252). After adjusting for covariates and log-25(OH)D values, the mean aBMD values of the femoral neck and lumbar spine showed significant decreases with increasing PTH levels in both males and females (p < 0.001). The present findings demonstrate that the aBMD of the femoral neck was significantly associated with 25(OH)D levels independent of PTH in both males and females and that the aBMD of the lumbar spine was significantly associated with 25(OH)D levels independent of PTH in males, but not females.

25-Hydroxyvitamin D and Parathyroid Hormone Levels Are Independently Associated with the Hemoglobin A1c Level of Korean Type 2 Diabetic Patients: The Dong-Gu Study

In type 2 diabetic patients, the relationships between 25-hydroxyvitamin D and parathyroid hormone levels, and glycemic control, remain unclear. We evaluated associations between 25-hydroxyvitamin D, parathyroid hormone, and hemoglobin A_1c levels after adjusting for other covariates, including log transformed 25-hydroxyvitamin D levels and log transformed parathyroid hormone levels, in Korean patients with type 2 diabetes. In total, 1,175 patients with type 2 diabetes were selected from 8,857 individuals who completed the baseline survey of the Dong-gu study, conducted in Korea from 2007 to 2010. After adjusting for other covariates, we found that the mean hemoglobin A_1c level was inversely associated with the 25-hydroxyvitamin D level (Q1: 7.47% [7.30–7.63], Q2: 7.25% [7.09–7.40], Q3: 7.17% [7.02–7.32], Q4: 7.19% [7.02–7.35]; p for trend = 0.021, p for between groups = 0.050) and the parathyroid hormone level (Q1: 7.35% [7.19–7.51], Q2: 7.34% [7.19–7.50], Q3: 7.28% [7.13–7.43], Q4: 7.09% [6.94–7.24]; p for trend = 0.022, p for between groups = 0.048). However, the mean fasting glucose level was not associated with either the 25-hydroxyvitamin D or parathyroid hormone level. In conclusion, inverse associations were evident between hemoglobin A_1c, 25-hydroxyvitamin D and parathyroid hormone levels in Korean patients with type 2 diabetes. The associations remained significant after adjusting for other covariates, including the log transformed 25-hydroxyvitamin D levels and log transformed parathyroid hormone levels.

Genome-wide association study in East Asians identifies two novel breast cancer susceptibility loci

Breast cancer is one of the most common malignancies among women worldwide. Genetic factors have been shown to play an important role in breast cancer aetiology. We conducted a two-stage genome-wide association study (GWAS) including 14 224 cases and 14 829 controls of East Asian women to search for novel genetic susceptibility loci for breast cancer. Single nucleotide polymorphisms (SNPs) in two loci were found to be associated with breast cancer risk at the genome-wide significance level. The first locus, represented by rs12118297 at 1p22.3 (near the LMO4 gene), was associated with breast cancer risk with odds ratio (OR) and (95% confidence interval (CI)) of 0.91 (0.88-0.94) and a P-value of 4.48 × 10^{-  8} This association was replicated in another study, DRIVE GAME-ON Consortium, including 16 003 cases and 41 335 controls of European ancestry (OR = 0.95, 95% CI = 0.91-0.99, P-value = 0.019). The second locus, rs16992204 at 21q22.12 (near the LINC00160 gene), was associated with breast cancer risk with OR (95% CI) of 1.13 (1.07-1.18) and a P-value of 4.63 × 10 ^{-  8} The risk allele frequency for this SNP is zero in European-ancestry populations in 1000 Genomes Project and thus its association with breast cancer risk cannot be assessed in DRIVE GAME-ON Consortium. Functional annotation using the ENCODE data indicates that rs12118297 might be located in a repressed element and locus 21q22.12 may affect breast cancer risk through regulating LINC00160 expressions and interaction with oestrogen receptor signalling. Our findings provide additional insights into the genetics of breast cancer.

Associations between body composition measurements of obesity and radiographic osteoarthritis in older adults: Data from the Dong-gu Study

Background

We examined the effects of fat deposition on radiographic osteoarthritis (OA) to determine the role of obesity in the pathogenesis of radiographic OA.

Methods

Data were taken from the Dong-gu cohort, a cross-sectional study of 2,367 subjects. Baseline characteristics, waist circumference (WC), waist-to-hip ratio (WHR), fat mass, and fat percentage were collected, along with X-rays of the knees and hands. Total knee and hand radiographic OA scores were summed using a semi-quantitative grading system, and then stratified by gender using a multiple linear regression model.

Results

After adjusting for confounders, weight was the only factor significantly associated with knee radiographic OA, regardless of gender (all p < 0.01). Regarding the hand, fat percentage had the largest effect on radiographic OA in males (p = 0.008), while WHR was the most significant factor in females (p = 0.001). For the knee, fat mass was the most important factor for radiographic OA in males (p = 0.001), while in females, body mass index was the most important factor (p < 0.001). Among the variables, only fat percentage was significantly related to both hand and knee radiographic OA in both genders (all p < 0.01).

Conclusions

Regardless of gender, weight was significantly associated with knee radiographic OA. Otherwise, fat deposition correlated with hand and knee radiographic OA in both genders, while the distribution of fat tissue was significantly associated with hand and knee radiographic OA only in females.

Association of APOE Genotype with Bone Mineral Density in Men and Women: The Dong-gu and Namwon Studies

Many studies have investigated relationships between APOE genotype and bone mineral density (BMD). However, the results of these studies have been inconsistent. Few studies have been carried out in Asian populations. We studied the relationship of the APOE gene polymorphism and BMD in two large population-based studies. The datasets included the Dong-gu Study (3575 men and 5335 women) and the Namwon Study (2310 men, 3512 women). Lumbar spine and femoral neck BMD were measured by dual-energy X-ray absorptiometry. APOE genotypes were analyzed by polymerase chain reaction–restriction fragment length polymorphism. The APOE genotypes were classified into APOE E2 (E2/E2 and E2/E3), APOE E3 (E3/E3), and APOE E4 (E3/E4 and E4/E4). The genotype distribution of the study population was in Hardy-Weinberg equilibrium. There were no significant differences among APOE genotype groups in lumbar and femoral neck BMD in either cohort. Our data do not support the hypothesis that the APOE genotype is associated with BMD.

HbA1c is significantly associated with arterial stiffness but not with carotid atherosclerosis in a community-based population without type 2 diabetes: The Dong-gu study

OBJECTIVES

We examined the associations between HbA1c levels and various atherosclerotic vascular parameters among adults without diabetes from the general population.

METHODS

A total of 6500 community-dwelling adults, who were free of type 2 diabetes and ≥50 years of age, were included. High-resolution B-mode ultrasound was used to evaluate carotid artery structure, including intima-media thickness (IMT), plaque, and luminal diameter. Brachial-ankle pulse wave velocity (baPWV), which is a useful indicator of systemic arterial stiffness, was determined using an automatic waveform analysis device.

RESULTS

No significant associations were observed between HbA1c, carotid IMT, plaque, or luminal diameter in a fully adjusted model. However, the odds ratio (95% confidence interval) for high baPWV (defined as the highest quartile) increased by 1.43 (1.19-1.71) per 1% HbA1c increase after adjusting for conventional risk factors in a multivariate logistic regression analysis. In addition, HbA1c was independently associated with baPWV in a multivariate linear regression analysis.

CONCLUSIONS

High-normal HbA1c level was independently associated with arterial stiffness, but not with carotid atherosclerotic parameters, in the general population without diabetes. Our results suggest that the functional atherosclerotic process may already be accelerated according to HbA1c level, even at a level below the diagnostic threshold for diabetes.

The relationships between bone mineral density and radiographic features of hand or knee osteoarthritis in older adults: data from the Dong-gu Study

OBJECTIVE

The relationship between OA and osteoporosis has exhibited contradictory features over the past four decades. The aim of this study was to determine using separate analysis of the radiographic features of OA whether various radiographic features of OA were associated differently with BMD in the Korean elderly.

METHODS

Data were derived from the Dong-gu cohort; 2354 subjects were enrolled in the present cross-sectional study. Baseline characteristics, the BMDs of the lumbar spine and femoral neck measured by DXA, and X-rays of knees and hands were collected. A semi-quantitative grading system was used to estimate the severities of individual radiographic features. We adjusted for confounders using multiple linear regression modelling to analyse the relationships.

RESULTS

After adjustment for confounders, hand and knee OA total scores were negatively associated with the BMDs of the lumbar spine and femoral neck, except for the total knee OA score and lumbar spine BMD. In detail, hand osteophytes and sclerosis exhibited positive relationships with the BMDs of the lumbar spine and femoral neck, except for hand osteophytes and femoral neck BMD. On the contrary, however, knee joint space narrowing (JSN), hand JSN, and hand subchondral cysts were negatively associated with the BMD of the lumbar spine and femoral neck. Knee JSN and hand subchondral cysts exerted the greatest effects on BMD.

CONCLUSION

Separate analysis of the radiographic features of OA better reveals associations of OA with the BMD of the lumbar spine and femoral neck.