Household and area income levels are associated with smoking status in the Korean adult population.

BACKGROUND: Some previous studies have suggested that area-level characteristics have effects on smoking. The aim of this study was to evaluate the associations between household income and area income on smoking in Korean adults. METHODS: This study was based on the Korean Community Health Survey (KCHS) performed in South Korea, between September and November 2009. In total, 222,242 subjects (103,124 men and 119,118 women) were included in the analysis. Information on smoking status was collected using a standardized questionnaire. Income status was determined by monthly household income. Household income was categorized as: <1 million won; <2 million won; <3 million won; and ≥3 million won. Area-level income categorized as quartiles. Data were analyzed using multilevel regression models. The analysis was conducted separately urban and rural, by sex. RESULTS: The lowest household income group had a higher risk of smoking than the highest household income group in both urban and rural areas for both men and women after adjusting for individual characteristics (urban men: odds ration [OR], 1.44; 95% confidence interval [CI], 1.36-1.53; rural men: OR, 1.33; 95% CI, 1.25-1.42; urban women: OR, 2.38; 95% CI, 2.06-2.76; rural women: OR, 1.51; 95% CI, 1.25-1.83). In men, the lowest area-level income group had a higher risk for smoking than the highest area-level income group in urban areas after adjusting for individual characteristics and household income (OR, 1.17; 95% CI, 1.02-1.33). In women, the lowest area-level income group had a lower risk for smoking than the highest area-level income group in rural areas after adjusting for individual characteristics and household income (OR, 0.52; 95% CI, 0.39-0.70). However, no association was observed between area-level income and smoking in rural areas for men or in urban areas for women. CONCLUSIONS: The results showed that smoking is strongly associated with household income status in both men and women, and area-level income is partly associated with smoking. Effects of area-level income on smoking differed by sex and region. These findings suggest that area characteristics have contextual effects on health related behavior independent of individual characteristics.

Association of smoking status, cumulative smoking, duration of smoking cessation, age of starting smoking, and depression in Korean adults.

BACKGROUND: Many previous studies did not sufficiently control for several confounding factors that may affect the association between smoking and depression, such as socioeconomic status. We investigated the association between depression and smoking status, smoking exposure, duration of smoking cessation, and age of starting smoking while controlling for socioeconomic factors. METHODS: This study was based on a community health survey performed in Jeollanam-do, South Korea, between September and November 2009. In total, 20,084 subjects (9,118 males and 10,966 females) were included in the analysis. Information on smoking characteristics, such as smoking status, pack-years of smoking, and age of starting smoking, was collected using a standardized questionnaire. Depression was defined using the Korean CES-D score. RESULTS: The odds ratios (ORs) of depression were 1.35 (0.92-1.98) for former smokers and 1.77 (1.27-2.48) for current-smokers among males, and 2.67 (1.38-5.16) for former smokers and 3.72 (2.11-6.54) for current-smokers among females, after adjusting for other confounding factors. Compared to light smoking, heavy smoking was significantly associated with depression in males [OR = 3.97, 95% confidence interval (CI) = 1.42-11.14], but not in females (OR = 1.24, 95% CI = 0.73-2.09). No significant associations between depression and age of starting smoking and duration of smoking cessation were observed among former smokers. CONCLUSIONS: Our data demonstrate that smoking is strongly associated with depression, particularly among females. These findings suggest that depression prevention may need to be combined with smoking prevention and that different strategies may be needed for males and females.

Methylenetetrahydrofolate reductase C677T polymorphism in patients with lung cancer in a Korean population.

BACKGROUND: This study was designed to investigate an association between methylenetetrahydrofolate reductase (MTHFR) C677T polymorphism and the risk of lung cancer in a Korean population. METHODS: We conducted a large-scale, case-control study involving 3938 patients with newly diagnosed lung cancer and 1700 healthy controls. Genotyping was performed with peripheral blood DNA for MTHFR C677T polymorphisms. Statistical significance was estimated by logistic regression analysis. RESULTS: The MTHFR C677T frequencies of CC, CT, and TT genotypes were 34.5%, 48.5%, and 17% among lung cancer patients, and 31.8%, 50.7%, and 17.5% in the controls, respectively. The MTHFR 677CT and TT genotype showed a weak protection against lung cancer compared with the homozygous CC genotype, although the results did not reach statistical significance. The age- and gender-adjusted odds ratio (OR) of overall lung cancer was 0.90 (95% confidence interval (CI), 0.77-1.04) for MTHFR 677 CT and 0.88 (95% CI, 0.71-1.07) for MTHFR 677TT. However, after stratification analysis by histological type, the MTHFR 677CT genotype showed a significantly decreased risk for squamous cell carcinoma (age- and gender-adjusted OR, 0.78; 95% CI, 0.64-0.96). The combination of 677 TT homozygous with 677 CT heterozygous also appeared to have a protection effect on the risk of squamous cell carcinoma. We observed no significant interaction between the MTHFR C677T polymorphism and age and gender or smoking habit. CONCLUSIONS: This is the first reported study focusing on the association between MTHFR C677T polymorphisms and the risk of lung cancer in a Korean population. The T allele was found to provide a weak protective association with lung squamous cell carcinoma.

p53 codon 72 polymorphism in patients with gastric and colorectal cancer in a Korean population.

BACKGROUND: The common p53 codon 72 polymorphism has been investigated as a risk factor for cancer in different populations; however, the results have been inconsistent. This study investigated the risk of developing gastric or colorectal cancer associated with the p53 codon 72 polymorphism in a Korean population. METHODS: We conducted a large-scale case-control study that included 2,213 gastric cancer patients; 1,829 colorectal cancer patients; and 1,700 healthy controls. Genotyping was performed with real-time polymerase chain reaction (PCR), using a TaqMan single-nucleotide polymorphism (SNP) genotyping assay. RESULTS: The frequencies of Arg/Arg, Arg/Pro, and Pro/Pro genotypes of the p53 codon 72 polymorphism were 43.3, 42.0, and 13.0% in the gastric cancer patients; 40.5, 45.0, and 14.0% in the colorectal cancer patients; and 43.2, 45.6, and 11.2% in the controls, respectively. The Pro/Pro genotype was associated with an increased risk of gastric [age- and sex-adjusted odds ratio (OR) = 1.25, 95% confidence interval (CI) = 1.01-1.56, P = 0.04] and colorectal cancer (OR = 1.36, 95% CI = 1.07-1.72, P = 0.01). There were no significant interactions between the p53 codon 72 polymorphism and smoking or drinking. CONCLUSIONS: Our results suggest that the Pro/Pro genotype is associated with modest increases in the risks of gastric cancer and colorectal cancer in a Korean population.

Cumulative smoking exposure, duration of smoking cessation, and peripheral arterial disease in middle-aged and older Korean men.

BACKGROUND: We investigated the association of cumulative smoking exposure and duration of smoking cessation with peripheral arterial disease (PAD). METHODS: The study population consisted of 2517 community-dwelling Korean men aged 50 years and older. Information on smoking characteristics such as smoking status, pack-years of smoking, and years since quitting smoking was collected using a standardized questionnaire. PAD was defined as an ankle-brachial index (ABI) less than 0.90 in either leg. RESULTS: The odds ratio (OR, 95% confidence interval) of PAD was 2.31 (1.20-4.42) for former smokers and 4.30 (2.13-8.66) for current smokers, after adjusting for other cardiovascular risk factors. There was a significant dose-response relationship between pack-years of smoking and PAD. Compared with those who had never smoked, the multivariate-adjusted ORs of PAD for smokers of 0.1-20.0, 20.1-40.0, and >40.0 pack-years were 2.15 (1.06-4.38), 2.24 (1.08-4.65), and 2.93 (1.41-6.09), respectively. There was a significant decrease in PAD risk as the years since quitting smoking increased. The multivariate-adjusted ORs of PAD for 11-20 and ≥ 21 years smoking cessation were 0.41 (0.19-0.86) and 0.49 (0.24-0.98), compared with current smokers. CONCLUSIONS: Cumulative smoking exposure and duration of smoking cessation were significantly associated with PAD in middle aged and older Korean men.

Association between albuminuria, carotid atherosclerosis, arterial stiffness, and peripheral arterial disease in Korean type 2 diabetic patients.

BACKGROUND: To evaluate the association between albuminuria, carotid atherosclerosis, arterial stiffness, and peripheral arterial disease (PAD) in Korean type 2 diabetic patients. METHODS: In total, 673 type 2 diabetic patients registered with the public health center participated. Following an overnight fast, venous blood and urine samples were collected and analyzed. The carotid intima-media thickness (IMT), amount of carotid plaque, brachial ankle pulse wave velocity (baPWV), and the ankle-brachial index of each patient were also assessed. RESULTS: Albuminuria was significantly associated with PAD (odds ratio (OR) 2.33; 95% confidence interval (CI) 1.28-4.25 for normoalbuminuria vs. microalbuminuria and OR 3.28; 95% CI 1.40-7.66 for normoalbuminuria vs. macroalbuminuria), but not with carotid plaque. The mean baPWV differed significantly according to the level of albumin relative to the creatinine ratio (1,764.79, 1,778.98, and 2,001.33, respectively; p < 0.001), while no significant difference was observed in the mean IMT value (0.73, 0.74, and 0.72, respectively; p = 0.399). CONCLUSIONS: Albuminuria was significantly associated with baPWV and PAD, but not with carotid plaque or CCA-IMT, in Korean type 2 diabetic patients.

Comparison of the Framingham Risk Score, UKPDS Risk Engine, and SCORE for Predicting Carotid Atherosclerosis and Peripheral Arterial Disease in Korean Type 2 Diabetic Patients.

BACKGROUND: To compare the predictability of the Framingham Risk Score (FRS), United Kingdom Prospective Diabetes Study (UKPDS) risk engine, and the Systematic Coronary Risk Evaluation (SCORE) for carotid atherosclerosis and peripheral arterial disease in Korean type 2 diabetic patients. METHODS: Among 1,275 registered type 2 diabetes patients in the health center, 621 subjects with type 2 diabetes participated in the study. Well-trained examiners measured the carotid intima-media thickness (IMT), carotid plaque, and ankle brachial index (ABI). The subject's 10-year risk of coronary heart disease was calculated according to the FRS, UKPDS, and SCORE risk scores. These three risk scores were compared to the areas under the curve (AUC). RESULTS: The odds ratios (ORs) of all risk scores increased as the quartiles increased for plaque, IMT, and ABI. For plaque and IMT, the UKPDS risk score provided the highest OR (95% confidence interval) at 3.82 (2.36, 6.17) and at 6.21 (3.37, 11.45). For ABI, the SCORE risk estimation provided the highest OR at 7.41 (3.20, 17.18). However, no significant difference was detected for plaque, IMT, or ABI (P = 0.839, 0.313, and 0.113, respectively) when the AUCs of the three risk scores were compared. When we graphed the Kernel density distribution of these three risk scores, UKPDS had a higher distribution than FRS and SCORE. CONCLUSION: No significant difference was observed when comparing the predictability of the FRS, UKPDS risk engine, and SCORE risk estimation for carotid atherosclerosis and peripheral arterial disease in Korean type 2 diabetic patients.

Association between hemoglobin A1c, carotid atherosclerosis, arterial stiffness, and peripheral arterial disease in Korean type 2 diabetic patients.

AIMS: To evaluate the association between hemoglobin A(1c) (HbA(1c)), carotid atherosclerosis, arterial stiffness, and peripheral arterial disease (PAD) in Korean type 2 diabetic patients. METHODS: A total of 370 type 2 diabetic patients registered with the public health center in Gokseng-gun, Korea, participated in this study. Following an overnight fast, venous blood was collected and analyzed by high-performance liquid chromatography. The carotid intima-media thickness (IMT), amount of carotid plaque, brachial ankle pulse wave velocity (baPWV), and ankle-brachial index (ABI) of each patient were also assessed. RESULTS: For categorical variables, we performed logistic regression after adjustment for other CVD risk factors. There was a significant association between HbA(1c) and carotid plaque [OR 2.66, 95% confidence interval (CI) 1.01 to 5.67 for the highest vs. the lowest tertile of HbA(1c)], and PAD (OR 3.75, 95% CI 1.30 to 10.81). For continuous variables, we performed analysis of covariance (ANCOVA) after adjustment for other covariates. The mean values of common carotid artery intima-media thickness (CCA-IMT) and baPWV were not significantly different according to the HbA(1c) tertiles. CONCLUSION: HbA(1c) was significantly associated with carotid plaque and PAD, but not CCA-IMT and baPWV in Korean type 2 diabetic patients.

p53 codon 72 polymorphism and the risk of lung cancer in a Korean population.

The aim of this study was to assess whether p53 codon 72 polymorphism is associated with an increased risk of lung cancer (LC) in a South Korean population. We conducted a population-based, large-scale, case-control study including 3939 patients with LC and 1700 controls. P53 codon 72 polymorphism was determined by real-time polymerase chain reaction (PCR). The frequencies of p53 codon 72 polymorphisms (Arg/Arg, Arg/Pro, and Pro/Pro) in LC were 37.0%, 46.2%, and 16.7%, respectively; frequencies in the controls were 43.2%, 45.6%, and 11.2%, respectively (p<0.01). The Arg/Pro and Pro/Pro genotype were significantly associated with increased risk of LC (odds ratio (OR)=1.22, 95% confidence interval (CI)=1.06-1.14 and OR=1.83, 95% CI=1.48-2.26, respectively) compared with the Arg/Arg genotype. Risk was compared in different subgroups. The OR of Pro/Pro genotype was significantly higher in small cell lung cancer (SCC) and squamous cell carcinoma (SQC) than in adenocarcinoma (ADC). Higher OR of Pro/Pro genotype was also seen among males. However, relationships between gender, age, smoking, and genotypes were not found. P53 codon 72 polymorphism was associated with an increased risk of LC in this Korean population; the association was especially noteworthy in SQC, SCC, and males.

[A comparison of fasting glucose and HbA1c for the diagnosis of diabetes mellitus among Korean adults].

OBJECTIVES: The American Diabetes Association (ADA) has recently recommended the HbA1c assay as one of four options for making the diagnosis of diabetes mellitus, with a cut-point of ≥ 6.5%. We compared the HbA1c assay and the fasting plasma glucose level for making the diagnosis of diabetes among Korean adults. METHODS: We analyzed 8710 adults (age 45-74 years), who were not diagnosed as having diabetes mellitus, from the Namwon study population. A fasting plasma glucose level of ≥ 126 mg/dL and an A1c of ≥ 6.5% were used for the diagnosis of diabetes. The kappa index of agreement was calculated to measure the agreement between the diagnosis based on the fasting plasma glucose level and the HbA1c. RESULTS: The kappa index of agreement between the fasting plasma glucose level and HbA1c was 0.50. CONCLUSIONS: The agreement between the fasting plasma glucose and HbA1c for the diagnosis of diabetes was moderate for Korean adults.

[Management of diabetic mellitus in low-income rural patients].

OBJECTIVES: Knowledge about the management status of diabetic mellitus (DM) is essential to improve diabetic management. Moreover, low income is associated with poor adherence to treatment and increased mortality. This study was performed to evaluate the management status of DM in low-income patients in a rural area. METHODS: We enrolled 370 patients with type 2 DM living in Gokseong county, JeollaNamdo. A well-trained examiner measured the height, weight, waist circumference, blood pressure, total cholesterol, triglyceride, high density lipoprotein cholesterol, fasting blood sugar and glycosylated hemoglobin (HbA1c) levels. Carotid ultrasonography was used to measure carotid artery carotid artery intima media thickness (IMT) and plaque. ankle-brachial index (ABI) was used to evaluate peripheral artery disease. A fundoscopic examination was performed to evaluate diabetic retinopathy. A history of diabetes complications and health-related questionnaires were also completed. RESULTS: The age of diabetic subjects was 68.7+/-8.7 years and the duration of diabetes was 8.9+/-8.2 years. Most (63.5%) had hypertension, and 45.7% had triglycerides below 150 mg/dl, 38.1% had low density lipoprotein cholesterol (LDL) cholesterol below 100 mg/dl, 48.7% had urine albumin to creatinine ratio (UACR) below 30 mg/g. Less than half (45.9%) achieved the goal of HbA1c less than 7% suggested by the American Diabetes Association (ADA). 10.6% had peripheral vascular disease, 11.9% had retinopathy, and 60.8% had chronic kidney disease. CONCLUSIONS: DM management in low income patients is very poor and requires further work to improve.