Associations between Living Alone and Smoking and Alcohol Consumption in Korean Adults.

BACKGROUND: Recently, single-person households have increased in Korea and this trend may have potential public health implications and affect various health behaviors. This study investigated the associations between living alone and health behaviors such as smoking and alcohol consumption among Korean adults. METHODS: We used data from the 6th Korea National Health and Nutrition Examination Survey between 2013 and 2015 and a total of 17,088 adults were included. We performed a multivariable logistic regression analysis and calculated odds ratios (ORs) with 95% confidence intervals (CIs). RESULTS: Single-person households accounted for about 10% of the total participants. The proportions of currently smoking and heavy alcohol consumption were higher among individuals living alone than those living together among younger women and middle-aged and elderly men and women. In the multivariable logistic regression analysis, living alone was associated with increased odds of currently smoking compared to living together among middle-aged men and women (OR, 7.37; 95% CI, 2.33-23.32 in men and OR, 2.36; 95% CI, 1.04-5.36 in women) after adjusting for confounding variables. CONCLUSION: From this nationwide, population-based study, we found that living alone is associated with increased odds of currently smoking, especially in middle-aged people. Public health concerns may be warranted for middle-aged single-person households to reduce health risks related to smoking.

Variabilities in Weight and Waist Circumference and Risk of Myocardial Infarction, Stroke, and Mortality: A Nationwide Cohort Study.

BACKGROUND: Evidence regarding the association between variabilities in obesity measures and health outcomes is limited. We aimed to examine the association between variabilities in obesity measures and cardiovascular outcomes and all-cause mortality. METHODS: We identified 4,244,460 individuals who underwent health examination conducted by the Korean National Health Insurance Service during 2012, with ≥3 anthropometric measurements between 2009 and 2012. Variabilities in body weight (BW) and waist circumference (WC) were assessed using four indices including variability independent of the mean (VIM). We performed multivariable Cox proportional hazards regression analyses. RESULTS: During follow-up of 4.4 years, 16,095, 18,957, and 30,200 cases of myocardial infarction (MI), stroke, and all-cause mortality were recorded. Compared to individuals with the lowest quartiles, incrementally higher risks of study outcomes and those of stroke and all-cause mortality were observed among individuals in higher quartiles of VIM for BW and VIM for WC, respectively. The multivariable adjusted hazard ratios and 95% confidence intervals comparing the highest versus lowest quartile groups of VIM for BW were 1.17 (1.12 to 1.22) for MI, 1.20 (1.16 to 1.25) for stroke, and 1.66 (1.60 to 1.71) for all-cause mortality; 1.07 (1.03 to 1.12) for stroke and 1.29 (1.25 to 1.33) for all-cause mortality regarding VIM for WC. These associations were similar with respect to the other indices for variability. CONCLUSION: This study revealed positive associations between variabilities in BW and WC and cardiovascular outcomes and allcause mortality. Our findings suggest that variabilities in obesity measures are associated with adverse health outcomes in the general population.

Obesity, abdominal obesity and subsequent risk of kidney cancer: a cohort study of 23.3 million East Asians.

BACKGROUND: Limited evidence exists regarding associations between obesity and kidney cancer among Asians. We examined the associations between obesity measures and risk of kidney cancer. METHODS: We included 23,313,046 adults who underwent health examinations provided by the Korean National Health Insurance Service 2009-2012 and performed multivariable Cox proportional hazards regression analyses. RESULTS: During 5.4 years of follow-up, 18,036 cases of kidney cancer were recorded, and cumulative incidence was 0.12%. General and abdominal obesity were associated with 1.32-fold increased risk of kidney cancer compared with groups without either obesity status. Underweight individuals showed decreased adjusted hazard ratio (HR) for kidney cancer (0.76, 95% confidence interval: 0.68-0.85) compared to those with normal body mass index (BMI), while the HRs increased among individuals with BMI 23-24.9 kg/m2 (1.23, 1.18-1.28), 25-29.9 kg/m2 (1.41, 1.36-1.46) and ≥30 kg/m2 (1.77, 1.65-1.90) (P for trend < 0.001). HRs of kidney cancer increased with increasing waist circumference (WC) (P for trend < 0.001). Compared to non-obese condition, the coexistence of general and abdominal obesity increased the HR (1.45, 1.40-1.50). CONCLUSIONS: This study demonstrated positive associations of BMI and WC with kidney cancer risk. General and abdominal obesity may be risk factors of kidney cancer.

Chronic renal dysfunction, proteinuria, and risk of Parkinson's disease in the elderly.

BACKGROUND: The roles of chronic kidney disease and proteinuria in the development of Parkinson's disease have not been widely studied. The objective of this study was to examine the associations of chronic renal dysfunction and proteinuria with the risk of PD in older adults using cohort data of the whole South Korean population. METHODS: We included 3,580,435 individuals aged ≥65 years who had undergone health checkups provided by the National Health Insurance Service of South Korea between 2009 and 2012 and were followed until 2015. Multivariable Cox proportional hazards regression models were performed. RESULTS: During a mean follow-up of 5.2 ± 1.3 years, 30,813 individuals (0.86% of the total population) developed PD. Lower estimated glomerular filtration rate and a higher degree of proteinuria on a dipstick test were associated with higher incidence probability of PD (log-rank P < 0.001). In Cox regression models, chronic renal dysfunction graded by estimated glomerular filtration rate (mL/min/1.73 m2 ) was associated with increased risk of PD after adjusting for potential confounding variables; hazard ratio (95% confidence interval) was 1.13 (1.10-1.17) for estimated glomerular filtration rate 60-90, 1.36 (1.31-1.42) for estimated glomerular filtration rate 30-60, and 1.47 (1.32-1.63) for estimated glomerular filtration rate <30 (P for trend <0.001). Proteinuria ≥1+ was also associated with increased risk of PD development (hazard ratio, 1.12; 95% confidence interval, 1.06-1.18). Coexistence of chronic kidney disease and proteinuria showed an increased hazard ratio of 1.33 (95% confidence interval, 1.23-1.45) for PD occurrence. CONCLUSIONS: Our findings suggest that chronic renal dysfunction and dipstick-positive proteinuria may be independent risk factors for the development of PD in older adults. © 2019 International Parkinson and Movement Disorder Society.

Associations between Breastfeeding and Type 2 Diabetes Mellitus and Glycemic Control in Parous Women: A Nationwide, Population-Based Study.

We investigated associations between breastfeeding duration and number of children breastfed and type 2 diabetes mellitus (T2DM) and glycemic control among parous women. We performed a cross-sectional analysis of data for 9,960 parous women from the Korea National Health and Nutritional Examination Survey (2010 to 2013). Having ever breastfed was inversely associated with prevalent T2DM (adjusted odds ratio [OR], 0.60; 95% confidence interval [CI], 0.42 to 0.87). All ranges of total and average breastfeeding duration showed inverse associations with T2DM. Even short periods of breastfeeding were inversely associated with T2DM (adjusted OR, 0.61; 95% CI, 0.38 to 0.99 for a total breastfeeding duration ≤12 months; adjusted OR, 0.65; 95% CI, 0.42 to 0.99 for an average breastfeeding duration per child ≤6 months). A longer duration of breastfeeding was associated with better glycemic control in parous women with T2DM (P trend=0.004 for total breastfeeding duration; P trend <0.001 for average breastfeeding duration per child). Breastfeeding may be associated with a lower risk of T2DM and good glycemic control in parous women with T2DM. Breastfeeding may be a feasible method to prevent T2DM and improve glycemic control.

Impact of body mass index and body weight variabilities on mortality: a nationwide cohort study.

BACKGROUND/OBJECTIVES: There is limited information regarding the impact of body mass index (BMI) and body weight (BWt) variabilities on mortality. This study aimed to investigate the association between BMI, BWt variabilities and subsequent mortality in the Korean population. SUBJECTS/METHODS: This study used a representative sample cohort enrolled in the national health examination program conducted by the Korean National Health Insurance Service, and 125,391 individuals were included and followed up until 2013 (mean follow-up period = 84 months). BMI and BWt variabilities were estimated as the standard deviation (SD) and coefficient of variation (CV) of serial measurements of BMI and BWt (BMI_SD, BWt_SD, BMI_CV, and BWt_CV). Cox proportional hazard regression models were used to evaluate the all-cause and cause-specific mortality according to variability indices. RESULTS: Baseline BMI showed a non-linear association with all-cause mortality. The highest quartile (Q4) groups of variability indices were associated with increased all-cause mortality risk compared to the lowest quartile (Q1) groups after adjusting for confounding factors (hazard ratio [95% confidence interval] = 1.23 [1.11-1.37] for BMI_SD; 1.25 [1.06-1.47] for BMI_CV; 1.33 [1.20-1.48] for BWt_SD; 1.42 [1.28-1.58] for BWt_CV). The hazard ratios of all-cause mortality increased from the Q2 to the Q4 groups of variability indices, in each sex group and among individuals aged ≥40 years. Furthermore, Q4 groups of variability indices were positively associated with cause-specific mortality compared to groups with Q1-Q3 of the indices (1.28 [1.05-1.56] for BWt_SD, 1.21 [1.001-1.47] for BMI_CV, 1.29 [1.06-1.56] for BWt_CV regarding cardiovascular diseases mortality; 1.18 [1.03-1.36] for BWt_SD, 1.21 [1.06-1.39] for BMI_CV, 1.26 [1.10-1.44] for BWt_CV regarding cancer mortality). CONCLUSIONS: Our results suggest that BMI and BWt variabilities are independent risk factors for all-cause and cause-specific mortality.

Metabolic syndrome and risk of Parkinson disease: A nationwide cohort study.

BACKGROUND: The association of metabolic syndrome (MetS) with the development of Parkinson disease (PD) is currently unclear. We sought to determine whether MetS and its components are associated with the risk of incident PD using large-scale cohort data for the whole South Korean population. METHODS AND FINDINGS: Health checkup data of 17,163,560 individuals aged ≥40 years provided by the National Health Insurance Service (NHIS) of South Korea between January 1, 2009, and December 31, 2012, were included, and participants were followed up until December 31, 2015. The mean follow-up duration was 5.3 years. The hazard ratio (HR) and 95% confidence interval (CI) of PD were estimated using a Cox proportional hazards model adjusted for potential confounders. We identified 44,205 incident PD cases during follow-up. Individuals with MetS (n = 5,848,508) showed an increased risk of PD development compared with individuals without MetS (n = 11,315,052), even after adjusting for potential confounders including age, sex, smoking, alcohol consumption, physical activity, income, body mass index, estimated glomerular filtration rate, and history of stroke (model 3; HR, 95% CI: 1.24, 1.21-1.27). Each MetS component was positively associated with PD risk (HR, 95% CI: 1.13, 1.10-1.16 for abdominal obesity; 1.13, 1.10-1.15 for hypertriglyceridemia; 1.23, 1.20-1.25 for low high-density lipoprotein cholesterol; 1.05, 1.03-1.08 for high blood pressure; 1.21, 1.18-1.23 for hyperglycemia). PD incidence positively correlated with the number of MetS components (log-rank p < 0.001), and we observed a gradual increase in the HR for incident PD with increasing number of components (p < 0.001). A significant interaction between age and MetS on the risk of incident PD was observed (p for interaction < 0.001), and people aged ≥65 years old with MetS showed the highest HR of incident PD of all subgroups compared to those <65 years old without MetS (reference subgroup). Limitations of this study include the possibilities of misdiagnosis of PD and reverse causality. CONCLUSIONS: Our population-based large-scale cohort study suggests that MetS and its components may be risk factors of PD development.

Associations of mental health and sleep duration with menstrual cycle irregularity: a population-based study.

This study aimed to examine whether the characteristics of mental health and sleep duration, alone or in combination, are associated with menstrual cycle irregularity. This population-based, cross-sectional study analyzed the data from 4445 women aged 19-49 years, who participated in the Korea National Health and Nutrition Examination Survey 2010-2012. A structured questionnaire was used to assess mental health characteristics, sleep duration, and menstrual cycle irregularity. A multivariable logistic regression analysis was performed. High stress, depressive mood, and suicidal ideation were associated with increased risk of menstrual cycle irregularity after adjusting for confounding variables (odds ratio [95% confidence interval] = 1.33 [1.07-1.65], 1.56 [1.17-2.07], and 1.37 [1.01-1.87], respectively). Short sleep duration (≤ 5 h a day) was significantly associated with higher odds of severe menstrual cycle irregularity with menstrual interval of greater than 3 months (2.67 [1.35-5.27]). Participants with sleep duration of ≤ 5 h a day with psychological stress, depressive mood, or suicidal ideation had higher odds of menstrual cycle irregularity (1.96 [1.26-3.05], 2.86 [1.50-5.44], and 2.25 [1.18-4.29]). This study suggests positive associations of mental health problems and short sleep duration with menstrual cycle irregularity among Korean female adults. Therefore, strategies to deal with psychological stress, depressive mood, and sleep duration are needed for improving the reproductive health of women suffering from menstrual disturbances.

Validation of the Korean Version of the Breakthrough Pain Assessment Tool in Cancer Patients.

CONTEXT: Breakthrough cancer pain has not been properly evaluated and treated because there are relatively few available measurements. The Breakthrough Pain Assessment Tool (BAT) is currently recognized as a brief, multidimensional, and reliable measurement. OBJECTIVES: The objective of this study was to validate the Korean version of the BAT (BAT-K) in adult cancer patients. METHODS: We conducted a forward-backward translation and cross-cultural equivalence test. The psychometric properties with 120 cancer patients were assessed using factor analysis, reliability, and validity. RESULTS: The Korean translation was well accepted by participants. Factor analysis revealed the presence of two underlying factors: frequency/severity and duration/medication efficacy. Cronbach alpha coefficient was 0.743. Severity, distress, and disruption of normal life showed strong reliability. The intraclass correlation for the test-retest reliability was 0.782 (95% confidence interval 0.694-0.854). The BAT-K had significant correlations with the Brief Pain Inventory, Pain Management Index, and Eastern Cooperative Oncology Group performance status (all P values < 0.05). CONCLUSION: The BAT-K is a valid and reliable measurement of breakthrough cancer pain in Korean cancer patients.