Trends in the Incidence and Etiology of Non-Traumatic Spinal Cord Injury in Korea: A Nationwide Population-Based Study From 2007 to 2020.

BACKGROUND: Although patients with non-traumatic spinal cord injury (NTSCI) have distinct epidemiological characteristics compared to those with traumatic spinal cord injury, no previous study has reported the incidence of NTSCI on a national scale in Korea. In this study, we examined the trend in incidence of NTSCI in Korea and described the epidemiological characteristics of patients with NTSCI using nationwide insurance data. METHODS: National Health Insurance Service data were reviewed for the period from 2007 to 2020. The International Classification of Diseases, 10th revision, was used to identify patients with NTSCI. Inpatients with newly diagnosed NTSCI on their first admission during the study period were included. Crude incidence was calculated using the annual number of NTSCI cases divided by the mid-year population estimates. Age-specific incidence was calculated by dividing the number of cases in 10-year age groups by the total number of individuals in that age group. Age-adjusted incidence was calculated using direct standardization. Annual percentage changes were calculated using Joinpoint regression analysis. The Cochrane-Armitage trend test was conducted to examine the trends of NTSCI incidence according to the types or etiologies of NTSCI. RESULTS: The age-adjusted incidence of NTSCI increased continuously from 24.11 per million in 2007 to 39.83 per million in 2020, with a significant annual percentage change (4.93%, P < 0.05). The age-specific incidence for those in their 70s and 80s or older was the highest and rapidly increased from 2007 to 2020. According to the types of paralysis in NTSCI, the proportion of tetraplegia decreased, whereas those of paraplegia and cauda equina increased significantly from 2007 to 2020. The proportion of degenerative diseases was the largest among all etiologies and increased significantly during the study period. CONCLUSION: The annual incidence of NTSCI in Korea is increasing significantly, particularly among older adults. As Korea is one of the countries with most rapidly aging population in the world, these results have significant implications, indicating that preventive strategies and sufficient rehabilitation medical services are warranted for the population of older adults.

Association between family conflict resolution methods and depressive symptoms in South Korea: a longitudinal study.

We investigated the relationship between family conflict resolution and depression, focusing on each component of family conflict resolution to determine which factors have stronger associations with depression. We used data from 2008 to 2015 of the Korea Welfare Panel Study. Our final sample included 3565 participants. For each participant, we included at least 2-8 years of follow-up data with a mean follow-up time of 4.05 ± 2.52 years. To identify the relationship between new-onset depressive symptoms and participants' family conflict resolution styles, we performed generalized estimating equation analysis with autoregressive working correlations to estimate adjusted odds ratios for new-onset depressive symptoms adjusted for covariates. Compared with positive family conflict resolution, negative family conflict resolution had a higher odds ratio for depressive symptoms (aOR 1.80, 95% CI 1.42-2.29). This relationship was strongly founded on participants who were women (aOR 2.35, 95% CI 1.55-3.94) with experience of verbal aggression (aOR 1.84, 95% CI 1.42-2.37) and threatening behaviors (aOR 1.89, 95% CI 1.25-2.85). Negative family conflict resolution has long-term associations with an elevated risk of depressive symptoms. In particular, we observed higher risks of depression with verbal and psychological conflict than with physical conflict. Health care providers and health policymakers should support the management and development of methods for dealing with family conflict to improve mental health at a family level, as well as an individual level.

Waist circumference trajectories and risk of type 2 diabetes mellitus in Korean population: the Korean genome and epidemiology study (KoGES).

BACKGROUND: To classify waist circumference (WC) trajectories and examine each trajectory's association with risk of incident type 2 diabetes mellitus (T2DM). METHODS: In Korean Genome and Epidemiology Study (KoGES 2001-2014), 4992 participants aged 40 years and above who received biennial health examinations from wave 1 to wave 4 (2001-2008) were selected. Five distinct trajectory groups were identified for WC using group-based trajectory modeling methods such as censored normal model. Cox proportional hazards model was used to examine the association of trajectories with risk of T2DM. RESULTS: During 31,118 person-years of follow-up (mean follow-up duration, 6.2 years), 276 incident cases of T2DM were identified. Through trajectory analysis, 5 distinct WC patterns were found during wave1 to wave 4, which were "Group A" was stable on very low levels, "Group B" was stable on low levels, "Group C" was stable on moderate levels, "Group D" had increasing pattern on elevated levels, "Group E" was shown increasing on high levels. Age-standardized incidences rates per 100,000 person-years were increased with WC expanding trajectory group (193.9 for Group A, 498.4 for Group B, 661.9 for Group C, 1845.9 for Group D, and 2045.0 for Group E). In multivariate analysis after adjusting for confounding variable at wave 4, Group B (Hazard ratio (HR), 2.2; 95% confidence interval (CI), and 1.1-4.6), Group C (HR: 2.5, 95% CI: 1.2-5.0), Group D (HR: 5.4, 95% CI: 2.7-10.9), Group E (HR: 7.3, 95% CI: 3.5-15.4) had a higher risk of T2DM than Group A. After further adjusting for body mass index strongly correlated with WC, the association was attenuated. CONCLUSIONS: WC trajectory was a significant predictor of T2DM risk in increasing trajectories on high level. This finding indicate the importance of WC management across prolong lifespan by assessing the prognosis and prevention strategies of high-risk populations for T2DM in middle-aged adults.

Dose-response relationship between gamma-glutamyltransferase and the risk of atherosclerotic cardiovascular diseases in Korean adults.

BACKGROUND AND AIMS: The value of gamma-glutamyltransferase (GGT) in the putative mechanisms underlying its association with cardiovascular disease is unclear. This study examined whether serum GGT value has an independent association and dose-response relationship with the risk of atherosclerotic cardiovascular disease (ASCVD). METHODS: This observational study included 419,433 subjects from the National Health Insurance Service database. Serum GGT levels were classified into sex-specific quartiles. We used Cox proportional hazard models to examine the effect of serum GGT values on the risk of ASCVD. We quantified associations of the serum GGT quartile groups with risk of ASCVD or each subtype through multivariate sub-distribution hazard models adjusted for covariates at baseline. RESULTS: During 4,572,993.8 person-years of follow-up for ASCVD, we documented 40,359 (9.6%) incident cases of ASCVD. The highest serum GGT group had a significant association with ASCVD in contrast to the lowest serum GGT quartile group (hazard ratio [HR] = 1.23, 95% confidence interval [CI] = 1.19-1.27). Serum GGT quartile groups 2, 3, and 4 had a significantly higher risk for incident hemorrhagic stroke than the serum GGT quartile group 1 (Q 2: HR = 0.92, 95% CI = 0.83-1.02; Q 3: HR = 1.03, 95% CI = 0.93-1.15; Q 4: HR = 1.29, 95% CI = 1.16-1.42; p for trend <0.001). For ischemic heart disease (IHD) and myocardial infarction, non-linear trends were shown according to increasing log-transformed GGT values. In the dose-response trends to assess the interaction effect of obese status, differences of trends were shown between serum GGT level and IHD or hemorrhagic stroke. CONCLUSIONS: The serum GGT value, which is known as a factor linked to cardiovascular diseases, has a strong independent association and dose-response relationship with hemorrhagic stroke risk in contrast to that with ischemic stroke or IHD.

Changes in secondhand smoke exposure levels and risk of type 2 diabetes in middle age: the Korean Genome and Epidemiology Study (KoGES).

Objectives: Secondhand smoke (SHS) was known as one of the risk factors for type 2 diabetes. So far, some studies revealed the association of SHS exposure and type 2 diabetes, however, no studies to show the relationship of cumulative SHS exposure with type 2 diabetes exist. Therefore, the objectives of this study were to identify subgroups of participants who share similar trajectories in SHS exposure levels in middle age by using latent class growth modeling, and determine the independent association of these SHS exposure level trajectories with risk of incident type 2 diabetes. Methods: In Korean Genome and Epidemiology Study (2001-2014), 2079 participants aged 40 years and above who received biennially health check-up to follow-up and with available information of SHS exposure were selected. Four distinct trajectory groups (low-stable, moderate to low, moderate, and high to low) were identified for SHS exposure levels using trajectory modeling methods. Multivariable Cox proportional hazards model was used to examine the association of trajectories with risk of type 2 diabetes. Results: During 24 083.3 person-years of follow-up (mean follow-up duration, 11.6 years), 200 incident cases of type 2 diabetes and 640 incident cases of impaired fasting glucose (IFG) were identified. In multivariable Cox model, 'High to low' trajectory was significantly associated with risk of type 2 diabetes (OR 1.9; 95% CI 1.3 to 2.8) compared with 'Low-stable'. For IFG, all trajectories had significantly 30%-30% higher risk of type 2 diabetes compared with the 'Low-stable' trajectory. Conclusions: Changes in SHS exposure levels have been shown to associate with subsequent type 2 diabetes risk. Reversing high exposure level of SHS in middle-aged adulthood may still lead to worse progressions of type 2 diabetes than remaining stable exposure level.

Inverse associations of bisphenol A and phthalate metabolites with serum bilirubin levels in Korean population.

Bisphenol A (BPA) and phthalates are endocrine disruptors that can induce oxidative stress. Serum bilirubin has antioxidant properties and may serve as a biomarker of oxidative stress. The objective of this study was to explore the relationship of BPA and phthalates with serum bilirubin levels in a Korean population. Urinary concentrations of BPA and six phthalate [mono-n-butyl phthalate (MnBP), mono-iso-butyl phthalate (MiBP), mono-(2-ethyl-5-oxohexyl) phthalate (MEOHP), mono-(2-ethyl-5- hydroxyhexyl) phthalate (MEHHP), mono-(2-ethyl-5-carboxypentyl) phthalate (MECPP), and mono-benzyl phthalate (MBzP)] were measured in 709 participants. Serum concentrations of BPA and three phthalate metabolites [MnBP, MiBP, and mono-(2-ethylhexyl) phthalate (MEHP)] were measured in 752 participants. After excluding missing variables, associations between above chemicals and serum bilirubin levels were analyzed using multivariate linear regression with age, sex, BMI, GGT, GOT, GPT, and alcohol intake adjustment. Participants were further stratified by sex. Among the urinary chemicals, BPA and four phthalate metabolites (MnBP, MEOHP, MEHHP and MECPP) were inversely associated with serum bilirubin levels (BPA: ß = - 0.071, P < 0.0001; MnBP: ß = - 0.055, P = 0.025; MEOHP: ß = - 0.101, P < 0.0001; MEHHP: ß = - 0.106, P < 0.0001; MECPP: ß = - 0.052, P = 0.003). In a case of serum chemicals, only MiBP showed significantly positive association (ß = 0.036, P = 0.016). After stratification by sex, the associations of urinary BPA remained both in male and female, of which urinary phthalates disappeared in female. The association of serum MiBP was disappeared after stratification. Urinary BPA and phthalate metabolites were inversely associated with serum bilirubin levels, whereas serum MiBP showed positive association with bilirubin. These results could provide clues for understanding the mechanisms of endocrine disruptor from oxidative stress to excretion from our body.

Trajectory of Smoking and Incidence of Atherosclerotic Cardiovascular Disease among Korean Young Adult Men.

Introduction: Smoking among young adults is associated with atherosclerotic cardiovascular disease (ASCVD) in middle age. Our aim was to analyze the trajectory of smoking in young adults and analyze the effects of the trajectory group on incident ASCVD. Methods: This study was conducted among 60,709 young adult men aged 20-29 years who received health screening every two years from 1992-2004. Trajectory analysis was performed through smoking survey data measured 7 times during this period. ASCVD, including ischemic heart disease (IHD) and stroke events were confirmed from 2005-2015. The association between the trajectory group and ASCVD risk was analyzed using Cox proportional hazard models, controlling for covariates and mediators. Results: Trajectory analysis showed that smoking categorized into five groups as follows: Group 1 (28.3%), low steady; Group 2 (14.7%), lowering; Group 3 (17.3%), high steady; Group 4 (15.6%), rise and fall; and Group 5 (24.2%), very high steady. The model performance of the trajectory model (Akaike information criterion; AIC = 51,670.78) with mediators was better than the model (AIC = 51,847.85) without mediators. Group 5 showed a 49% higher risk of ASCVD than Group 1. The risk of IHD was 1.63-times higher for Group 5 and 1.31-times higher for Group 4, compared to Group 1. Compared to Group 1, Group 5 had a 1.36- and 1.58-times higher risk for total stroke and ischemic stroke, respectively. Conclusions: In young adult men, the multiple measured trajectory model with mediators was far more informative than one-time smoking for explaining the association with cardiovascular disease.

Association between depressive-symptom trajectories and cognitive function in the late middle-aged and older population: results of the Korean Longitudinal Study of Ageing.

This study investigated the association between depressive symptoms and cognitive function according to four different trajectories of depressive symptoms in the late middle-aged and older South Korean population. Panel data from the Korean Longitudinal Study of Ageing were analyzed. We used latent class trajectory models to identify four trajectories of depressive symptoms. We performed linear mixed-effects regression analysis to assess associations between depressive-symptom trajectories and MMSE scores. Of 4,374 participants, 18.4%, 4.9%, 55.2%, and 21.5% were classified as having a low, increasing, moderate declining, and high depressive-symptom trajectory, respectively. Individuals with an increasing trajectory (ß = -0.729, P ≤ 0.001), moderate trajectory (ß = -0.278, P = 0.003), and high trajectory (ß = -1.605, P ≤ 0.001) had lower MMSE scores compared with those in the low trajectory group. These relationships were particularly strong among women; individuals who were physically inactive; those who were separated, divorced, or single; and those with hypertension or cerebrovascular disease. Each trajectory group for depressive symptoms was associated with cognitive decline. Moreover, female, physically inactive, and single individuals, as well as those with hypertension and cerebrovascular disease should be particularly mindful of their mental and physical health to prevent cognitive decline.

Association between Smoking Behavior Patterns and Glycated Hemoglobin Levels in a General Population.

This study investigated the association of smoking behaviors, including dual smoking (smoking both cigarettes and e-cigarettes), cigarettes smoking, and previous smoking, with glycated hemoglobin (HbA1c) levels. National Health and Nutrition Examination Survey (KNHANES) data from 2014⁻2016 was used. Associations between smoking behavior patterns and HbA1c levels were analyzed via multiple regression. Among 8809 participants, individuals who were dual smokers and cigarettes smokers had significantly higher HbA1c levels than non-smokers (dual: ß = 0.1116, p = 0.0012, single: ß = 0.0752, p = 0.0022). This relationship strengthened in subgroups of men (dual: ß = 0.1290, p = 0.0013, single: ß = 0.1020, p = 0.0014, ex: ß = 0.0654, p = 0.0308), physically inactive subjects (dual: ß = 0.1527, p = 0.0053, single: ß = 0.0876, p = 0.0197), and overweight (dual: ß = 0.1425, p = 0.0133) and obese individuals (dual: ß = 0.1694, p = 0.0061, single: ß = 0.1035, p = 0.0217). This study suggests that smoking behaviors are likely to increase the risk of HbA1c level in a general population. The health effects of dual smoking remain uncertain and should be addressed in the future.