This study aims to provide a systematical introduction of age-period-cohort (APC) analysis to South Korean readers who are unfamiliar with this method (we provide an extended version of this study in Korean). As health data in South Korea has substantially accumulated, population-level studies that explore long-term trends of health status and health inequalities and identify macrosocial determinants of the trends are needed. Analyzing long-term trends requires to discern independent effects of age, period, and cohort using APC analysis. Most existing health and aging literature have used cross-sectional or short-term available panel data to identify age or period effects ignoring cohort effects. This under-use of APC analysis may be attributed to the identification (ID) problem caused by the perfect linear dependency across age, period, and cohort. This study explores recently developed three APC models to address the ID problem and adequately estimate the effects of A-P-C: intrinsic estimator-APC models for tabular age by period data; hierarchical cross-classified random effects models for repeated cross-sectional data; and hierarchical APC-growth curve models for accelerated longitudinal panel data. An analytic exemplar for each model was provided. APC analysis may contribute to identifying biological, historical, and socioeconomic determinants in long-term trends of health status and health inequalities as well as examining Korean's aging trajectories and temporal trends of period and cohort effects. For designing effective health policies that improve Korean population's health and reduce health inequalities, it is essential to understand independent effects of the three temporal factors by using the innovative APC models.
Aging ; Cohort Effect ; Cohort Studies ; Health Policy ; Korea ; Methods ; Socioeconomic Factors

This study aims to provide a systematical introduction of age-period-cohort (APC) analysis to South Korean readers who are unfamiliar with this method (we provide an extended version of this study in Korean). As health data in South Korea has substantially accumulated, population-level studies that explore long-term trends of health status and health inequalities and identify macrosocial determinants of the trends are needed. Analyzing long-term trends requires to discern independent effects of age, period, and cohort using APC analysis. Most existing health and aging literature have used cross-sectional or short-term available panel data to identify age or period effects ignoring cohort effects. This under-use of APC analysis may be attributed to the identification (ID) problem caused by the perfect linear dependency across age, period, and cohort. This study explores recently developed three APC models to address the ID problem and adequately estimate the effects of A-P-C: intrinsic estimator-APC models for tabular age by period data; hierarchical cross-classified random effects models for repeated cross-sectional data; and hierarchical APC-growth curve models for accelerated longitudinal panel data. An analytic exemplar for each model was provided. APC analysis may contribute to identifying biological, historical, and socioeconomic determinants in long-term trends of health status and health inequalities as well as examining Korean's aging trajectories and temporal trends of period and cohort effects. For designing effective health policies that improve Korean population's health and reduce health inequalities, it is essential to understand independent effects of the three temporal factors by using the innovative APC models.
Aging ; Cohort Effect* ; Cohort Studies* ; Health Policy ; Korea ; Methods ; Socioeconomic Factors

OBJECTIVE: We examined changes in general health status, the prevalence of depression and post-traumatic stress disorder (PTSD) symptoms, and the existence of pre-trauma contributing factors in an agricultural population following a massive flood. METHODS: Eighty-three of 160 residents of Garisan-ni, Inje-gun, Gangwon-do, were assessed using the Korean version of the 36-Item Short-Form Health Survey (SF-36-K) between April and June 2006, just prior to a massive flood. Among those initially assessed, 58 residents were available for follow-up 18 months after the flood. Participants completed the SF-36-K, Beck Depression Index (BDI), Minnesota Multiphasic Personality Inventory (MMPI)-PTSD, and the Korean version of the Impact of Event Scale-Revised (IES-R) to detect depression and PTSD. Trauma experiences were also assessed. Factors related to changes in health status were then analyzed. RESULTS: SF-36-K total scale scores decreased significantly, suggesting a significant reduction in health-related quality of life. The largest reductions were noted in physical and social functioning. Fifty-three percent of the subjects were at least mildly depressed, and 17% had severe depression. In addition, 22% had PTSD on both the IES-R and MMPI-PTSD. Factors that contributed to the deterioration of health status following the flood were the number of disaster events and existence of depression (as assessed by the BDI). CONCLUSION: The flood was found to lead to deterioration of health status and to provoke depression and PTSD among the agricultural population in the mountainous region. We suggest that the number of disaster event experiences and existence of depression contriuted to changes in health status after the flood.
Depression ; Disasters* ; Follow-Up Studies ; Gangwon-do ; Health Surveys ; MMPI ; Prevalence ; Prospective Studies* ; Quality of Life ; Stress Disorders, Post-Traumatic

The Rejuran(R) is a new filler product made from purified polynucleotides. Here we present data from an animal study and a clinical trial to examine the durability, efficacy and safety of the Rejuran(R) on crow's feet. For the animal study, 25 mice were divided into three groups: Group 1 received phosphate buffered saline (PBS); Group 2 were treated with Yvoire(R); and Group 3 were treated with Rejuran(R). The durability and efficacy of each treatment were assessed by microscopy and staining. In the clinical trial, 72 patients were randomized to receive Rejuran(R) treatment for crow's feet on one side and Yvoire-Hydro(R) on the contralateral side, at a ratio of 1:1. Repeated treatments were performed every two weeks for a total of three times, over a total of 12 weeks' observation. All injections and observations of efficacy and safety were performed by the same two investigators. In the animal study, the Rejuran(R) group showed similar durability and inflammatory response to the Yvoire(R) group. Upon efficacy assessment, the Rejuran(R) group showed the greatest elasticity and collagen composition, and a significant difference in skin surface roughness and wrinkle depth. In the clinical trial, the primary and secondary objective efficacy outcome measure showed no statistical significance between the two groups, and in safety outcomes there were no unexpected adverse effects. Our data suggest that the Rejuran(R), as a new regenerative filler, can be useful to reduce wrinkles, by showing evidence for its efficacy and safety.
Adult ; Animals ; Dermatologic Surgical Procedures/*methods ; Double-Blind Method ; Elasticity/drug effects ; Female ; Humans ; Hyaluronic Acid/adverse effects/*therapeutic use ; Injections, Intradermal ; Male ; Mice ; Middle Aged ; Polynucleotides/adverse effects/*therapeutic use ; Skin ; Skin Aging ; Surgery, Plastic/*methods ; Treatment Outcome ; Wound Healing

Diabetic nephropathy (DN) can affect quality of life (QoL) because it requires arduous lifelong management. This study analyzed QoL differences between DN patients and patients with other chronic kidney diseases (CKDs). Methods: The analysis included subjects (n = 1,766) from the KNOW-CKD (Korean Cohort Study for Outcomes in Patients with Chronic Kidney Disease) cohort who completed the Kidney Disease Quality of Life Short Form questionnaire. After implementing propensity score matching (PSM) using factors that affect the QoL of DN patients, QoL differences between DN and non-DN participants were examined. Results: Among all DN patients (n = 390), higher QoL scores were found for taller subjects, and lower scores were found for those who were unemployed or unmarried, received Medical Aid, had lower economic status, had higher platelet counts or alkaline phosphatase levels, or used clopidogrel or insulin. After PSM, the 239 matched DN subjects reported significantly lower patient satisfaction (59.9 vs. 64.5, p = 0.02) and general health (35.3 vs. 39.1, p = 0.04) than the 239 non-DN subjects. Scores decreased in both groups during the 5-year follow-up, and the scores in the work status, sexual function, and role-physical domains were lower among DN patients than non-DN patients, though those differences were not statistically significant. Conclusion: Socioeconomic factors of DN were strong risk factors for impaired QoL, as were high platelet, alkaline phosphatase, and clopidogrel and insulin use. Clinicians should keep in mind that the QoL of DN patients might decrease in some domains compared with non-DN CKDs.

Objective: To evaluate the diagnostic performance of susceptibility map-weighted imaging (SMwI) taken in different acquisition planes for discriminating patients with neurodegenerative parkinsonism from those without. Materials and Methods: This retrospective, observational, single-institution study enrolled consecutive patients who visited movement disorder clinics and underwent brain MRI and 18F-FP-CIT PET between September 2021 and December 2021. SMwI images were acquired in both the oblique (perpendicular to the midbrain) and the anterior commissure-posterior commissure (AC-PC) planes. Hyperintensity in the substantia nigra was determined by two neuroradiologists. 18F-FP-CIT PET was used as the reference standard. Inter-rater agreement was assessed using Cohen’s kappa coefficient. The diagnostic performance of SMwI in the two planes was analyzed separately for the right and left substantia nigra. Multivariable logistic regression analysis with generalized estimating equations was applied to compare the diagnostic performance of the two planes. Results: In total, 194 patients were included, of whom 105 and 103 had positive results on 18F-FP-CIT PET in the left and right substantia nigra, respectively. Good inter-rater agreement in the oblique (κ = 0.772/0.658 for left/right) and AC-PC planes (0.730/0.741 for left/right) was confirmed. The pooled sensitivities for two readers were 86.4% (178/206, left) and 83.3% (175/210, right) in the oblique plane and 87.4% (180/206, left) and 87.6% (184/210, right) in the AC-PC plane. The pooled specificities for two readers were 83.5% (152/182, left) and 82.0% (146/178, right) in the oblique plane, and 83.5% (152/182, left) and 86.0% (153/178, right) in the AC-PC plane. There were no significant differences in the diagnostic performance between the two planes (P > 0.05). Conclusion There are no significant difference in the diagnostic performance of SMwI performed in the oblique and AC-PC plane in discriminating patients with parkinsonism from those without. This finding affirms that each institution may choose the imaging plane for SMwI according to their clinical settings.