• East Asian mathematical journal
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• v.35 no.3
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• pp.305-318
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• 2019

Over the past decades, the Lee-Carter model [1] has attracted much attention from various demography-related fields in order to project the future mortality rates. In the Lee-Carter model, the speed of mortality improvement is stochastically modeled by the so-called mortality index and is used to forecast the future mortality rates based on the time series analysis. However, the modeling is applied to long time series and thus an important structural change might exist, leading to potentially large long-term forecasting errors. Therefore, in this paper, we are interested in detecting the structural change of the Lee-Carter model and investigating the actuarial implications. For the purpose, we employ the tests proposed by Coelho and Nunes [2] and analyze the mortality data for six countries including Korea since 1970. Also, we calculate life expectancies and whole life insurance premiums by taking into account the structural change found in the Korean male mortality rates. Our empirical result shows that more caution needs to be paid to the Lee-Carter modeling and its actuarial applications.

• Korean Journal of Adult Nursing
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• v.29 no.1
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• pp.98-107
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• 2017

Purpose: The purpose of this study was to investigate the effect of geriatric syndrome on mortality among community-dwelling older adults in Korea. Methods: Data were obtained from the Actual Living Condition of the Elderly and Welfare Need Survey, with a baseline study in 2008 and a 3-year follow-up of mortality data. The mortality risk was measured using the hierarchical Cox proportional hazard model. Results: In Cox regression analysis, male (Hazard Ratio [HR], 2.53; 95% Confidence Interval [CI], 2.12~3.01), old age (HR, 2.14; 95% CI, 1.82~2.53), low education level (HR, 1.31; 95% CI, 1.04~1.65), limitation in instrumental activities of daily living (HR, 1.91; 95% CI, 1.60~2.28), depressive symptoms (HR, 1.21; 95% CI, 1.01~1.43), and frailty (HR, 2.32; 95% CI, 1.78~3.03) significantly affected mortality risk. Conclusion: Based on the results of this study, nursing intervention programs should be provided to decrease preventable death in older adults.

• Journal of the Korean Data and Information Science Society
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• v.24 no.3
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• pp.571-584
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• 2013

Various risk factors other than age and sex affecting human mortality have been identified and quantitatively analyzed by previous studies in many area of research. Marital status is one of key mortality risk factors which affect life expectancy directly or indirectly. Relevant results have implication on risk management for both of social and private insurance. In this paper, a mortality model to reflect mortality differential according to marital status and possible transitions among marital status is designed. Various actuarial calculations were performed and related issues were discussed.

• Journal of Korean Neurosurgical Society
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• v.56 no.4
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• pp.303-309
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• 2014

Objective : The purpose of this study was to retrospectively review cases of intracerebral hemorrhage (ICH) medically treated at our institution to determine if the CT angiography (CTA) 'spot sign' predicts in-hospital mortality and clinical outcome at 3 months in patients with spontaneous ICH. Methods : We conducted a retrospective review of all consecutive patients who were admitted to the department of neurosurgery. Clinical data of patients with ICH were collected by 2 neurosurgeons blinded to the radiological data and at the 90-day follow-up. Results : Multivariate logistic regression analysis identified predictors of poor outcome; we found that hematoma location, spot sign, and intraventricular hemorrhage were independent predictors of poor outcome. In-hospital mortality was 57.4% (35 of 61) in the CTA spot-sign positive group versus 7.9% (10 of 126) in the CTA spot-sign negative group. In multivariate logistic analysis, we found that presence of spot sign and presence of volume expansion were independent predictors for the in-hospital mortality of ICH. Conclusion : The spot sign is a strong independent predictor of hematoma expansion, mortality, and poor clinical outcome in primary ICH. In this study, we emphasized the importance of hematoma expansion as a therapeutic target in both clinical practice and research.

• Animal cells and systems
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• v.14 no.4
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• pp.291-296
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• 2010

Population ecological characteristics of growth and mortality play an important role in understanding the population dynamics of marine mammals. The instantaneous coefficients of natural and bycatch mortality were estimated for minke whales (Balaenoptera acutorostrata) in Korean waters using a population assessment model composed of bycatch and abundance data. The survivorship curve of this population was fitted to the data, and then the curve was revised using age-specific relative bycatchability coefficients ($q_t$). Instantaneous coefficients of natural and bycatch mortality of minke whales were estimated as 0.024/year and 0.076/year, respectively, and from this the survival rate was estimated as 0.905. This estimated survival rate was comparable to other cetaceans in other regions. The $q_t$ for this population ranged from 0.020 to 0.193. The revised survival rates were higher when the $q_t$ was taken into account. The mortality coefficient, survival rate, $q_t$ and survivorship curves had not previously been determined for minke whale in this area. This estimate could serve as fundamental information to assess the status of this population and for conservation and rational management.

• The Korean Journal of Emergency Medical Services
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• v.25 no.3
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• pp.37-48
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• 2021

Purpose: Mortality due to trauma is relevant to both low-income and high-income countries. A diversity of causes leads to mortality such as, socioeconomic status and geographic factors. This study sought to differentiate between cases of mortality in a metropolitan city and a rural area, with data from critical trauma patients. Methods: Community-based severe trauma surveillance data from 2018 was used in this study. Logistic regression was conducted to compare the odds ratios between deaths that occurred in a metropolitan city and a rural area. Multiple logistic regression by controlling variables such as type of medical institution and injury severity score was conducted to estimate the effect on the trauma patients. Results: In total, 28,217 participants were selected as total population. We observed that the odds of death decreased as the level of the trauma center increased. Compared to the metropolitan city, the odds ratio of rural areas was 1.44. The odds ratio increased as the injury severity score increased. Conclusion: This study suggests that the mortality of critical trauma patients is higher in rural areas than in metropolitan cities. More studies are needed to expand on this.

• Korean Journal of Fisheries and Aquatic Sciences
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• v.57 no.3
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• pp.292-301
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• 2024

It is challenging to simultaneously estimate parameters in a stock-recruitment relationship, steepness, and natural mortality rate with the other parameters within an age-structured assessment model even in a data-rich situation. Such a problem leads to uncertainty in estimates of management references such as maximum sustainable yield (MSY), which are affected by those components. The objective of this study was to evaluate the effects of those parameters on MSY by analyzing the process of estimating the MSY. For illustration, we used two data sets: The chub mackerel Scomber japonicus in the Korean waters and the yellowtail flounder Limanda ferruginea in the Southern New England-Mid Atlantic. As a result, the natural mortality rate influenced spawning stock biomass per recruit, yield per recruit, and MSY, while steepness affected MSY. A sensitivity analysis enabled us to estimate the natural mortality rate and steepness. The optimal set of steepness and natural mortality was 1.0 and 0.37 per year for the chub mackerel, and 0.35, and 0.8 per year for the yellowtail flounder, respectively.

• Journal of Chest Surgery
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• v.24 no.11
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• pp.1045-1057
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• 1991

Over the past four decades after World War II a great deal of data and clinical experiences have been accumulated relating to the diagnosis and surgical treatment of cardiovascular diseases in Korea. Clinical data after the first open heart surgery by Professor Yung Kyoon Lee on August 7, 1959 up to 1984 revealed the total number of cardiovascular surgery in Korea as 13,100 cases performed in 22 institutes with overall hospital mortality of 7.7%[Cardiovascular Surgery in Korea 1985], Publishing committee of the Korean Thoracic and Cardiovascular Surgical Society collected the data of cardiovascular surgical cases in Korea again in between 1985 and 1990 from 38 institutes out of total 42 institutes of open heart centers in Korea. The results are: 1. The survey reply ratio was 90.5%[38 out of 42 institutes]. 2. Of the total 30,061 cases of cardiovascular surgery reported from 38 institutes 1,402 cases were failed as hospital mortality of 4.7%[4.5% of the 21,761 operations for congenital, and 5.2% of the 8,300 operations for acquired heart diseases]. Out of the total congenital cases, 17,303 cases were acyanotic group with a operative mortality as 2.0%, and 4,458 cases were cyanotic group with a hospital mortality as 14.le The incidence of corrective operations for complex congenital cardiac anomalies were increasing recently with decreasing age group. 3. During the year in 1990, 38 institutes performed 5,427 cardiovascular surgery with a hospital mortality of 3.4%. 4. Of the total cumulative 6,458 cases for cardiac valve surgery more than 90% cases were put to prosthetic valve replacement with hospital mortality as 4.8%. And the incidence of re-Do valve surgery was increasing recently as 13.1% in 1990. 5. Coronary artery bypass graft was increasing recently with 7.9% of hospital mortality in total 440 cases. Intracardiac operation for intractable arrhythmia was started since 1987 as 49 cases in total. Experiences on VAD and ECMO were also reported sporadically in recent year. 6. Home made oxygenator[OXYREX] is now in clinical use, and under animal experiment for clinical trial in near future.

• Asian Pacific Journal of Cancer Prevention
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• v.15 no.22
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• pp.10027-10031
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• 2014

Background: We investigated the risk of cancer mortality according to obesity status and metabolic health status using sampled cohort data from the National Health Insurance system. Materials and Methods: Data on body mass index and fasting blood glucose in the sampled cohort database (n=363,881) were used to estimate risk of cancer mortality. Data were analyzed using a Cox proportional hazard model (Model 1 was adjusted for age, sex, systolic blood pressure, diastolic blood pressure, total cholesterol level and urinary protein; Model 2 was adjusted for Model 1 plus smoking status, alcohol intake and physical activity). Results: According to the obesity status, the mean hazard ratios were 0.82 [95% confidence interval (CI), 0.75-0.89] and 0.79 (95% CI, 0.72-0.85) for the overweight and obese groups, respectively, compared with the normal weight group. According to the metabolic health status, the mean hazard ratio was 1.26 (95% CI, 1.14-1.40) for the metabolically unhealthy group compared with the metabolically healthy group. The interaction between obesity status and metabolic health status on the risk of cancer mortality was not statistically significant (p=0.31). Conclusions: We found that the risk of cancer mortality decreased according to the obesity status and increased according to the metabolic health status. Given the rise in the rate of metabolic dysfunction, the mortality from cancer is also likely to rise. Treatment strategies targeting metabolic dysfunction may lead to reductions in the risk of death from cancer.

• Asian Pacific Journal of Cancer Prevention
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• v.17 no.7
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• pp.3265-3269
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• 2016

Background: Around half of input data in the global burden of disease cancer collaboration (GBD-CC) and GLOBOCAN projects come from low quality sources, mainly from developing countries. This may lead to loss of precision in estimates. Our question was: Are the absolute values and trends of the GBD-CC and GLOBOCAN estimates for lung cancer (LC) in Iran consistent with available statistics?. Materials and Methods: Incidence and mortality statistics were extracted from national reports (N.IRs & N.MRs) and GBD-CC (GBD-incidence & mortality) and GLOBOCAN databases for 1990-2013 where available. Trends were analyzed and absolute values and annual percentage changes (APCs) were estimated and compared. Incompleteness of case ascertainment at the Iranian national cancer registry and Iranian national civil registration was assessed for better understanding. Results: Trends of N.IRs were significantly rising for males (APC: 19.4; 95% CI: 12.5-26.7) and females (23.2; 16.0-30.8). Trends of GBD-incidence were stable for males (-0.2; -1.5-1.1) and females (-1.0; -2.3-0.4). Absolute N.IRs were less than GBD-incidence steadily except for 2009. Trend of N.MRs was increasing up to 2004, but stable thereafter. Trends of GBD-mortality were also stable. Absolute N.MRs were less than GBD-mortality for years up to 2003 and more than GBD-mortality since 2005. The estimates of GLOBOCAN were more than N.IRs and N.MRs. Conclusions: The GBD-CC and GLOBOCAN values for LC in Iran are underestimates. Generation of data quality indices to present along with country specific estimates is highly recommended.