• Communications for Statistical Applications and Methods
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• v.26 no.6
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• pp.557-573
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• 2019

Mortality study is an essential component of actuarial risk management for life insurance policies, annuities, and pension plans. Life expectancy has drastically increased over the last several decades; consequently, longevity risk associated with annuity products and pension systems has emerged as a crucial issue. Among the various aspects of mortality study, a consideration of the cause-of-death mortality can provide a more comprehensive understanding of the nature of mortality/longevity risk. In this case study, the cause-of-mortality data in Korea and the US were analyzed along with a multinomial logistic regression model that was constructed to quantify the impact of mortality reduction in a specific cause on actuarial values. The results of analyses imply that mortality improvement due to a specific cause should be carefully monitored and reflected in mortality/longevity risk management. It was also confirmed that multinomial logistic regression model is a useful tool for analyzing cause-of-death mortality for actuarial applications.

• Communications for Statistical Applications and Methods
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• v.28 no.6
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• pp.611-626
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• 2021

Marital status has been identified as an important risk factor affecting adult mortality. Many studies have found that marriage has positive effects on mortality and increases life expectancy. Since most pension contracts providing retirement income are provided to married couples, mortality assumption for actuarial valuation based on the entire population is likely to overestimate the actual mortality of the group of beneficiaries specified in the contracts. This study considered the differences in mortality according to marital status to analyze the length and value of the payments of a typical pension contract for a married couple. The study quantified the effect on actuarial measurements of considering marital status in mortality assumptions with a multi-state model framework using Korean experience mortality data organized by marital status. The results of analysis indicate that considering marital status in mortality assumptions improves mortality risk management.

• Environmental and Resource Economics Review
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• v.16 no.3
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• pp.683-699
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• 2007

This study applied the choice experiment (CE) method to measure values of statistical lives from multi-attributed mortality risk reduction choices. The four characteristics of mortality risk (i.e. cause of death, voluntariness of mortality risk, timing of death, magnitude of mortality risk reduction) are utilized to design the alternatives of choice sets. The estimation results for the multinomial logit model show that individuals are willing to pay 27,930 won per year for a change from the status quo to a $\frac{1}{100}$ mortality risk reduction for 10 years, 116,773 won per year for mortality risk reduction associated with adults, 97,682 won per year for voluntary mortality risk reduction, 77,234 won per year for involuntary mortality risk reduction. There were several estimates of VSL related to different attributes of mortality risk. The mean VSLs of infant/child/young adult ranged from 1,165 million won to 1,367 million won. The mean VSLs ranged from 1,631 million won to 1,833 million won for adult, and were between 1,128 million won and 1,330 million won for old person.

• Health Policy and Management
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• v.17 no.3
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• pp.87-105
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• 2007

The purpose of this study was to analyze whether nonemergency, isolated coronary artery bypass graft (CABG) surgery for high- or low-risk patients biases the assessment of the risk-adjusted mortality rates of hospitals. This study used 2002 National Health Insurance claims data for tertiary hospitals in Korea. The study sample consisted of 1,959 patients from 23 tertiary hospitals. The risk-adjustment model used the patients' biological, admission, and comorbidity data identified in the claims. The subjects were classified into high- and low-risk groups based on predicted surgical risk. The crude mortality rates and risk-adjusted mortality rates for low-risk, high-risk, and all patients in a hospital were compared based on the rank and the four intervals defined by quartile. Also, the crude mortality rates of the three groups were compared with their 95% confidence intervals of predicted mortality rates. The C-statistic (0.83) and Hosmer-Lemeshow test ($X^2$=11.47, p=0.18) indicated that the risk-adjustment model performed well. Presenting crude mortality rates with their 95% confidence intervals of predicted rates showed higher agreements among the three groups than using the rank or intervals of mortality rates defined by quartile in the hospital performance assessment. The crude mortality rates for the low-risk patients in 21 of the 23 hospitals were located on the same side of their 95% confidence intervals compared to that for all patients. High-risk patients and all patients differed at only one hospital. In conclusion, the impact of risk selection by hospital on the assessment results was the smallest when comparing the crude inpatient mortality rates of CABG patients with the 95% confidence intervals of predicted mortality rates. Given the increasing importance of quality improvements in Korean health policy, it will be necessary to use the appropriate method of releasing the hospital performance data to the public to minimize any unwanted impact such as risk-based hospital selection.

• Journal of Preventive Medicine and Public Health
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• v.39 no.2
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• pp.115-122
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• 2006

Objectives : This study was conducted to examine the relationships of the several socioeconomic position indicators with the mortality risk in a representative longitudinal study of South Korea. Methods : The 1998 National Health and Nutrition Examination Survey was conducted on a cross-sectional probability sample of South Korean households, and it contained unique 13-digit personal identification numbers that were linked to the data on mortality from the National Statistical Office of Korea. Of 5,607 males and females, 264 died between 1999 and 2003. Cox's regression was used to estimate the relative risks (RR) and their 95% confidence intervals (CI) of mortality. Results: Socioeconomic differences in mortality were observed after adjustments were made for gender and age. Compared with those people having college or higher education, those people without any formal education had a greater mortality risk (RR=2.21, 95% CI=1.12-4.40). The mortality risk among manual workers was significantly greater than that for the non-manual workers (RR=2.73, 95% CI=1.47-5.06). A non-standard employment status was also associated with an increase in mortality: temporary or daily workers had a greater mortality risk than did the full-time workers (RR=3.01, 95% CI=1.50-6.03). The mortality risk for the low occupational class was 3.06 times greater than that of the high and middle occupational classes (95% CI=1.75-5.36). In addition, graded mortality differences according to equivalized monthly household income were found. A reduction of monthly household income by 500 thousand Korean Won (about 400 US dollars) was related with a 20% excess risk of mortality. Self-reported poor living standards were also associated with an increased risk of mortality. Those without health insurance had a 3.63 times greater risk of mortality than the insured (95% CI=1.61-8.19). Conclusions: This study showed the socioeconomic differentials in mortality in a national longitudinal study of South Korea. The existence of socioeconomic mortality inequalities requires increased social discussion on social policies in Korean society. Furthermore, the mechanisms for the socioeconomic inequalities of mortality need to be explored in future studies.

• Journal of Veterinary Clinics
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• v.34 no.2
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• pp.82-86
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• 2017

We determined the risk factors for late embryonic mortality in dairy cows. We diagnosed pregnancy at 31 days and then confirmed the diagnosis at 45 days after artificial insemination (AI) via ultrasonography. The presence of an embryo with a heartbeat was the criterion for a positive pregnancy diagnosis. A diagnosis of late embryonic mortality was made when there was no positive sign of pregnancy in cows previously diagnosed as pregnant. The overall incidence of late embryonic mortality among 3,695 pregnancies was 6.9%. Logistic regression analysis revealed that herd size, AI month, synchronization protocol, and postpartum disease were important risk factors for late embryonic mortality. Herd size > 100 (odds ratio [OR]: 0.66, p < 0.05) and 50-100 lactating cows (OR: 0.63, p < 0.01) had lower risks of late embryonic mortality than herd size < 50 lactating cows. Cows inseminated during May-July had a higher risk (OR: 1.49, p < 0.05) of late embryonic mortality than cows inseminated during February-April. Cows inseminated after estrus following $PGF_{2{\alpha}}$ treatment also had a higher risk (OR: 1.77, p < 0.001) of late embryonic mortality than cows inseminated following natural estrus. Lastly, cows with postpartum disease tended to have a higher risk (OR: 1.26, p < 0.1) of late embryonic mortality than cows without postpartum disease. In conclusion, late embryonic mortality associated with the herd size, AI month, synchronization protocol, and postpartum disease in dairy cows.

• Safety and Health at Work
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• v.7 no.3
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• pp.251-255
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• 2016

Background: Building demolition can lead to emission of dust into the environment. Exposure to silica dust may be considered as an important hazard in these sites. The objectives of this research were to determine the amount of workers' exposure to crystalline silica dust and assess the relative risk of silicosis and the excess lifetime risk of mortality from lung cancer in demolition workers. Methods: Four sites in the Tehran megacity region were selected. Silica dust was collected using the National Institute for Occupational Safety and Health method 7601 and determined spectrophotometrically. The Mannetje et al and Rice et al models were chosen to examine the rate of silicosis-related mortality and the excess lifetime risk of mortality from lung cancer, respectively. Results: The amount of demolition workers' exposure was in the range of $0.085-0.185mg/m^3$. The range of relative risk of silicosis related mortality was increased from 1 in the workers with the lowest exposure level to 22.64/1,000 in the employees with high exposure level. The range of the excess lifetime risk of mortality from lung cancer was in the range of 32-60/1,000 exposed workers. Conclusion: Geometric and arithmetic mean of exposure was higher than threshold limit value for silica dust in all demolition sites. The risk of silicosis mortality for many demolition workers was higher than 1/1,000 (unacceptable level of risk). Estimating the lifetime lung cancer mortality showed a higher risk of mortality from lung cancer in building demolition workers.

• Quality Improvement in Health Care
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• v.17 no.1
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• pp.69-78
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• 2011

Objectives : The purpose of this study was to determine whether the published AMI report card could reduce in-patient mortality, 7-day after discharge mortality, and length of stay (LOS). Methods : Interrupted time-series intervention analysis was used to evaluate the impact of the report card for AMI care quality in November 2005 in terms of risk-adjusted in-patient mortality, risk-adjusted 7-day after discharge mortality, and DRGs case-mix LOS using the claim data of Health Insurance Review and Assessment Service. Results : Public disclosure of AMI care quality decreased risk-adjusted in-patient mortality and DRGs case-mix LOS by 0.00050% per month and 0.042 days per month respectively, however there was no effect on risk-adjusted 7-day after discharge mortality. Patterns of effect of public disclosure on AMI outcomes were a fluctuating pattern on risk-adjusted mortalities and a pulse impact for 1 month on DRGs case-mix LOS. Conclusions : We found the public disclosure of AMI care quality had decreasing effects on risk-adjusted in-patient mortality and DRGs case-mix LOS, but the size of the effect was marginal.

• Journal of Preventive Medicine and Public Health
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• v.37 no.2
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• pp.120-126
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• 2004

Objectives : This study sought to examine relationships between alcohol drinking and cardiovascular disease mortality and all-cause mortality. Methods : From March 1985 through December 1999, 2,696 males and 3,595 females aged 55 or over as of 1985 were followed up for their mortality until 31 December 1999. We calculated the mortality risk ratios by level of alcohol consumption. Among the drinker, the level of alcohol consumption was calculated by the frequency of alcohol comsumption and the type of alcohol. Cox proportional hazard model was used to adjust for confounding factors. Results : Among males, compared to abstainer, heavy drinker had significantly higher mortality in all cause(Risk ratio=1.35), cardiovascular disease(Risk ratio=1.52) and cerebrovascular disease(Risk ratio =1.66). Although not significant, moderate drinker had lower ischemic heart disease mortality(Risk ratio =0.38). Among females, there was no statistically significant association between alcohol comsumption and mortality. Conclusion : The results of this study suggest that alcohol drinking has harmful effect on all-cause mortality, cardiovascular disease mortality and cerebrovascular disease mortality among males, especially in heavy drinker among males. Minimal evidence on protective effect for cardiovascular disease mortality in low or moderate drinker is observed.

• Korean Journal of Community Nutrition
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• v.21 no.4
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• pp.354-365
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• 2016

Objectives: Studies that reported the association between diet quality/nutritional intake status and mortality have rarely used long-term follow-up data in Asian countries, including Korea. This study investigated the association between the risk of mortality (all-cause and cause-specific) and the diet quality/nutritional intake status using follow-up 12-year mortality data from a nationally representative sample of South Koreans. Methods: 8,941 individuals who participated in 1998 and 2001 Korea Health and Nutrition Examination Surveys were linked to mortality data from death certificates. Of those individuals, 1,083 (12.1%) had died as of December, 2012. Cox proportional hazard models were used to estimate the relative risks of mortality according to the level of diet quality and intakes of major nutrients. Indicators for diet quality index and nutritional intake status were assessed using MAR (mean adequacy ratio) and energy and protein intake level compared with the 2010 Korean DRI. Results: Higher diet quality/nutritional intake status were associated with lower mortality; the mortality risk (95% confidence interval) from all-cause of lowest MAR group vs highest was 1.66 (1.27 to 2.18) among ${\geq}30$ year old, and 1.98 (1.36 to 2.86) among 30~64 year old individuals. Those with below 75% of energy and protein intake of Korean DRI had higher mortality risks of all-cause mortality compared to the reference group. Diet quality/nutritional intake status was inversely associated with mortality from cardiovascular diseases and cancer. Conclusions: Poor Diet quality/nutritional intake status were associated with a higher risk of mortality from all-cause and mortality from cardiovascular diseases and cancer among South Korean adults.