• Economic Analysis
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• v.26 no.3
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• pp.48-70
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• 2020

Using data from the Household Income and Expenditure Survey over the period 1994-2016, we estimate the coefficient of relative prudence in order to capture precautionary saving motive. To do this, we adopt a cohort approach, where we transform such microdata into sample cohort means. Together with initial income involving liquidity constraint, we estimate the relative prudence derived from the Euler equation. The two-stage least-squares (2SLS) between estimate of it obtained from the cohort panel data analysis is too small for the existence of precautionary saving motive, as in previous studies, while the 2SLS random effects estimate is so reasonable. Moreover, the liquidity-constrained cohorts tend to be more sensitive to uncertainty, relative to the unconstrained ones.

• Safety and Health at Work
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• v.14 no.3
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• pp.279-286
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• 2023

Background: This study aimed to evaluate the association between exposure to occupational hazards and the metabolic syndrome. A secondary objective was to analyze the additive and multiplicative effects of exposure to risk factors. Methods: This retrospective cohort was based on 31,615 health examinees at the Pusan National University Yangsan Hospital in Republic of Korea from 2012-2021. Demographic and behavior-related risk factors were treated as confounding factors, whereas three physical factors, 19 organic solvents and aerosols, and 13 metals and dust were considered occupational risk factors. Time-dependent Cox regression analysis was used to calculate hazard ratios. Results: The risk of metabolic syndrome was significantly higher in night shift workers (hazard ratio = 1.45: 95% confidence interval = 1.36-1.54) and workers who were exposed to noise (1.15:1.07-1.24). Exposure to some other risk factors was also significantly associated with a higher risk of metabolic syndrome. They were dimethylformamide, acetonitrile, trichloroethylene, xylene, styrene, toluene, dichloromethane, copper, antimony, lead, copper, iron, welding fume, and manganese. Among the 28 significant pairs, 19 exhibited both positive additive and multiplicative effects. Conclusions: Exposure to single or combined occupational risk factors may increase the risk of developing metabolic syndrome. Working conditions should be monitored and improved to reduce exposure to occupational hazards and prevent the development of the metabolic syndrome.

• Management Science and Financial Engineering
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• v.16 no.3
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• pp.49-70
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• 2010

Customer population management models can be classified into three categories: the first category includes the models that analyze the customer population at cohort level; the second one deals with the customer population at aggregate level; the third one has interest in the interactions among the customer populations in the competitive market. Our study proposes a model that can analyze the dynamics of customer population in consumer-durables market at aggregate level. The dynamics of customer population includes the retention curves from the purchase or at a specific duration time, the duration time expectancy at a specific duration time, and customer population growth or decline including net replacement rate, intrinsic rate of increase, and the generation time of customer population. For this study, we adopt mathematical ecology models, redefine them, and restructure interdisciplinary models to analyze the dynamics of customer population at aggregate level. We use the data of previous research on dynamic customer population management at cohort level to compare its results with those of ours and to demonstrate the useful analytical effects which the precious research cannot provide for marketers.

• Research in Community and Public Health Nursing
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• v.18 no.4
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• pp.513-522
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• 2007

Purpose: The purpose of this study was to gain knowledge of successful aging for the Korean elderly and to identify the effects of an intervention program on the change of the knowledge Method: Data were collected from 134 elders from 3 schools for the elderly in H City. The Successful Aging Scale was used to collect data and modified CDSMP was applied as the intervention. Descriptive statistics, t-test, ANOVA and ANCOVA were used. Results : The total score of the knowledge of successful aging among the elderly cohort was 2.44 out of 3, and the scores of the factors making up old age were 2.66 for the success of children, 2.63 for self-control, 2.56 for self-efficacy, and 2.05 for happy marriage. Life satisfaction from the success of children and self-control were strongly correlated(r=0.7036, p=0.000). Conclusion: The self-management program brought positive changes to the knowledge of successful aging through the self-control parameter, and although it could not change the degree of knowledge of the overall successful aging among the elderly cohort, the program represents the first Korean nursing intervention focused on self-management techniques needed for successful aging.

• Physical Therapy Rehabilitation Science
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• v.12 no.1
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• pp.72-79
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• 2023

Objective: Despite known associations between negative body image and health declines in chronic pain patients, few studies have examined longitudinal associations between psychological stress and perceived hand deformities. This study examined whether psychological distress was associated with hand deformities 4 years later and if rural and urban adults differed in the association. Design: A community-based cohort study. Methods: Community dwelling adults (mean age=51.97, 52.3% women) in a rural (n=2968) and urban area (n=2784) provided demographic data at baseline and, in the 4-year follow-up, responded to questionnaires about psychological distress. Perceived hand deformities were assessed at the 8-year follow-up. Linear regression was conducted to examine the effects of psychological distress on hand deformities and moderation by residential areas. Results: The perceived hand deformities were more likely among those with severe psychological stress, hand osteoarthritis, or any chronic disease condition (p<0.01) but less likely among those with younger age, higher education, or income (p<0.01). The regression results showed that psychological distress predicted more perceived hand deformities 4 years later even after adjusting for demographic and health covariates (p<0.01). The residential areas did not significantly moderate the association between distress and hand deformities. Conclusions: This study suggected that psychological distress may trigger later perception of hand deformities in both urband and rural adults. The findings indicate that stress management interventions that are customizable to regional contexts may be effective at preventing negative body image related health problems of community-dewelling adults.

• Journal of the Korean Society of Food Culture
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• v.14 no.4
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• pp.371-383
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• 1999

This report gave analysis of food demand both in Korea and Japan through introducing the concept of cohort analysis to the conventional demand model. This research was done to clarify the factors which determine food demand of the household. The traits of the new model for demand analysis are to consider and quantify those effects on food demand not only of economic factors such as expenditure and price but also of non-economic factors such as the age and birth cohort of the householder. The results of the analysis can be summarized as follows: 1) The comparison of the item-wise elasticities of food demand demonstrates that the expenditure elasticity is higher in Korea than in Japan and that the expenditure elasticity is -0.1 for cereal and more than 1 for eating-out in both countries. In respect to price elasticity, the absolute values of all the items except alcohol and cooked food are higher in the Korea than in Japan, and especially the price elasticities of beverages, dairy products and fruit are predominantly higher in Japan. In this way, both expenditure and price elasticities of a large number of items are higher in Korea than in Japan, which may be explained from the fact that the level of expenditure is higher in Japan than in Korea. 2) In both of Korea and Japan, as the householder grows older, the expenditure for each item increases and the composition of expenditure changes in such a way that these moves may be regarded as due to the age effect. However, there are both similarities and differences in the details of such moves between Korea and Japan. Those two countries have this trait in common that the young age groups of the householder spend more on dairy products and middle age groups spend more on cake than other age groups. In the Korea, however, there can be seen a certain trend that higher age groups spend more on a large number of items, reflecting the fact that there are more two-generation families in higher age groups. Japan differs from Korea in that expenditure in Japan is diversified, depending upon the age group. For example, in Japan, middle age groups spend more on cake, cereal, high-caloric food like meat and eating-out while older age groups spend more for Japanese-style food like fish/shellfish and vegetable/seaweed, and cooked food. 3) The effect of the birth cohort effect was also demonstrated. The birth cohort effect was introduced under the supposition that the food circumstances under which the householder was born and brought up would determine the current expenditure. Thus, the following was made clear: older generations in both countries placed more emphasis upon stable food in their composition of food consumption; the share of livestock products, oil/fats and externalized food was higher in the food composition of younger generation; differences in food composition among generations were extremely large in Korea while they were relatively small in Japan; and Westernization and externalization of diet made rapid increases simultaneously with generation changes in Korea while they made any gradual increases in Japan during the same time period. 4) The four major factors which impact the long-term change of food demand of the household are expenditure, price, the age of the householder, and the birth cohort of the householder. Investigations were made as to which factor had the largest impact. As a result, it was found that the price effect was the smallest in both countries, and that the relative importance of the factor-by-factor effects differed among the two countries: in Korea the expenditure effect was greater than the effects of age and birth cohort while in Japan the effects of non-economic factors such as the age and birth cohort of householder were greater than those of economic factors such as expenditures.

• Annals of Occupational and Environmental Medicine
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• v.35
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• pp.41.1-41.11
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• 2023

Background: Shift work has been reported to have several harmful effects on the human body. However, a small number of studies have evaluated the association between shift work and adverse effects on the thyroid. In our longitudinal study, we examined the causal association between shift work and the risk of hypothyroidism. Methods: A Kangbuk Samsung Cohort Study was conducted on 112,648 men without thyroid disease at baseline who were followed up at least once between 2012 and 2019. Shift work status and shift schedule types were categorized using standardized questionnaires. Hypothyroidism was defined using the reference ranges of serum thyroid-stimulating hormones and free thyroxine levels. Hazard ratios (HRs) and 95% confidence intervals (CIs) for incident hypothyroidism were estimated using Cox proportional hazards regression analyses with the daytime work group as the reference. Results: During the 501,237 person-years of follow-up, there were 6,306 incident cases of hypothyroidism (incidence density, 1.26 per 100 person-years). The multivariable-adjusted HR of incident hypothyroidism for the shift work total group that included all shifts compared with the daytime work group was 1.27 (95% CI: 1.15-1.40). For the fixed evening, fixed night, rotating shift, and other shift workers, the multivariable-adjusted HRs (95% CI) were 1.11 (0.76-1.61), 2.18 (1.20-3.93), 1.39 (1.23-1.56), and 1.00 (0.82-1.22), respectively. In subgroup analyses by age, the association between shift work and hypothyroidism was more pronounced in younger participants (< 40 years; HR: 1.31; 95% CI: 1.16-1.47). Conclusions: Our large-scale cohort study showed an association between shift work and the incidence of hypothyroidism, especially in younger workers with night shifts.

• Journal of Preventive Medicine and Public Health
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• v.53 no.6
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• pp.476-486
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• 2020

Objectives: The objective of this study was to estimate the risk of lung cancer in relation to angiotensin II receptor blocker (ARB) use among patients with hypertension from the Korean National Health Insurance Service-National Health Screening Cohort. Methods: We conducted a retrospective cohort study of patients with hypertension who started to take antihypertensive medications and had a treatment period of at least 6 months. We calculated the weighted hazard ratios (HRs) and their 95% confidence intervals (CIs) of lung cancer associated with ARB use compared with calcium channel blocker (CCB) use using inverse probability treatment weighting. Results: Among a total of 60 469 subjects with a median follow-up time of 7.8 years, 476 cases of lung cancer were identified. ARB use had a protective effect on lung cancer compared with CCB use (HR, 0.75; 95% CI, 0.59 to 0.96). Consistent findings were found in analyses considering patients who changed or discontinued their medication (HR, 0.50; 95% CI, 0.32 to 0.77), as well as for women (HR, 0.56; 95% CI, 0.34 to 0.93), patients without chronic obstructive pulmonary disease (HR, 0.75; 95% CI, 0.56 to 1.00), never-smokers (HR, 0.64; 95% CI, 0.42 to 0.99), and non-drinkers (HR, 0.69; 95% CI, 0.49 to 0.97). In analyses with different comparison antihypertensive medications, the overall protective effects of ARBs on lung cancer risk remained consistent. Conclusions: The results of the present study suggest that ARBs could decrease the risk of lung cancer. More evidence is needed to establish the causal effect of ARBs on the incidence of lung cancer.

• Journal of Preventive Medicine and Public Health
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• v.36 no.4
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• pp.367-372
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• 2003

Objectives : There are many concerns about ginseng as a cancer chemopreventive substance, but there have been few epidemiological studies on ginseng, This study sought to examine the relationships between ginseng intake and cancer incidence in the Kangwha cohort. Methods ; Between March 1985 and December 1999, 2697 males, aged 55 or over, as of 1985, were followed up for their cancer incidence. The cancer incidence rate, standardized incidence ratio and risk ratios were calculated according to ginseng intake. A Cox proportional hazard model was used to adjust for age at entry, smoking, alcohol intake, hypertension, and body mass index. Results & Conclusions : The ginseng intake group had the same cancer (C00-C97) incidences (Standardized Incidence Ratio: SIR=1.11, 95% Confidence Interval=0.97-1.27) and the same risk ratio (RR=1.09, 95% Confidence Interval=0.85-1.41) as the no-intake group. Analyzing the subjects that had followed up from 1990, however, the ginseng intake group had lower cancer incidences at all sites (RR=0.79, 95% Confidence Interval=0.58-1.09). This was a cohort study to try and evaluate the association between ginseng intake and the incidences of cancer, The results of this study provide no clear conclusions on the cancer preventive effects of ginseng. Therefore, further study is needed in the future.

• Asian Pacific Journal of Cancer Prevention
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• v.16 no.18
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• pp.8359-8364
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• 2016

Background: Thailand has come to an epidemiologic transition with decreasing infectious diseases and increasing burden of chronic conditions, including cancer. Breast cancer has the highest incidence rates among females throughout Thailand. This study aimed to identify the current burden and the future trends of breast cancer of Lopburi, a province in the Central Thailand. Materials and Methods: We used cancer incidence data from the Lopburi Cancer Registry to characterize and analyze the incidence of breast cancer in Central Thailand. With joinpoint and age-period-cohort analyses, the incidence of breast cancer in the province from 2001 to 2010 and project future trends from 2011 to 2030 was investigated. Results: Age-adjusted incidence rates of breast cancer in Lopburi increased from 23.4 to 34.3 cases per 100,000 female population during the period, equivalent to an annual percentage change of 4.3% per year. Both period and cohort effects played a role in shaping the increase in incidence. Joinpoint projection suggested that incidence rates would continue to increase in the future with incidence for women ages 50 years and above increasing at a higher rate than for women below the age of 50. Conclusions: The current situation where early detection measures are being promoted could increase detection rates of the disease. Preparation of sufficient budget for treatment facilities and human resources, both in surgical and medical oncology, is essential for future medical care.