• KDI Journal of Economic Policy
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• v.31 no.1
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• pp.105-138
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• 2009

Although the decline in fertility rate is generally observed along the history of economic development throughout the world, the continuing decline hitting below the replacement level in Korea over the recent years gathered serious social concerns on the ground that it accelerates the process of population aging. The total fertility rate in Koreareached 2.08 in 1983, and gradually fell to the levels of 1.08 in 2005 and 1.26 in 2007. The policy debate over the role of the government has been focused mainly on the level of theoretical discussion without substantial basis on firm empirical evidence and the determinants of fertility. The objective of the paper is to empirically investigate the fertility effect of the female wage, which is understood as one of the most important determinants of fertility in Koreasince 1980 focusing on one aspect of fertility, namely birth spacing. Using the Korean National Fertility Survey conducted in 2006, I estimate a duration model of first and second births taking into account individual heterogeneity, which turned out to be an important factor to control for. Compared with previous studies in the literature on the Korean fertility, the study has an advantage of using the complete pregnancy history of women in a more representative sample. Unlike the previous studies, the analysis also deals with the endogeneity of marriage by treating a certain age, rather than age at marriage, as the time in which a woman becomes exposed to the risk of pregnancy. The study shares the common problem in the literature on birth spacing of lacking relevant wage information for respondents in a retrospective survey. I estimate the wage series as a function of the basic characteristics using the annual Wage Structure Survey from 1980 to 2005, which is considered as a nationally representative sample for wage information of employees. The results suggest that the increase in female wage by 10 percent leads to a decrease in second birth hazard by 0.56~0.92 percentage points and that the increase in spouse's wage by the equal amount is accompanied by the increase in second birth hazard by 0.36~1.13 percentage points. These estimates are more precisely estimated and of smaller magnitude than those presented by the previous studies. The results are robust to the different specifications of the wage equation. The simulation analysis based on the predicted values shows that about 17% of the change in the second birth hazard over the period 1980 to 2005 was due to the change in the female wage. Although there is some limitation in data, the results can be viewed as one estimate of the role of female wage on the recent fertility decline in Korea. The question raised by the paper is not a normative one of whether a government should promote childbearing but a positive one thatexplains fertility decline. Therefore, if there is a wide consensus on promoting childbearing, the finding suggests that the policies designed to reduce the opportunity cost of women in the labor market would be effective. The recent movement of implementing a wide range of family-friendly policies including child care support, maternity leave, parental leave and tax benefit in developed countries should be understood in this context.

• Journal of the Korean Society for Marine Environment & Energy
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• v.9 no.4
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• pp.243-252
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• 2006

Influence of the increasing carbon dioxide concentration in seawater on various marine organisms is assessed in this article with regard to the impacts of anthropogenic $CO_2$ introduced into surface or deep oceans. Recent proposals to sequester $CO_2$ in deep oceans arouse the concerns of adverse effects of increased $CO_2$ concentration on deep-sea organisms. Atmospheric introduction of $CO_2$ into the ocean can also acidify the surface water, thereby the population of some sensitive organisms including coral reefs, cocolithophorids and sea urchins will be reduced considerably in near future (e.g. in 2100 unless the increasing trend of $CO_2$ emission is actively regulated). We exposed bioluminescent bacteria and benthic amphipods to varying concentrations of $CO_2$ and also pH for a short period. The ${\sim}l.5$ unit decrease of pH adversely affected test organisms. However, amphipods were not influenced by decreasing pH when HCl was used for the seawater acidification. In this article, we reviewed the biological adverse effects of $CO_2$ on various marine organisms studied so for. Theses results will be useful to predict the potential risks of the increase of $CO_2$ concentrations in seawater due to the increase of atmospheric $CO_2$ emission and/or sequestration of $CO_2$ in deep oceans.

• Journal of dental hygiene science
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• v.17 no.6
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• pp.487-494
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• 2017

There is little evidence on the effects of environmental tobacco smoke (ETS) on prevalence of periodontal disease. The aims of this study were to explore the trends of prevalence of periodontal disease and types of exposure to smoke, including ETS according to the survey year, identify factors affecting periodontal disease, and compare the effect size of periodontal disease between active smokers and secondhand smokers. Data on 11,643 individuals were obtained from the fourth and fifth Korean National Health and Nutritional Examination Surveys. Information on exposure to ETS at home and work was self-reported. Severity of periodontal disease was evaluated using the community periodontal index. A multivariate logistic regression analysis was performed to model periodontal disease using types of smoking and the survey year. Overall, the prevalence of periodontal disease was 26.0% (n=3,029) and about 9% of the study population were secondhand smokers. The prevalence of periodontal disease among smokers was significantly increased according to smoking types by year. Active smokers showed a statistically significant adjusted odds ratio (aOR) for having periodontal disease except in the year 2007, whereas secondhand smokers had significant associations only in 2010 (aOR, 1.68; 95% confidence interval, 1.05 to 2.70) compared to non-smokers. For secondhand smokers, the statistical relationship of predicting periodontal disease was weaker than that of active smokers. However, ETS should separately be considered as an important risk factor for periodontal disease. This study suggested the need for further investigation of the impact of ETS on prevalence of periodontal disease using in-depth research designs and objective measurements for assessing periodontal disease and ETS.

• Journal of the Society of Disaster Information
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• v.11 no.4
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• pp.556-569
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• 2015

With about 75% of the population of Korea criticizing the government's disaster policy and a failure to respond to large-scale emergency like the Sewol ferry sinking means that there is a deep distrust in the government. In order to prevent dreadful disasters such as the Sewol ferry sinking, it is important to secure a prime time with respect to disaster safety. Improving crisis management skills and managerial role of police officers who are in close proximity to the people is necessary for the success of disaster management. With disaster management as one of the most essential missions of the police, as a part of a national crisis management, a step by step strengthening of the disaster safety management system of the police is necessary, as below. First, at the prevention phase, law enforcement officers were not injected into for profit large-scale assemblies or events, but in the future the involvement, injection should be based on the level of potential risk, rather than profitability. In the past and now, the priortiy was the priority was on traffic flow, traffic communication, however, the paradigm of traffic policy should be changed to a safety-centered policy. To prevent large-scale accidents, police investigators should root out improper routines and illegal construction subcontracting. The police (intelligence) should strengthen efforts to collect intelligence under the subject of "safety". Second, with respect to the preparatory phase, on a survey of police officers, the result showed that 72% of police officers responded that safety management was not related to the job descriptions of the police. This, along with other results, shows that the awareness of disaster safety must be adopted by, or rather changed in the police urgently. The training in disaster safety education should be strengthened. A network of experts (private, administrative, and police) in safety management should be established to take advantage of private resources with regard to crisis situtions. Third, with respect to the response phase, for rapid first responses to occur, a unified communication network should be established, and a real-time video information network should be adopted by the police and installed in the police situation room. Fourth, during the recovery phase, recovery teams should be injected, added and operated to minimize secondary damage.

• Journal of agricultural medicine and community health
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• v.31 no.3
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• pp.263-273
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• 2006

Objectives: This study was conducted to investigate the trend of health statue of the elderly living in rural area according to drinking patterns. Methods: This study was conducted with 2,421 elderly people (male 1,273 and female 1,148) residing in the selected 25 villages, with exclusion of a few elderly people who were in hospital, out for a long time or had an unknown address. This study were carried out, face-to-face interviews with the subjects were made from January to March 2002. Results: The investigation of drinking state showed that for male subjects, drinkers accounted for 48.8%, nondrinkers 35.1% and abstainers from drinking 16.1%, whereas for female subjects, drinkers accounted 15.3%, nondrinkers 80.2% and abstainers from drinking 4.5%. The health status was analyzed according to drinking pattern. For elderly men, abstainers from drinking showed worse health state than nondrinkers and drinkers. Elderly women showed the same result. It is widely known that drinking are the important causes of chronic diseases. Therefore, it is needed to provide the elderly with education on control of preventable health risk factors and effect of living state on health, in order to prevent aggravation of health level of the elder population aged 65 and over. This will also help them promote their health. It will be desirable that for the elderly, the objective will focus on health promotion rather than treatment of diseases. Conclusions: Carry out health plan for rural communities and health maintenance programs and health promotion of the elderly in those communities shall be developed. In addition, preventive education and health examination shall be conducted more frequently with the elderly who drink but are still healthy.

• Journal of agricultural medicine and community health
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• v.40 no.3
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• pp.115-125
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• 2015

Objectives: Colorectal cancer is one of the major cancers in South Korea. We described the time trends in colorectal cancer incidence in Daejeon, a metropolitan city, and Chungcheongnam-do (Chungnam), a rural province, South Korea. Methods: Using the databases from the Daejeon Cancer Registry (DCR) and the Chungnam Cancer Registry (CCR), age-standardized (to world standard population) rates for incidence (ASRW) were calculated. Average annual percent change (AAPC) was assessed as a trend indicator. The completeness (such as the mortality/incidence ratio) and validity (such as the death certificate only %, microscopic verification %, primary site uncertain %, and age unknown %) were analyzed to examine the data quality of DCR and CCR. Results: Incidence of colorectal cancer showed increasing trend in both sexes. Over the years 2000-2012 in Daejeon, ASRW was increased significantly from 37.2 to 51.7 per 100,000 person-years (AAPC, 3.9%) among men and from 17.1 to 28.4 (AAPC, 3.9%) among women, respectively. In Chungnam, ASRW was also increased from 29.8 to 50.1 per 100,000 person-years (AAPC, 5.1%) among men and from 15.9 to 26.6 (AAPC, 3.2%) among women, respectively. The AAPC for colon cancer was greater than rectal cancer in both Daejeon and Chungnam. The trend of rectal cancer incidence was differ by sex (AAPC in men vs women, 2.7% vs 1.7% in Daejeon; 3.5% vs 0.8% in Chungnam). Indices of completeness and validity showed that the quality control of DCR and CCR was adequate to describe the trends of ASRW. Conclusions: Both Daejeon and Chungnam have had a rapid increase in colorectal cancer incidence. Monitoring and intervention are required on the risk factors which may contribute to this trend.

• Korean Journal of Food Science and Technology
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• v.37 no.4
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• pp.660-670
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• 2005

Standard procedure for development of food list was established based on food intake data of 2001 National Health and Nutrition Survey and 2002 Seasonal Nutrition Survey for Total Diet Study. Foods were sorted in descending order of mean intake, and 54 items within cumulative percentage of 80 were selected, followed by selection of 16 additional items with consumption frequency of 10% or higher. Based on higher consumption in certain seasons, regions, sexes, and age classes, 14 additional items were added. Additional 17 items with probable high contents of heavy metals or 23 items with probable high pesticide residues were added. Altogether, 101 and 107 individual food items were included for heavy metal and pesticide residue lists, accounting for 84.9 and 83.3% mean energy intakes of Korean population, respectively.

• Korean Journal of Environmental Biology
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• v.31 no.4
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• pp.322-332
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• 2013

This study was conducted to understand the control mechanism of Sika deer (Cervus nippon taiouanus) populations which are adapted to the natural forest areas and the semi-natural forest areas of Korea. We monitored and analyzed the behaviour patterns and habitat characteristics of Sika deers. After we released 12 Sika deers (male 3, female 9) each at the two study areas in and around Seoul under the approval of Korean government, we monitored them through our survey researchers' naked eyes from May 2011 to January 2012. We discriminated their habitat patterns to 4 major places - eating food place, drinking water place, daytime rest place, and nighttime rest place. Our results showed that Sika deer preferred the open grassland habitats for feeding and resting in daytime but the closed bushland for their protection and sleep. We also found the recommended sex ratio of adult male to female in a herd was 1 : 4~9 for breeding and they had few cubs in a herd. The average amount of food for 1 adult deer was 391.62 kg of fresh grasses and 286.90 kg of hay per year. Our results suggest that the amount of drinking water required for a deer when grazed on grasses during spring and summer seasons is 256.8 L and when a deer feeds on dry food during autumn and winter seasons, 209.8 L of water is required. From these results, we observe that the amount of drinking water was affected substantially by the moisture content of their food. This observational study must be very valuable for land managers to judge the number of deers that should be released in natural areas without high risk and to ascertain the sex ratio of large mammals including Sika deer. Therefore, we conclude that this population control mechanism study consists of efficient basic data and their values must be very effective for various purposes.

• Journal of Preventive Medicine and Public Health
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• v.29 no.4 s.55
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• pp.765-783
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• 1996

This study surveyed and measured the level and structure of cancer deaths and their trends over time for offering the fundamental data of e cancer prevention and control in Pusan city in the future. Authors conducted the study of descriptive epidemiology using materials derived from the computerized data of total 3,722 certified cancer deaths in Pusan city from January 1 to December 31, 1993 registered on the National Statistical Once, the Republic of Korea. The obtained results were as follows: 1. According to the total registered cases of deaths(16,331 cases) in Pusan city during 1993, cancer(3,722 cases) and cerebrovascular disease(2,118 cases) were the first and second cause of deaths as 23.1% and 16.9%, respectively. These pattern showed the change between cancer (14.7%) and cerebrovascular disease(18.5%) in order of frequency in comparison to 1982. Also, the total number of cancer deaths was increased in comparison to 1982. The rate of death certification by physicians was 87.1% of all registered deaths, which was increased to 6.8% in comparison to 1982(80.3%). 2. Crude death rate and cancer specific death rate was 4.06 per 1,000 populations and 93.8 per 100,000 populations(male:117.8, female:70.0), respectively. The former was similar to that of 1982, but the latter was increased to 1.6 times as that of 1982. 3. Age-adjusted cancer specific death rate by standardization with whole country population was 111.9(male:141.5, female:106.7) per 100,000 populations, higher than not age-adjusted cancer specific death rate(93.8), and the sex difference was statistically significant with male predominance (p<0.05). 4. Cancer specific death rate by age was generally increased with age and most of cancer deaths(male:91.8%, female:88.5%) occurred since 40 years old. 5. The major cancer(cancer specific death rate per 100,000 populations) in male was liver(30.6) followed by stomach(25.6), lung(21.9), and GB and EHBD(5.7), in female stomach(15.7), liver(9.9), lung(7.3), and uterus(6.9). The relative frequency of the leading three cancer among total cancer deaths marked 66.3% in male and 47.l% in female, and decreased in comparison to 1982(male:72.2%, female:54.5%). 6. The total ratio of male to female cancer specific death rate showed 1.68 to 1 with male predominance. And the ratio was above 2.0 in larynx, oral cavity & pharynx, esophagus, liver, lung, bladder cancer and the ratio was $1.0\sim1.9$ in stomach, pancreas, gall bladder and EHBD, brain, rectum and anus cancer, leukemia, but the ratio was reversed in thyroid and colon cancer. In conclusion, cancer was the first cause of deaths. The proportion of lung cancer was increased, that of stomach & uterine cancer was decreased relatively, and liver cancer was constantly higher proportion. In the future, it is necessary to conduct the further investigations on the cancer risk factors considering areal specificity.

• Journal of Nutrition and Health
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• v.47 no.2
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• pp.113-123
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• 2014

Purpose: Vitamin D has been known to play an important role in the central nervous system and brain functions in the human body, and cumulative evidence has shown that vitamin D deficiency might be linked with various mental health conditions. Epidemiologic studies have shown that vitamin D deficiency may be associated with higher risk of depression in the US and European populations. However, limited information is available regarding the association between vitamin D status and depression in the Korean population. The objective of this study was to examine the associations between vitamin D levels and prevalence of depression. Methods: We conducted a cross-sectional analysis using nationally representative data from the 2008-2010 Korean National Health and Nutrition Examination Survey from which serum 25-hydroxyvitamin D concentrations were available. A total of 18,735 adults who had available demographic, dietary, and lifestyle information were included in our analysis. We defined "depression" with a diagnosis by a physician. "Depressed condition" was defined as having feelings of sadness or depression without diagnosis by a physician. Results: The prevalence of depression was 1.63% and 5.43% in Korean men and women, respectively; 12.5% of men and 26.1% of women were defined as the group having depressed conditions. In multivariate logistic regression models, no significant associations were observed between vitamin D status and prevalence of depression or depressed conditions in Korean men and women. Conclusion: We found no association between vitamin D insufficiency and depression/depressed conditions in Korean adults. Future large prospective studies and randomized controlled trials are needed to confirm this relationship.