• Journal of Preventive Medicine and Public Health
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• v.34 no.4
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• pp.323-330
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• 2001

Objective : To examine the association between age at menopause and mortality in a population-based sample of women in Kangwha, Korea. Methods : From the Kangwha Cohort, followed-up from 1985 to 1999, the data of the over 55 year old female group(n=3,596) was used in this study to examine the association between age at menopause and mortality. We calculated the all causes mortality risk ratio and the cancer mortality risk ratio by age at menopause grouping using the Cox Proportional Hazards Model with adjustments for age, BMI, smoking, education, chronic disease, self-rated health status, alcohol consumption and age at first birth. Result and conclusion : Compared to women who had menopause at 45-49 years, the all causes mortality risk ratio was 1.24 for women with menopause at less than 40 years(95% CI=1.01-1.53) and 1.05 for women with menopause at over 50 years(95% CI=0.92-1.20). Also, compared to women who had menopause at 45-49 years, the cancer mortality risk ratio was 1.53 for women with menopause at less than 40 years(95% CI=0.78-2.98) and 1.17 for women with menopause at over 50 years(95% CI=0.77-1.80).

• Journal of Preventive Medicine and Public Health
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• v.35 no.4
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• pp.305-312
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• 2002

Objectives : The reproductive history of women has been suggested to have a possible influence on the risk of osteoporotic fractures. The purpose of this study was to assess the association between reproductive history and hip fractures in the elderly women. Methods : The study subjects were drawn from women members of the Korean Elderly Pharmacoepidemiologic Cohort (KEPEC), aged 65 years or over, whose reproductive histories were available, and who were beneficiaries of the Korea Medical Insurance Corporation (KMIC) in 1993 and lived in Busan city, Korea. The information on reproductive histories, and possible confounders, were collected from mailed questionnaires. Potential hip fracture cases were collected from the claims data obtained between 1993 and 1998, with a hospital survey conducted to confirm the final diagnoses. Rate ratios and their 95% confidence intervals, were calculated using a Cox's proportional hazard model. Results : Following up 5,215 women for 6 years, 51 cases were confirmed with hip fractures. When adjusted for age, weight and physical activity, the rate ratio of hip fractures in women who had given birth three or more times was 0.56 (95% CI: 0.25-1.25), compared with those who had given birth two or less times. When adjusted for age, number of births, weight and physical activity, the rate ratio in women who first gave birth when younger than 22 years was 0.60 (95% CI: 0.34-1.08) compared with those who had giving birth at 22 years or older. Conclusions : According to these findings, an early age when first giving birth might decrease the risk of hip fractures in elderly Korean women.

• Journal of Preventive Medicine and Public Health
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• v.51 no.6
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• pp.281-288
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• 2018

Objectives: We investigated the association between cholecystectomy or appendectomy and the subsequent risk of colorectal cancer (CRC) in the Korean population. Methods: A retrospective cohort study was conducted with the National Health Insurance Service-National Sample Cohort of Korea; this sample was followed up from January 1, 2002, until the date of CRC incidence, loss to follow-up, or December 31, 2015. The exposure status of cholecystectomy and appendectomy was treated as a time-varying covariate. The calculated risk of CRC was stratified by follow-up period, and the association between these surgical procedures and CRC was investigated by a Cox regression model applying appropriate lag periods. Results: A total of 707 663 individuals were identified for analysis. The study population was followed up for an average of 13.66 years, and 4324 CRC cases were identified. The hazard ratio (HR) of CRC was elevated in the first year after cholecystectomy (HR, 1.71; 95% confidence interval [CI], 1.01 to 2.89) and in the first year and 2-3 years after appendectomy (HR, 4.22; 95% CI, 2.87 to 6.20; HR, 2.34; 95% CI, 1.36 to 4.03, respectively). The HRs of CRC after applying 1 year of lag after cholecystectomy and 3 years of lag after appendectomy were 0.80 (95% CI, 0.57 to 1.13) and 0.77 (95% CI, 0.51 to 1.16), respectively. Conclusions: The risk of CRC increased in the first year after cholecystectomy and appendectomy, implying the possibility of bias. When appropriate lag periods after surgery were applied, no association was found between cholecystectomy or appendectomy and CRC.

• Safety and Health at Work
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• v.13 no.1
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• pp.112-116
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• 2022

Background/Aims: The Gachon Regional Occupational Cohort Study (GROCS) is a large-scale longitudinal study of occupational safety and health data (covering Work Environment Monitoring, Workers' Health Surveillance, and Occupational Health Service) conducted by the Gachon University Gil Medical Center (GUGMC) in Incheon, Republic of Korea. We conducted GROCS to identify the health effects of workers' occupational risks, behavior, socioeconomic status, and life style. Methods: The GROCS includes data from Work Environment Monitoring, Workers' Health Surveillance, and Occupational Health Service. The baseline year for all data collection was 2018. Work Environment Monitoring was conducted in 240 companies located in Incheon. General Health Examination and Special Health Examination were performed on 32,725 and 9,504 workers, respectively. Occupational Health Services were provided to 16,883 workers in 171 companies. These data have been collected and operated at an external data management institution and were provided as a retrospective cohort after removing personal identification information. Results: In 2018, the total number of companies was 2,854, among which which 488 special Health Examination, 171 Work Environment Monitoring, and 240 Occupational Health Service. The proportion of companies undergoing Special Health Examination was 17.1%, the proportion of companies undergoing Work Environment Monitoring was 8.4%, and the proportion of Companies undergoing Occupational Health Service was 6.0%. Conclusion: GROCS expects researchers to utilize its useful and reliable resource for occupational health and surveillance with for academic or political purposes to lead to improved workers' health and working environment.

• Nutrition Research and Practice
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• v.16 no.sup1
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• pp.21-36
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• 2022

BACKGROUND/OBJECTIVES: The long-term health impacts of dietary sugar have begun to be reported. The committee on the 2020 Dietary Reference Intakes for Koreans for sugar intended to update the scientific evidence on the association of added sugar intake with health outcomes, including mortality. This study evaluated the evidence on the association of dietary sugar with the all-cause and cardiovascular disease mortality from cohort studies. SUBJECTS/METHODS: The PubMed and ScienceDirect databases were searched until July 2021. The search terms were based on multiple combinations of keywords, such as added sugar, beverage, and mortality, included in the title or abstract. Two authors independently assessed the eligibility criteria of study selection and extracted the information from each selected article for this systematic review. RESULTS: The literature search identified 276 articles. Seventeen cohort studies met the inclusion criteria and were included in this systematic review. This study extracted information on the cohort and participants, dietary assessment methods, exposure and its comparison groups, health outcomes, and risk measures. Five articles reported added sugar intake, and 15 articles reported the food sources of the added sugar in the association with mortality. Increased mortality was observed in higher added sugar intake and a lower intake of less than 5% of energy, while higher discrepancies between gender, age groups, and countries were noted. In addition, nutritious sugary foods and beverages did not increase mortality. CONCLUSIONS: A 'U' or 'J' shaped relationship between the added sugar intake and mortality was estimated. The observed discrepancy indicated the need for more evidence to establish the dose-response relationship for Koreans.

• 한국노년학
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• v.30 no.4
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• pp.1225-1237
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• 2010

This study aims to analyze the factors affecting consumption inequality in the 10 years following the financial crisis, applying the cohort method on the data for the first to the eleventh wave of the Korean Labor and Income Study produced by the Korean Labor Institute. The study found that consumption inequality increased rapidly immediately following the financial crisis, and then decreased gradually until increasing again from 2005 onward. Analyzed in terms of age-time-cohort effects, there was a significant change in consumption inequality around the age of mid-forties, and the decrease in consumption inequality was smaller in the younger generations than in the older ones. This suggests that as the current younger generations age over time, consumption inequality may become greater. Also, when the factors in population-cohort-age effects from 1998 onward are analyzed, the age effect in consumption inequality becomes smaller, whereas the role of the rising average age due to demographic shifts seems to be increasing. This means that consumption inequality may become a serious problem in the rapidly aging society. Therefore, there is a need to consider ways to bolster social security and to provide further public assistance in the low-income retiree.

• Journal of the Korean Society of Clothing and Textiles
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• v.38 no.1
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• pp.33-45
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• 2014

This study investigates urban household consumption patterns for clothing items in different income cohorts through the analysis of an Almost Ideal Demand System (AIDS) model. Korea quarterly time-series statistics data for urban household expenditures from 1990 to 2013 analyzed household demand. The price and total consumption expenditure elasticities of 4 clothing items (outer wear, shoes, clothing related services and other miscellaneous clothing) for 7 income cohorts were estimated to investigate the clothing consumption patterns of different income cohorts. The study results show that the different household income cohorts have different consumption patterns for clothing items. The elastic demand of total consumption expenditures in the lowest household income cohort suggests that they consume clothing items as luxuries while other households mostly consume them as necessities. The price elasticity for all household income cohorts and clothing items (except the highest household income cohort and outer wear) was found to be elastic. The highest household income cohort had an inelastic price demand for all clothing items that implied a less sensitive clothing consumption change for the clothing price change than other households.

• Asian Pacific Journal of Cancer Prevention
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• v.14 no.9
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• pp.5153-5155
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• 2013

Background: Because of the gender disparity in the incidence of thyroid cancer, this study aimed to determine the association between reproductive factors and thyroid cancer. Methods: A total of 10,767 eligible women from the Khon Kaen Cohort, recruited and interviewed between 1990 and 2001, were followed up until 2011. The data were linked to the Khon Kaen Population-Based Cancer Registry to detect thyroid cancer cases. Results: There was 17 thyroid cancer cases detected, an incidence of 11.2 per 100,000 person-years, of which 70.6 % were papillary tumors. The incidence was apparently greater among those with an early age of menarche, nulligravida women, and oral contraceptive users. Conlusions: There was a trend for thyroid cancer to develop in relation to longer estrogen exposure. This evidence is inconclusive but warrants further investigation.

• Journal of Gastric Cancer
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• v.16 no.3
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• pp.182-190
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• 2016

Purpose: This study aimed to establish a large-scale database of patients with gastric cancer to facilitate the development of a nationalcancer management system and a comprehensive cancer control policy. Materials and Methods: An observational prospective cohort study on gastric cancer was initiated in 2010. A total of 14 cancer centers throughout the country and 152 researchers were involved in this study. Patient enrollment began in January 2011, and data regarding clinicopathological characteristics, life style-related factors, quality of life, as well as diet diaries were collected. Results: In total, 4,963 patients were enrolled until December 2014, and approximately 5% of all Korean patients with gastric cancer annually were included. The mean age was $58.2{\pm}11.5$ years, and 68.2% were men. The number of patients in each stage was as follows: 3,394 patients (68.4%) were in stage IA/B; 514 patients (10.4%), in stage IIA/B; 469 patients (9.5%), in stage IIIA/B/C; and 127 patients (2.6%), in stage IV. Surgical treatment was performed in 3,958 patients (79.8%), endoscopic resection was performed in 700 patients (14.1%), and 167 patients (3.4%) received palliative chemotherapy. The response rate for the questionnaire on the quality of life was 95%; however, diet diaries were only collected for 27% of patients. Conclusions: To provide comprehensive information on gastric cancer for patients, physicians, and government officials, a large-scale database of Korean patients with gastric cancer was established. Based on the findings of this cohort study, an effective cancer management system and national cancer control policy could be developed.

• Clinical and Experimental Reproductive Medicine
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• v.41 no.4
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• pp.158-164
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• 2014

Objective: To assess whether an early GnRH antagonist start leads to better follicular synchronization and an improved clinical pregnancy rate (CPR). Methods: A retrospective cohort study. A total of 218 infertile women who underwent IVF between January 2011 and February 2013. The initial cohort (Cohort I) that underwent IVF between January 2011 and March 2012 included a total of 68 attempted IVF cycles. Thirty-four cycles were treated with the conventional GnRH antagonist protocol, and 34 cycles with an early GnRH antagonist start protocol. The second cohort (Cohort II) that underwent IVF between June 2012 and February 2013 included a total of 150 embryo-transfer (ET) cycles. Forty-three cycles were treated with the conventional GnRH antagonist protocol, 34 cycles with the modified early GnRH antagonist start protocol using highly purified human menopause gonadotropin and an addition of GnRH agonist to the luteal phase support, and 73 cycles with the GnRH agonist long protocol. Results: The analysis of Cohort I showed that the number of mature oocytes retrieved was significantly higher in the early GnRH antagonist start cycles than in the conventional antagonist cycles (11.9 vs. 8.2, p=0.04). The analysis of Cohort II revealed higher but non-significant CPR/ET in the modified early GnRH antagonist start cycles (41.2%) than in the conventional antagonist cycles (30.2%), which was comparable to that of the GnRH agonist long protocol cycles (39.7%). Conclusion: The modified early antagonist start protocol may improve the mature oocyte yield, possibly via enhanced follicular synchronization, while resulting in superior CPR as compared to the conventional antagonist protocol, which needs to be studied further in prospective randomized controlled trials.