• Journal of Preventive Medicine and Public Health
• /
• v.40 no.2
• /
• pp.108-113
• /
• 2007

When conducting large-scale cohort studies, numerous statistical issues arise from the range of study design, data collection, data analysis and interpretation. In genomic cohort studies, these statistical problems become more complicated, which need to be carefully dealt with. Rapid technical advances in genomic studies produce enormous amount of data to be analyzed and traditional statistical methods are no longer sufficient to handle these data. In this paper, we reviewed several important statistical issues that occur frequently in large-scale genomic cohort studies, including measurement error and its relevant correction methods, cost-efficient design strategy for main cohort and validation studies, inflated Type I error, gene-gene and gene-environment interaction and time-varying hazard ratios. It is very important to employ appropriate statistical methods in order to make the best use of valuable cohort data and produce valid and reliable study results.

• Asian Pacific Journal of Cancer Prevention
• /
• v.14 no.7
• /
• pp.3993-4003
• /
• 2013

Scientific evidence for the primary prevention of cancer caused by physical activity of regular moderate-intensity or greater is rapidly accumulating in this field. About 300 epidemiologic studies on the association between physical activity and cancer risk have been conducted worldwide. The objectives of this paper were three-fold: (i) to describe briefly the components of physical activity and its quantification; (ii) to summarize the most important conclusions available from comprehensive reports, and reviews of the epidemiologic individual and intervention studies on a role physical activity in cancer prevention; (iii) to present proposed biological mechanisms accounting for effects of activity on cancer risk. The evidence of causal linked physical activity and cancer risk is found to be strong for colon cancer - convincing; weaker for postmenopausal breast and endometrium cancers - probable; and limited suggestive for premenopausal breast, lung, prostate, ovary, gastric and pancreatic cancers. The average risk reductions were reported to be 20-30%. The protective effects of physical activity on cancer risk are hypothesized to be through multiple interrelated pathways: decrease in adiposity, decrease in sexual and metabolic hormones, changes in biomarkers and insulin resistance, improvement of immune function, and reduction of inflammation. As there are several gaps in the literature for associations between activity and cancer risk, additional studies are needed. Future research should include studies dealing with limitations in precise estimates of physical activity and of a lack of consensus on what defines sedentary behavior of individuals and those linked with the proposed biomarkers to cancer risk and controlled exercise intervention trials.

• Archives of Plastic Surgery
• /
• v.44 no.2
• /
• pp.144-149
• /
• 2017

Background The purpose of this study was to identify the epidemiologic characteristics of hand tendon injuries in children and to compare these with those of adults. Methods This retrospective study was conducted on acute traumatic tendon injuries of the hand treated at our institution from 2005 to 2013, based on medical records and X-ray findings. Age, sex, hand injured, mechanism of injury, tendons and zones injured, number of affected digits, and comorbidities and complications were analyzed. Patients were divided into 2 groups: a pediatric group (${\leq}15years$) and an adult group (>15 years). Results Over the 9-year study period, 533 patients were surgically treated for acute traumatic tendon injuries of the hand. In the pediatric group (n=76), being male, the right hand, the extensor tendon, complete rupture, the middle finger, and glass injury predominated in hand tendon injuries. In the adult group (n=457), results were similar, but injury to the index finger and knife injury were the most common. An accompanying fracture was more common in the adult group and complication rates were non-significantly different. Conclusions This comparative analysis revealed no significant epidemiologic intergroup differences. The belief that pediatric tendon injuries tend to be less severe is misplaced, and careful physical examination and exploration should be conducted in pediatric cases of hand injury.

• Tuberculosis and Respiratory Diseases
• /
• v.41 no.3
• /
• pp.289-298
• /
• 1994

Background: Most studies of Mycoplasma pneumonia involve a group of admitted patients in hospital, usually with major medical illness. So we investigated the epidemiologic and radiologic features during the course of outbreak of pneumonia in Chunnam coastal area. Methods: We retrospectively studied the epidemiologic and clinical feature of 105 patients with serologically proven Mycoplasma pneumonia treated at Kwang-Yang Hospital during a epidemic period of Jun.1993 to Dec.1993. All cases of pneumonia developed in this period were also reviewed and compared with serologically proven group. Results: 1) There were 63 males and 42 females. 2) More than half(57%) of cases belonged to 5-9 years of age group, and mean age was 6.5 years old. Mean age was steadily decreased as prevalence of Mycoplasma pneumonia had been subsided. 3) A major determinant of the outbreak seemed to be the population density rather than the population size. 4) The common radiologic features were interstitial in type, and 67 cases was restricted to one lobe. Lobar types are more common in late childhood, and interstitial or diffuse types in early childhood. Conclusion: These epidemiologic and radiographic characteristics would contribute to the diagnosis of Mycoplasma pneumonia.

• Clinical and Experimental Pediatrics
• /
• v.64 no.1
• /
• pp.3-11
• /
• 2021

There is a growing body of literature on the adverse health effects of ambient air pollution. Children are more adversely affected by air pollution due to their biological susceptibility and exposure patterns. This review summarized the accumulated epidemiologic evidence with emphasis on studies conducted in Korea and heterogeneity in the literature. Based on systematic reviews and meta-analyses, there is consistent evidence on the association between exposure to ambient air pollution and children's health, especially respiratory health and adverse birth outcomes, and growing evidence on neurodevelopmental outcomes. Despite these existing studies, the mechanism of the adverse health effects of air pollution and the critical window of susceptibility remain unclear. There is also a need to identify causes of heterogeneity between studies in terms of measurement of exposure/outcome, study design, and the differential characteristics of air pollutants and population.

• Journal of agricultural medicine and community health
• /
• v.18 no.2
• /
• pp.161-171
• /
• 1993

Mycoplasma pneumoniae(M. pneumoniae) is a primary pathogene of the respiratory tract in children. Most studies of such pneumonia involve a group of admitted patients in hospital, usually with major medical illness. We retrospectively studied the epidemiologic and clinical feature of 105 patients with serologically proven M. pneumoigic pneumonia treated at Gwang-Yang Hospital during a epidemic period of Jun. 1993 to Dec. 1993. All cases of pneumonia developed in this period were also reviewed and compared with serologically proven group. The results were as follows. 1. There were 63 males and 42 females, and the male /female ratio was 1.5 : 1. 2. More than half(57%) of cases belonged to 5-9 years of age group, and mean age was 6.5 years old. 3. Mean age was steadily decreased as prevalence of mycoplasmal pneumonia had been subsided. 4. The date of index case was June 26th, and that of median case was 3 months after the index case. 5. A major determinant of the outbreak seemed to be the population density rather than the population size. 6. Recurrence and serious complication were not observed in this period. 7. All cases of pneumonia developed in this period might be attributed to M. pnemoniae. These epidemiologic and clinical characteristics would contribute to the prevention and diagnosis of mycoplasmal pneumonia.

• Proceedings of the Korean Society of Toxicology Conference
• /
• 2001.10a
• /
• pp.33-34
• /
• 2001

Cancer chemoprevention Chemoprevention with strategies using food phytochemicals is currently regarded ascompose one of the noticeable most visible and promising scientific fields for cancer control. A large body of data from both epidemiologic and rodent studies has demonstrated that the ingestion of various vegetables and fruits is occasionally beneficial for cancer risk reduction of cancer risks in humans.(omitted)

• Journal of Digestive Cancer Research
• /
• v.8 no.2
• /
• pp.97-101
• /
• 2020

Metformin is a widely used first-line anti-diabetic drug worldwide. Epidemiologic studies using the large population-based cohort database have shown the association between metformin uses and reduced risk of various type cancers including gastric cancer. In the gastric cancer prevention, metformin use was associated with the significant reduction of gastric cancer risk, especially for long-term metformin users. However, there is no well-designed randomized controlled clinical trial investigating the effect of metformin as a chemopreventive drug for gastric cancer. Therefore, further well-designed clinical trials will be needed to implement metformin for chemoprevention of gastric cancer.

• Korean Journal of Child Studies
• /
• v.19 no.2
• /
• pp.35-47
• /
• 1998

Negative life events, self-esteem, perceived social support, and maladjustment were studied longitudinally among late elementary children. Subjects were 241 boys and girls for depression and 258 for antisocial behavior. The instruments were the Adolescent Perceived Events Scale, the Rosenberg Self-Esteem Scale, the Social Support Scale for Children, the Revised Korean Version of the Center for Epidemiologic Studies' Depression Scale, and the Antisocial Behavior Scale. The results showed that the way variables were reciprocally related to one another in patterns over a period of one year differed by internal and external adjustment. For depression, depression at Time 1 had effects on self-esteem, social support, and depression at Time 2. For antisocial behavior, negative life events at Time 1 influenced negative life events, self-esteem, social support, and antisocial behavior at Time 2. The findings were discussed in relation to the effects of negative life events, self-esteem, and perceived social support on maladjustment.

• Korean Journal of Child Studies
• /
• v.18 no.1
• /
• pp.39-52
• /
• 1997

This study focused on factors influencing Internal and external problem (depression and antisocial) behavior among late-elementary children. Subjects were 481 boys and girls enrolled in the fourth. fifth. and sixth grades of public school. The contribution of grade. sex. stress, self-esteem. and social support from parents, teachers, and friends as well as school performance were studied. The instruments were the Adolescent Perceived Events Scale, the Self-Esteem Scale, the Social Support Scale for Children, the Revised Korean Version of the Center for Epidemiologic Studies' Depression Scale and Antisocial Behavior Scale. Results indicated that sex, stress, self-esteem, and the support of parents, teachers and friends reduced the level of depression. Grade, sex, stress, self-esteem, and teachers' support were related to the level of antisocial behavior. The results were discussed in terms of the effects of stress, personal and social resources, and school achievement on depression and antisocial behavior.